50/50

Nitrox50. 50% O₂, 50% N₂. Commonly used as a travel mix.

80/20

Nitrox80. 80% O₂, 20% N₂. See stroke mix.

A

AAS

Alternate Air Source, such as a pony bottle.

ab(s) (1)

Abalone(s), a California shell fish pursued by divers and sea otters. The sea otters are better at it.

abs (2)

What studly macho divers think they have but don't.

ab irons

Tool used to get abalone off rock.

ABLJ

Adjustable Buoyacy Life Jacket, horse-collar style, forerunner of the BC. (British)

AGA

A popular full face mask, the AGA Divator MKII. In New York pronounced "auger" (with a strong "AW" sound in the beginning).

AGA and com gear

An AGA equipped with a microphone and speakers to allow a diver to communicate by voice, typically through a wire to a surface support team.

AGE

Arterial Gas Embolism, bubble causing obstruction to a blood vessel

AI

Assistant Instructor

air hog

Diver who sucks tank dry in record time. (Or in less time than it takes their buddy.)

aluminum 80

Most common tank in industry. Nominal capacity 80 cu. ft.

alpha flag

International maritime signal flag, meaning "Diver down, keep clear!". Compare with the U.S. dive flag

AOW

Advanced Open Water (PADI qualification)

artificial spit

Small bottles of liquid purchased at exorbitant prices by divers who do not know better to keep their masks defogged. Made by having divemaster candidates fill small bottles with REAL spit.

artifact

An item removed from a wreck. See souvenir.

ASD

Atrial Septal Defect, 'Hole in Heart'

ATA

Absolute pressure. Includes the atmospheres of pressure you rack up under the water and the atmosphere of pressure at the sea level ATM machine.

AV

Artificial Ventilation. EAR. (British)

B

back roll

Leave a boat by sitting on its rail and then rolling backwards into the water.

backscatter

What you get in your picture after bozo the CN kicks the bottom.

bail-out bottle (1)

A small bottle filled with your favorite beverage to hold you until your friends come to bail you out of the Cozumel jail.

bail-out bottle (2)

SD

bail-out bottle (3)

Extra cylinder of gas carried by a surface supplied diver or a rebreather diver to enable them to reach safety in the event of an interruption of their primary supply. For saturation divers, this would typically be to reach a habitat.

barotrauma

Damage caused by water or air pressure.

BC

Buoyancy Compensator.

Braille dive

Viz so bad you have to just feel your way around.

BCD

Buoyancy Control Device.

beaver

On old wetsuit jackets it hung down in the back. You pulled it through your legs, and velcroed it to the front of the jacket. Also called a beaver tail.
Historical note: Some 'real men' claim to have been able to fasten this without obtaining a high pitched voice. This is probably apocryphal.

bend-O-matic

Dive computer

bent (1)

Suffering from DCS.

bent (2)

Suffering from too much tequila.

blowing off

Omitting something, typically omitting required decompression.

blue water

Un-green water. Typically found somewhere you are not. Like Cozumel.

bolt snap

Brass or stainless steel fitting with a gate activated by your thumb.

bondage wings (1)

Impressive looking back mounted BC by OMS. Features dozens of little rubber straps to confine the bladder when not inflated. Implicated in a number of tech diving tragedies.

bondage wing (2)

A diving S&M toy

Bottle

Cylinder.

bottom dump

Valve on the bottom of a BC which allows you to empty air while in a head-down mode.

bottom mix (1)

Mix breathed at the bottom, especially when other gas mixes are used for travel and/or deco. Bottom mix should have ppO₂ less than 1.4. END is typically chosen to be 99 fsw or 132 fsw.

bottom mix (2)

What is found in the bottom of used margarita glasses.

bounce
or bounce dive

To dive and surface at intervals repeatedly. A dive where you turn around to ascend immediately after reaching the bottom.

BSAC

British Sub Aqua Club.

BT

Bottom Time - definition is agency dependant.

buddy (1)

For the benefit of officious Divemasters - your nominal partner when you practice the "Same Day, Same Ocean" diving principle

buddy (2)

The person who always sees more interesting things on a dive than you do; knows the scientific names of all of those furry little green things that live under rock ledges; reveals to the rest of the passengers that your diving techniques are all wrong; and leaves you to wash out their gear at the end of the day.

buddy (3)

A person you're happy to go for a drink with.

bug

Lobster. Also crawfish in Louisiana

bug bag

Lobster Bag. Generally of mesh and/or canvas. To carry all the lobsters that you catch, or the artifacts you recover.

bug hunting

Hunting for bugs.

butt-mounting

Dangling the battery pack of a cannister light underneath your doubles, rather than on the right hip. Considered the height of strokery by Hogarthians.

