-
aback :
-
toward the back, to the rear. Also, when the wind presses against
the front or forward part of the sail or sails. Also, to surprise
or disconcert; as to be taken aback.
-
abaft :
-
behind or to the rear; toward the stern; astern or aft.
-
ABLJ :
-
abbreviation for Adjustable Buoyancy LifeJacket, the old
horsecollar style.
-
absolute pressure :
-
the total pressure at any depth, which is a sum of atmospheric
pressure and hydrostatic pressure; calculated from a vacuum being
rated as the zero point.
-
absolute temperature scale :
-
temperature measured on a scale in which the hypothetical lowest
limit of physical temperatures is assigned the value of zero
(abÆsolute zeÆro), as in the kelvin and rankine scales; also
called absolute temperature or absolute scale. [nb: the degree
intervals of the kelvin scale are the same as celsius, as the
rankine are the same as fahrenheit]
-
absolute zero :
-
the hypothetical temperature at which all molecular activity and
kinetic energy ceases; computed at -273.16°C or
-459.69°F, and represented as 0°K and 0°R. [nb: the
degree intervals of the kelvin scale are the same as celsius, as
the rankine are the same as fahrenheit]
-
ABT :
-
abbreviation for Actual Bottom Time; also called bottom time.
-
abyssal :
-
pertaining to the biogeographic zone of the ocean bottom between
the bathyal and hadal zones; from depths of approximately 13,000
to 21,000 feet. Also, like an abyss, being immeasurable or
unfathomable.
-
accommodation ladder :
-
a portable flight of steps suspended from the side of a vessel to
give crew and/or passenger ingress and egress access from smaller
boats alongside; also known as boarding ladder.
-
actual bottom time :
-
the total amount of time a diver spends descending or at depth;
calculated to begin upon descent and ends upon starting the
ascent; also called bottom time.
-
ACUC :
-
abbreviation for American Canadian Underwater Certifications,
being Canada's scuba certification body.
-
ACV :
-
abbreviation for an Air-Cushion Vehicle or Air-Cushioned Vehicle;
also known as a hovercraft.
-
adjusted no-decompression limit :
-
the maximum bottom time for repetitive dives, being equal to the
no-decompression limit plus residual nitrogen time.
-
adrift :
-
anything unsecured, or that has slipped its mooring or fast, as
being out of control, including items improperly stowed, or
things lost overboard.
-
advection :
-
the horizontal flow of air, water, or the like, which often
entails a change of temperature or humidity; as distinct from
convection.
-
aeroembolism :
-
an obstruction of the circulatory system caused by one or more
air bubbles; a condition of decompression sickness.
-
afoul :
-
to be or become entangled, or in a state of collision; as to run,
come, or fall afoul.
-
aft :
-
at the rear or stern, or toward the back of a vessel or craft.
-
AGE :
-
acronym for Arterial Gas Embolism; also called air embolism.
-
ahoy :
-
call used by seafarers to hail or alert others; derived "hoy", as
to hoist.
-
air :
-
a gas mixture present in the earth's atmosphere that's necessary
for human respiration, containing 21% oxygen, 78% nitrogen, and
1% other gases (mainly argon) which is compressed into air tanks
for recreational scuba diving.
-
air compressor :
-
a machine that's used to transfer pressurized air into tanks for
scuba diving; the air is compressed from the atmospheric level
(14.7 psi at sea level) to the capacity of the tank, usually
between 2500-3000 psi. [nb: according to the first law of
thermodynamics, the internal energy of a gas increases when the
gas is compressed]
-
air-cushioned vehicle :
-
a craft that rides on a cushion of air, is kept aloft by fans and
driven forward by propellers; abbreviated ACV.
-
air embolism :
-
an obstruction (gas bubble, or other embolus) that has the
potential to rupture a vessel or organ as a result of the
increase in pressure when blood gases begin to expand or cease to
circulate; a characteristic injury from breath holding during the
ascent after a dive. Also called arterial gas embolism (AGE) or
venous gas embolism (VGE).
-
air pressure :
-
the weight of air, calculated by the force exerted per unit area;
measured at sea level the air pressure is 14.7 pounds per square
inch (psi), decreasing with altitude.
-
Aldis lamp :
-
a hand-held or portable signal lamp that's used to flash messages
in Morse code; eponymously after the British inventor, A.C.W.
Aldis.
-
alfa :
-
the phonetic representation of the letter 'A'; which is also
represented by a maritime signal flag in the international code.
When hoisted alone, the alfa burgee warns that there is a diver
down (underwater), and other vessels should steer clear at slow
speed; when accompanied by three numeral flags, this signal also
includes the radius within which divers are working. [nb: "alfa"
denotes the phonetic letter, "alpha" denotes the first in a
series]
-
algorithm :
-
a set of rules for solving a problem in a finite number of steps;
as the set of equations used in dive profiles and decompression
tables to compute air supply, air mixture, underwater duration,
and dive intervals.
-
alternate air source :
-
any device a diver can use in place of the primary regulator, in
order to make an ascent while still breathing normally.
-
altitude diving :
-
underwater diving while at heights above sea level, as when
quarry or cave diving in uplands; the decompression stops used
for dives at altitude are different from those used for the same
dive profile at sea level.
-
alveolus / alveoli :
-
the tiny bunched air sacs at the end of the bronchioles in the
lungs where gas exchange occurs with the circulatory system.
-
ambient light :
-
the sunshine penetrating underwater, diminishing with depth and
turbidity, that's used as illumination.
-
ambient pressure :
-
the surrounding pressure; being the effective pressure from the
weight of the water and atmosphere around the diver at any
particular depth.
-
anadromous :
-
pertaining to fish that migrate from saltwater to spawn in
freshwater; as distinguished from catadromous.
-
analog :
-
a mechanism that represents data by measurement to a continuous
physical variable (eg: voltage, pressure, etc) and displayed on a
readout by a pointer or hands on a dial.
-
anchor :
-
any heavy device or similar item that's dropped by a tethering
chain or cable to the bottom of a body of water that's used for
restraining the motion of a vessel or some other floating object;
to be "at anchor" by holding fast or controlling motion.
-
anchorage :
-
a seaport or harbor with secure docking facilities for a ship.
-
ANDI :
-
abbreviation for Association of Nitrox Divers International; also
American Nitrox Divers Incorporated.
-
ANDL :
-
abbreviation for Adjusted No-Decompression Limit
-
anoxia :
-
the mental and physical disturbances that result from hypoxia, a
lack of oxygen or suffocation.
-
Antarctic Circle :
-
a parallel of latitude that marks the farthest point (66.5°S)
south of the equator where the sun appears above the horizon each
day of the year.
-
anticoagulant :
-
an agent that inhibits coagulation, especially something that
prevents blood from clotting or congealing; the use of such
medications (including aspirin) is particularly dangerous to
divers due to the barotrauma of air-filled body cavities.
-
AOW :
-
abbreviation for Advanced Open Water, a scuba certification.
-
aquaclude :
-
an earth layer that inhibits or precludes the passage of water,
such as shale, or unfractured igneous and metamorphic rocks.
-
aqua-lung :
-
the name of the original open-circuit, self-contained, underwater
breathing equipment, developed by Emile Gagnan and Jacques
Cousteau in 1942 during World War Two; consisting of a regulator
and a high pressure air cylinder that supplied the required
breathing gas at ambient pressure through a demand valve. This
system superseded the earlier attempts at constant-flow
compressed-air breathing setups. [nb: "Aqualung" and "Aqua Lung"
are registered trademarks of commercial products]
-
aquanaut :
-
a scuba diver who works for an extended period of time from and
around a submerged dwelling.
-
aquifer :
-
a geological formation of permeable rock, gravel, or sand
containing or conducting groundwater, especially one that
supplies the water for wells, springs, and the like.
-
Archimedes' principle :
-
a mechanistic theorem on relative displacement that states a body
immersed in a fluid is buoyed up by a force equal to the weight
of the displaced fluid, or a floating object displaces an amount
of water that is equal in weight to the floating object; which is
used by divers to calculate the buoyancy of an object.
-
Arctic Circle :
-
a parallel of latitude that marks the farthest point (66.5°N)
north of the equator where the sun appears above the horizon each
day of the year.
-
argon :
-
a colorless, odorless, chemically inactive, monatomic, gaseous
element that makes up less than 1% of air; it is sometimes used
as a dry suit breathing gas.
-
arm :
-
an inlet or cove, as "an arm of the sea". Also, a curved piece on
an anchor that terminates in a fluke.
-
artesian well :
-
a well in which water rises under pressure from a permeable
stratum overlaid by impermeable rock.
-
arterial gas embolism :
-
a condition in which gas bubbles enter the arterial system and
cause damage by blocking blood flow to vital organs, most
commonly the brain; which most often occurs when air passes
through the walls of capillaries and alveoli into the
bloodstream; also called "air embolism".
-
articles of agreement :
-
a contract, between the captain of a ship and a crewmember,
regarding stipulations of a voyage that's signed prior to and
upon termination of a voyage; also called "shipping articles".
-
artificial respiration :
-
the stimulation of natural respiratory functions in a person
whose breathing has failed by forcing air into and out of the
lungs; to simulate, by various means, pulmonary ventilation.
-
artificial spit :
-
a commercial product that imitates the properties of a natural
secretion; being small bottles of specially compounded liquid
that's used by divers to keep the window of their masks defogged.
-
ascent bottle :
-
an extra or reserve gas cylinder that has been prepositioned to
accommodate the mandatory in-water decompression stops on deep
dives; also called stage bottle.
-
ascent / descent line :
-
an anchored line, suspended from a boat or buoy, that's used to
control a diver's rate of ascent or descent, to provide
orientation in low light on deep dives, and to secure reserve gas
cylinders for decompression stops; a type of safety line that's
also called "drop line".
-
asphyxiation :
-
the extreme condition (suffocation) caused by lack of oxygen and
excess of carbon dioxide in the blood, produced by interference
with respiration or insufficient oxygenated air; as derived from
"stopping of the pulse". Also, to lose consciousness by impairing
normal breathing; to cause to choke or smother, as by gas or
other noxious agents.
-
astern :
-
situated behind something else, as being to the rear of a
specified craft. Also, a backward direction.
-
ATA :
-
abbreviation for Atmosphere Absolute.
-
athwart :
-
from side to side, across, crosswise; not aligned or
adjacent.
-
ATM :
-
abbreviation for a standard atmosphere; this established constant
is approximately equal to the typical air pressure at earth mean
sea level, and is defined as: 1 atm = 101325 Pa / 101.325 kPa, or
760 mm Hg, or 14.7 psi.
[nb: a rule of thumb used by divers states that the pressure
exerted by ten metres (33 feet, depending upon salinity) depth
of water is approximately equal to one atmosphere]
-
atmosphere absolute :
-
the ambient pressure, including the barometric pressure of the
air above the water; abbreviated ATA.
-
atmospheric pressure :
-
the normal amount of pressure exerted by the earth's atmosphere,
being 14.7 pounds per square inch (called "one atmosphere") at
sea level; also known as "barometric pressure". [nb: atmospheric
pressure typically doubles at 33' below sea level, and is
halved at 18,000ft above sea level]
-
atoll :
-
a ring-shaped coral reef, or a string of closely spaced small
coral islands, enclosing or nearly enclosing a shallow lagoon;
previously called atollon.
-
AUF :
-
abbreviation for the Australian Underwater Federation.
-
auxiliary bridge :
-
on large ships and ocean liners, a secondary room setup with
duplicate controls that may be used as a substitute or reserve in
case of need.
-
avast :
-
an imperative directive or command to stop or cease; perhaps
derived from "hold fast".
-
avocational :
-
a certified volunteer who assists on a research or exploration
project, such as marine archaeology or aquatic biology, as
undertaken by students or professionals in other fields during
their vacations so as to gain experience and advance knowledge.
-
Avogadro's law :
-
the principle that equal volumes of all gases at the same
temperature and pressure contain the same number of molecules;
thus the molar volume of all ideal gases at 0°C and a
pressure of 1atm is 22.4 liters; named after Amadeo Avogadro.
[nb: when the temperature of a gas is absolute zero, its volume
is also zero]
-
Avogadro's number :
-
the constant (6.022 x 1023) representing the number of
atoms in a gram atom, or the number of molecules in a gram
molecule of a given substance; also called "Avogadro's constant".
-
AWARE :
-
abbreviation for Aquatic World Awareness Responsibility and
Education, being a PADI nonprofit environmental foundation.
-
A-yoke :
-
a tank valve that provides a high pressure seal between the tank
valve and the regulator first stage, and works by compressing an
O-ring between two metal seats; also known as a compressed O-ring
valve, this yoke assembly holds the seal in place.
-
back-mount :
-
an equipment configuration wherein the air tanks are attached
onto the divers back by a harness and backplate; as opposed to
side-mount.
-
backplate :
-
a mounting plate, made of aluminum, steel, or molded plastic,
through which the diving harness is threaded, and to which the
tanks and BC are mounted; the original design was by Greg
Flannigan in 1979.
-
backwash :
-
water thrown backward by the motion of oars, propellers, paddle
wheels, or any other means of propulsion. Also, to clean
something out, such as a clogged filter, by reversing the flow of
fluid passing through it. Also, a condition, or the effects of a
condition, usually undesirable, that continues long after the
event which caused it; aftermath, consequence, result, upshot.
-
backward roll entry :
-
a self-protective water entry method in which the fully equipped
seated diver rolls off the side or stern of the boat, allowing
the air tanks to strike the surface first, while the diver's body
is in a tuck, face mask held in place, and then continues the
roll underwater into a prone swimming position; any extra gear or
bottles ride in the diver's protected "breadbasket" for a safe
and secure entry; also called "back roll entry" or "flip-flop
entry".
-
backwater :
-
water held or forced back, as by a dam, flood, or tide. Also, to
halt or reverse the forward movement of a vessel by applying
opposite propulsion; backwash. Also, to literally back up, as to
retreat, or to figuratively back down, as to back-pedal. Also, an
isolated or stagnant place that has been literally or
figuratively bypassed; undeveloped, regressive, or backward.
-
bail-out bottle :
-
an air cylinder containing an emergency supply of breathing gas
that's used to escape from trouble with the primary air supply.
-
ballast :
-
a heavy material (including sea water) carried on a vessel to
control draft and stability.
-
bank :
-
a broad seafloor elevation (eg: sandbank) around which the water
is relatively shallow, but not a hazard to surface navigation.
-
bar :
-
a centimeter-gram-second unit of pressure (term derives from
"weight") that's equal to one million dynes per square centimeter
(15 psi, 101 kPa); used by divers to represent the force exerted
upon a given area, and equivalent to the force of one atmosphere.
Also, a long ridge of sand (ie: sand bar), gravel, or other
material near or slightly above the surface of a body of water,
often an obstruction to navigation.
-
barometric pressure :
-
atmospheric pressure affected by weather, as measured by an
aneroid barometer, wherein standard atmospheric pressure has a
value that's equivalent to the pressure exerted by a column of
mercury 29.92 inches (760 mm) high, or 1013 millibars (101.3
kilopascals).
-
barotrauma :
-
injury, generally to the middle ear or paranasal sinuses,
resulting from imbalance between ambient pressure and that within
the affected cavity.
-
barrier island :
-
a broadened barrier beach, which may be habitable in places, that
provides a measure of protection for the mainland, as during
hurricanes and tidal waves.
-
basin :
-
a partially enclosed, sheltered area along a shore where boats
may be moored. Also, a natural or artificial hollow place
containing water.
-
bathyal :
-
pertaining to the biogeographic region of the ocean bottom
between the sublittoral and abyssal zones; from depths of
approximately 660 to 13,000 feet.
-
bathyscaphe :
-
a navigable submersible vessel, with an observation chamber in
its hull, that's used for exploring the ocean's depths; coined by
Auguste Piccard.
-
batten :
-
a thin or narrow strip of lumber attached to sailcloth to keep it
flat or taut. Also, to cover a hatch or other opening so as to
make it watertight.
-
bay :
-
a body of water that forms an indentation in the shoreline, which
is larger than a cove but smaller than a gulf. Also, in the south
Atlantic statesregion, an arm of a swamp.
-
BC :
-
abbreviation for Buoyancy Compensator.
-
BCD :
-
abbreviation for Buoyancy Control Device; enables the diver to
regulate buoyancy to control depth, and acts as a flotation
device on the surface.
-
beach :
-
an expanse of sand or pebbles along a shore, often washed by the
tide or waves. Also, to haul something or run a boat onto the
shore. Also, to cause to be unemployed or idle; as "on the
beach".
-
beachmaster / beach master :
-
the person responsible for the accountability of persons and
equipment on shore, and in charge of the on shore work party;
more commonly called a 'dive marshal'.
-
belay :
-
to fasten by connection or attachment so as to make secure,
especially a rope or line used by someone for descent or ascent.
Also, an imperative directive to stop or cease, desist or quit.
Also, a secure object or other safe projection that's sturdy
enough to anchor a rope or line under a full load.
-
beam :
-
the maximum width (breadth) of a ship.
-
Beaufort scale :
-
a scale indicating the speed or force of wind, enumerated 0-12 or
0-17, commonly expressed as "Force #"; devised by British Admiral
Francis Beaufort around 1855.
-
beaver :
-
a piece of neoprene fabric that hangs down in the back on a
wetsuit jacket and is drawn forward between the legs to attach to
the front, covering the diver's crotch; also called "beaver tail"
and "butt flap".
-
beach drift :
-
the drifting of marine sediments in patterns parallel to the
contours of a beach, due to the action of waves and currents;
also called "littoral drift" or "longshore drift".
-
bearing :
-
a horizontal direction, expressed in degrees, east or west of the
true or magnetic north (or south) direction. Also, one's relative
position or direction, often expressed as "bearings".
-
bends :
-
common term for decompression sickness (DCS) or aeroembolism.
Also, the wales of a vessel; thick planking immediately below the
waterways of a wooden vessel.
-
benthos :
-
the biogeographic region that includes the bottom of a lake, sea,
or ocean, and the littoral and supralittoral zones of the shore;
also known as benthic division or benthonic zone.
-
bergy bit :
-
a small iceberg, somewhat larger than a growler.
-
berth :
-
a shelflike sleeping space aboard ship. Also, the space, at a
safe distance from shore, that's been allotted for a vessel to
dock or lie at anchor; a water surface mooring area that's
delineated by either floating or fixed dock structures, for the
purposes of embarking, disembarking, and the wet storage of a
recreational boat. Also, a job or position; a place or situation
of employment.
-
bight :
-
a looped or slack part of a rope. Also, a bend or curve in the
shoreline of a sea or river. Also, a body of water bounded by
such a bend, as a bay or gulf.
-
bilge :
-
either of the rounded areas that form the transition between the
bottom and the sides on the exterior of a hull; derived by
alteration of "bulge". Also, an enclosed area at the bottom of a
vessel where seepage collects; usually called "bilges". Also, the
seepage collected in this space; also called "bilge water". Also,
slang for foolish talk or worthless ideas; nonsense, claptrap,
malarkey, confetti, snow, blow smoke.
-
bilge keel :
-
a keellike projection along a ship's bilge to retard rolling;
also called "baby keel".
-
billethead :
-
a carved ornamental scroll or volute, terminating a stem or
cutwater at its upper end, in place of a figurehead; also called
scrollhead.
-
black water :
-
the dark depths of seawater that's below the level of penetration
of sunlight; being at or below a depth of 90ft or two atmospheres
of pressure.
-
blink :
-
a brightening of the base of a cloud layer caused by the
reflection of light by snow or ice, as derived from gleam,
twinkle, glitter, or shine.
-
block :
-
a housing or part enclosing one or more freely rotating, grooved
pulleys, about which ropes or chains pass to form a hoisting or
hauling tackle; also known as "tackle block" or "block 'n'
tackle". Also, an obstruction, obstacle, hindrance, or stoppage.
-
blue hole :
-
a sinkhole in a lake or the sea which is subject to tides,
causing its flow to reverse; such sinkholes are often the
entrance to a cave.
-
blue jacket :
-
informal designation for a seaman or sailor, by reference to his
blue duffel or pea jacket.
-
blue nose :
-
a ship that has crossed the Arctic Circle (between the North
Frigid Zone and the North Temperate Zone) or Antarctic Circle
(between the South Frigid Zone and the South Temperate Zone), so
called from painting the hawsepipes blue, as being representative
of the cold; the ship's company of such a voyage may be called
"blue noses". [nb: alternatively, the "Order of the Blue Nose" is
reserved exclusively for the Arctic Circle, and the "Order of the
Red Nose" exists as an exclusive distinction for the Antarctic
Circle]
-
blue water :
-
nautical reference to the open sea, or oceangoing; also
represented as "deep water", and sometimes spelled "blue-water".
-
bluff :
-
a bold coastline or precipitous headland. Also, a full blunt bow
on a vessel. Also, a cliff or headland with a broad steep face.
-
board :
-
the side of a ship; or the windward tack of a ship's course.
-
boarding float :
-
a platform-type structure, either floating or fixed, stationary
or adjustable that's designed for short-term moorage of boats,
and to facilitate pedestrian access to and from boats in the
water; it's located on, along side of, or near a boat launch
ramp; also known as a boarding pier (qv).
-
boarding party :
-
a group of persons who board a vessel, especially to attack,
seize, or search it.
-
boarding pier :
-
the portion of a pier where a boat is temporarily secured for the
purpose of embarking or disembarking.
-
boat deck :
-
a superstructure deck on which most of the lifeboats of a ship
are stowed.
-
boat dock :
-
a boat slip or berth (qv).
-
boating party :
-
a group of persons who board a vessel for transport or
recreation, especially when paying for the privilege.
-
boat launch ramp :
-
a sloped surface at the edge of a body of water that's designed
and constructed (usually paved) for the launching and retrieval
of trailered boats and other watercraft.
-
boat ramp :
-
a boat launch ramp (qv).
-
boat slip :
-
a boat dock or berth (qv).
-
boatswain's chair :
-
a wooden plank or canvas seat that's hung by ropes over the side
of a ship's rail, deck, bridge, and the like for stable access
while performing construction, maintenance, or rescue work.
-
boatswain's locker :
-
a storage compartment, usually located forward, where tools,
line, and other small equipment for working on deck is stowed.
-
boatswain's pipe / boatswain's whistle :
-
a simple musical device used by the boatswain to make shipboard
announcements over the public address (PA) or loudspeaker system.
-
bollard :
-
a substantial post on a wharf or deck ("bitt") made of wood,
metal, or concrete that's used for mooring vessels.
-
BOLT :
-
a mnemonic acronym for the in water check performed prior to
diving: Bubbles (manifold and valve check), Out of air (S-drill),
Lights, Turn Time (Thirds).
-
bolt snap :
-
a hardware device, made of brass or stainless steel, that has a
spring-loaded thumb-gate, can be double ended or have a swivel on
one end, that's used to clip items to the diver's harness; also
known as a piston bolt.
-
boom :
-
any of various spars, beams, or poles projecting from a mast, as
used to extend a ship's sails, to handle cargo, to guide objects,
or to hold devices; also called a derrick or crane, an arm or
stick. Also, a chain, cable, or the like serving to obstruct
navigation.
-
boot :
-
a plastic footing that fits on the rounded bottom of a scuba tank
that allows it to be stood upright without support; not used in
cave diving due to being an entanglement hazard.
-
bootie / bootee :
-
a waterproof (neoprene) socklike foot covering, serving to
insulate and protect the diver's foot and ankle, that's worn
inside open-heeled flippers or fins; also called "footie".
-
booty :
-
an unexplored ("virgin") cave.
-
bottle :
-
slang for the cylinder, usually steel or aluminum, of pressurized
breathing gas that's used in scuba diving.
-
bounce dive :
-
in recreational diving, a descent to a specific depth, often the
seafloor maximum, that's immediately followed by a return ascent
back to the surface with the least delay, which is represented in
a dive profile resembling a spike; also called a "yo-yo dive". In
commercial diving, the alternative to saturation diving.
-
bourdon tube :
-
a spiral or c-shaped tube that changes its shape when pressure
increases at depth; used in depth gauges to alter the position of
the denotative indicator as the tube changes shape; derived from
the drone or low-pitched tone emitted by musical instruments.
-
bow :
-
the front of a craft or vessel; designated by the color white;
also called prow or stem. Also, the abbreviation for Basic Open
Water, a scuba certification. Also, the foremost oar, situated at
the forward end, when rowing a boat.
-
bower :
-
an anchor carried at the bow of a vessel.
-
bowsprit :
-
a spar projecting from the upper end of the bow of a sailing
vessel, for holding the tacks of various jibs or stays, and often
supporting a jib boom; as derived from bow pole.
-
boy :
-
an apprentice seaman or fisherman, especially one who has not
before gone to sea (eg: cabin boy).
-
Boyle's law :
-
the principle that, for relatively low pressures, the pressure of
an ideal gas kept at constant temperature varies inversely with
the volume of the gas; named after Robert Boyle, it's also called
Mariotte's law; also expressed as PV=k (Pressure)(Volume) =
(constant of proportionality), or PV=nRT.
-
braided line :
-
woven nylon line that has better abrasion resistance than twisted
line.
-
brash ice :
-
small, brittle fragments of suspended sea ice or floating river
ice; also called brash.
-
breaking strength :
-
the load that will cause a line or rope to fail.
-
breakthrough :
-
indicates the entry of carbon dioxide into the inhalation side of
the breathing loop from the absorbent canister on a Rebreather.
-
breakwater :
-
a barrier that breaks the force of incoming waves, as before a
harbor or bay. [nb: this term has been mistakenly used to mean
"where waves break" before a shore or upon shoals; which is
properly known as 'surf']
-
breathing loop :
-
the part of a rebreather system that includes the mouthpiece,
hoses, inhalation bag, exhalation bag, and absorbent canister.
-
breech :
-
the end of a block or pulley farthest from the supporting hook or
eye.
-
breeches buoy :
-
a life preserver with a pants-like canvas seat for hauling a
shipwrecked or disabled person on or off a vessel; also called
"britches buoy".
-
bridge :
-
a structure spanning and providing passage over an opening or
past an obstacle. Also, the platform from which a vessel is
controlled and navigated.
-
brightwork :
-
the polished metal parts on a ship. Also, all plain or varnished
woodwork that is kept scoured on a vessel.
-
brine :
-
the sea or ocean; the water of the sea. Also, water saturated or
strongly impregnated with salt; any saline solution.
-
broach :
-
to veer to windward. Also, to break the surface of water from
below, such that the rudder cannot be used to steer.
-
brow :
-
a gangplank, gangway, or passageway. Also, the edge of a steep
place or drop-off, as a brink or brim, by analogy with the brow
of the head.
-
brown water :
-
nautical reference to shallows, shoals, littoral or estuarial
waters.
-
BSAC :
-
abbreviation for British Sub-Aqua Club, a club-based organisation
that serves, since 1953, as the governing body for the sport of
scuba diving in the United Kingdom.
-
bubblehead :
-
slang for a submariner; also known as a dipper, boomer, or
dolphin.
-
buddy :
-
a diving partner, or the member of a team or group who's
designated to be a safety companion.
-
buddy breathing :
-
the sharing of the same demand valve by two or more divers,
generally after an out-of-gas emergency.
-
buddy check :
-
the inspection by one diver of another's diving equipment to
ensure that it's properly configured and functioning correctly;
this procedure is conducted before the start of the dive.
-
buddy diving :
-
underwater diving with a designated partner (not just swimming in
a group) so as to improve each diver's chance of surviving an
accident by the shared observance of safety procedures; also
called "backup" or buddy system.
-
bugeye :
-
a ketch-rigged (ie: two masted with the larger mainmast forward)
sailing vessel; so called after the former practice of painting a
large eye on each side of the ship's bow.
-
bulkhead :
-
a reinforced wall-like partition inside ships and aircraft, often
air- or water-tight.
-
bull rail :
-
a low continuous safety rail, slightly raised and blocked,
running along the edge of a boat deck, berth, dock or pier; as
used for tying on mooring lines to prevent drifting, or for
bracing carts and carriers, objects or people to prevent them
from falling overboard; sometimes called a "curb" or "curbing".
-
bull's-eye :
-
a small circular opening or window set into a roof, ship's deck
or overhead, to admit light; sometimes called "deadlight".
-
bull's-eye squall :
-
a squall forming in fair weather that's characterized by the
peculiar appearance of the small isolated cloud marking the top
of the invisible vortex of the storm.
-
bulwarks :
-
a protective wall enclosing the perimeter of a deck, especially
the main or weather deck.
-
buoy :
-
an anchored float used as a marker or as a mooring, as derived
from "boye a float", beacon [v: cresset]. Also, any of various
buoyant devices for supporting a person in the water, as a "life
buoy" or "life preserver".
-
buoyancy :
-
upward pressure exerted by the fluid in which a body is immersed;
or the amount of lift acting on a submerged object, being that
force equal to the weight of the water displaced by the object.
-
buoyancy compensator :
-
a vest, jacket, or backpack containing a distensible air bladder
that can be inflated and deflated to regulate a diver's buoyancy
underwater; also called buoyancy control device (BCD).
-
buoyancy control :
-
the ability to maintain neutral buoyancy while swimming at any of
various depths determined by the diver; problems include:
fluctuating currents, changing temperature, altered weight or
load, defective BCD bladder or valve, mis- or maladjusted BCD,
inexperience. An essential skill of practical diving technique.
-
burgee :
-
a small nautical flag or pennant that's used for identification
or as a signal; derived from a mark of the owner.
-
burst disk :
-
a safety release fixture located on the valve of a scuba tank
that prevents over-pressurization of the tank. [nb: according to
the first law of thermodynamics, the internal energy of a gas
increases when the gas is compressed]
-
burton :
-
any of various small tackles rove in a particular way for use on
shipboard; a metathetic variant of breton or briton (tackle).
-
BWRAF :
-
a mnemonic for "Begin With Review And Friend" that's used in PADI
training.
-
cable :
-
any strong heavy rope or cord made of twisted strands, especially
one made with metallic wire. Also, a thick hawser made of rope,
wire, or chain. Also, a strong heavy rope or cord that operates a
mechanism. Also, a unit of length equal to 720 feet on land, or
606 feet at sea.
[nb: 12 inches = 1 foot, 3 feet = 1 yard, 6 feet / 2 yards = 1
fathom, 16.5 feet = 1 rod (aka: pole or perch), 66 feet / 4 rods
= 1 chain (90 feet / 15 fathoms = 1 anchor chain), 10 chains /
660 feet (1/8 statute mile) = 1 furlong, 120 fathoms / 720 feet =
1 land cable, 101 fathoms / 606 feet (1/10 nautical mile) = 1
cable, 3 statute miles = 1 land league, 3 nautical miles = 1 sea
league / shot]
-
CAGE :
-
abbreviation for Cerebral Arterial Gas Embolism.
-
caisson :
-
a protective environment for working underwater, consisting of a
pressurized watertight chamber. Also, a watertight structure
built against a damaged hull to render it watertight; also known
as cofferdam. Also, a float for raising a sunken vessel; also
known as a camel or pontoon. Also, a boatlike structure used as a
gate for a dock or the like.
-
calf :
-
a mass of ice detached from a glacier, iceberg, or floe.
-
camel :
-
a float for lifting a deeply laden vessel sufficiently to allow
it to cross an area of shallow water; also called a pontoon.
Also, a float serving as a fender, as between a vessel and a
pier.
-
canal :
-
an artificial waterway used for navigation, irrigation, or other
application. Also, a channel or other watercourse, such as a long
narrow arm of the sea that penetrates far inland.
-
canister light :
-
a type of dive light wherein the battery pack is strapped to the
diver's belt or harness while the light is hand held.
-
cape :
-
a piece of land jutting into some large body of water, as a point
or headland, promontory or spit. Also, a ship that has good
steering qualities.
-
Cape Horn fever :
-
an illness feigned by malingerers.
-
capillary :
-
one of the minute blood vessels between the terminations of the
arteries and the beginnings of the veins where the gas exchange
takes place between the bloodstream and the tissues or the air in
the lungs.
-
capsize :
-
to turn bottom up, to keel over or overturn.
-
capstan :
-
any of various windlasses, rotated in a horizontal plane by hand
or machinery, used for winding in ropes, cables, and the like.
-
carbon dioxide :
-
a colorless, odorless, incombustible gas that's present in the
atmosphere and formed during respiration; it's a metabolic
byproduct of oxygenation that can stimulate respiration or
depress the central nervous system.
-
carbon monoxide :
-
a colorless, odorless, poisonous gas that's produced when carbon
burns with insufficient air; its toxicity derives from its
affinity for hemoglobin, which competitive bond denies oxygen
availability to tissues during inhalation.
-
careen :
-
to cause a vessel to tip, lean, list, sway, or heel over to the
side. Also, to clean or repair the hull of a vessel by laying
onto its side. Also, a headlong rush, as rash, impetuous, or
uncontrolled action.
-
castoff / cast-off :
-
to let a ship go, to loose a vessel from its mooring, or to
launch a boat; also known as shove-off or simply cast, as derived
from 'throw'. Also, to turn the head of a sailing ship away from
the wind, especially when getting underway or during departure.
Also, to discard, reject, or abandon people or things, as a
castaway.
-
catadromous :
-
pertaining to fish that migrate from freshwater to spawn in the
saltwater sea; as distinguished from anadromous.
-
cathead :
-
a projecting timber or metal beam to which an anchor is hoisted
and secured.
-
cat's-paw :
-
a light breeze that ruffles the surface of the water over a small
area. Also, a hitch made in the bight of a rope to hold the hook
of a tackle.
-
cave :
-
a hollow in the earth that opens more or less horizontally. Also,
to cause supporting material to collapse or overlying material to
fall (cave-in).
-
cavern :
-
a large cave that is mostly or entirely underground.
-
cavitation :
-
the rapid formation and collapse of pockets of vapor in a flowing
liquid of very low pressure, often causing structural damage to
propellers, pumps, and related mechanisms. Also, the formation of
cavities, especially in some part of the human body; as derived
from cavity.
-
cay :
-
a small low island; often called 'key'.
-
C-card :
-
contraction of Certification card, which is a summary
representation by an authorized agency as evidence that the
bearer has completed a certain level of diver training.
-
CCR :
-
abbreviation for Fully-Closed Circuit Re-breather.
-
CDAA :
-
abbreviation for the Cave Diving Association of Australia.
-
celsius :
-
a temperature scale in which 0 represents the freeze point and
100 the boiling point; also called centigrade. [nb: the degree
intervals of the kelvin scale are the same as celsius, as the
rankine are the same as fahrenheit]
-
CESA :
-
abbreviation for Controlled Emergency Swimming Ascent, which
involves exhaling while swimming toward the surface, when no
other air is available, so as to prevent lung expansion injury
from breath holding when a diver is out of air.
-
chain :
-
a sequence of metallic rings that pass through one another and
are linked together for use in securing, supporting, or hauling.
Also, a surveyor's measure for establishing distance by a 100
foot (30m) or 66 foot (20m) length, wherein each link is exactly
the same as every other, for ready and consistent computation.
[nb: 12 inches = 1 foot, 3 feet = 1 yard, 6 feet / 2 yards = 1
fathom, 16.5 feet = 1 rod (aka: pole or perch), 66 feet / 4 rods
= 1 chain (90 feet / 15 fathoms = 1 anchor chain), 10 chains /
660 feet (1/8 statute mile) = 1 furlong, 120 fathoms / 720 feet =
1 land cable, 101 fathoms / 606 feet (1/10 nautical mile) = 1
cable, 3 statute miles = 1 land league, 3 nautical miles = 1 sea
league / shot]
-
chain locker :
-
a storage compartment for the proper stowage of cable and hawser
aboard a vessel.
-
chandler :
-
a trader in specialized supplies (eg: ship chandler). Also, a
maker or seller of candles (wax) or soap (tallow); as derived
from 'chandelier'.
-
channel :
-
the bed of a stream, river, or other watercourse or waterway.
Also, the deeper part of a waterway, especially the navigable
route between two bodies of water. Also, an artificial waterway
constructed and maintained for the safe passage of navigable
vessels. Also, a wide strait, as between a continent and an
island. Also, a horizontal timber or ledge built outboard from
the side of a sailing vessel that's used to spread shrouds and
backstays outward; by alteration of "chain wale" (chain-wale).
-
channel marker :
-
a colored or numbered buoy, or other aid to navigation, that's
located alongside a navigable waterway to ensure safe passage;
also called daymark (green or red), can buoy (numbered odd,
colored green), or nun buoy (numbered even, colored red).
[nb: pass along marked channels by staying left of the red
signals and right of the green signals, or by keeping the red
signals on the red side of the boat and green signals on the
green side of the boat]
-
chantey / chanty :
-
a rhythmic work song, especially used by sailors.
-
Charles' law :
-
the principle that the volume of an enclosed gas is directly
proportional to its absolute temperature, or V=kT (Volume) =
(constant of proportionality)(Temperature); also known as
Gay-Lussac's law.
Also, if pressure is constant, the volume of a gas expands by a
constant fraction as temperature increases.
-
chart :
-
a hydrographic or marine map.
-
chart datum :
-
the level of the lowest tide at a particular place, recorded with
heighths and depths of tides; abbreviated CD.
-
charter :
-
an arrangement by which all or part of a ship, or other
conveyance, is leased for a particular group, journey, or
activity. Also, the trip, journey, tour, or vacation made using
such an arrangement.
-
chart table :
-
the desktop surface, typically horizontal, used for displaying a
marine or hydrographic map, a nautical chart, which is consulted
for known hazards, and upon which an intended course is planned
or the actual course is plotted; the modern electronic version is
known as the "central navigation console".
-
chicken ladder :
-
slang for an inclined plank with transverse cleats that's used as
a temporary bridge onto a vessel; a brow or gangplank, walkway or
passageway.
-
chine :
-
an angular intersection of the sides and bottom of a vessel; or a
longitudinal member running behind this intersection.
-
chock :
-
a wedge to fill-in a gap or a device to brace an object, any
support or reinforcement; also called "chock block", and derived
from "choke", as close or tight.
-
chockablock :
-
having the blocks drawn close together, as when the tackle is
hauled to the utmost; crowded together, close or tight.
-
chop :
-
the short irregular motion of a turbulent wave. Also, the rough
water of a turbulent lake or sea.
-
chum :
-
an inexperienced or novice sailor, especially someone on his
first float or cruise; also called pollywog, nugget, or fresh
catch.
-
chumming :
-
slang for vomiting overboard when seasick, after the fishing
practice of dumping bait in the water to attract fish.
-
clear the decks :
-
the removal of everything not required so as to have ready access
during seaborne operations.
-
cleat :
-
a strong device, usually metal with one or more projections,
that's used to secure tie-downs, as on a deck or pier [dock
cleat] for mooring. Also, a wedge-shaped block or strip of
resistant material fastened to a surface to serve as a check or
support; also called a chock. Also, a resistant strip fastened
across a surface, as on a ramp [gangway cleat], to provide sure
footing.
-
clew :
-
either lower corner of a square sail, or the lower after corner
of a fore-and-aft sail. To "spread a large clew" is to carry a
large amount of sail, which will present an impressive
appearance.
-
clew down :
-
to secure a sail in an unfurled position.
-
clew up :
-
to haul the lower corner(s) of a sail up to the yard by means of
(clew) lines.
-
closed-circuit / closed-circuit system :
-
an underwater breathing system which does not release exhaled
gasses as exhaust, but filters and recycles the discharge back
into the gas supply; also called "re-breather". Closed-circuit
re-breathers generally supply two breathing gases to the loop:
one is pure oxygen and the other is a diluting gas (diluent) such
as air, nitrox, or trimix. The major task of the closed-circuit
re-breather is to control the oxygen concentration, known as the
oxygen partial pressure, in the loop and to warn the diver if it
is becoming dangerously low or high as depth changes.
-
close-hauled :
-
to sail a vessel as close to the wind as possible, with sails as
flat as possible.
-
CMAS :
-
abbreviation for Confederation Mondiale des Activitias
Subaquatiques; the World Federation of Underwater Activities,
established in 1959.
-
coaming :
-
the protective rim or raised bulwark surrounding an opening in a
bulkhead or deck that's designed to exclude water; also called a
"knee-knocker" or "shin-scraper".
-
coast :
-
the land beside the sea, as a shore, often serving as a border;
also known as "coastline", and derived from "side wall". Also, to
be sustained or to continue on acquired momentum.
-
cockpit :
-
a sunken, open space, generally in the after part of a small
boat, that provides access to the controls and instruments needed
by the crew when operating a vessel at sea.
-
cold harbor :
-
a place of refuge or retreat, typically primitive, that lacks the
usual amenities, especially fresh water and other creature
comforts; such a haven is also called a cold camp or fly camp.
-
collapse depth :
-
the design depth beyond which the hull structure of a submersible
is presumed to suffer catastrophic failure to the point of total
collapse; such "crush depth" is referenced to the axis of the
pressure hull, and is affected by material defect or decline, by
hull penetrations, or by other relevant factors.
-
command signal :
-
a signal from one diver that requires a response from another
diver; including: OK, Hold, and Surface. The OK hand signal is
formed by connecting the thumb and forefinger in a circle with
the other three fingers extended, or by making a circular motion
with the dive light. The Hold hand signal is a closed fist. The
Surface (turn the dive and exit) hand signal is an upward
pointing thumb with the other fingers in a fist; such termination
is also called "thumbing the dive".
-
compartment :
-
a partitioned area or space, as a cabin or hold on a vessel.
-
confluence :
-
a flowing together of two or more streams, rivers, or the like
into a singular course or unified movement. Also, their place of
[con]junction into a body of water formed by such confluence.
-
conning tower :
-
the housing over the main entrance to the interior of a
submarine, accommodating its periscope and antennas, and used as
an observation platform; also called the "sail" or fairwater.
-
constriction :
-
a narrow passage or small opening that's not large enough for two
divers to swim through together (ie: minor constriction); or that
requires gear removal to negotiate (ie: major constriction); also
known as a squeeze, restriction, tight, sidemount passage, no
mount.
-
convection :
-
the vertical flow of air, water, or the like, which often entails
a change of temperature or humidity; as distinct from advection.
-
cordelle :
-
a heavy rope formerly used for towing boats on rivers; derived as
a diminutive of 'cord', cordelling is one of the methods of
hauling a watercraft upstream.
-
cove :
-
a small indentation or slight recess, usually sheltered, in the
shoreline of a sea, lake, or river.
-
covered berth :
-
a roofed mooring area that's intended to protect a boat from the
effects of sun and weather.
-
coxswain :
-
the person, generally a boatswain's mate, who's in charge of
steering and/or directing the crew of a boat.
-
crab :
-
a maneuver in which a craft is headed partly into the wind to
compensate for drift. Also, a mechanical contrivance for hoisting
or pulling heavy weights, a truckle.
-
crash-dive / crash dive :
-
to dive rapidly at a steep angle, as when a swimmer imitates the
emergency maneuver of a submarine or other submersible.
-
creature feature :
-
slang for a submerged corpse, typically a gruesome one beginning
to suffer the ravages of immersion and marine predation but
either insufficiently bloated to float, or one too decomposed for
gaseous accumulation, but not yet unrecognizable or skeletal.
[nb:the rate of decomposition for a corpse underwater is about
half that of one exposed to the open air]
-
creep :
-
to grapple; to attempt to seize, hold, grip, or fasten. Also,
slang for a grappling iron or grapnel.
-
crepuscular :
-
wildlife that becomes active in the dimness of twilight.
-
crest :
-
the foamy top of a wave. Also, the point of highest flood, as of
a tide.
-
cringle :
-
an eye or grommet formed on the boltrope of a sail to permit the
attachment of lines; as derived from "circle".
-
crosshead :
-
a crosspiece on a rudderpost by which the rudder is turned. Also,
a transverse member that's variously employed to transfer
alignment or for transmitting energy.
-
crown :
-
the part of an anchor at which the arms join the shank; also
called "head".
-
crow's nest :
-
a lookout platform high atop a ship's main mast, or any
observation point with a commanding view.
-
crush depth :
-
properly called collapse depth, being the submergence level at
which the hull or pressure hull of a vessel suffers catastrophic
failure, which is typically well below its design depth; compare
maximum operating depth and test depth.
-
cutwater :
-
the forward edge of the stem of a ship. Also, an upstream face of
a bridge pier or piling, sharp edged or sharply pointed, arranged
for resisting the effects of moving water or ice.
-
cyclone :
-
the word 'cyclone', introduced in 1848 by British meteorologist
Henry Piddington, confused "wheel" with "revolve", but has since
been accepted as the denotation for the large-scale atmospheric
wind-and-pressure system that's characterized by low pressure at
its center and by circular wind motion (ie: counterclockwise in
the northern hemisphere, clockwise in the southern hemisphere).
-
cylinder :
-
the aluminum or steel container that contains pressurized
breathing gas for underwater diving; also known as tank or
bottle.
-
Dalton's law :
-
the principle that the total pressure of a gas mixture is equal
to the sum of the partial pressure of its components; or the
total pressure exerted by a mixture of gases is the sum of the
pressures that would be exerted by each of the gases if it alone
were present and occupied the total volume; also called "Dalton's
law of partial pressures", "law of partial pressures", and named
after John Dalton, the English chemist and physicist.
-
dam :
-
an earthen or masonry barrier that's used to obstruct the flow of
water, built across a stream or river. Also, a body of water so
confined by such a barrier; impoundment, reservoir.
-
dangly :
-
anything hanging from a diver’s gear that could result in silting
or an entanglement hazard, such as exposed knobs, consoles,
unsecured straps and lanyards.
-
dasher block :
-
a block at the end of a yard or gaff that's used for supporting a
signal or ensign halyard; also called "jewel block".
-
davit :
-
any of various crane-like devices used on ships for moving
or supporting boats, anchors, and other objects.
-
Davy Jones's locker :
-
the bottom of the ocean, which serves as a graveyard and junkyard
for all that's lost at sea.
-
DBAR :
-
abbreviation for decibar, being one tenth of a bar, or
approximately a meter of depth in water.
-
DCI :
-
abbreviation for DeCompression Illness.
-
DCS :
-
abbreviation for DeCompression Sickness; also called the bends or
aeroembolism.