BWRAF

PADI training acronym: "Begin With Review And Friend". Alt: "Bad Women Really Are Fun"; "Big White Rabbits Are Furry".

 

C

canister light

A light where the battery is strapped to your belt and the light is held in your hand.

CAPS

Cave mapping software and electronic survey equipment

cattle boat

We've all been there, done that. There are no cows on a cattleboat, at least not the four legged kind.

CESA

Controlled Emergency Swimming Ascent

C-card

Certification card

chamber (1)

Hyperbaric chamber, for diagnosis and treatment of DCS

chamber (2)

The room that contains the pot.

chamber ride (1)

To be compressed in a chamber.

chamber ride (2)

What you do on your last day at the hotel in Cozumel. See chamber (2).

charlie foxtrot

Euphemism for clusterfuck, derived from initials.

check-out

What you do on your last day at the hotel in Cozumel.

 

chokes

 

Form of DCS in which you are unable to breathe effectively. Generally fatal unless treated quickly with on-site O₂ and prompt recompression.

chumming

Feeding the fishes. Performed voluntarily by fishermen in order to attract large fishes. Performed by divers involuntarily.

clear (1)

equalize ears

clear (2)

free of nitrogen - clear to fly

clusterfuck

Complete pandemonium, often the result of strokery. Diving on the wrong day with the wrong equipment and the wrong attitude. American. See incident pit.

CM

Cutis marmorata.

CMAS

Conféderation Mondiale des Activitiés Subaquatiques, or in English the World Underwater Federation. International federation of scuba organisations. in the United States only the YMCA and the United Stateds Underwater Federation are members.

CN

Clueless Newbie.

CNS O₂ toxicity

Also known as the Paul Bert Effect, tox, or oxtox.

computer

Dive computer. I can't think of any time anyone thought we were talking about something with a keyboard.

CPR

Cardio-Pulmonary Rescusitation

cricket

A lobster below the legal size.

cu. ft.

Cubic feet. 1 cubic foot = 28.31685 liters.

cylinder

Tank

 D

DAN

Divers Alert Network. When you have a big problem, call (919) 684-8111. Web site: http://www.dan.ycg.org/.

DCI

Decompression Illness, including DCS and AGE

DCS

Decompression Sickness, the 'bends'

DDRC

Diving Diseases Research Centre, in Plymouth, England. The leading hyperbaric treatment and research centre in Britain.

dead reckoning (1)

Navigating without using external referents, using compass, initial known position, and estimates of speed, current, wind, etc.

dead reckoning (2)

The navigation method preferred by divers who never learned to use a compass. So called because they are frequently found dead.

deco mix (1)

Gas mixture used for decompression, such as 80/20 or 100% O₂.

deco mix (2)

alt: 1 part Bacardis, 1 part Jack Daniel's, 2 parts lemonade.

deep air

Like deep throat, only different.

deep air diving

alt: See muff diving

de-fizzing

off-gassing. See Wrolf's Bubble Theory
alt: taking away feeshes fizzies

deserved hit

DCS occuring after violating table or computer limits.

Doing It Right

DIR

DIA

Doom Induced Nausea. Feeling in the pit of your stomach when you are about to do a dive which is completely out of your comfort zone or experience. A George-ism.

DIN valves (1)

Superior alternative to a yoke fitting for first stage. Screws in rather than clamps on, and O-ring is "captured" inside valve, reducing chance of O-ring failure.

DIN valves (2)

The noise made when insufficient care is taken loading tanks into a vehicle, and the valves are banging together.

DIR

Term invented by George Irvine III to describe the practices that he and others derived from Hogarthian principles. See Hogarthian Diving Style

dive

Does anyone think this involves a springboard?

dive babe

Woman who is a real diver - opposite of a chick

dive chick

Female diver who puts on make-up; brushes hair; has her boyfriend assemble her kit; and then has him carry it to the water before doing her dive.

dive dry

Diving in a dry suit.

dive flag

Red flag with white diagonal stripe from top of staff to bottom of fly: . Means the same as the international alpha flag, but is almost unknown outside the U.S. and cultural vassals. Within or near U.S. waters, the best policy is to fly both. Outside, fly the alpha flag.

DM

Dive Master

double-disking

Using 2 burst disks on the valve of your tank to decrease the chance of losing all your air.

double steel 104's

Pair of steel cylinders, nominal capacity 104 cu. ft, connected together with bands and a manifold.

DPV

Diver Propulsion Vehicle. Scooter.

drift deco

hanging from a lift bag or DSMB during your deco (usually for high currents)

D rings

D-shaped rings. Attach to BC webbing with weight retainers.

DSMB

Delayed Surface Marker Buoy, SMB which is inflated at end of dive. (British)

DUI

Diving Unlimited International. Manufacturer best known for their dry suits

DV

Demand Valve, usually the second stage. (British)

 E

EAD

Equivalent Air Depth The depth at which air would cause as much decompression obligation as a nitrox with a given fO₂ at a given depth.

EAD	= (Depth+33') fN2/0.79 - 33'
	= (Depth+33') (1-fO2)/0.79 - 33'

All depths in fsw .

EAN, EANx

Enriched Air Nitrox

EAR

Expired Air Rescusitation (preferred term now is AV in Britain)

EAV

Expired Air Ventilation (British)

END

Equivalent Narcotic Depth. The depth at which air would cause as much narcosis as a given mix and depth. END is typically chosen to be 99 fsw or 132 fsw for a bottom mix. Assuming that O₂ and N₂ are equally narcotic in practice; ignoring the narcotic potential of He (which is small, or perhaps non existent); and with depths in fsw:

END	= ((1-fHe) (Depth / 33 +1)-1) * 33
	= (Depth+33') (1-fHe) - 33'

Many texts have not been updated to reflect the finding that O₂ and N₂ are approximately equally narcotic, and instead attribute all narcosis to ppN₂. This changes the formula to:

END = (( fN₂/.791 ) (depth / 33 +1)-1) * 33 Obsolete

To make things worse, O₂ & N₂ are probably not equipotent for narcosis at all concentrations. It seems that at certain ratios, the O₂ component is more narcotic than N₂; and in other ratios, the N₂ is more potent. 

But assuming O₂ & N₂ are equipotent for narcosis is the best current practice.

EX-buddy

person who - after you have put up with all of their foibles - gets to the bar and insists that it's your shout!

 F

FAQ

Collection of Frequently Asked Questions (and answers). See the rec.scuba FAQ.

fart bag

Drysuit.

feed the fish

vomit

FFA

Feet First Ascent. Learning technique used by new drysuit divers.

FFM

Full Face Mask

FFW

Feet of Fresh Water

fin ladder

A pole with pegs attached to either side to facilitate climbing out of the water with your fins on.

flounder gig

A speargun spear with a SS cable attached to a T. This is used for flounder collecting.

fHe.

Fraction of helium (He) in a mix. In air, fHe = 0, unless you are near certain natural gas wells, a birthday party, or tech divers.

fN₂.

Fraction of nitrogent (N₂) in a mix. In air, fN₂ = 0.791 = 79.1%. Actually this is a lie, counting the approximately 1% of other gasses in air (noble gasses etc.) as though they are nitrogen, but it is close enough.

fO₂.

Fraction of O₂ in a mix. In air, fO₂ = 0.209 = 20.9%.

free diver

Breath hold diver. Good guys, see Freediver brings gas

foul the hook

To tie the wreckhook upside down to facilitate leaving the wreck. Usually done by the last person up.

FSW

Feet of Salt Water

 G

gaiters

Rig designed to reduce the amount of air the lower legs of a drysuit. See FFA.

gerry line

Granny line.

get wet

What all divers want to do - go diving.

golden triangle

Area between the chin and the nipples where it is easiest to access equipment such as knives and regulators.

Goodman handle

A U-shaped attachment to the light head of a canister light for attaching the light head to your hand.

GPS

Global Positioning System

granny line

Line which goes from the stern platform or hangbar to the anchor line.

 H

h valve

tank valve with two outlets.

halocline

Boundary between layers of water of different salinities. Looks like a barrier of mist.

hang

To perform a decompression stop.

hang bar

Bar slung underneath boat for convenience during decompression stops

hang line

Horizontal line rigged for convenience during decompression stops

hang tank

Extra tank, ideally of deco mix, staged at deco stop.

Hawaiian sling

A long spear with an elastic loop at one end and 3-pointed gig on the other. You catch the loop in your thumb and pull the spear back. When you let go, the spear shoots forward, hopefully into a fish.

heliox

Breathing mix of helium and oxygen.

hit

Incident of DCS.

Hogarthian principles

Principles behind Hogarthian system, named for William Hogarth Main. Originated for cave diving but now adopted more widely. See Hogarthian Diving Style

Hogarth rig

Hogarth rigged dive gear.

Hogarth rigged

A method of rigging your gear for maximum survivabililty.

homebrew

mix, especially nitrox, brewed up at home, or by adding oxygen to a cylinder and then taking it to dive store for fill. Implicated in a number of fatalities.

hookah

regulator for breathing surface supplied air, either from a tank or a compressor, typically down to about 30 feet.

hoover

air hog

horsecollar

the old style floatation device (now BC).