-
DCS I :
-
decompression sickness, a syndrome caused by bubbles of inert gas
forming in the tissues and bloodstream during or after ascent
from an underwater dive, involving only muscle and joint pain,
fatigue, and/or skin irritation (itching, rash).
-
DCS II :
-
decompression sickness, a syndrome caused by bubbles of inert gas
forming in the tissues and bloodstream during or after ascent
from an underwater dive, involving the central nervous system,
respiratory system, or circulatory system.
-
deadhead :
-
a sunken, semisubmerged, or floating object that's a hazard to
navigation.
-
dead in the water :
-
adrift without motive, power or propulsion; also called hull.
-
dead lift :
-
to raise or move something substantial without mechanical
assistance; being any act or exercise requiring a significant
effort.
-
deadlight :
-
a strong shutter able to be screwed against the interior of a
porthole in heavy weather. Also, a thick pane of glass set in the
hull or deck to admit light; sometimes called "bull's-eye".
-
dead-reckoning :
-
estimated calculation of one's present position based upon
compass readings, speed, and distance traveled from the last
known point, with allowances for drift from wind or currents;
also known as "guesstimate" or "by guess and by God".
-
dead water :
-
water eddying beside a moving hull, especially directly astern.
Also, a slack current in a part of a stream.
-
deadwood :
-
a solid construction, serving only as reinforcement, located
between the keel of a vessel and the stem or sternpost.
-
debarkation net :
-
a specially prepared type of General Purpose net, cargo net, or
other similar mesh employed when scaling, as during insertion or
extraction, but especially during debarkation from or embarkation
of a transport ship.
-
deck :
-
a floor-like surface occupying all or most of one level in a
superstructure or hull.
-
deckhead :
-
the undersurface of a deck.
-
deco mix :
-
a gas mixture used during decompression.
-
decompression :
-
the gradual reduction in atmospheric pressure experienced after
immersion in deep water or breathing compressed air, resulting in
the equalization of gases in body tissues once they have been
saturated with nitrogen.
-
decompression chamber :
-
a controlled environment for raising and lowering atmospheric
pressure with selective air mixtures; also called a hyperbaric
chamber.
-
decompression diving :
-
a diving practice that goes beyond the standard No-Decompression
time/depth limits in order to extend bottom time, which requires
one or more decompression stops during ascent regardless of the
type of equipment used; violation of the mandatory in-water stops
may result in decompression sickness.
-
decompression illness :
-
a diagnosis of dysbaric injuries related to underwater diving,
which stems from uncertainty about the mechanistic causation of
similar or related neurological symptoms, when the etiology or
pathophysiology cannot be determined, and is ultimately
immaterial to the treatment regimen. It has been suggested that
this diagnosis encompass all manifestations of diseases following
a reduction in ambient pressure, such as ascending from a dive.
-
decompression sickness :
-
a complex of symptoms caused by the escape of nitrogen bubbles
from solution in the fluids that were absorbed originally at
higher atmospheric pressure, as a result of the abrupt reduction
in that pressure; it is characterized by headache, pain in the
arms, legs, joints, and epigastrium, itching of the skin,
vertigo, dyspnea, coughing, choking, vomiting, weakness and
sometimes paralysis, and severe peripheral circulatory collapse.
It is also known as the bends, aeroembolism, caisson disease, and
decompression disease.
-
decompression stop :
-
the time period that a diver must spend at a constant depth in
shallower water after diving at greater depth in order to safely
eliminate inert gases from the diver's body so as to avoid
decompression sickness.
-
decompression tables :
-
cards or booklets printed with index and conversion arrays that
allow divers to determine the decompression stops required for a
particular dive profile and breathing gas, so as to avoid
decompression sickness. Decompression tables assume that the dive
is simple and straightforward, an invariable "square dive". These
calculations also determine the requisite surface intervals
between dives. Also called dive tables or tables.
-
deep six :
-
to throw or cast overboard while at sea, as when discarding,
abandoning, or jettisoning something in more than six fathoms of
water; derived from soundings by fathom (6feet), expressed as "by
the deep six" (36feet). Also, burial at sea. [nb: refers only to
objects; people fall "overboard"]
-
defogging solution :
-
a natural (spit) or commercial (artificial compound) liquid
that's used as a treatment to prevent condensation on the window
of the diver's mask while underwater.
-
dehydration :
-
the abnormal depletion of water or other bodily fluids during
exertion ... it's an irony to be thirsty while swimming.
-
deliquesce :
-
to become liquid by absorbing moisture from the air. Also, to
melt away.
-
demand valve :
-
a pressure valve, generally placed in the diver's mouth, which
provides gas from the diving regulator when the diver inhales;
also called mouthpiece.
-
demersal :
-
bottom-dwelling marine life that persists at the lowest ocean
layers.
-
depth gauge :
-
a calibrated device, analog or digital, that indicates the
distance underwater from the surface (sea level) that the
measurement is being taken, as derived from the ambient pressure.
-
descent line :
-
the ascent / descent line; a type of safety line that's also
called "drop line".
-
deviation :
-
the angle of error of a magnetic compass on a given heading as a
result of local magnetism; the declination from true north.
-
diameter indexing safety system :
-
an Intermediate pressure port where a hose attaches, leading to a
demand valve or other apparatus.
-
diaphragm :
-
the musculomembranous partition or wall of muscle and connective
tissue separating the thoracic cavity from the abdominal cavity,
with constriction of this thoraco-abdominal diaphragm being
essential for respiration.
-
diel :
-
pertaining to a 24-hour period, as when referring to the regular
daily cycle of an organism's physiology or behavior.
-
dike / dyke :
-
an embankment for controlling or holding back the waters of the
sea or another body of water. Also, a ditch or causeway. Also, an
embankment, barrier, or other obstacle, especially one made from
excavated material.
-
diluent :
-
a diluting substance, such as oxygen added to nitrogen.
-
DIN :
-
abbreviation for Deutsche Industrie Normen, being the German
industrial standards agency, which proliferated criteria
worldwide before ISO; later construed as 'Das Ist Norm' for "that
is (the) standard"; sometimes (mis-)represented as "Deutsches
Institut fuer Normung". The fitting that connects the first stage
of a regulator to the compressed air tank on a high pressure
scuba system is identified by this DIN standard.
-
dinghy :
-
any small boat designed as a tender or lifeboat, whether
propelled by rowing or paddling, by sail or motor.
-
dirt dart :
-
slang for an overloaded diver who has either improperly set his
buoyancy compensator, or whose mechanism has failed, causing him
to rapidly plunge to the seafloor immediately upon entry into the
water; such malfunction is potentially fatal. [cf: picul]
-
DISS :
-
abbreviation for Diameter Indexing Safety System.
-
ditch :
-
slang for any body of water that's channeled or confined, such as
a river or strait, regardless of size, used informally as a term
of convenient reference.
-
diurnal :
-
day or daytime; daily or daily cycles; as opposed to nocturnal or
seasonal.
-
diurnal thermocline :
-
in general, is established each day by heating of the surface
water and is destroyed the following night by cooling and/or
mixing.
-
dive computer :
-
a waterproof electronic device that measures the dive profile and
displays related safety information; as the dive computer
automatically measures actual depth and elapsed time, it performs
a continuous calculation of the partial pressure of gases in the
body based on the actual dive profile. A dive computer will
address the same problems as decompression tables, but it is also
able to warn of excessive ascent rates and missed decompression
stops, as well as report the water temperature, and the pressure
of the breathing gas remaining in the diving cylinder. A dive
computer reduces the need for the diver to carry a separate watch
and depth gauge, and relieves the diver of computations, which
may be subject to human error.
-
dive marshal :
-
the person responsible for the accountability of students and
equipment during training classes; being responsible for
recording names, checking equipment, recording water entry and
exit times. This safety and security associate functions like a
lifeguard, and is sometimes identified as a "beachmaster".
-
divemaster :
-
a professional qualified to oversee scuba diving operations, as
in salvage work or at a school or resort, and responsible for
procedures and safety, monitoring the whereabouts of divers
underwater or at the surface, and making rescues whenever
necessary.
-
dive profile :
-
a two dimensional graphical representation of a complete dive
showing its depth and elapsed time. This profile is often used
when describing a dive's probable decompression obligation. It's
also known as a depth/time profile, and its coordinate charting
is variously configured as square, multilevel, spike, and so
forth.
-
dive tables :
-
numerical tables used by scuba divers to determine time limits of
dives, according to depth, as well as possible decompression
delays during ascent, and the requisite surface intervals between
dives; also called decompression tables or tables.
-
diver propulsion vehicle :
-
an underwater transport for divers and equipment that's used to
extend travel by increasing their speed of movement.
-
diving bell :
-
a chamber with an open bottom in which persons can go underwater
without special apparatus, water being excluded from the upper
part by compressed air fed in by a hose.
-
diving boat :
-
a craft or other vessel used as a tender for divers or others
working under water.
-
diving mask :
-
a protective shield worn while under water; also called "face
mask", "swim mask", or simply "mask" (qv).
-
diving reflex :
-
a physiological reflex of humans, other mammals, reptiles, and
birds, that's triggered by immersion in cold water, having the
effect of slowing the heart rate and diverting blood flow to the
brain, heart, and lungs; serving to conserve oxygen until
breathing resumes and to delay potential brain damage.
-
diving suit :
-
any of various waterproof garments for underwater swimming or
diving, especially one that is weighted, hermetically sealed, and
supplied with pressurized air.
-
dock :
-
a landing pier or wharf. Also, the space or waterway between two
piers or wharves, as for receiving a ship while in port.
Also, such a waterway, enclosed or open, together with the
surrounding piers, wharves, and other structures. Also, a dry
dock.
-
DODO :
-
acronym for Dead Object Drifting Obstacle (or "Dead Or Drifting
Object") indicating inert debris or incidental hazards to
navigation; since such flotsam is not underway, the craft or
vessel must maneuver to avoid damage.
-
dolphin :
-
any small toothed cetacean, especially one possessed of a
beaklike snout; compare porpoise. Also, a buoy, pile, or cluster
of piles used as a fender or mooring. Also, a rope or strap round
a mast to support the puddening, where the lower yards rest in
the slings.
-
Doppler ultrasound bubble detector :
-
a diagnostic device used in hyperbaric medicine to determine the
presence (by Doppler shift) of bubbles in the bloodstream that
may presage decompression sickness.
-
double berth :
-
a mooring that accommodates two boats, with a finger pier on only
one side of each berthed vessel.
-
DPV :
-
abbreviation for Diver Propulsion Vehicle; sometimes called a
scooter.
-
draft :
-
the depth to which a vessel is immersed when bearing a given
load.
-
dragrope :
-
a rope that's been attached to something and is then used to drag
or haul it. Also, the end of a rope that's hanging loose or
trailing behind its point of attachment; a trawl.
-
drainage basin :
-
the area drained by a river and all its tributaries; also called
a "catchment area" or "drainage area".
-
drift dive :
-
a dive in which the divers drift with the current, and the dive
boat follows the freely drifting divers.
-
D-ring :
-
a metal ring in the shape of a capital letter 'D' that's used on
the harness for attaching items by clipping onto them; chest
mounted D-rings are often bent outward to aid in the clipping
process.
-
drogue :
-
a bucket or canvas bag used as a vessel's "sea anchor".
-
drop line :
-
an anchored line, suspended from a boat or buoy, that's used to
control a diver's rate of ascent or descent, to provide
orientation in low light on deep dives, and to secure reserve gas
cylinders for decompression stops; a type of safety line that's
also called "ascent / descent line".
-
droxtal :
-
a tiny ice particle, formed by direct freezing of supercooled
water droplets with little growth directly from the vapor,
causing most of the visibility reduction in ice fog; the term
derives from a combination of the words drop and crystal.
-
dryback / dry back :
-
slang for a sailor who has not served aboard a ship at sea,
especially someone who has not experienced naval warfare; being
someone who has not gotten "wet" or been "wetted down".
-
dry bag :
-
a collapsible watertight container used for carrying clothes,
gear, and artifacts; it will float if not overloaded.
-
dry dock :
-
a structure able to contain an entire ship, leaving all parts of
the hull accessible for construction or maintenance.
-
dry suit / drysuit :
-
a close-fitting, double-layered, watertight synthetic garment
worn by a deep sea diver in very cold environments, usually with
thermal underwear, that's designed to protect the diver's body
from the water or pressure by circulating a warming layer of air
internally, which also serves to equalize descent pressures.
-
dual regulator system :
-
a reserve regulator that's already situated in series with the
primary, so as to enable an uninterrupted air flow; the use of
two regulators on a single air supply.
-
dump station :
-
a facility located in a marina, on docks or on shore, that's
specifically designed to receive sewage from the portable toilets
and holding tanks carried aboard vessels.
-
Dutchman's breeches :
-
the opening of two patches of blue in an otherwise stormy sky,
giving the promise of better weather; being a fancied allusion to
making a pair of short trousers (knickers or knickerbockers) with
small bits of clear sky.
-
dyne :
-
the standard centimeter-gram-second unit of force, equal to the
force that produces an acceleration of one centimeter per second
per second on a mass of one gram. [nb: 1000 dynes = 1 millibar, 1
millibar = 1/1000 bar]
-
EAD :
-
abbreviation for Equivalent Air Depth.
-
EAN :
-
abbreviation for Enriched-Air Nitrox; also represented as EANx.
-
easy :
-
formed in a long curve, so as to make a gradual transition
between the bottom and sides of a vessel; or having gently curved
surfaces leading from the middle body to the stern of a vessel,
as of the run of a hull; not abrupt; slack.
-
ebb tide :
-
the reflux of tide or the outflow of falling water from the tidal
current; as opposed to flood tide.
-
eddy :
-
a counter current running at variance with the main current in a
stream or other body, especially one having a rotary or whirling
motion (such as a small whirlpool).
-
embarcadero :
-
a pier or wharf, especially a waterfront section that's been
commercially developed.
-
enriched-air nitrox :
-
a nitrogen/oxygen mixture containing more than 21 percent oxygen,
usually made by mixing air and oxygen; abbreviated EAN or EANx.
-
epilimnion :
-
the layer of water above the thermocline, being that overlying
region of a thermally stratified lake or reservoir in which there
is a rapid decrease in temperature with water depth.
-
EPIRB :
-
Emergency Position-Indicating Radio Beacon, being a global
maritime distress and safety broadcast device that's required by
Coast Guard boating regulations; a signal device, usually carried
aboard maritime craft, that when activated in an emergency will
broadcast its location to search aircraft and orbital satellites
to enable rescue.
-
equalization :
-
the forcing of air into an open space (eg: dive mask) or cavity
(eg: middle ear) so as to attain balance or to offset increasing
hydrostatic pressure; used to prevent a "squeeze".
-
equatorial tide :
-
a semimonthly tide that appears when the moon is over the
equator.
-
equatorial trough :
-
the quasi-continuous belt of low atmospheric pressure that lies
between the subtropical high-pressure belts of the northern and
southern hemispheres.
-
equivalent air depth :
-
the underwater depth at which air would cause as much
decompression obligation as nitrox with a given O2 concentration.
-
erythropoiesis :
-
the making of red blood cells.
-
erythropoietin :
-
a hormone that stimulates production of red blood cells and
hemoglobin in the bone marrow.
-
esplanade :
-
an open level space, especially one serving for public access
along a shore.
-
estuary :
-
that part of the lower course (mouth) of a river in which the
river's current meets the sea's tide. Also, an arm or inlet of
the sea at the lower end of a river.
-
eurybathic :
-
freshwater or marine life that can tolerate a wide range of
depths; as opposed to stenobathic.
-
eustachian tube :
-
a canal extending from the middle ear to the pharynx; eponymously
after Bartolommeo Eustachio, an Italian anatomist. By permitting
air to leave or enter the middle ear, this tube equalizes air
pressure on either side of the eardrum.
-
exposure suit :
-
a garment worn by divers for thermal protection. Also, a high
visibility insulated garment worn while working topside when
unprotected immersion may be life-threatening; this survival
coverall is sometimes called a "pumpkin suit" due to its color.
-
face mask :
-
a protective shield worn while under water; also called "swim
mask", "diving mask", or simply "mask" (qv).
-
fahrenheit :
-
a temperature scale in which 32 represents the freeze point and
212 represents the boiling point. [nb: the degree intervals of
the kelvin scale are the same as celsius, as the rankine are the
same as fahrenheit]
-
fairlead :
-
a rigging guide or fitting for pulley, thimble, block, or CAPSTAN
which prevents chafing of the line.
-
fairwater :
-
a hydrodynamic structure on a ship designed to direct or deflect
the flow of water; being the modern name for the conning tower of
a submarine.
-
fairway :
-
an unobstructed passage or area, being the navigable portion of a
waterway.
-
fall :
-
the part of the rope of a tackle to which the power is applied in
hoisting. Also, the flap opening at the front of some types of
men's trousers.
-
fantail :
-
the open area near the stern of a vessel, which may have
bulwarks; also called the afterdeck.
-
fast :
-
made or held secure, as firmly fixed in place. Also, firmly tied,
as a knot. Also, closed and made secure, as a hatch or cover,
door or shutter. Also, close or near.
-
fast ice :
-
ice that is grounded on or attached to the bottom of an area
covered by shallow water.
-
fathom :
-
a nautical unit of length equal to 6 feet (1.8 m); as derived
from "span of arms" or embrace. Also, to measure depth by means
of a sounding line; to sound.
-
Fathometer :
-
the trademarked brand of a sonic depth finder; often used
generically.
-
FAUI :
-
abbreviation for the Federation of Australian Underwater
Instructors.
-
favonian :
-
mild or favorable; propitious, by reference or allusion to the
west wind.
-
fender :
-
any shield or cushion, buffer or bumper that's hung over the side
of a vessel to lessen shock or to prevent chafing, such as a balk
of timber, a bundle of rope, a rubber tire, or the like; derived
by shortening from defender, as a guard.
-
fetch :
-
an area where ocean waves are being generated by the wind. Also,
to move or maneuver nautically; to arrive or reach by water.
-
fiddlehead :
-
a billethead (or scrollhead) having a form similar to the volute
carved at the upper end of a violin.
-
figurehead :
-
a carved bust or full-length figure that's built into the bow of
a sailing ship.
-
fin :
-
a horizontal winglike appendage to the underwater portion of a
hull, often adjustable, as the planes for controlling the dive of
a submarine, or the fin keel for damping the roll of a surface
vessel. Also, slang for one of a pair of paddlelike devices,
usually made of rubber, that are worn on the feet as an aid in
swimming and underwater diving; imitative of the broad flat limbs
or the membranous organs of aquatic animals that are used for
steering and propulsion; also called flipper. Also, slang for the
human hand.
-
finger float :
-
an access walkway that defines the size of a berth; also known as
a finger pier, so called from its finger-like resemblance. [v:
phalanx, phalange]
-
finger pier :
-
a structural extension from a dock that's delineated for the
berthing or mooring of vessels (or other watercraft) for the
purpose of embarking or disembarking, and for wet storage; also
known as finger float.
-
first stage :
-
the first phase of pressure reduction by the regulator assembly,
set to deliver intermediate air pressure from the high pressure
air cylinder to the second stage of the regulator.
-
firth :
-
a long, narrow indentation of the seacoast; also represented as
"frith".
-
fjord :
-
a long, narrow arm of the sea, bordered by steep cliffs, that's
usually formed by glacial erosion; also represented as "fiord".
Also, in Scandinavia, a bay.
-
flagship :
-
the primary or principal vessel of a group or line; typically the
best or most important one, as the headquarters ship or boat with
the superior crew.
-
flank speed :
-
the maximum possible speed of a ship; in the progression of
prescribed standard speeds, an increase faster than full speed.
[v: amain]
-
flipper :
-
slang for one of a pair of paddlelike devices, usually made of
rubber, that are worn on the feet as an aid in swimming and scuba
diving; imitative of the broad flat limbs or the membranous
organs of aquatic animals that are used for steering and
propulsion; also called fin. Also, slang for the human hand.
-
float :
-
slang for a tour aboard ship at sea; being a cruise out from port
and back. Also, a group of ships operating together in the same
area.
-
floater :
-
slang for a corpse that's risen by bloat to the surface; once
gases pass off (usually by venting during predation), the corpse
again sinks to the seafloor. [nb:the rate of decomposition for a
corpse underwater is about half that of one exposed to the open
air]
-
floe :
-
a sheet of floating ice, or a detached portion thereof, chiefly
on the surface of the sea that's smaller than an ice field; also
called ice floe, as derived from "layer".
-
floeberg :
-
a mass of ice floes resembling an iceberg.
-
flood tide :
-
the inflow of rising water from the tidal current; as opposed to
ebb tide.
-
flotsam :
-
wreckage or refuse found floating on water; as derived from
"float".
-
flowstone :
-
a layered deposit of calcium carbonate that's been left by thin
sheets of flowing water, as in a cave.
-
fluke :
-
the retentive part of an anchor that catches in the seafloor,
especially the flat triangular piece at the end of each arm.
Also, the barbed head of a harpoon, spear, arrow, or the like.
Also, a stroke of good luck or a chance happening; an
accidentally successful act or event.
-
flying bridge :
-
a small open deck, situated above the main cabin or pilothouse of
a vessel, having duplicate bridge controls.
-
forecastle :
-
the part of the weather deck forward of the foremast, and which
may have bulwarks. Also, a superstructure at or immediately aft
of the bow or prow of a vessel, that's used as a shelter for
stores and machinery, or as quarters for sailors.
-
forecastle head :
-
the extreme fore part of a forecastle superstructure. Also, the
extreme fore part of the main weather deck of a vessel that has
no forecastle superstructure.
-
forward roll entry :
-
a self-protective water entry method in which the fully equipped
standing diver bends forward into a body tuck from a pier, deck,
or other platform, with face mask held in place, allowing the air
tank to strike the surface first, and then continues the roll
underwater into a prone swimming position; any extra gear or
bottles ride in the diver's protected "breadbasket" for a safe
and secure entry.
-
foul :
-
that which is clogged or obstructed with foreign matter. Also,
stormy or inclement, as foul conditions that impede navigation.
Also, obstructed or entangled, as a foul anchor. Also, a
collision, to collide; as derived from "to stink".
-
founder :
-
the wrecking or sinking of a vessel.
-
fountainhead :
-
the origin or source, as the spring from which a stream flows.
-
freak wave :
-
an abnormally large wave that occurs on a seemingly random basis
in the oceans; this unpredictable sea wave is also known as a
"rogue wave". Of enormous proportion, great in height and
steepness, these unexpected waves sometimes travel in a direction
at an angle to the prevailing seas, or occur where waves meet
opposing currents.
-
freeboard :
-
the portion of the side of a vessel's hull that's above the
water; in particular, the distance between the uppermost fully
watertight deck and the demarcated official load-line. Also, the
vertical distance from the water surface to the top of the deck
of a vessel or dock.
-
free diving :
-
underwater diving without supplemental air or breathing
equipment; also called breath-hold diving.
-
freeing port :
-
an opening in the bottom of a bulwark used for the rapid drainage
of a weather deck in heavy seas; a type of scupper.
-
freshet :
-
the sudden rise in the level of a stream, or a flooding that's
caused by heavy rains or by the rapid melting of snow and ice.
Also, a freshwater stream that flows into the sea.
-
frogman :
-
nickname for a scuba diver, especially one on a military mission.
-
FSW :
-
abbreviation for foot/feet of sea water.
-
fuel dock :
-
a dedicated structure, or a delineated area on a larger structure
(ie: pier, dock, bulkhead, etc), that is specifically used for
the dispensing of boat fuel; also called "marine service
station", "fuel dispensing facility", or "fueling station".
-
Fujita scale :
-
a scale indicating the speed or force of cyclonic wind, as that
of a tornado or waterspout.
-
fully-closed circuit re-breather :
-
an intact cycle of breathing gases that produces no discharge of
bubbles and enables long duration dives, as used by recreational
and military divers, especially photographers. Re-breathers using
a fully closed-circuit generally supplies two breathing gases to
the loop: pure oxygen and a diluent (eg: air, nitrox, or trimix),
and controls the oxygen partial pressure concentrated at any
underwater depth. In fully automatic closed-circuit systems, a
metering mechanism injects oxygen into the loop when it detects
that the oxygen concentration has fallen below the required
level. Alternatively, the diver may be able to manually control
the mixture by adding diluent gas or oxygen, but this is a risky
adjustment that can produce dangerous results with only small
volumes added.
-
gaff :
-
a metallic hook attached to a long handle that's used for landing
large fish, or for fishing objects from the water. Also, a spar
rising aft from a mast, primarily used to support the head of a
quadrilateral fore-and-aft sail (gaff sail).
-
gale :
-
a very strong wind; properly, a wind of 32-63mph, as measured on
the Saffir-Simpson scale.
-
gangplank :
-
a narrow plank, often inclined, that's used as a temporary bridge
onto a vessel; a brow serving as a walkway or passageway.
-
gangway :
-
a narrow walkway or passageway. Also, an opening in the railing
or bulwark of a vessel for use as a passageway. Also, a temporary
bridge at the opening in the railing or bulwark of a vessel; also
known as a brow or gangplank.
-
gantline :
-
a rope rove through a single block that's hung from a spar, mast,
funnel, or other stanchion, used as a means of hoisting workers,
tools, flags, or the like; as derived from earlier "girtline",
being a line for girding.
-
gasoline alley :
-
an aisle, corridor, passageway, or gangway connecting the
bulkheads of several fuel storage and engine compartments in the
bowels of a ship.
-
gat :
-
a passage or channel that extends inland from a shore; derived
from "hole" or "opening".
-
Gay-Lussac's law :
-
the principle that, for relatively low pressures, the density of
an ideal gas at constant pressure varies inversely with the
absolute temperature of the gas; also called Charles' law, and
named after Joseph Louis Gay-Lussac, a French chemist and
physicist.
-
giant stride entry :
-
the most common water entry method in which the fully equipped
standing diver takes a long step from a pier, deck, or other
platform into the water, with chin tucked and mask securely held,
and then immediately closes legs together in a scissor-kick as
soon as the water surface has been broken, to stay shallow and
remain upright for a quick check of equipment before making a
controlled descent; also called "spread-eagle" jump and
"lifesaving" leap. Any extra gear and bottles are either held in
the hands or are lowered separately on ropes.
-
gig :
-
a small lightweight boat propelled by long oars, as a scull or
dinghy.
-
giggles 'n' bangs :
-
slang for the hull noise, from creaks and groans to thumps and
pops, induced by the effects of high pressure at greater depths
on submerged vessels.
-
gimlet / gimblet :
-
to rotate a suspended anchor to a desired position.
-
glory hole :
-
the quarters on a ship that are occupied by the stewards or
stokers. Also, a small storeroom within the hull of a ship,
usually at the stern; also called "lazaretto". Also, an enclosed
space or locker for stowing loose gear. Also, a place for
concealing valuables, a cache hideaway or treasure trove.
-
goat locker :
-
the Chief Petty Officer's quarters aboard a submarine; derived
from the space where a milch goat was kept aboard sailing ships.
-
goggles :
-
large spectacles furnished with special lenses and reinforced
rims for the protection of the eyes from injury.
-
gore :
-
a triangular piece of material inserted in a garment, sail, or
the like, to give it greater width or a desired shape. [cf:
godet, gusset] Also, one of the panels, usually tapering or
shaped, making up a garment or other fabric construction.
-
goring :
-
the triangular area along a leech of a square sail, created by
the presence of a gore.
-
gox :
-
abbreviation for gaseous oxygen.
-
GPS :
-
abbreviation for Global Positioning System, being a satellite
based method of triangulation used during navigation; high-tech
successor to sextant.
-
gradient :
-
the rate of change with respect to distance of a variable
quantity, as temperature or pressure, in the direction of maximum
change; used as a vector of angle during ascent or descend.
-
granny line :
-
a line which goes from the stern platform or transom to the
anchor line; also called "gerry line".
-
grapnel :
-
a device consisting of one or more hooks or clamps that's used
for holding or grasping; also called a "grapple", "grappling
iron", "gang hook", or "creep". Also, a small anchor or
anchor-like device with three or more flukes that's used for
grappling or dragging; as derived from "grape hook".
-
grapple :
-
to hold or make fast to something, as with a grapnel or grappling
iron, a gang hook or creep; to seize or fasten. Also, to struggle
or wrestle with something, such as a problem or an obstacle.
-
green water :
-
seawater that doesn't break up into spray or spume.
-
groundswell :
-
a broad, deep swell or rolling of the sea, due to a distant storm
or gale.
-
groundwater :
-
water in a below ground aquifer that flows from high to low areas
except when a pressure gradient causes the water to move against
gravity, at a speed related to the magnitude of the pressure
gradient and the permeability of the aquifer. Groundwater
intersects surface water through springs, streams, rivers, lakes,
swamps, and other features.
-
growler :
-
a small iceberg, but one large enough to be a navigational
hazard.
-
groyne / groin :
-
a small jetty extending from a shore to prevent beach erosion.
-
guard rail :
-
a railing system, including a top rail, located along the edge of
a walkway, gangway, passageway, stairway, or other transit
surface so as to minimize the possibility of an accidental fall;
also called handrail or safety rail.
-
guess-warp :
-
a rope fastened to a vessel or wharf, and used to tow or haul a
boat or vessel into place; also called "guess-rope".
-
guideline :
-
an emplaced rope or cord that serves to direct someone's passage
over unfamiliar terrain; a safety line laid temporarily through
an entanglement or maze that marks the route and establishes the
entrance, which is retrieved by the last diver when exiting.
-
guide pile :
-
a pile that holds a floating dock on location, and allows the
dock to rise and fall with changing water levels.
-
gulf :
-
a portion of an ocean or sea that's partly enclosed by land.
Also, a deep hollow, as a chasm or abyss. Also, any great or wide
separation. Also, something that engulfs or swallows up.
-
gunk hole :
-
a quiet anchorage, as in a cove, used by small yachts.
-
gun tackle :
-
a tackle composed of a fall rove through two single blocks and
secured to one of them so as to secure a mechanical advantage of
two or three, neglecting friction, depending on the arrangement.
-
gunwale :
-
the upper edge of the side or bulwark of a vessel; also
represented as "gunnel". Also, the sheer strake of a wooden
vessel; the uppermost strake beneath the plank-sheer.
-
gut :
-
a narrow passage, as a channel of water. Also, to remove the
vital or essential parts from something.
-
guts :
-
from the abdomen or bowels, fortitude and determination. Also,
the inner working parts of a device or mechanism.
-
gypsyhead :
-
a flanged drum on a winch that's used for winding in lines.
-
hadal :
-
pertaining to the biogeographic region of the ocean bottom below
the abyssal zone; below approximately 20,000 feet, being the
greatest ocean depths.
-
Haldanian :
-
a relative theory by John Scott Haldane that nitrogen is taken up
and given off in exponential fashion during a dive, and that
there is some safe ratio of pressure change for ascent.
-
half-time :
-
the time required for body tissue to absorb or release half of
the total gas required to reach equilibrium with the surrounding
gas pressure.
-
halocline :
-
a well-defined vertical salinity gradient in ocean or other
saline water; a visible boundary, like a barrier of mist, between
layers of water of different salinities.
-
halyard :
-
any of various lines or tackles for hoisting a flag,
sail, spar, or other object into position.
-
handy :
-
term of approbation for capable seamen or skillful sailors who
are dexterous and adroit, deft and nimble; not lubberly. Also, a
craft or vessel that is easily maneuvered, responsive to
controls.
-
hang :
-
a diver remaining stationary at a particular depth or location
for a specific time, especially when performing a staged
decompression.
-
hang tank :
-
an extra air tank of breathing gas that's staged at the
decompression stop.
-
harbor :
-
a natural or artificial part of a body of water, situated along
the shore or coast, that's deep enough to anchor a ship and
provide protection against winds, waves, and currents; often
having docks or other port facilities. Also, any place of shelter
or refuge, a haven or retreat, an asylum or sanctuary, such as a
cold harbor.
-
hard-and-fast :
-
a ship run aground. Also, something unalterable.
-
hard hat :
-
the helmet used with a dry suit during underwater construction
and salvage diving; the two-part helmet (bonnet and corselet)
includes viewing ports and connectors for air and communication
lines.
-
hard suit :
-
slang for the Atmospheric Diving Suit, being an articulated
self-contained hard-shell protective body covering for deep
underwater explorations (2000' max 6hrs).
-
harness :
-
an arrangement of webbing straps with quick release buckles
that's worn by a diver for attaching the buoyancy compensator,
tanks, and any peripheral apparatus or gear.
-
hatch :
-
an opening in the DECK of a vessel used as a passageway, or the
cover over such an opening; also called a "hatchway" (not a
"watertight door" in a BULKHEAD).
-
hawsepipe :
-
an iron or steel pipe situated in the stem or bow of a vessel
through which an anchor cable passes.
-
hawser :
-
a heavy cable used for mooring or towing [nb: this line is never
called a 'rope'].
-
head :
-
a toilet or lavatory on a boat or ship. Also, the forepart of a
vessel; its bow or stem. Also, the part of an anchor at which the
arms join the shank; also called "crown". Also, the upper edge of
a quadrilateral sail, or the upper corner of a jib-headed sail.
-
heading :
-
the course or direction of travel for a person, party, or vessel.
Also, the angle between the axis of a vessel and some reference
line.
-
head sea :
-
a formation of waves running in a direction opposite to that of a
vessel.
-
headway :
-
forward movement, advancement, or progress. Also, the interval of
time or distance, relative to the situation or circumstances,
between two vessels traveling in the same direction over the
same route. [cf: forereach]
-
heave :
-
to lift or hoist. Also, to forceably throw something, especially
a weighted line (eg: heaving line). Also, to pull or haul on a
rope, line, cable, or the like. Also, the rise and fall of the
waves or swell of a sea. Also, the vertical rise and fall of a
craft or vessel. Also, to halt or stop the advance of a craft or
vessel ("heave to") by causing it to lose headway. Also, to move
in a certain direction or into a certain position or situation,
as "the ship hove into sight". Also, to vomit, retch,
regurgitate, throw-up, upchuck, barf, toss cookies, ralph,
disgorge, nausea, mal de mer, or puke.
-
heave-ho :
-
an exclamatory call or chant used by sailors when hauling or
working, especially used to signal that the anchor's aweigh.
-
heaving line :
-
a light or thin cord or rope, with its trailing end weighted by a
knot, that's used to toss overboard to a swimmer or small boat,
or to a wharf or mole, or between vessels for transferring larger
cables; also known as a "messenger line" or "throw line".
-
heliair :
-
a blended breathing gas consisting of a mixture of oxygen,
nitrogen, and helium, that's often used during the deep phase of
dives using Technical diving techniques. The helium and air blend
has a 21:79 ratio of oxygen and nitrogen.
-
heliox :
-
a blended breathing gas consisting of a mixture of oxygen and
helium, that is often used during the deep phase of dives using
technical diving techniques. Since sound travels faster in heliox
than in air, voice formants are raised, making divers' speech
incomprehensible to people not accustomed to it. Being more
expensive, its use is often limited to commercial dives.
-
helium :
-
an inert, colorless, odorless, tasteless chemical element, which
exists, except in extreme conditions, only as a gas. It is not
toxic and has no known biological effect. It is the second most
abundant element in the universe, with its boiling and melting
points among the lowest of the elements; significant amounts are
found on earth only in natural gas. Helium is used in cryogenics,
in deep-sea breathing systems, for inflating balloons, and as a
protective gas for many purposes.
-
helm :
-
the steering apparatus, as a wheel or tiller, by which a vessel
is navigated. Also, the point, position, or location of control.
[nb: where the ship's steering wheel has been replaced by
joysticks for controlling propulsion pods and thrusters, the helm
is called an "integrated bridge system workstation"]
-
Henry's law :
-
the principle that the amount of a gas that dissolves in a liquid
is proportional to the partial pressure of the gas over the
liquid, provided that no chemical reaction takes place between
the liquid and the gas; or the amount of gas that will dissolve
in a liquid at a given temperature is almost directly
proportional to the partial pressure of that gas; as devised by
William Henry, an English chemist.
-
high seas :
-
the open sea or ocean that's beyond the limit of a country's
territorial waters; also called "international waters".
-
hoise :
-
to hoist, haul, or rouse, to pull together, as derived from
"hissa" and "huzzah" work chants.
-
hoist :
-
any lifting apparatus, such as tackle or boom; derived from
hoise.
-
hold :
-
the cargo space in the hull of a vessel, especially between the
lowermost deck and the bottom. Also, any individual compartment
or bay of a larger cargo space that's closed by bulkheads and has
its own hatch or hatchway; as a variant derived from hole.
-
holdfast :
-
something used to hold or secure a thing in place.
-
holding tank :
-
any retention system (eg: Type III Marine Sanitation Device)
on-board a vessel that functions by receiving and holding sewage,
which is periodically emptied at approved pumpout sites or dump
stations, or discharge beyond the 3 mile offshore limit (except
within federally designated No-Discharge Areas).
-
hook :
-
slang for an anchor of any style, also called "killick", as used
as a retainer or brake.
-
hookah :
-
surface-supplied compressed air apparatus that's used by several
divers in series during shallow dives in calm waters; the air is
delivered to the divers through a long hose.
-
horsecollar :
-
slang for the old style floatation device worn around the
neck, known as the adjustable buoyancy lifejacket (ABLJ),
replaced by the buoyancy compensator (BC).
-
hovercraft :
-
a passenger vehicle that rides on a cushion of air, that's kept
aloft by fans and driven forward by propellers; trademarked name
for an air-cushioned vehicle (ACV).
-
Hovering Act :
-
an international law that restricts or forbids the loitering of
vessels (foreign or domestic) within the prescribed limits of a
coastal nation; this act stipulates that foreign vessels may be
boarded, and their shipping manifests checked by the appropriate
government officials, when beyond the three-mile limit of a
coastal nation.
-
HP hose :
-
the high pressure hose that connects the first stage of the
regulator to the air pressure gauge.
-
HRC :
-
Hyperbaric Rescue Craft; a self-contained, self-propelled escape
module used by saturation divers when weather or other emergency
conditions jeopardize their life-support.
-
HSAI :
-
abbreviation for Handicapped Scuba Association International.
-
hull :
-
the outermost and lowermost hollow portion of a ship or other
vessel that floats partially submerged while supporting its
infrastructure and superstructure; the "shell" or "skin" of a
BOAT or amphibious craft enabling it to float. [nb: the hull on
European ships bears a resemblance to fish, while the hull on
Asian junks bears a resemblance to waterfowl] Also, to drift, as
a ship or other craft, without power or propulsion; also called
"dead in the water".
-
hurricane :
-
a violent cyclonic storm, occurring especially in the
northwestern and midwestern Atlantic and its tropical inlands,
having wind speeds of or in excess of 74mph, as measured on the
Saffir-Simpson scale; derived from "Hurakan", the name of the
Caribbean Indian storm god.
-
hurricane deck :
-
a deck at the top of a passenger steamer, having a roof supported
by light scantlings; sometimes represented as "hurricane-deck".
-
H-valve :
-
a tank valve with two outlets.
-
HWL :
-
abbreviation for high water level.
-
hydrodynamics :
-
the branch of fluid dynamics that deals with liquids; the science
dealing with the laws governing water or other liquids in motion.
-
hydrofoil :
-
a winglike surface form that creates perpendicular thrust against
water so as to lift a vessel to which these members are attached
while that vessel is moving. Also, a vessel with such members
attached.
-
hydrogen :
-
a colorless, odorless, flammable gas, being the lightest and most
abundant of the elements; It has been proposed as a substitute
for helium in deep commercial and military diving.
-
hydrogeology :
-
the science dealing with the occurrence and distribution of
underground water.
-
hydrography :
-
the science of the measurement, description, and mapping of the
surface waters of the earth, especially pertaining to navigation.
-
hydrology :
-
the science dealing with the occurrence, circulation,
distribution, and properties of the waters of the earth and its
atmosphere.
-
hydrophone :
-
a device for detecting sounds transmitted through water, as for
detecting or locating marine life or other objects moving
underwater.
-
hydrostatic pressure :
-
fluid force exerted on the body's equilibrium, such as the amount
of pressure from the weight of water above a submerged diver.
-
hydrostatic test :
-
the required annual examination of pressurization tanks that are
filled with water instead of air.
-
hyperbaric chamber :
-
a steel vessel in which atmospheric pressure can be raised or
lowered by air compressors, used to treat aeroembolism, and to
provide a selective air mixture environment for certain medical
procedures; also called a decompression chamber.
-
hypercapnia :
-
the presence of an excessive amount of carbon dioxide in the
blood. A result of shallow skip breathing or excessive
hyperventilation in free diving, as well as Deep Diving on
compressed air. Hypercapnia will let nitrogen narcosis increase
as well as making it more likely that oxygen toxicity will occur;
heat loss can be increased, Heart rate and rhythm altered, and
decompression illness will be more likely to occur.
-
hypolimnion :
-
the layer of water below the thermocline, being that underlying
region of a thermally stratified lake or reservoir in which there
is a rapid decrease in temperature with water depth.
-
hypothermia :
-
a subnormal body temperature; a drop in the body's core
temperature as a result of exposure to cold.
-
hypoxemia :
-
the inadequate oxygenation of the blood.
-
hypoxia :
-
an abnormal bodily condition in which oxygen intake is
insufficient or utilization is inadequate; often exhibited as
unconsciousness.
-
IAHD :
-
abbreviation for the International Association of Handicapped
Divers.
-
IAND :
-
abbreviation for International Association of Nitrox Divers.
-
IANTD :
-
abbreviation for the International Association of Nitrox and
Technical Divers.
-
ice anchor :
-
a large, hooklike device for setting in ice to anchor a vessel,
or to provide a hold for a hawser in warping it along; also
called "ice drag".
-
iceberg :
-
a large mass of ice, detached from a glacier, and floating out to
sea.
-
iceblink :
-
a yellowish luminosity near the horizon or on the underside of a
cloud that's caused by the reflection of light from sea ice; also
called "blink", as derived from 'blink' meaning gleam, twinkle,
glitter, or shine.
-
ice-crystal haze :
-
a type of very light ice fog composed only of ice crystals (no
droxtals or water vapor) that's usually associated with ice
crystal precipitation, and is observable to altitudes as great as
7000m. Viewed from the ground, ice-crystal haze may be dense
enough to hinder observation of celestial bodies, sometimes even
the sun. However, when viewed from above, the ground is usually
visible and the horizon only blurred. For very sparse ice-crystal
haze during daytime, sunlight reflecting from crystal faces
produces sparkling in the air, which crystallization is commonly
known as "diamond dust".
-
icefall :
-
a jumbled mass of ice in a glacier. Also, a mass of ice
overhanging a precipice. Also, ice falling from a glacier,
iceberg, or the like.
-
ice fog :
-
a type of fog partly composed of suspended ice crystals and
droxtals, that occurs at very low temperatures, and usually in
clear, calm weather in high latitudes; because the sun is usually
visible, it may cause halo phenomena. Ice fog is almost always
present at air temperatures of -13°F/-45°C in the
vicinity of a source of water vapor, such as herds of animals,
volcanoes, the open water of fast-flowing streams or of the sea,
and especially products of combustion for heating or propulsion.
Ice fog is also known as "ice-crystal fog", "frozen fog", "frost
fog", "frost flakes", "air hoar", "rime fog", and "pogonip".
-
ice foot :
-
a belt of ice frozen to the shore, formed chiefly as a result of
the rise and fall of the tides.
-
impoundment :
-
a body of water confined within an enclosure, as a reservoir.
-
inert :
-
having little or no ability to act, react, or interact; having no
inherent power of motion or resistance.
-
inert gas :
-
any chemically inert gaseous element, such as helium, neon,
argon, krypton, xenon, and radon; found in group 8A or 0 of the
periodic table, and also known as "noble gas".
-
inlet :
-
an indentation of a shoreline, usually long and narrow, such as a
small bay or arm. Also, a narrow passage between islands. Also, a
point of entry or place of admission; entrance.
-
intercostal :
-
between the ribs; the muscles between the ribs which contract
during inspiration to increase the volume of the chest cavity.
-
International Ice Patrol :
-
an annual U.S. Coast Guard patrol of the North Atlantic ocean
during the ice season to ascertain the locations of icebergs so
as to warn ships at sea: undertaken after a 1914 agreement among
fourteen maritime countries.
-
International Orange :
-
a shade of bright orange, highly visible at a great distance and
in murky weather, that's been used since 1955 to color rescue or
emergency gear, safety devices and appliances, survey equipment
and vehicles, including boats and aircraft, hangars and control
towers; also known as "safety orange" or "blaze orange".
-
intertidal :
-
pertaining to the littoral region that is above the low-water
mark and below the high-water mark.
-
iridescence :
-
a play of lustrous, changing colors.
-
ischemia :
-
a local deficiency of blood supply that's produced by obstacles
to the arterial flow, by vasoconstriction, or by other
inadequacies of a part or organ.
-
island :
-
a tract of land that's completely surrounded and detached; as
derived from isolate. [nb: a seaman defines an island as a hazard
to navigation that's inhabited by drunks, whores, thieves,
farmers, and other lubbers who were stupid enough to abandon the
ship!]
-
isle :
-
any island, especially when small.
-
islet :
-
a very small island.
-
ISO :
-
abbreviation for the International Standardization Organization.
-
isotherm :
-
a curve representing changes in volume and pressure while at the
same temperature.
-
isthmus :
-
a narrow strip of land, bordered on both sides by water,
connecting two larger bodies of land; also called a neck or
strait.
-
jackline :
-
a rope, webbing, or wire cable that's strung from padeyes or
cleats along the port and starboard sides of a ship, from bow to
stern, during foul weather and limited visibility, so that a
safety harness ("jackline harness") can be connected, allowing
passengers and crewmembers to move safely on the topside deck
whenever there's a risk of falling or being swept overboard; a
temporary safety rigging to secure lives aboard a vessel during
hazardous conditions.
-
Jacob's ladder :
-
a flexible ladder consisting of rope, cable, or chain side-rails
and fixed wooden or aluminum rungs, as used on vessels and
aircraft; also called a "pilot ladder" or "jack ladder", "caving
ladder" or "scaling ladder", as derived from the Biblical dream
of a ladder ascending from earth to heaven. Also, a webbing or
rope ladder deployed for insertions and/or extractions of people
employing transport vessels or aircraft instead of debarkation
nets or rappel lines.
-
jetsam :
-
goods or supplies that are deliberately cast overboard from a
vessel so as to lighten or stabilize it in an emergency, as
derived from "jettison"; such cargo typically sink where
castaway, but may be later washed ashore.
-
jetty :
-
a pier or structure of stones, piles, or the like, projecting
into a body of water to protect a harbor, deflect the current, or
other stabilization. Also, a wharf or landing pier. Also, the
piles or wooden structure protecting a pier.
-
jewel block :
-
a block at the end of a yard or gaff that's used for supporting a
signal or ensign halyard; also called "dasher block".
-
jibe :
-
to alter course so that a fore-and-aft sail, or its boom, shifts
from one side to the other when running before the wind.
-
Jonah :
-
a person or thing regarded as bringing misfortune or bad luck; a
jinx, as derived from the minor prophet in the Bible who's thrown
overboard from his ship for his impiety.
-
jolly boat :
-
a light boat carried at the stern of a sailing vessel.
-
Jonline :
-
a length of line typically used to attach to an anchor line to
provide spacing for decompressing divers at the same stop depth.
-
Joule's law :
-
the principle that the internal energy of a given mass of an
ideal gas is solely a function of its temperature; a secondary
law of thermodynamics [v: joule = SI unit of energy] named after
James Prescott Joule, an English physicist.
-
jury mast :
-
a temporary mast that has been erected to replace one that was
lost or destroyed.
-
jury-rig :
-
to repair or assemble something hastily, or from whatever is at
hand, as for temporary use; to improvise an expedient or
makeshift.
-
J-valve :
-
a spring-loaded mechanism which shuts off a diver's air supply
when reduced to a certain tank pressure, as was formerly used to
trigger the switch to the reserve air supply, and compel the
diver's ascent.
-
kedge :
-
to advance a vessel or load along a waterway by pulling
incrementally, as with a small anchor; as derived from to tie or
fasten. Also, the small anchor used for such incremental hauling.
-
keel :
-
a central fore-and-aft structural member in the bottom of a
ship's hull, extending from the stem to the sternpost; in Asia
it's known as a "dragon's spine".
-
kelvin :
-
the base unit of temperature in the International System of Units
(SI) which is defined to be 1/273.1 of the triple point of water.
[nb: the degree intervals of the kelvin scale are the same as
celsius, as the rankine are the same as fahrenheit]
-
key :
-
a reef or low island; properly called 'cay'. Also, a pin, bolt,
wedge, or other piece that's inserted into a hole or space so as
to hold the parts of a mechanism together. Also, slang for a unit
of measure (mass) equivalent to one kilogram (kg).
-
knee-knocker :
-
slang for the protective rim or bulwark surrounding an opening in
a bulkhead or deck, designed to exclude water; this coaming is
also called a "shin-scraper".
-
knighthead :
-
either of a pair of upright members (apostle) flanking and
securing the bowsprit of a ship at the bow, often used as mooring
bitts. Also, a plate at the fore end of a forecastle through
which a spike bowsprit passes on a topgallant sailing ship.
-
knot :
-
a constrictive interlacement used for fastening rope, line, cord,
and the like. Also, a unit of speed equal to one nautical mile
(or about 1.15 statute miles) per hour. Also, a unit of measure,
being either one nautical mile, or a line marked 47'3" (13.79m)
long.
-
K-valve :
-
a simple on/off valve.
-
ladderwell :
-
the staircase, usually skeletonized, whether fitted with rungs or
steps, with or without handrails ("ladderrail"), running between
decks on-board ships.
-
lagan :
-
goods that are deliberately thrown or sunk in the sea but are
attached to a buoy so that they may be recovered, being a form of
jetsam; as derived from a net laid in the sea.
-
lagoon :
-
any small body of shallow water that's connected to a larger body
by an intermittent or restricted flow, or separated from the sea
by a natural barrier of dunes or reefs.
-
lake :
-
a considerably sized body of either fresh or salt water that's
surrounded by land.
-
lambert :
-
the centimeter-gram-second (cgs) unit of luminance or brightness,
equivalent to 0.32 candles per square centimeter and equal to the
brightness of a perfectly diffusing surface emitting or
reflecting one lumen per square centimeter; abbreviated: L.
-
Lambert's law :
-
the law that the luminous intensity of a perfectly diffusing
surface in any direction is proportional to the cosine of the
angle between that direction and the normal to the surface, for
which reason the surface will appear equally bright from all
directions; also called "cosine law", named after the German
mathematician Johann Heinrich Lambert. [v: Beer-Lambert law of
optics; Willebrord van Roijen Snell law of refractive index]
-
laryngospasm :
-
severe constriction of the larynx in response to the introduction
of water or noxious stimuli; commonly called choking.
-
latitude :
-
an imaginary circle on the earth's surface formed by the
intersection of a plane parallel to the plane of the equator,
bearing east and west, and designated in degrees of latitude
north or south of the equator along the arc of any meridian of
longitude; also known as "parallel of latitude".
-
lave :
-
to flow along, against or past; as the tide washes the shore, or
when a current washes the seafloor.
-
lay line :
-
term used by cave divers to designate the initial exploration
line in a booty ("virgin") cave system.
-
lead :
-
an opening or direction that affords passage to a place, such as
an open channel through a field of floating ice. Also, the
direction of a rope, wire, or chain. Also, the distance between
the center of lateral resistance and the center of effort of a
sailing ship, usually expressed decimally as a fraction of the
water-line length.
-
leader :
-
any of various devices for guiding a running rope; also called
"lead".
-
league :
-
a unit of distance which has varied at different times and
places, apparently originating as the Gaulish equivalent of 1.5
Roman miles, but lately measures about 3 miles (4.8km) in
English-speaking countries.
[nb: 12 inches = 1 foot, 3 feet = 1 yard, 6 feet / 2 yards = 1
fathom, 16.5 feet = 1 rod (aka: pole or perch), 66 feet / 4 rods
= 1 chain (90 feet / 15 fathoms = 1 anchor chain), 10 chains /
660 feet (1/8 statute mile) = 1 furlong, 120 fathoms / 720 feet =
1 land cable, 101 fathoms / 606 feet (1/10 nautical mile) = 1
cable, 3 statute miles = 1 land league, 3 nautical miles = 1 sea
league / shot]
-
ledge :
-
a reef, ridge, or line of rocks in a body of water.
-
leech :
-
either of the lateral edges of a square sail; or the after edge
of a fore-and-aft sail.
-
leech line :
-
a line for hauling the middle of a leech of a square sail up to
the yard.
-
leech rope :
-
a boltrope along a leech.
-
leeway :
-
the drift of a vessel from its course or heading due to
crosswinds or currents [cf: leeward, windward]. Also, a margin
of space, time, or materials, being an extra or surplus; a degree
or element of freedom, of latitude.
-
lifeboat :
-
an accessory craft, also called a dinghy or tender, required to
be available on any aircraft or vessel operating on or over
water, usually stocked with a limited supply of medical equipment
and survival provisions, so as to enable passengers and crew to
be rescued from sinking.
-
life jacket :
-
a sleeveless jacket of buoyant or inflatable construction that's
used for supporting the wearer in deep water so as to prevent
drowning; also called "life vest" or "air jacket" (British).
-
lifeline :
-
a line or rope available for saving life, as one attached to a
lifeboat, or a heave line cast from a vessel. Also, any of
various lines running above the decks, between spars or other
structures of a ship or boat, giving sailors something to guide
or grab when in danger of falling overboard or washing away.
Also, the line by which an underwater diver is lowered and
raised. Also, any of several anchored lines used by swimmers for
support.
-
lift bag :
-
a type of underwater balloon or specialized buoyancy compensator
that can be attached to a submerged object, inflated with air,
and brought to the surface without great exertion; available in
either small or large capacity, and may be joined in series for
heavier loads.
-
lighter :
-
a large, open, flat-bottomed vessel used to transport cargo from
ship to wharf, often towed or pushed; a sailless junk or barge
used to ferry passengers, especially when reserved for pageants.
-
limber hole :
-
any of a series of holes pierced through a frame or floor to
allow the passage of accumulated moisture. [cf: weep hole]
-
limnology :
-
the scientific study of bodies of fresh water, such as lakes and
ponds, with reference to their biological, geographical,
physical, and other features.
-
line :
-
a rope, cable, or other cordage used on a vessel or at sea. Also,
any actual or representative connection, as in communications.
Also, a course of direction, as a route or heading. Also,
indication of a boundary or limit, as a demarcated safety zone.
Also, an outline or contour.
-
line squall :
-
a storm that advances along a front forming a more or less
definite line.
-
liquescent :
-
becoming liquid; tending toward a liquid state; melting.
-
list :
-
to lean to one side, or to cause to incline toward one side, as a
ship or other vessel; sway or careen.
-
littoral :
-
pertaining to the shore of a lake, sea, or ocean. Also,
pertaining to the biogeographic region between the sublittoral
zone and the high-water line on ocean shores, and sometimes
including the supralittoral zone above the high-water line. Also,
pertaining to the region of freshwater lake beds from the
sublittoral zone up to and including damp areas on shore.
-
littoral drift :
-
see beach drift.
-
load-line mark :
-
any of various lines marked on the sides of a cargo vessel to
indicate the depth to which a vessel may be immersed under
certain conditions; also represented as "load-line" or "load
line".
-
loch :
-
a lake. Also, a partially protected or landlocked bay; a narrow
arm of the sea.
-
lock :
-
an enclosed chamber in a canal, dam, or other impoundment with
gates at each end, that's used for raising or lowering vessels
from one level to another by admitting or releasing water. Also,
short for an air lock or decompression chamber.
-
logbook :
-
a record of a diver's history that catalogues, at a minimum, the
date, location, depth, duration, type, gear, and sequential
total; many diver's include transport, party, weather, and any
observations or incidents.
-
longitude :
-
(forthcoming); aka: meridian of longitude
-
lost river :
-
common referent for a flowing waterway that disappears
underground at one or more points during its course of travel.
-
lotic :
-
pertaining to or living in flowing water; as derived from "wash".
-
lox :
-
abbreviation for liquid oxygen.
-
LP hose :
-
the low pressure hose that connects the first stage of the
regulator to the second stage or inflator.
-
LPM :
-
abbreviation for liters per minute; a measurement of the flow
rate of a liquid or gas.
-
lubberly :
-
to be awkward or inexperienced around watercraft, such as a
"landlubber"; also represented as "slubberly" for careless and
"Dutch talent" for unskilled; to be "ham-handed" rather than
"dab-handed".
-
lubber's hole :
-
an open space near the top on a mast through which a sailor may
pass to reach a perch, instead of climbing out on the futtock
shrouds. [v: futtock shroud: any of several metal rods secured at
their lower ends to a futtock band and at their upper ends to a
futtock plate, connecting the lower mast to the topmast rigging]
-
luff :
-
to set the helm so as to bring the head of a ship closer or
directly into the wind, with sails shaking. Also, to raise or
lower the outer end of the boom of a crane or derrick, moving its
load horizontally.
-
LWL :
-
abbreviation for low water level.
-
mainstay :
-
anything that serves as chief part or primary support; including
an essential person, such as the "anchorman" or "right-hand man".
Specific naval use as the stay that secures the mainmast forward.
-
main walkway :
-
a floating structure in a marina to which finger floats are
attached so as to define individual berths, and to provide
pedestrian access between the berths and a marginal walkway or
the shore.
-
makefast :
-
any structure to which a ship is tied up, as a bollard or buoy.
Also, to securely tie onto such a structure.
-
make way :
-
an informal directive to get out of someone's way; a warning to
get out of the way of something that's not responsive, or is out
of control.
-
making way :
-
when a vessel is proceeding by its own power, whether manual or
mechanical propulsion; also represented as "making headway".
-
manifold :
-
a connection that enables a single regulator to access the
breathing gas in both pressure tanks.
-
manometer :
-
an instrument for measuring the pressure of a fluid, consisting
of a liquid filled tube, the level of which indicates the fluid
pressure in decibars (dbar) or bars on a calibrated scale.
Pressure is commonly measured by its ability to displace a column
of liquid in a tube, which is often expressed in a measure of
that liquid (eg: inches of mercury). [nb: a rule of thumb used by
divers states that the pressure exerted by ten metres depth of
water is approximately equal to one atmosphere]
-
marginal walkway :
-
a floating structure in a marina that provides pedestrian access
between two or more main walkways and the shore, and may serve as
a platform for lighting, fuel stations, sewage pumpout
facilities, lift stations, and utility lines.
-
marina :
-
a boat basin offering dockage and services for recreational small
watercraft, including wet and dry storage.
-
marker :
-
a high visibility indicator, typically luminous or reflective or
brightly colored, that's used to designate the correct or safest
path through an entanglement or maze; also called "route marker"
or "trip beacon", "guidepost" or "signpost", these signals may be
temporary or semi-permanent, and employed whenever a safety line
is inappropriate. [v: lodestar, polestar]
-
marl :
-
a friable earthy deposit consisting of clay and calcium
carbonate, as floating suspended in murky or turbid waters, and
coating anything drawn from those waters; an archaic term for
earth or soil. Also, to wind a rope or cable with marline, every
turn being secured by a hitch; as derived from "ensnare"
(marlyn).
-
marline / marlin :
-
light cordage of two-fiber strands, laid up left-handed.
-
Martini's law :
-
an approximation for a relative comparative scale of competence
and coordination, wherein each 50 feet of depth breathing air
underwater is the equivalent of one martini consumed on an empty
stomach; a condition most noticeable at depths of 100 fsw and
below.
-
mask :
-
a protective cover consisting of a skirted transparent window
(ie: plexiglas) constructed to provide air space between the eyes
and the exterior water, permitting both eyes to see in the same
plane, and usually made of neoprene, silicone, or another
synthetic rubber. A regular diving mask covers only the eyes and
nose, while a full face mask encloses the entire face. The mask
is also called a "swim mask", "face mask", or "diving mask".
-
mask squeeze :
-
an uncomfortable or painful condition created when the air inside
the dive mask is compressed by the external pressure, causing a
suction on the face and eyes that swells delicate tissues, which
can cause permanent eye damage if not equalized; this imbalance
can be alleviated by exhaling through the nose.
-
maximum operating depth :
-
the lowest safe depth at which a submarine or other submersible
is not to exceed during normal operations; this "never exceed
depth" is a determination made by naval authority in
consideration of design and manufacturing limits, and has been
specified as half (Europe) or two-thirds (USN) of the test depth.
-
MCD :
-
Massive Catastrophic Decompression; also known as "explosive
decompression", wherein air pressure erupts through the human
body as a result of improper nitrogen off-gassing after deep-sea
diving.
-
mediastinum :
-
the area in the chest that lies between the lungs, is bounded by
the sternum, the spinal column, and the diaphragm, and contains
the heart, esophagus, trachea, and other thoracic structures;
term derives from "a low ranking slave".
-
meridian of longitude :
-
(forthcoming);
-
messenger :
-
a smaller line used to haul a heavier line or cable across an
intervening space; also known as "messenger line", "heaving
line", or "throw line".
-
metabolism :
-
the sum of the physical and chemical processes in an organism by
which its substance is produced, maintained and destroyed, and by
which energy is made available. [cf: anabolism, catabolism]
-
meters of seawater :
-
a unit of pressure, which varies slightly with temperature and
salinity, but a practical convention accepts that each meter of
seawater imposes a pressure of 0.1 bar (DBAR), or that each meter
is equivalent to 0.1 atmosphere (0.1013 bar); abbreviated msw.
-
MHW :
-
abbreviation for mean high water.
-
minisub :
-
a small submarine, holding only one or a few persons, as used in
naval special operations, underwater explorations, or when
conducting underwater experiments; a contraction of miniature
submarine, and also called "midget sub".
-
mixed gas :
-
any breathing medium that is blended with oxygen and other gases,
having either a single inert gas (eg: heliox, nitrox) or multiple
inert gases (ie: trimix).
-
MLW :
-
abbreviation for mean low water.
-
mole :
-
a breakwater, groyne / groin, or jetty used to form or protect an
anchorage or harbor, to reinforce or protect a pier, wharf, or
quay.
-
monkey fist :
-
a casting knot (often a figure-8 on a bight) added to the
trailing-end of a rope or line to lend weight and direction for
throwing.
-
moor :
-
to secure a ship, boat, or other vessel in a particular place by
lines, cables, or anchors.
-
mooring pile :
-
a pile situated at the entrance to and in the center of a double
berth, to which both vessels may be secured.
-
mossback :
-
an old fashioned sailor, as from a canny fish or wise turtle,
especially a traditionalist, conservative, or reactionary; also
called a sea dog, old salt, or shellback.
-
mouthpiece :
-
the demand valve receptacle, held in the diver's mouth, at the
terminus of the regulator assembly of a scuba apparatus; a
similar device (without pressure stage) terminates a snorkel.
-
MSW :
-
abbreviation for metres of seawater.
-
multiday :
-
a dive series with a surface interval of more than 24 hours
between consecutive dives; dives that require a substantial delay
so extending the time on station; juxtaposed to single-day.
-
multilevel dive :
-
a dive profile that extends over more than one depth, expending
time at each, before finally returning to the surface; juxtaposed
to square dive.
-
NACD :
-
abbreviation of the National Association for Cave Diving; also
represented as NA4CD.
-
NASDS :
-
abbreviation for National Association of Scuba Diving Schools,
which merged with Scuba Schools International (SSI) in 1999.
-
narrows :
-
a narrow part of a strait, river, channel, ocean current, or
other body of constricted water.
-
NAUI :
-
abbreviation for National Association of Underwater Instructors.
-
nautical mile :
-
officially known as the "International Nautical Mile", being a
unit of distance at sea or in the air equal to 1.852 kilometers.
Also, a unit of distance, formerly used in the U.S. for
navigation, equal to 6080.20 feet (1853.25 m), or the length of a
minute of latitude at the latitude in question (decreasing toward
the poles); abbreviated NM. [nb: a "geographic mile" is the
length of a minute of longitude on the equator]
-
NDL :
-
abbreviation for No-Decompression Limit.
-
neck :
-
a strait or channel; narrows. Also, a narrow strip of land, as an
isthmus or a cape.
-
Neptune :
-
the god of water in the Roman religion; being an indigenous god
of fertility who was later identified with Poseidon, the Greek
god of the sea; a festival, the Neptunalia, was annually (July
23) celebrated in his honor. Also, used allegorically to
represent the sea or ocean.
-
neritic :
-
pertaining to the region of water lying directly above the
sublittoral zone of the sea bottom; also called neritic zone.
-
newton :
-
the base unit of force in the International System of Units (SI)
which is equal to the force that produces an acceleration of one
meter per second per second on a mass of one kilogram.
-
niggerhead :
-
slang for an isolated coral outcropping, or any knob-like
solitary protrusion, such as pillow lava, often semisubmerged,
that's a hazard to navigation. Also, naval slang for a small
winch or capstan. Also, old reference in the British Navy for a
mooring post made from a cannon, buried muzzle upright, that's
capped with a slightly oversized ball. Also, a large decorative
knot, used to finish a special line or lanyard (such as one
suspended from the clapper of a ship's bell); sometimes called
"Turk's Head".
-
nip :
-
an abrupt turn or twist in a rope. Also, a part of a rope or
chain bound by a seizing or nipper. Also, to seize a taut rope to
another rope.
-
nipper :
-
a short rope for seizing an anchor cable to a messenger from a
capstan.
-
nitrogen :
-
a colorless, odorless, inert gaseous element that constitutes
about 78% of the volume of the atmosphere and is present in
combined form in organic tissues; it's used by divers in varying
concentrations as part of the breathing gas mixture, with
specific side-effects (eg: nitrogen narcosis, decompression
sickness).
-
nitrogen narcosis :
-
a stupor or euphoria, also called "rapture of the deep", that's
induced in deep-sea divers when nitrogen from air enters the
blood at higher than atmospheric pressure.
-
nitrox :
-
a gas mixture of nitrogen-oxygen with an oxygen content other
than 21%, with "oxygen-enriched air" and "enriched-air nitrox"
rated greater than 21%, that's used to extend the
no-decompression limit; the most common nitrox mixtures are NOAA
Nitrox I at 32% oxygen and NOAA Nitrox II at 36% oxygen.
-
nm :
-
the abbreviation for nautical mile, also known as "International
Nautical Mile". [cf: geographic mile]
-
NOAA :
-
abbreviation for the National Oceanic and Atmospheric
Administration, in the U.S. Department of Commerce; which is
responsible for describing the earth's environment and predicting
changes in conserved or managed resources.
-
noble gas :
-
any chemically inert gaseous element, such as helium, neon,
argon, krypton, xenon, and radon; found in group 8A or 0 of the
periodic table, and also known as "inert gas".
-
nocturnal :
-
night, nighttime, or nightly; as opposed to diurnal.
-
no-decompression :
-
a dive that does not require any staged stops during the return
ascent to the surface; a dive profile scheduled by the use of
tables or computer.
-
no-decompression limit :
-
a mathematical representation, plotted in minutes, of the
theoretical amount of nitrogen that body tissues can absorb
without substantial risk of decompression sickness.
-
NSS-CDS :
-
abbreviation for the National Speleological Society – Cave
Diving Section.
-
ocean :
-
the vast body of salt water that covers almost three-fourths of
the earth's surface, and commonly subdivided into geographic
regions named the Atlantic, Pacific, Indian, Arctic, and
Antarctic.
-
oceanography :
-
the branch of physical geography dealing with the ocean.
-
oceanology :
-
the science concerned with the practical application of
oceanography.
-
octopus :
-
a backup or secondary regulator, usually attached to the same
first stage as the primary regulator, and especially used by open
water (OW) divers.
-
OEA :
-
abbreviation for Oxygen Enriched Air, which designation is often
synonymous with nitrox.
-
off-gas :
-
to eliminate inert gases (such as nitrogen) from the diver's body
so as to avoid decompression sickness.
-
OK / okay :
-
a hand signal indicating safe and sound, correct or satisfactory,
approval or agreement, being a gesture that forms an open circle
with the thumb and forefinger, with the other three fingers
spread and extended; also known as A-OK, this acknowledgement
should not be confused with a "thumbs-up" sign, which means
ascend.
-
old salt :
-
slang for an experienced sailor or master mariner; also called a
sea dog, shellback, mossback.
-
on-gassing :
-
the absorption of nitrogen into various tissues that takes place
as the partial pressure of nitrogen increases with depth.
-
on the beach :
-
someone who is not engaged in seafaring or not involved in marine
activities; being unemployed or without a ship; being withdrawn
or idle; being inactive or retired.
-
OOA :
-
abbreviation for Out Of Air; the emergency situation when a diver
has no breathing gas; also called "out-of-gas".
-
open water :
-
a designation, by various certifying authorities, of the primary
level of scuba training; abbreviated OW. Also, a diving
environment without obstacles or obstructions between the diver
and the surface.
-
o-ring :
-
a small replaceable gasket, made of rubber or some other
waterproof synthetic (eg: neoprene), that's used to close or seal
watertight fittings.
-
orlop :
-
the lowest deck above the space at the bottom of the hull of a
ship; also called orlop deck.
-
outrigger :
-
the framework that extends outward from the side of a boat to
support a float that increases stability. Also, a spar rigged
outward from a ship's rail or the like, as for extending a sail.
Also, a projecting beam, as for supporting a hoisting tackle.
Also, a bracket extending outward from the side of a shell or
skiff to support an oarlock; or the boat itself so modified.
-
overboard :
-
over the side of a ship or boat, especially into the water. Also,
to metaphorically go to extremes, as in behavior, speech, or the
like.
-
overhead :
-
a ceiling-like covering of the exposed support members
for the above compartment in a vessel. Also, an obstruction to a
direct ascent to the open water at the surface.
-
overhead dive :
-
underwater diving in wrecks or caves, or elsewhere without
unobstructed open water to the surface.
-
overlay :
-
a transparent sheet that's placed over a map or chart for noting
corrections, instructions, additional information, and the like.
-
OW :
-
abbreviation for Open Water.
-
oxygen :
-
a colorless, odorless, inert gaseous element that constitutes
about 21% of the volume of the atmosphere and is present in
combined form in organic tissues; it's used by divers in varying
concentrations as part of the breathing gas mixture, with
specific side-effects (eg: hypoxia, oxygen toxicity).
-
oxygen debt :
-
a deficiency of oxygen in the body resulting from strenuous
physical activity.
-
oxygen re-breather :
-
the oldest type of re-breather, as once commonly used by navies,
supplying only pure oxygen, which is toxic when inhaled under
pressure, thus limiting its use to a depth of 20-30 feet (under 1
ATM). In some re-breathers, the oxygen cylinder has two first
stages in parallel, one is constant flow and the other is a plain
on-off valve called a "bypass"; both feed into the same exit
pipe, which feeds the breathing bag. Some simple oxygen
re-breathers had no constant-flow valve, but only the bypass, and
the diver had to operate the valve at intervals to refill the
breathing bag as the oxygen was used. Oxygen re-breathers are
sometimes used when decompressing from a deep open-circuit dive,
because breathing pure oxygen makes the nitrogen diffuse out of
the blood more quickly.
-
oxygen partial pressure :
-
the concentration of oxygen in an air mixture, especially when
combined in a dilute re-breathing or closed-circuit loop.
-
oxygen toxicity :
-
an abnormal bodily condition in which an increased concentrations
of oxygen intake has over-exposed body tissues, which can result
in convulsions or unconsciousness, leading to death by drowning;
being a characteristic risk of breathing mixed gases under
pressure.
-
pack ice :
-
a large area of floating marine ice whose pieces are driven
together by wind and current; also called ice pack.
-
packet :
-
a small vessel that carries mail, goods, and passengers on a
regular and fixed route; the first ships to keep a schedule,
regardless of payload. Also, a small package or parcel.
-
PADI :
-
abbreviation for Professional Association of Diving Instructors;
being the world's largest diver training and recreational diving
membership organization.
-
pan :
-
a drifting piece of flat thin ice, as formed on a bay or shore;
term derived from face. Also, a natural depression in the ground,
as one containing water, mud, or mineral salts. Also, an
artificial depression in the ground, as made for evaporating sea
water so as to obtain salt.
-
parallel of latitude :
-
the proper or formal name for 'latitude', being an imaginary line
on the earth's surface connecting all points bearing east and
west that are equidistant from the equator, which on most maps
are shown in multiples of 5 degrees. Because of their special
position, four fractional parallels are also shown: Tropic of
Cancer, Tropic of Capricorn, Arctic Circle, and Antarctic Circle.
Parallels of latitude and meridians of longitude together form a
grid by which any point on the earth's surface can be specified.
-
partial pressure :
-
the pressure exerted by any component gas in a mixture of gases,
such as oxygen in air; the pressure that a gas in a mixture of
gases would exert if it occupied the same volume as the mixture
at the same temperature.
-
party :
-
a specific individual, especially one affiliated with others.
Also, a group gathered for some special purpose or temporary
task, such as a search party. Also, a social gathering for
recreation or entertainment, usually involving conversation and
refreshments; as derived from share.
-
pascal :
-
the base unit of pressure in the International System of Units
(SI) which is equal to one newton per square meter; abbreviated
Pa.
-
Pascal's law :
-
the law that an external pressure applied to a fluid in a closed
vessel is uniformly transmitted throughout the fluid; named after
the French philosopher and mathematician Blaise Pascal.
-
passageway :
-
an interior hallway that permits horizontal travel within a ship,
as an aisle, corridor, or alley used as a pathway or walkway.
-
pea jacket :
-
a blue, double-breasted, coarse woolen jacket worn by seamen or
sailors; also called peacoat.
-
pelagic :
-
pertaining to the open seas or oceans; also called pelagic zone.
-
pennant :
-
a long tapering flag or burgee, as used for signaling or
identification.
-
permanent thermocline :
-
a temperature gradient in a body of water that's not affected by
the seasonal and diurnal changes in surface forcing; it is
therefore located below the yearly maximum depth of the mixed
layer and the influence of the atmosphere.
-
PFD :
-
Personal Floatation Device; a life preserver in the form of a
buoyant or inflatable vest.
-
phosphorescence :
-
the property or appearance of being luminous at temperatures
below incandescence, as from slow oxidation or after exposure to
light or other radiation. Also, any luminous radiation emitted
from a substance after the removal of the exciting agent, as a
phosphorescent wake.
-
pier :
-
a structure supported by flotation [floating pier] or built on
posts extending from land [fixed pier] out over water that's used
for access to or from the water (as a landing place for ships),
and for other activities. Also, a square pillar used for support,
as of bridge spans.
-
pierhead :
-
the outermost end of a pier or wharf. Also, informal regional
reference to a breakwater.
-
pile :
-
a long slender structural member, typically composed of wood,
concrete, steel, or plastic, that's driven into the seafloor of a
basin or inlet to secure and guide docks.
-
pilothouse :
-
an enclosed structure on the deck of a ship from which it can be
navigated; also known as wheelhouse.
-
pitch :
-
the up or down nosing of a ship about its transverse axis. Also,
longetudinal oscillation or linear plunge, as a ship's
alternating bow and stern rocking. Also, the distance that a
given propeller would advance in one revolution.
-
pitch-pole :
-
a vessel capsizing lengthwise, due to waves cresting higher than
the keel length.
-
plank :
-
a timber, thicker than a board, used on the deck or strake of
boats and ships; also used as a brow or gangway (ie: gangplank).
-
plank owner :
-
a sailor who's been aboard since the vessel was commissioned into
service; also called "plank holder". Also extended to persons who
formed an initial party or the original group on an extended
venture, project or voyage.
-
plankton :
-
the aggregate of passively drifting, or somewhat motile,
organisms occurring in a body of water, primarily comprising
microscopic algae and protozoa. [v: phytoplankton, zooplankton]
-
pleura :
-
one of a pair of serous membranes, each of which covers the
outside of a lung, and folds back to line the corresponding
inside of the chest wall and diaphragm.
-
plimsoll mark :
-
a contrasting line or band painted on the exterior hull of a
merchant ship indicating its load level or depth level from
cargo; also known as Plimsoll line, load-line mark, load-line, or
waterline.
-
plot :
-
to determine by means of measurements or coordinates, and to mark
on a map or chart, a graphic plan or transparent overlay, the
resultant course of a vessel or craft. Also, the place, located
on or near the bridge, that's used for performing such
calculations; also called "nav plot".
-
Poiseuille's law :
-
the law that the velocity of a liquid flowing through a capillary
is directly proportional to the pressure of the liquid and the
fourth power of the radius of the capillary, and is inversely
proportional to the viscosity of the liquid and the length of the
capillary; named after Jean Leonard Marie Poiseuille, a French
physiologist. [v: Poiseuille's viscosity coefficient,
Poiseuille's space]
-
pollywog :
-
an inexperienced or novice sailor, especially someone on his
first float or cruise; also called chum, nugget, or fresh catch.
-
polynya :
-
an irregularly shaped area of persistently (unfrozen) open water
that is sustained by warming winds or currents of ocean heat,
which often occur near coasts, fast ice, or ice shelves.
-
pond :
-
a body of water, smaller than a lake, which is sometimes
artificially formed, as by damming a stream. Also, to collect
into a pool, puddle, pan, or other pound; as derived from
"impoundment". [v: dub]
-
pony bottle :
-
common term for a secondary gas cylinder carried by divers as a
redundant air source; having their own first and second stages,
these tanks can be used as an alternate or emergency air source.
-
pool :
-
a small body of standing water; pond. Also, a still, deep place
in a stream. Also, any small collection of liquid on a surface;
puddle. Also, a subterranean accumulation; reservoir.
-
poop :
-
a wave breaking or taking seas over the stern of a vessel. Also,
a superstructure or poop deck at the stern of a vessel.
-
poop deck :
-
a weather deck on the superstructure at the stern of a
vessel, and which may have bulwarks.
-
porpoise :
-
any of certain toothed cetaceans having a blunt or rounded snout;
derived from sea hog or hog fish; compare dolphin. Also, to leap
clear of the water, as when a speeding boat hits a wave and
leaves the surface.
-
port :
-
the left-hand side of a vessel or craft when facing forward, and
designated by the color red; formerly known as larboard
(larborde) or loadboard for the "loading side" set against the
wharf. Also, a place with docking facilities for ships to load or
unload passengers or cargo, as a "port of entry" or "port of
call". Also, an exterior opening or aperture on a craft or vessel
for various uses, including portal and porthole.
-
portage :
-
to carry a boat and supplies overland from one navigable waterway
to another. Also, the route over which such a carry is done.
-
porthole :
-
a small, round, window-like opening, usually covered with a
hinged watertight glass closure, set into the side of a vessel
for admitting air and light.
-
Poseidon :
-
the god of the sea and protector of all waters in the Greek
religion. After the fall of the Titans, Poseidon was allotted the
sea. He was worshiped especially in connection with navigation;
but as the god of fresh waters, he was also worshiped as a
fertility god. Poseidon was represented as extremely powerful,
with a violent and vengeful disposition. He carried the trident,
with which he could split boulders and cause earthquakes. When
Laomedon failed to pay him for building the walls of Troy,
Poseidon sent a sea monster to ravage the Troad and years later
vengefully assisted the Greeks in the Trojan War. His grudge
against Odysseus is one of the themes of the Odyssey. He was the
husband of Amphitrite, who bore him Triton, and by others he
fathered many more sons, who usually turned out to be strong,
brutal men (like Orion) or monsters (like Polyphemus). In
Thessaly and other areas he was important as Hippios, god of
horses, and was the father of Pegasus. The Romans identified him
with Neptune.
-
pot :
-
slang for the hyperbaric chamber used as a sustained environment
in saturation diving.
-
pothole :
-
a hole cut into submerged bedrock by the erosive action of sand
and gravel that's whirled about by eddying water.
-
ppO2 meter / ppO2 meter :
-
an oxygen-sensitive electro-galvanic fuel cell that automatically
monitors and measures the concentration of oxygen in the
breathing gas loop of fully closed-circuit re-breather systems so
as to detect and adjust the partial pressure mixture.
-
pressure :
-
the exertion of force upon a surface by a substance (eg: object,
fluid, gas, etc) in contact with it; such a force per unit area
is measured by pascal (Pa), newton, pounds per square inch (PSI),
pound-force per square inch absolute (PSIA), pound-force per
square inch gauge (PSIG), bar, decibar (dbar), millibar (mb), or
dyne.
-
pressure hull :
-
the inner, pressure-resistant hull of a submarine or other
submersible; the crush depth of a submersible is affected as much
by the buoyancy of a submersible as by the physical resistance of
its pressure hull.
-
pressure ridge :
-
a fracture wall produced by the compression of grinding and
colliding ice floes.
-
pressure suit :
-
an airtight protective suit that can be inflated to maintain
approximately normal atmospheric pressure on a person in an
aberrant or anomalous environment; also called pressurized suit.
-
propeller :
-
a device having a revolving hub with radiating blades that
rotates in a fluid (eg: water, air) for propelling a craft by
thrust; made of cast iron or steel, bronze or composite alloy,
it's mounted singly before the rudder, or twinned to either side
of the keel, having evolved from fixed to variable pitch to
achieve constant speed, and counter rotating to balance torque
when mounted in multiples; simultaneously invented in 1837 by
Swedish-American engineer John Ericsson and English inventor Sir
Francis P. Smith to supersede the less efficient paddle wheel.
-
prow :
-
the forepart of a craft or vessel, designated by the color white;
also called bow or stem.
-
PSI :
-
abbreviation for Pounds per Square Inch, a measure that's used to
describe the force of pressure acting on a given area; 1 psi
approximately equals 6.895 kPa.
-
PSIA :
-
abbreviation for Pounds-force per Square Inch Absolute, which is
the gauge rating plus sea level atmospheric pressure.
-
PSID :
-
abbreviation for PSI Difference, which refers to a measurement of
the difference between two pressures.
-
PSIG :
-
abbreviation for Pounds-force per Square Inch Gauge.
-
PSISG :
-
abbreviation for PSI Sealed Gauge, which measures the difference
in pounds per square inch between a chamber of air sealed at
atmospheric pressure and the pressure at the measuring point.
-
PSIVG :
-
abbreviation for PSI Vented Gauge, which measures the difference
between the measuring point and the local pressure.
-
puddle :
-
a small pool of water or other liquid. Also, slang for any body
of water, regardless of size, used informally as a term of
convenient reference. [v: dub]
-
pulpit :
-
on smaller ships and other watercraft, a safety rail rising from
the deck near the bow, and extending around it.
-
pumpout site :
-
a facility that pumps out and receives sewage from a holding tank
on-board a vessel; also called pumpout station.
-
purge valve :
-
an actuator that will clear or empty a device by replacement upon
demand, as to vent a regulator of water with a burst of air by
manually depressing a plunger.
-
purl :
-
to flow with curling or rippling motion, as a shallow stream does
over stones. Also, a circle or curl made by the motion of water,
as a ripple or eddy; possibly derived from "bubble up" or "gush"
[Norwegian 'purla']. Also, to flow with a murmuring sound.
-
quarterdeck :
-
that part of a vessel's weather deck running from midship to the
stern or poop deck, and which may have bulwarks.
-
quay :
-
a landing place constructed along the edge of a body of water,
typically built of solid masonry.
-
rankine :
-
an absolute temperature scale with a degree interval equal to
fahrenheit. [nb: the degree intervals of the kelvin scale are the
same as celsius, as the rankine are the same as fahrenheit]
-
Raoult's law :
-
this law states that the addition of solute to a liquid lessens
the tendency for the liquid to become a solid or a gas due to a
lowering of the concentration of water molecules; quantitatively,
the solvent's vapor pressure in solution is equal to its mole
fraction times its vapor pressure as a pure liquid, but this
mathematical relation is accurate only for dilute solutions; the
vapor pressure of mixed liquids is dependent on the vapor
pressures of the individual liquids and the molar vulgar fraction
of each present in solution; named after F.M. Raoult.
-
rapid ascent :
-
a too swift or uncontrolled ascent toward the surface, being
faster than the currently recommended rate of 60 feet (18m) per
minute, which may be caused by overinflation, poor buoyancy
control, being underweight, or panicked.
-
rapture of the deep :
-
phrase coined by Jacques Y. Cousteau for nitrogen narcosis.
-
RBT :
-
abbreviation for Residual Bottom Time.
-
reach :
-
a straight portion of a river or channel between two bends. Also,
a level portion of a canal, as between locks; sometimes called
"pound". Also, any continuous stretch or extent of something, as
'a reach of dunes'. Also, a point of sailing in which the wind is
within a few points of the beam, either forward of the beam
(close reach), directly abeam (beam reach), or abaft the beam
(broad reach). Also, to sail with the wind forward of the beam
but so as not to require sailing close-hauled.
-
re-breather :
-
an underwater breathing system which does not release exhaled
gasses as exhaust, but filters and recycles the discharge back
into the gas supply; also called "closed-circuit system".
-
recompression :
-
a repressurization treatment for air embolism or decompression
sickness, where an individual is re-introduced to a controlled
high pressure environment, as in a decompression chamber, and
gradually returned to normal pressure.
-
redundancy :
-
the provision of a duplicate system or of superfluous equipment
as a backup, so as to reasonably prevent failure or harm (eg:
double inflator, stage bottle, extra light, etc).
-
reef :
-
a ridge of rocks or sand, often of coral debris, at or near the
surface of the water. Also, to make something secure with tie
downs. Also, part of a sail that is ("shortened") rolled and tied
down to reduce the area exposed to the wind.
-
reef knot :
-
a square knot, wherein the ends cross in different directions,
coming out alongside the standing parts, which allows the bights
to tighten, producing a secure knot that's used for tying things
down; also called "flat knot".
-
regulator :
-
a scuba diving device that lowers the level of pressurized air,
typically to that at sea level (1 ATM); a reduction valve that
controls the flow of breathing gas from the reservoir to the
mouthpiece. A device on scuba equipment for regulating the rate
at which a constant pressure of compressed gas is fed through a
breathing tube in proportion to the depth of water.
-
repeat dive :
-
any dive whose profile is affected by a previous dive; also
called repetitive dive, and typically involves a surface interval
delay.
-
reservoir :
-
a natural or artificial place where water is collected and stored
for use; impoundment. Also, a receptacle or chamber for holding a
liquid or fluid. Also, a subterranean accumulation of liquid or
gas held in porous and permeable sedimentary rock; pool.
-
residual bottom time :
-
additional time to be spent on the bottom when calculating the no
decompression limits for a successive dive in a repetitive dive
sequence; abbreviated RBT.
-
residual nitrogen time :
-
the hypothetical amount of nitrogen absorbed in body tissues
after a dive, which is represented by minutes added to the
no-decompression limit for a repetitive dive; RNT is an off-gas
dive table calculation.
-
respiration :
-
the act of breathing or respiring; the inspiratory and expiratory
processes; being the inhalation and exhalation of air in the
oxidation of organic compounds occurring within tissues and
cells, producing energy for cellular processes, and the
byproducts of carbon dioxide and water. An exchange of gases
between a living organism and its environment.
-
respiratory arrest :
-
the cessation of breathing; apnea.
-
respiratory system :
-
the organs and tissues involved in drawing oxygen into the body
and removing carbon dioxide; in mammals, includes the nasal
cavity, pharynx, trachea, bronchi, lungs, and the diaphragm.
-
reverse block :
-
when the internal pressure of an air space is greater than the
external pressure.
-
reverse squeeze :
-
the effect of pressure during ascent on enclosed spaces that
contain air (eg: dive mask, dry suit) or body cavities (eg:
sinuses, middle ear), which discomfort or pain can be relieved by
equalization.
-
RIB :
-
abbreviation for Rigid Inflatable Boat, or Rigid-hull Inflatable
Boat; also called a "squidgie".
-
rigging :
-
lifting or hauling tackle. Also, the ropes and other lines used
on a ship to support the masts and spars, to work the sails and
yards.
-
riptide :
-
a tide that's in opposition to other tides, causing a violent
disturbance in the sea.
-
river :
-
a natural stream of water of fairly large size that's flowing in
a definite course or channel, or in a series of diverging and
converging channels. Also, a similar stream of something other
than water, as "a river of lava" or "a river of ice".
-
RNT :
-
abbreviation for Residual Nitrogen Time.
-
rode :
-
the line or chain that connects a buoy to an anchor.
-
rogue wave :
-
an abnormally large wave that occurs on a seemingly random basis
in the oceans; this unpredictable sea wave is also known as a
"freak wave". Of enormous proportion, great in height and
steepness, these unexpected waves sometimes travel in a direction
at an angle to the prevailing seas, or occur where waves meet
opposing currents.
-
roll :
-
axial plunge, swaying or rocking, as of a ship's alternating side
to side, port to starboard movement.
-
roller :
-
a long, unbroken, swelling wave that advances slowly.
-
rolling wave :
-
a long heavy sea wave as it advances toward the shore.
-
rotten ice :
-
ice that's pitted or honeycombed from melting.
-
round turn :
-
a wrap of rope or line around an object one-and-a-half times so
as to reduce the load over a small diameter (less than 3"), or
to relieve knot tension by increasing friction.
-
ROV :
-
abbreviation for Remotely Operated Vehicle.
-
rudder :
-
a vertical blade at the stern of a vessel that can be turned to
change the vessel's direction when the vessel is in motion. Also,
any means of directing or guiding a course.
-
rudderhead :
-
the upper end of a rudderpost to which a tiller, quadrant, or
crossbar yoke is attached.
-
rudderpost :
-
the vertical member on which a ship's rudder is mounted; a
sternpost.
-
running knot :
-
a slipknot.
-
running light :
-
any of various navigation or warning lights that are required to
be displayed by a vessel when operating between sunset and
sunrise, or during inclement weather or other low visibility
conditions.
-
running noose :
-
a loop formed in a cord or rope by means of a slipknot; it binds
tighter as the cord or rope is pulled; also called "slip noose".
-
running rigging :
-
rigging used for handling sails, yards, and the like; as
contrasted with standing rigging. Also, rigging used for handling
cargo.
-
SAA :
-
abbreviation for the Sub-Aqua Association.
-
safety line :
-
a line connecting paired divers when visibility is marginal or
compromised. Also, a guideline laid temporarily through an
entanglement or maze that marks the route and establishes the
entrance; this guideline is retrieved by the last diver when
exiting. Also, any line rigged on a vessel (eg: lifeline) or from
a float (eg: ascent / descent line) for the protection of divers
and crew.
-
safety stop :
-
a specific period of time spent at a particular depth to assist
in nitrogen off-gassing during a dive ascent; a safety stop,
which is not mandatory by definition, should still be performed
even within no decompression limits.
-
Saffir-Simpson scale :
-
a scale indicating the speed or pressure of cyclonic storms,
enumerated 1-5, and commonly expressed as "Category #" [ie:
Category 1: 65-82 kts/74-95 smph @ 980 mb/28.94" hg; Category 2:
83-95 kts/96-110 smph @ 965-979 mb/28.50-28.91" hg; Category 3:
96-113 kts/111-130 smph @ 945-964 mb/27.91-28.47" hg; Category 4:
114-135 kts/131-155 smph @ 920-944 mb/27.17-27.88" hg; Category
5: +135 kts/+155 smph @ 919 mb/27.16" hg]; also cited as
"Safford-Simpson Scale".
-
sailor :
-
a seaman or seafarer; also called swabby, squid, gob, anchor
clanker, or old salt.
-
Saint Adjutor :
-
venerated in the Latin church as the patron saint of swimmers,
boaters, and drowning victims; also known as Adjutor of Vernon.
As a knight in the First Crusade, he escaped Muslim persecution
and captivity by calming the sea with holy water and the sign of
the Cross before swimming away in his chains; he became a hermit
in his later life.
-
Saint Christopher :
-
the "Christ-bearer" was once a saint and martyr of the Greek and
Latin churches, but the patron saint of travelers was dropped
from the liturgical calendar in 1969; he was the protecting saint
against floods, fires, and earthquakes, and his image was
believed to keep the viewer from harm.
-
salinity :
-
the degree or proportion of a saline solution, including mineral
and chemical salts.
-
sally ship :
-
to cause a vessel to list alternately from side to side by
shifting crewmembers or a party of passengers back and forth
across its main deck so as to free a grounded hull, enabling a
stranded vessel to withdraw.
-
salty :
-
to be sharp, witty, or piquant. Also, to be vulgar or
coarse. Also, to be ship shape or squared away. Also, to be
experienced or knowledgeable, be "handy as an old salt".
-
salty dog :
-
any item lost or destroyed during operations at sea.
-
salvage :
-
saving a ship or its cargo. Also, saving anything from shipwreck,
fire, or other danger or peril; as to retrieve, recover, or
rescue. Also, compensation given to those who save a ship or its
cargo.
-
sand bar :
-
a mass of sand formed in a river or sea by the action of tides or
currents, often an obstruction to navigation.
-
saturation :
-
the complete uniting, by solution or combination, of one
substance with another; to impregnate or imbue thoroughly; the
degree to which a gas is dissolved in the blood or tissues.
-
saturation diving :
-
diving performed after the body is fully saturated with nitrogen,
which is a much longer time period underwater than is permitted
in recreational diving tables.
-
sault :
-
a waterfall or rapid of frothy water running over shoals; as
derived from 'leap'.
-
scantling :
-
a dressed timber of relatively slight width and thickness, or a
rolled metal member of similar dimensions, used for support or
framing in a vessel. Also, the dimension, in cross section, of a
framing member; as derived from a small quantity or amount
(scant, gauge).
-
scooter :
-
slang for a Diver Propulsion Vehicle (DPV).
-
scow :
-
any flat-bottomed vessel with a rectangular hull and sloping
ends, such as a barge, sailboat, rowboat, johnboat, dory, punt,
gondola, dinghy, or skiff; as derived from "ferryboat".
-
SCR :
-
abbreviation for Semi-Closed Circuit Re-breather.
-
screw :
-
slang for propeller (qv).
-
SCUBA :
-
acronym for Self Contained Underwater Breathing Apparatus; a
portable breathing device for free-swimming divers. An
experimental underwater breathing system was first employed by
Dr. Freminet in 1772. In 1825, a helmeted "diving dress" with a
self-contained air tank was introduced by William James. The
"aqua-lung" was invented (1943) during WWII by Jacques Y.
Cousteau.
-
scud :
-
to run quickly or move hurriedly, as wind driven clouds or mist.
Also, to run a boat or ship before a gale with little or no sail
set.
-
scupper :
-
a drain situated at the edge of a deck that's exposed to the
weather, allowing accumulated water to debouch into the sea or
into the bilges.
-
scuttle :
-
a small hatch or port, or its hatchway cover, located in the top,
sides, or bottom of a vessel. Also, to deliberately sink
something, or to intentionally ruin or destroy something.
-
SDI :
-
abbreviation for SCUBA Diving International, being a
qualification agency created in 1999 by Technical Diving
International (TDI).
-
sea :
-
the salt waters that cover the greater part of the earth's
surface, the subdivisions of which are more or less definitely
marked off by land boundaries (eg: North Sea, Ross Sea, Bering
Sea, Coral Sea, Mediterranean Sea, etc). Also, one of the seven
seas; ocean. Also, a large lake or landlocked body of water.
Also, the degree or amount of turbulence of a body of water, as
caused by the wind. Also, a large wave, or the waves. Also, the
work, travel, and shipboard life of a sailor.
-
sea anchor :
-
any of various devices, such as a drogue, that are dropped
overboard at the end of a cable so as to hold the bow of a vessel
into the wind.
-
seabed :
-
the seafloor (qv).
-
sea change :
-
a major transformation or alteration.
-
sea chest :
-
a container for holding personal belongings aboard ship.
-
seacock :
-
a valve in the hull of a ship for admitting seawater into some
internal chamber, as for ballast.
-
sea daddy :
-
slang for a sailor's mentor or sponsor.
-
sea fence :
-
a durable mesh suspended from a cable that's strung between buoys
so as to isolate or confine a select area, usually for protective
purposes; extending to the seafloor, the mesh is typically sized
to permit the passage of fishes, but not people.
-
seafloor :
-
the solid surface underlying a body of water; also called seabed.
-
sea gate :
-
a navigable channel giving access to the sea.
-
sea level :
-
the surface of the sea at a mean horizontal plane between high
and low tides. [nb: the curvature of the earth restricts
visibility at sea level to only three nautical miles (3nm)]
-
seaman :
-
a sailor or seafarer; also called swabby, squid, gob, anchor
clanker, or old salt.
-
seamount :
-
an undersea mountain rising prominently above the seafloor but
having its summit well below the surface of the water; also known
as tablemount. [nb: not tableland]
-
seaport :
-
a port, harbor, or anchorage that accommodates seagoing vessels.
-
sea room :
-
unobstructed space at sea in which a vessel can maneuver.
-
seashore :
-
land along the sea between the ordinary high-water and low-water
marks; shore.
-
sea smoke :
-
a steam or evaporation fog that's formed when water vapor is
added to air which is much colder than the vapor's source, most
commonly when very cold air drifts across relatively warm water;
also called "water smoke", "arctic sea smoke", "antarctic sea
smoke", and "frost smoke".
-
seasonal thermocline :
-
a temperature gradient in a body of water that's not affected by
the diurnal changes in surface forcing; in general, it is
established each year by heating of the surface water in the
summer, and is destroyed the following winter by cooling at the
surface and wind-driven mixing.
-
sea wall :
-
a strong wall or embankment that serves as a breakwater, or is
used to prevent the encroachments of the sea.
-
second-foot :
-
a unit of measure for liquid flow, especially of rivers, being
equal to one cubic foot per second.
-
second stage :
-
the second phase of pressure reduction by the regulator assembly,
set to deliver low air pressure from the medium pressure of the
first stage of the regulator to the breathable air at the
mouthpiece.
-
seiche :
-
an occasional but sudden oscillation of the water in a lake, bay,
estuary, reservoir, or other containment that produces
fluctuations in the water level, which are caused by wind,
earthquakes, landslides, avalanches, changes in barometric
pressure, and so forth.
-
semi-closed circuit re-breather :
-
a re-breather that continuously vents a small amount of excess
gas from the system while the breathing gas is injected at a
constant rate to the diver. Semi-closed circuit equipment
generally supplies only one breathing gas (eg: air, nitrox, or
trimix) that has a maximum operating depth that is safe for the
depth of the scheduled dive. The oxygen mixture must be carefully
chosen to avoid toxicity or hypoxia as the work rate of the dive
changes. Semi-closed circuit equipment, which is fairly simple
and inexpensive, provides good underwater duration for military
and recreational divers.
-
service float :
-
a floating structure equipped to supply oil, fuel, water, sewage
pumpout, and other related services to boats.
-
set and drift :
-
the tangential deflection of a ship from its intended course
under the influence of wind and current, with 'set' being the
direction of that deflection, and 'drift' being the speed in
knots of the displacement.
-
sextant :
-
an astronomical instrument used at sea to determine latitude and
longitude by measuring angular distances, especially the
altitudes of the sun, moon, and stars; as derived from the "sixth
part of a unit".
-
shallows :
-
the shallow part of a body of water; shoal.
-
sheer :
-
to swerve or deviate from a course, as a divergence. Also, in
shipbuilding, the fore-and-aft upward curve of the hull of a
vessel at the main deck or bulwarks. Also, the position in which
a ship at anchor is placed to keep it clear of the anchor. Also,
any very steep perpendicular or vertical extension; precipitous.
-
sheet :
-
a thin line, cord, or wire used in reeving tackle and the rigging
of sails [nb: like a hawser, it is never called a rope]. Also, a
sail on a boat or ship.
-
shellback :
-
an experienced sailor, especially someone who has crossed the
equator and undergone the arcane rites of Neptune; also called a
sea dog, old salt, or mossback.
-
shingle :
-
small waterworn stones or pebbles. Also, the area, such as a
beach or riverbed, where these small stones or pebbles wash up,
lying in a loose mass.
-
shipmate :
-
a companion or comrade who serve together on the same vessel;
often extended in camaraderie to any seaman or sailor in the
"brotherhood of the sea".
-
ship's complement :
-
persons permanently assigned to a ship, its permanent party or
staff, as distinguished from those temporarily on-board for
transport or a cruise; often misspelled "ship's compliment".
-
shipshape :
-
everything in proper order, trim and tidy; also called snug or
salty.
-
shiver :
-
to shake, quiver, quaver, or tremble with chill ("the shivers"),
being an involuntary physiological response of muscular
contractions that are intended to increase the lowered body
temperature with activity. Also, the shaking of sails on a vessel
headed too close to the wind.
-
shoal :
-
a place where the depth of water is shallow, especially where the
seafloor (eg: sandbank, sand bar) is visible at low tide. Also, a
large number of things, as a school of fish or throng of people.
-
shore :
-
the land along the edge of a sea, lake, or river, including a
beach, tideland, or shoal; especially a 'seashore', being that
ground between the ordinary high-water and low-water marks. Also,
a supporting post or beam, a prop or strut, especially one braced
against the side of a building or a ship in drydock.
-
shoreline :
-
that line where the shore and water meet.
-
shot :
-
a unit of measure for anchor chain equal to 15 fathoms (90 feet,
27m). Also, an obsolete unit of measure equal to a league (3
nautical miles or 4.8km); as derived from 1.5 Roman miles, which
seems to be the origin of the conventional claim for a three-mile
limit of territorial waters extending offshore.
[nb: 12 inches = 1 foot, 3 feet = 1 yard, 6 feet / 2 yards = 1
fathom, 16.5 feet = 1 rod (aka: pole or perch), 66 feet / 4 rods
= 1 chain (90 feet / 15 fathoms = 1 anchor chain), 10 chains /
660 feet (1/8 statute mile) = 1 furlong, 120 fathoms / 720 feet =
1 land cable, 101 fathoms / 606 feet (1/10 nautical mile) = 1
cable, 3 statute miles = 1 land league, 3 nautical miles = 1 sea
league / shot]
-
shove-off :
-
to launch (as in "launch the boat") or to execute (as
in carry-on), sometimes expressed as castoff. Also, slang for
leave / depart or go away / get away / get out.
-
showboat :
-
anyone or anything that stands-out; anything done more
for attention than for practicality or function, as a show-off or
razzle-dazzle. Formerly a flamboyantly theatrical steamboat.
-
SI :
-
abbreviation for Surface Interval. Also, the abbreviation for the
International System of [physical] Units, which includes meter
(length), kilogram (mass), second (time), ampere (electric
current), kelvin (temperature), mole (amount of substance), and
candela (luminous intensity).
-
side-mount :
-
an equipment configuration wherein the air tanks are attached to
the side of the diver, between the arms and torso, which
arrangement is used for low bedding plane passages with very
little vertical clearance, a situation where the back-mount
configuration is problematic.
-
signal flag :
-
a small cloth panel, distinctively colored and patterned, used to
post messages or notices on a ship's superstructure; also called
burgee or pennant.
-
significant wave :
-
in ocean wave forecasting, a fictitious wave with a size and
interval equal to the average height and period of the highest
one-third of actual waves that pass a fixed measuring point. The
generation of waves on water does not result in a uniform wave
height, but in a spectrum of waves distributed from the smallest
capillary waves to the largest freak waves; within this spectrum
there is a finite possibility of each of the wave heights to
occur, with the largest waves being the least likely (only 1 in
1000 waves will be nearly double the significant wave height or
higher). The wave height most commonly observed and forecast is
the "significant wave height", which is defined as the average of
the one third highest waves.
-
silt-out :
-
a complete loss of visibility caused by the turbidity of
disturbed silt, typically from careless finning.
-
single berth :
-
a mooring that accommodates one boat, with a finger pier on each
side of the berthed vessel.
-
single-day :
-
a dive series with a surface interval of less than 24 hours
between consecutive dives; a single day of diving, regardless of
the number of dives completed in that period; juxtaposed to
multiday.
-
sinkhole :
-
a hole formed in soluble rock by the action of water, which
serves to conduct surface water to an underground passage. Also,
a depressed area in which drainage, waste, or debris collects;
pan.
-
siphon :
-
a tube or pipe that uses atmospheric pressure to draw liquid from
one level to another, especially when mechanically transferring
the contents of one container to another. Also, an outlet or
drain in the bedrock or seafloor that draws water into a lower
level pool or chamber; as opposed to a spring or seep. Also, a
projecting tubular part of some animals through which liquid
enters or leaves their body, such as mollusks, chitons, squids,
and octopuses.
-
skeg :
-
any flat protrusion or projection on the outside of the hull
supporting a rudder at its lower end, located abaft a sternpost
or rudderpost. Also, an extension of the keel of a small craft
that's designed to improve steering; as derived from cutwater.
-
skimmer :
-
slang for a surface sailor; someone who makes his living at sea
level.
-
skin :
-
informal term for a thin exposure suit, typically made of spandex
or other polyurethane fabric, that's used in warm water diving;
also called "skin suit".
-
skin diving :
-
free-breathing and free-swimming underwater diving, often
performed with only a face mask and flippers, without a
protective suit or supplemental air; elapsed time and depth are
determined by breath-hold duration.
-
slack :
-
not tight, taut, firm, or tense; lax or loose. Also, slow,
sluggish, or indolent; as when the wind, water, or tide is moving
very slowly. Also, negligent; careless; remiss.
-
slack water :
-
water that is free of currents, especially a body of water that's
between tides. Also, the time period when water is between tidal
currents, as at the cessation of flow when a current turns.
-
SLAM :
-
abbreviation for Scuba Lifesaving and Accident Management, a YMCA
diver rescue course.
-
sling / sling-eye :
-
a strap, band, or the like, forming a loop by which something may
be suspended or carried. Also, a rope, chain, net, or the like
used for hoisting cargo, or for holding it while being hoisted.
Also, a chain for supporting a hoisting yard.
-
slings :
-
the middle area of a hoisting yard where the hoisting chains are
attached.
-
sludge :
-
a deposit of mud, mire, or ooze at the bottom of a body of water.
Also, any of various sediment deposits or mixtures of finely
powdered substances with some type of liquid. Also, a slurry of
broken ice floating on the sea. Also, slang for strong coffee.
-
slue / sluing :
-
to turn or swing around, especially when pivoting or rotating
about its own axis.
-
sluice :
-
an artificial channel for conducting water, sometimes surplus,
often fitted with a gate ("sluice gate") for regulating the flow;
also called a sluiceway. Also, to flush or cleanse something with
a rush of water; as derived from "exclude".
-
slurry :
-
a thin mixture of an insoluble substance suspended in a liquid.
-
slush :
-
partly melted snow. Also, liquid mud; watery mire. Also, waste or
refuse, especially from cooking. Also, a mixture of grease and
other materials used for lubrication.
-
SMB :
-
abbreviation for Surface Marker Buoy.
-
smuggler's trap :
-
a compartment or well aboard ship, usually concealed, that's used
to hide transported contraband, from munitions to medicines,
including persons, so as to avoid confiscation or taxation; being
a temporary stash, hidey-hole, or hideaway, wherein 'trap'
derives from "suitcase" and not "contrivance".
-
snaking :
-
netting stretched between the BULWARK and LIFELINE, or between
the GUNWALE and footrope on a vessel to prevent objects
(including people during storms) from falling overboard.
-
snorkel :
-
a J- or S-shaped tube through which a swimmer can breathe while
moving at or near the surface of a body of water; often used
while skin diving.
-
snowblink :
-
a white luminosity on the underside of clouds that's caused by
the reflection of light from a snow surface; also called "blink",
as derived from 'blink' meaning gleam, twinkle, glitter, or
shine.
-
snuba :
-
a portmanteau word, joining SNorkel and scUBA, that's used to
designate an introductory experience of underwater swimming with
close supervision that doesn't involve training or certification.
The swimmer, who is tethered to a dive certified guide, uses the
regular mask, fins, and weight belt, but the mouthpiece is
connected to a long hose that feeds air from a series of tanks or
a compressor on the surface. This tandem dive experience, with
the least amount of paraphernalia, introduces the novice to the
underwater world without intimidation. A raft with outboard
handles is often used as the dive platform to increase the
swimmer's confidence. This method is a popular initiation for
tourists visiting the tropics, and is usually restricted to
protected areas, where wind, current, and waves are negligible.
These escorted dives are usually brief and are limited to depths
no greater than 20 feet.
-
snug :
-
a trim, tidy, or compactly arranged ship or its parts; shipshape.
Also, a compact and confined harbor or anchorage. Also, to lie
closely together; to nestle closely.
-
solo diving :
-
the practice of diving underwater without a partner, which
activity is not recommended and is not permitted on charter
boats; at a minimum, the availability of an alternate air source
is recommended.
-
soniferous / sonify :
-
conveying or producing sound, as a "sonified layer" or an
"ensonified area"; obstructed or obscured by turbulence.
-
sound :
-
a relatively narrow passage of water between larger bodies of
water, or between the mainland and an island. Also, an inlet,
arm, or recessed portion of the sea. Also, to measure or try the
depth of water at sea by letting down a lead or plummet at the
end of a line, or by some equivalent means. Also, to examine or
test the seafloor or the bottom of a deep hole with a lead that
brings up adhering bits of matter. Also, to go down (to touch
bottom) or to plunge downwards; to dive. Also, to seek, fathom,
or ascertain by examination or investigation. Also, the sensation
produced by stimulation of the organs of hearing by vibrations
transmitted through the air or some other elastic medium, which
travel at approximately 12miles/minute through air and 52
miles/minute through water; the particular auditory effect
produced by a given cause.
[nb: the velocity and distance that sound travels in either air
or water depends upon atmospheric pressure, medium temperature,
molecular density, and turbulence; such that under equivalent
conditions, sound moves faster in salt water than in fresh,
faster in fresh water than in air. The audible range of sound
wave frequencies for humans is 20 - 20,000 Hz; above which
ultrasonic waves may be felt, instead of heard.] [cf: ultrasound]
-
spar :
-
a stout pole, such as a mast, yard, boom, gaff, or the like.
-
spear gun :
-
a device for shooting a barbed missile under water.
-
spew :
-
foam, froth, or scum that's been discharged or ejected, as "spew
forth".
-
SPG :
-
abbreviation for Submersible Pressure Gauge.
-
spicule :
-
one of the small, hard, calcareous or siliceous bodies that serve
as the skeletal elements of various marine and freshwater
invertebrates; also known as sclerite. Large spicules, visible to
the naked eye, are referred to as megascleres, while smaller
microscopic ones are termed microscleres.
-
spindrift :
-
spray swept along the surface of the sea by a violent wind.
-
spit :
-
saliva or spittle, as a natural secretion ejected or expectorated
onto the window of the diving mask to prevent fogging. Also, a
narrow point of land projecting into a body of water. Also, a
long narrow shoal extending from the shore. Also, any of various
rods, pins, or the like used for particular purposes.
-
splash :
-
slang for an underwater dive.
-
split fins :
-
a set of flippers or fins that work like an underwater propeller.
-
spray :
-
droplets of water that are broken-up and blown or cast into the
air. Also, any liquid or other material in particle form that's
discharged into the air.
-
spume :
-
foamy matter floating on a liquid, as froth churned by a
turbulent sea.
-
squall :
-
a sudden violent wind, often accompanied by rain, snow, or sleet;
as derived from "shriek". [nb: regional variants include
Abroholos, Barat, Borasco, Brubu, Chubasco, Churada, Papagayo,
Suestado, Sumatra, Tehuantepecer, and the like]
-
square away :
-
to prepare something for inspection or operation; to get
organized or ready for something, such as a drill or evolution.
-
squared away :
-
someone who is smart or capable; something that performs well, is
responsive and effective.
-
square dive :
-
a dive profile wherein the diver descends immediately to full
depth, then remains at that level for the duration until
resurfacing. This profile is approximately rectilinear when
plotted in a coordinate system, where one axis is depth and the
other is duration. A square dive is juxtaposed by a multilevel
dive.
-
squat :
-
the tendency of a motorcraft or vessel to draw more water astern
when in motion forward than when stationary or halted. Also, a
thing of little or no value, as naught or nothing, rush or zilch,
cipher or nullity, zip or zero. Also, the minimum amount or
degree, as the least bit.
-
squeeze :
-
the effect of pressure during descent on enclosed spaces that
contain air (eg: dive mask, dry suit) or body cavities (eg:
sinuses, middle ear), which discomfort or pain can be relieved by
equalization. Also, the experience of a diver going through a
narrow passage, small opening, or constriction.
-
squid :
-
slang for a seaman or sailor; also called swabby or gob.
-
SSI :
-
abbreviation for Scuba Schools International, which merged with
the National Association of Scuba Diving Schools (NASDS) in 1999.
-
stage :
-
the platform of the elevator used to transport hard hat or hard
suit divers to the deep-sea floor, to recover them and any small
objects; derived from "standing place".
-
stage bottle :
-
the secondary scuba cylinder that is used to carry different gas
mixtures for consumption during various phases of decompression,
as used by technical divers; a tank used to carry extra breathing
gas; also called "sling bottle".
-
staged decompression :
-
regular timed stops at particular depths during ascent to allow
for nitrogen off-gassing.
-
stanchion :
-
an upright bar, beam, post, or support, as used when securing or
supporting something.
-
standing rigging :
-
rigging on a boat that remains permanently in position as a means
of steadying various spars, shrouds, stays, and the like; as
contrasted with running rigging.
-
starboard :
-
the right-hand side of a vessel craft when facing forward, and
designated by the color green; formerly known as steerboard for
the "steering side".
-
stateroom :
-
a private room or compartment on a ship, or other conveyance.
-
stay :
-
any of various strong ropes or wires for supporting, securing, or
steadying masts, funnels, and the like; also represented as
stayed or stay·ing, as derived from "to hold in place". Also,
something used to support or steady a thing, as a prop or brace;
a strip or rod used to stiffen or strengthen. Also, to put a
sailing ship on the other tack; to change to the other tack.
-
steam fog :
-
fog formed when water vapor is added to air that is much colder
than the vapor's source, most commonly when very cold air drifts
across relatively warm water. No matter what the nature of the
vapor source, the water vapor, upon becoming mixed with and
cooled by the cold air, rapidly condenses. It should be noted
that although advection of air is necessary to produce steam fog,
it differs greatly from an advection fog in the usual sense,
which is caused by warm, moist air moving over a cold surface.
Steam fog is commonly observed over lakes and streams on cold
autumn mornings as well as in polar regions. It is sometimes
confused with ice fog, but its particles are entirely liquid.
Steam fog is also called "sea smoke", "arctic sea smoke",
"antarctic sea smoke", "frost smoke", "water smoke", "sea mist",
and "steam mist".
-
stem :
-
an upright at the forward part of a vessel into which the side
timbers or plates are jointed, designated by the color white;
also called bow or prow.
-
stenobathic :
-
freshwater or marine life that can tolerate limited changes in
depth; as opposed to eurybathic.
-
stern :
-
the back or rear of a craft or vessel; designated by the color
black.
-
sternpost :
-
an upright member rising from the after end of a keel; a
rudderpost or propeller post.
-
storm :
-
a disturbance of normal atmospheric conditions that manifests
itself by strong or heavy winds, and often accompanied by rain,
thunder and lightning, snow, hail, or sleet. Alternatively,
either an instance of heavy precipitation (eg: rainstorm,
snowstorm) unaccompanied by strong winds, or a sudden and violent
wind (ie: windstorm) alone.
-
storm warning :
-
a showing of storm signals subsequent to an alert notification of
severe winds and threatening weather, especially cyclonic
conditions [nb: Tropical Depression: 20-34 kts/23-39 smph;
Tropical Storm: 35-64 kts/40-73 smph; Hurricane: 65+ kts/74+
smph].
[nb: due to axial tilt during earth's rotation, the hemispheric
seasons are not the same length, with the southern summer /
northern winter being the shortest season, and northern summer /
southern winter being the longest]
-
strainer :
-
slang for the sieve-like obstruction in a waterway that sifts
objects and debris from the flow, often occluding the flow by
accumulation; a hazardous trap that can drown the unwary.
-
strait :
-
a narrow passage of water connecting two larger bodies of water.
Also, an isthmus or neck. Also, a position of difficulty,
distress, or need.
-
strake :
-
a continuous course of hull planks or plates on a ship.
-
stream :
-
a body of water of indeterminate size that flows in a channel or
watercourse, such as a river, rivulet, freshet, brook, rill, run,
streamlet, or runnel. Also, a steady current or continuous flow
in water, as in a river or the ocean. Also, to place an object in
the water at the end of a line that's attached to a vessel;
trawl.
-
strobe :
-
a high-intensity light with a variable frequency flash, as used
in signaling and photography.
-
sublittoral :
-
of or pertaining to the biogeographic region of the ocean bottom
between the littoral and bathyal zones; from the low water line
to the edge of the continental shelf, or to a depth of
approximately 660 feet. Also, situated in the zone of a lake
extending from the lowest depth of rooted photosynthetic plants
to the level at which the photosynthetic rate of flora equals the
respiration rate.
-
submarine :
-
a vessel that can be submerged and navigated under water; also
known as sub, guppy, pig boat, boomer, sewer pipe, clockwork
mouse.
-
submergence recovery vehicle :
-
an air-transportable deep-sea submarine; abbreviated SRV.
-
submersible :
-
a boat or other vessel that's capable of submerging and operating
under water, such as a submarine. Also, a device designed for
underwater work or exploration, such as a bathyscaphe.
-
submersible pressure gauge :
-
a meter, either analog or digital, that monitors and displays the
amount of air pressure in the scuba cylinder; a required item of
scuba gear.
-
suicide clip :
-
a hardware device with a spring-loaded angular gate, which can
inadvertently engage and attach a diver to an underwater object,
or can accidently disengage from a guideline or other connection;
also called "boat clip" or "marine snap link".
-
sunami :
-
misspelling of tsunami (qv).
-
super saturation :
-
an unstable situation where the pressure of a gas dissolved in
the blood or tissues is higher than the ambient pressure of that
gas.
-
supralittoral :
-
pertaining to the region of a lake or ocean shore that is above
the shoreline but is often damp from spray or capillary action of
the water.
-
surf :
-
the swell of the sea that breaks in a foamy mass or line upon a
sloping shore or upon shoals. Also, to float (surfing) or swim
(body surfing) on the crest of a wave toward shore.
-
surface interval :
-
a period of time spent on the surface between dives, especially a
delay between repeat dives; abbreviated SI.
-
surface marker buoy :
-
a float denoting a dive site, to which an ascent line may be
attached, and may be used as a safety device to warn when divers
are swimming underwater; abbreviated SMB.
-
surface supplied compressed air diving :
-
underwater diving with the breathing air continuously supplied by
an air hose from a compressor on the surface, which can be used
for both professional and sport diving.
-
surfactant :
-
an active substance produced in the lungs to reduce surface
tension in alveoli and small airways, and that coats the lungs to
prevent their collapse.
-
swabby :
-
slang for a seaman or sailor; also called squid or gob.
-
swell :
-
a long and unbroken wave, or a series of such "rollers".
-
swim mask :
-
a device consisting typically of a transparent glass or plastic
panel fitted into a flexible rubber gasket that fits snugly
around the eyes, over the cheeks, and usually over the nose; also
called "face mask" or "diving mask", as used by SCUBA and skin
divers.
-
swimsuit :
-
a garment worn for swimming or for recreational activities in and
around water; also called swimming suit or bathing suit.
-
tables :
-
decompression tables; also called dive tables.
-
tackle :
-
any specialized apparatus, equipment, or gear, including
rigging. Also, a leverage system of pulleys.
-
tadpole :
-
nickname for a frogman trainee.
-
taffrail :
-
the upper part of the stern of a ship. Also, a safety rail above
the stern of a ship.
-
tank :
-
slang for the steel or aluminum cylinder of pressurized breathing
gas that's used in scuba diving; also called "bottle".
-
TBT :
-
abbreviation for Total Bottom Time.
-
TDI :
-
abbreviation for Technical Diving International.
-
TDT :
-
abbreviation for Total Dive Time.
-
technical dive :
-
an underwater dive deeper than 130 feet using a breathing gas
other than compressed air, and requiring at least one
decompression stop during ascent. This category also encompasses
overhead dives, and the use of special training or equipment.
-
tekkie / techie :
-
a technical and gadget oriented diver ... the more the better! A
tekkie dive profile always uses exotic gas mixtures, and a tekkie
BCD has at least 6 D-rings attached! A tekkie dive maximizes
complexity and difficulty! A tekkie aspires to be the most
authoritative expert ... on everything!
-
telltale :
-
any of various devices or mechanisms for alerting, indicating, or
registering, including a suspended line, ribbon, or feather hung
so as to indicate wind direction.
-
tempest :
-
a violent windstorm with rain.
-
test depth :
-
the rated maximum safe depth to which a submarine or other
submersible is tested by actual or simulated submergence, as
based upon design and manufacturing limits.
-
thermocline :
-
an underwater layer of boundary water that differs in temperature
and salinity from those bordering it above and below; it is the
region in a thermally stratified body of water which separates
warmer oxygen-rich surface water from cold oxygen-poor deep water
and in which temperature decreases rapidly with depth. Also, a
layer in a large body of water, such as a lake, that sharply
separates regions differing in temperature, so that the
temperature gradient across the layer is abrupt. Also, the
intermediate summer or transition zone in lakes that's situated
between the overlying epilimnion and the underlying hypolimnion,
defined as that middle region of a thermally stratified lake or
reservoir in which there is a rapid decrease in temperature with
water depth. Typically, the temperature decrease reaches 1°C
or more for each meter of descent (equivalent to 0.55°F per
foot).
-
thirds :
-
the practice of dividing the volume of air (in cubic feet or psi)
into thirds: with one third for the penetration, one third for
the exit, and one third for emergency use; also called the "rule
of thirds".
-
thorax :
-
the part of the mammalian trunk between the neck and the abdomen,
containing the heart and lungs in a bony cage of ribs, sternum,
and vertebrae, and separated from the lower trunk by the
diaphragm; also known as the chest.
-
throughflow :
-
the horizontal movement of water beneath the saturated land
surface once it has infiltrated the less permeable compacted
soil, moving downwards and sideways under gravity and running
underground until it reaches a river, lake, or other body of
water. Also, the transport of ocean water in a horizontal current
from one body to another by way of a channel (such as the
Indonesian throughflow) as an adjustment in sea levels, with or
without the augmented movement of seasonal winds; also known as
an "oceanic conveyor belt".
-
thumbing the dive :
-
a command signal used to terminate the dive and direct other
divers to exit to the surface; this "thumbs-up" hand signal
consists of an upward pointing thumb with fingers closed into a
fist.
-
thumbs-up :
-
a hand signal indicating ascent; not to be mistaken for a gesture
of approval or agreement.
-
tidal range :
-
the difference in height between the highest (hwl) and lowest
(lwl) water levels occurring about every 12-hours.
-
tidal wave :
-
common reference to a large, destructive ocean wave that was
produced by a seaquake, hurricane, or other cataclysm. Also,
either of the two great wavelike swellings of the ocean surface
that move around the earth on opposite sides and give rise to
tides, as caused by the attraction of the moon and sun.
-
tide :
-
the periodic rise and fall of the waters of the ocean and its
inlets, produced by the attraction of the moon and sun, and
occurring about every 12-hours. Also, the inflow, outflow, or
current of water at any given place resulting from the waves of
tides. Also, a flood tide, being the inflow of rising water.
Also, betide; to happen or befall.
-
tide gate :
-
a gate that permits water to flow through when the tide moves in
one direction, but closes automatically when the tide moves in
the opposite direction. Also, a restricted passage through which
the tide flows swiftly, such as a strait. [cf: water gate]
-
tidehead :
-
the inland limit of the tide.
-
tiller :
-
a bar or lever fitted to the head of a rudder that's used for
turning the rudder in steering.
-
timberhead :
-
the top end of a timber, rising above the deck and serving for
belaying ropes or attaching lines. Also, a bollard resembling
this in position and use.
-
toe rail :
-
the raised lip at the edge of a weather deck that's designed to
prevent someone's feet from slipping or sliding overboard.
-
tongue :
-
a narrow strip of land extending into a body of water; cape.
Also, a section of ice projecting outward from the submerged part
of an iceberg.
-
topside :
-
on deck, or on the outer-surface of the hull above the waterline,
often refers only to the main deck; also known as "topsides".
-
tornado :
-
the word 'tornado' is a metathetic variant of "tronada", a
violent thunderstorm, which is characterized as a violent
funnel-shaped windstorm occurring over localized land.
-
Torricelli's law :
-
the law that states that the speed of flow of a liquid from an
orifice is equal to the speed that it would attain if falling
freely a distance equal to the height of the free surface of the
liquid above the orifice; named after Evangelista Torricelli, an
Italian physicist.
-
total bottom time :
-
the amount of time that a diver spends underwater, being the sum
of actual bottom time and residual nitrogen time.
-
touch signal :
-
contact communications used in a low visibility environment;
including: Go (by a push), Stop (by a pull), Back Up (by several
rapid pulls), Turn (by taps on side to move), Exit (by taps on
head).
-
towhead :
-
a sand bar in a river, especially a sand bar with a stand of
cottonwood trees.
-
trachea :
-
the tube that extends from the larynx to the bronchi, which
serves as the principal passageway for air to and from the lungs;
this airway is also called the windpipe.
-
tramp :
-
a freight vessel that transports cargo wherever the shippers
direct, having no regular schedule and no fixed port or route;
also called "tramp steamer" or "tramp ship".
-
transition layer :
-
the stratified layer of a body of water that's situated between
the mixed layer and the undisturbed fluid beneath it; being the
uppermost (epilimnion) thermocline or the thermocline closest to
the surface at any given time. Also, the capping inversion or
entrainment zone at the top of the convective mixed layer. Also,
the statically stable layer near the base of convective clouds in
the Tropics. Also, the thin layer that separates thicker layers
of different characteristics.
-
transom :
-
a flat termination at the stern of a ship above the water line;
or any of the transverse beams attached to the sternpost of a
ship that strengthen the stern.
-
travel gas :
-
the breathing mixture used for descent and ascent.
-
trawl :
-
a recovery line trailing from a moving craft or vessel, which
enables divers or swimmers to be extracted from a body of water
by attaching themselves onto the line while the craft or vessel
continues, without stopping to embark the departing personnel,
who are later transferred to their host ship; this term derives
from "trail", and is also called "trawl line" (nb: fishermen use
a "trawl net").
-
trench :
-
a long narrow depression in the deep-sea floor, being the site of
one or more ocean deeps.
-
trigger snap :
-
a hardware device used to attach gear to the diver's harness; it
has a swivel on one side and a split circular other end with one
side of the split being a spring-loaded lever (trigger).
-
trim :
-
the set of a ship in the water, especially the most advantageous
posture with respect to the intended course and the prevailing
conditions; also called attitude adjustment.
-
trimix :
-
a breathing gas mixture of nitrogen, helium, and oxygen.
-
trim weight :
-
weights attached to the diver that allow adjustment for trim and
swimming position.
-
Tropic of Cancer :
-
a parallel of latitude that marks the farthest point (23.5°N)
north of the equator where the sun's rays fall vertically.
-
Tropic of Capricorn :
-
a parallel of latitude that marks the farthest point (23.5°S)
south of the equator where the sun's rays fall vertically.
-
truck :
-
a circular piece of wood fixed on the head of a mast or the top
of a flagstaff, usually containing small holes for the roving
through of signal halyards. Also, any of various wheeled frames
used for transporting large or heavy objects, including packages
and cartons, trunks and crates; also called dolly or hand truck.
Also, miscellaneous articles of little worth; odds and ends.
-
tsunami :
-
an unusually large sea wave produced by a seaquake or undersea
volcanic eruption; originating in Japanese as "harbor wave".
-
turn :
-
to pass or twist a rope entirely around an object; as derived
from "round off" or "make circles". Also, a single circular or
convoluted shape, as of a coiled or wound rope.
-
turn the tide :
-
an expression of figurative reversal, as to reverse the course of
events, especially from one extreme to another; as derived from
the literal reversal of flow.
-
Type III MSD :
-
the Type III Marine Sanitation Device, a sewage retention system
or holding tank (qv).
-
typhoon :
-
a tropical cyclone or hurricane of the western Pacific, its seas
and inland areas; as derived from Chinese for great wind. [cf:
Greek Typhoeus / Typhon]
-
undercurrent :
-
a water current that flows below the upper currents or beneath
the surface.
-
undertow :
-
any strong subsurface current that's moving in a direction
different from that of the surface current, especially the
seaward flow of subsurface water from waves breaking on a beach.
-
underway / under way :
-
a moving vessel, as a boat or ship that's no longer at anchor or
in port; a vessel that's not stationary, is in motion relative to
the seafloor, but may not be under its own propulsive power.
-
Valsalva maneuver :
-
an attempt to adjust pressure in the middle ear by forcibly
expelling air against a closed glottis, or against closed lips
and pinched nostrils, which inflates the Eustachian tubes while
decreasing intrathoracic pressure, hampering venous return to the
heart; eponymously after Antonio M. Valsalva, an Italian
anatomist.
-
vampire gauge :
-
slang for a penetration monitor that samples blood gas (abg)
diffusion at the wrist, which is used on deep underwater dives.
-
van der Waals equation :
-
the Johannes van der Waals formula is a gas law involving the
pressure, temperature, and volume of real gas variations, instead
of ideal gas at absolute temperature, and is given as: (P +
a/v2) (v - b) = RT, or (pressure plus constant value a
squared)(volume minus constant value b) = (real gas temperature).
-
veer :
-
said of the wind when it changes. Also, to slacken a cable and
let it run out [v: pay].
-
veer and haul :
-
to alternately pull on and slacken a rope or line, as in warping,
until the vessel gains headway.
-
venous gas embolism :
-
a condition in which gas bubbles enter the venous system and
cause damage by blocking blood flow to vital organs, most
commonly the heart and lungs; also called "air embolism".
-
vertigo :
-
a dizziness or disordered condition brought on by the inequality
of pressures in the inner ear; a sign of ear barotrauma that may
range from minor ear squeeze to perforation of the eardrum.
-
VGE :
-
abbreviation for Venous Gas Embolism.
-
visibility :
-
the viewing distance or visual capacity for underwater objects as
factored by bottom composition, turbidity, suspended matter, and
water temperature.
-
visual reversal :
-
a perceptual distortion where the distance to an underwater
object appears farther away than the actual distance.
-
volute :
-
an object having a spiral, twisted, or rolled-up conformation,
especially the turn or whorl of a spiral seashell. Also, the
scrolled ornament terminating a handrail or cutwater.
-
vortex :
-
a whirling mass of water, especially one operating with the force
of suction, as a whirlpool.
-
wake :
-
the track of waves left by a vessel moving through water; as
derived from a "hole in the ice". Figuratively, as "in the wake
of", means consequently or closely behind.
-
wale :
-
any of certain strakes of thick outside planking on the sides of
a wooden ship.
-
waler :
-
a structural member that's fastened along the edges of a dock
system to hold it together, to provide stability, and to protect
the flotation pontoons and utility feeds.
-
Wallacea :
-
a biogeographical transition zone of islands between the Sunda
shelf and the Sahul shelf, an area separating Australia from
Southeast Asia for the past seventy million years. Initially
recognized for its significance by the British naturalist Alfred
Russel Wallace, it marks the division between two major faunal
groups: oriental animals (elephants, tigers, and apes) and
Australasian animals (marsupials and monotremes). The so-called
"Wallace Line", which runs between Bali and Lombok, is a boundary
that separates the ecozones of Asia and Australasia, with the
organisms living west of this line related to Asiatic species,
and most of the species east of this line endemic to Australia,
New Guinea, New Zealand, and neighboring islands.
[v: Weber's Line, Huxley's Line, Lydekker's Line]
-
warp :
-
a rope smaller than a cable and used as mooring lines. Also, to
move a vessel from one place to another by means of incremental
hauling on a rope made fast to some fixed object, or to a kedge
(kedging).
-
watch :
-
a lookout, guard, sentinel, or selected crewmembers who serve as
such while aboard a vessel. Also, a period of time during which
part of the crew is on duty attending to the workings of their
ship. Also, one of the periods into which the day and/or night is
divided while at sea.
-
watch-and-watch :
-
the necessity to stand alternate watches, due to an absence or
incapacity of other crewmembers; variously arranged as 4- or
6-hours on- and off-duty until the situation changes; this
routine is also called "port and starboard" or "port and stupid"
... an exhausting schedule that can inadvertently generate
mistakes and accidents.
-
watch bill :
-
a roster of regularly scheduled duties assigned to crewmembers.
-
watch cap :
-
a soft stocking-cap, knitted of dark blue wool and worn with a
turned-up cuff folded at the bottom, that's suitable for wear
during cold weather by seamen or sailors.
-
watercourse :
-
any natural channel conveying water, seasonally or otherwise, as
a river or stream; a waterway. Also, a conduit or canal made for
the conveyance of water, as a race or aqueduct.
-
waterfront :
-
land on the edge of a body of water. Also, the part of a city or
town on the land beside a body of water.
-
waterhead :
-
the source of a river or stream; a fountainhead. Also, a body of
water that's been impounded as a reservoir for irrigation or
other utility.
-
waterline / water-line / water line :
-
the line in which water at its surface borders upon a floating
body; being just the part of the outside of a ship's hull that's
at the level of the water. Also, any of a series of lines on the
shipwright's architectural hull plans of a vessel that represent
the level to which the vessel is immersed or the bottom of the
keel. Also, a tube, pipe, or hose for conveying liquids.
-
waterlocked :
-
enclosed entirely, or almost entirely, by water. Also, living in
water cut off or shut away from the sea; compare landlocked.
-
waterlog :
-
to cause a boat, ship, or other vessel to become uncontrollable
as a result of flooding. Also, to soak, fill, or saturate with
water so as to make soggy or useless; apparently derived as a
back-formation of waterlogged.
-
watermanship :
-
skill in rowing or boating.
-
watershed :
-
the area or region drained by a stream, river, or other
watercourse. Also, an important point of division or transition.
-
waterspout :
-
a funnel-shaped or tubular portion of a cloud that's so laden
with mist and spray that it resembles a solid column of water
connecting the ocean, or other body of water, to the sky; a
tornado at sea.
-
waterway :
-
any natural channel conveying water, seasonally or otherwise, as
a river or stream; a watercourse.
-
waveson :
-
goods that appear upon the waves or floating at sea after a
shipwreck.
-
way :
-
movement or passage through water, as being underway or making
headway. Also, a ramp, usually two or more, along which the hull
of a boat slides when being launched.
-
weight belt :
-
a buckled belt worn around a diver's waist which holds enough
weights to offset the diver's buoyancy.
-
well :
-
a natural or artificial hole, as a depression or reservoir, for
the containment of water, or to supply a spring or fountain.
Also, a part of a weather deck between two superstructures,
extending from one side of a vessel to the other.
-
wet suit :
-
a close-fitting rubber garment worn by a skin or SCUBA diver in
cold water, that allows a thin insulating layer of water to
collect between the diver's body and the suit, in order to retain
body heat.
-
wharf :
-
a structure built on the shore of a harbor or estuary, or
projecting into such a body of water, for the mooring of vessels
and the transfer of passengers or cargo.
-
whimsy / whimsey :
-
an odd or capricious windstorm that creates turbulent water.
-
whip :
-
to overlay or cover cordage or rope with thread or line, as for
prevention of damage by friction, fraying, or raveling [cf:
puddening, mousing, baggywrinkle]. Also, a tackle consisting of a
fall rove through a single standing block (single whip), or a
fall secured at one end and rove through a single running and a
single standing block (double whip). Also, the hose used for
filling compressed air tanks.
-
whipping :
-
the binding on the end of a line or wire to prevent unraveling.
-
whirlpool :
-
a swift circular motion of water, caused by the meeting of
opposing currents, often producing a downward spiral.
-
whitecap :
-
a broken wave with a foaming crest; also called "white horses"
for their dancing movement.
-
white water :
-
frothy water, as in whitecaps and rapids. Also, light-colored
seawater over a shoal or sandy bottom.
-
white squall :
-
a strong sudden gust of wind that arises without warning,
exhibited by broken water or whitecaps; usually seen in whirlwind
form during clear weather in the tropics.
-
whole gale :
-
a wind of 55-63mph, as measured on the Saffir-Simpson scale.
-
wildcat :
-
that portion of a windlass that engages the links of the anchor
chain so that it can be heaved in. [cf: pawl, dog]
-
winch :
-
a machine having a drum on which to coil a rope, cable, or chain
used for hauling, pulling, or hoisting; sometimes called a
"windlass".
-
winding :
-
the act or process of turning a vessel end for end between buoys,
or along-side a wharf or pier.
-
winding hole :
-
the place in a canal or channel where long and/or narrow boats
are able to turn around; also known as "winded".
-
windlass :
-
a mechanical device used to pull in cable or chain, such as an
anchor rode; a capstan or winch.
-
windless :
-
a cranked handle used for mechanical winding. [cf: capstan-bar,
handspike]
-
windsock :
-
a tapered tubular cloth vane ("weather vane") or TELLTALE, that
pivots to catch the wind, swinging freely so as to indicate the
direction toward which the wind is blowing.
-
wings :
-
informal term for inflatable bladders (air cells) that ride on
either side (surrounding) of back mounted tanks, and have a
specified lift capacity, generally from 35 to 100 pounds.
-
within limits :
-
representation of a dive profile that conforms to the table
limits specified for the safe conditions of a dive.
-
woe betide :
-
distress comes, suffering comes to pass, trouble happens, grief
is visited upon, befallen by sorrow; not bêtise or betied.
[cf: woebegone (beset with woe)]
-
wrap :
-
technique for attaching guideline to a rock, especially at the
secondary tie-off.
-
yardarm :
-
either end of a center-mounted spar or yard; also called stick.
In modern vessels, the place where flags and pennants are often
attached.
-
yaw :
-
the rotation of a ship about its vertical axis so as to cause its
longitudinal axis to deviate from the heading in its horizontal
plane; the deviating motion or axial oscillation of a vessel
from its straight course or stable attitude.
-
Y-Valve :
-
a tank valve with two outlets; also called a slingshot valve.
-
zip tie :
-
ratcheted plastic strip that is used to securely attach accessory
items to a bolt clip; used in lieu of tied line.
-
Z-knife :
-
a line-cutter consisting of a handle and blade guard with a razor
blade inside a slot.
|