HP hose

High Pressure Hose. Goes from 1st stage to air pressure gauge.

hydro

Hydrostatic testing for tank integrity

I

IANTD

International Association of Nitrox and Technical Divers

inflatable

Generally means a RIB.

incident pit

Series of events which individually would not be dangerous, but each causes a problem, which is increased by the next, until you have a major incident. The incident pit is a conceptual 'pit' with progressively steeper sides. Anything going wrong pushes you slightly further into the pit. As the sides steepen, it gets progressively more difficult to get out. British. See clusterfuck.

ingassing

Taking on additional nitrogen (and/or other inert gases).

instroketor

Instructor who perpetuates strokery by instilling in students his own defective attitudes and techniques.

IP

Intermediate Pressure, i.e. the pressure between the first and second stages

isolating manifold

manifold that also has a valve to isolate the two tanks, to preserve half the gas supply in the event of a failure.

J

Jersey reel

A large spool designed to hold ¼ diameter sisal line. Used in conjuction with a lift bag.

Jon line

6-8 ft. line used to attach diver to anchor/shot line for deco so you don¹t wear your arms out. Named for Jon Hulbert, a well-known NE wreck diver.

J-valve

Old fashioned tank valve with a reserve lever, which signals that pressure is down to 300-500 psi by making breathing difficult. Often seen with reserve feature disabled on old steel 72s.

K

K-valve

Regular tank valve

kelp crawl

Strange motion used to get over kelp on the surface.

kit

(Dive) Gear. British.

L

legal bugs

Vs. shorts. Lobsters that are long enough to be taken, and do not have eggs on them.

lift bag

A device which you attach to an object you would like to lift off the bottom. Shaped like a upsidedown garbage bag, you pump air into to raise your object.

loot and scoot

Wreck diving in the Great Lakes.

LORAN

Long-range Navigation.

A radionavigation system using land-based radio transmitters (operated in the United States by the USCG) and receivers to allow mariners, aviators, and (more recently) those interested in terrestrial navigation to determine their position.

Highly accurate (better than 0.25 nautical mile (NM) absolute accuracy in the defined coverage area), available (99.7% availability), 24-hour-a-day, all-weather radionavigation system. Loran-C (the present version of this system) coverage extends over the conterminous United States, portions of Alaska, and many other areas of the world.

Source: LORAN-C Users Handbook

Less accurate (for absolute position) than GPS, but cheaper, and universally installed on U.S. boats. LORAN is still more accurate for returning to a prior position (such as a wreck.)

Lorraine Smith Effect

pulmonary O2 toxicity

LP hose

Low Pressure hose. Goes from 1st stage to 2nd stage or to inflator.

M

manifold

plumbing to connect to tanks so that one regulator can access the gas in both. See isolating manifold

MARES

Diving equipment manufacturer.

mix [noun]

mixture of gases, often a trimix

MOD

Maximum Operating Depth for a mix, given a maximum ppO₂.

MOD = (max ppO₂ / fO₂ - 1) * 33 fsw

N

NACD

National Association for Cave Diving

NAUI

National Association of Underwater Instructors.
Not Another Underwater Idiot.
Need Another Underwater Instructor.

NDL

No-Decompression Limit

NDS

No Decompression Stop - no decompression limit according to table or computer

NED

Network of Egghead Divers. See information on rec.scuba

newbie

Some one new at diving, computers or anything else.

nitrox

Any mixture of nitrogen and oxygen. Nitrox 32, Nitrox 36, Nitrox 50, Nitrox 80, etc: Nitrox with 32%, 36%, 50%, and 80% of oxygen respectively.

Nitrox I

Nitrox 32. The NOAA term, the term Nitrox 32 is more precise and therefore preferred.

Nitrox II

Nitrox 36.

NSS-CDS

National Speleological Society-Cave Diving Section

O

O₂ clean

Clean enough of combustibles such as oil to allow use with high pressure O₂.

ocky

Octopus (British)

OCN

Obnoxious Clueless Newbie.

octo

Octopus

Octopus

Extra second stage regulator, for benefit of your buddy should they want to use your air.

offgassing

Reducing the load of nitrogen (and/or other inert gases).

OMS

Ocean Management Systems, an equipment vendor well known for their low pressure steel tanks, and also unfortunately for their bondage wings.

OOA

Out Of Air

OS

O.S. Systems, Inc., Shell dry suit manufacturer. See also this unofficial site.

outgassing

Offgassing

OW

Open Water. The lowest level of PADI certification for scuba diving.

P

P

Pressure

PADI

Professional Association of Dive Instructors.
Put Another Dollar In.
Pay And Dive Immediately.
Patches Available During Instruction.
Produce Another Dumb Instructor.
Patch and Dollar Industry.
Patches And Decals Included.
Pissed-off Another Dive Instructor.
The largest certifying agency in the U.S.A.

PDIC

Professional Diving Instructors Corporation. Certifying agency.

PFO

Patent Foramen Ovale, openable flap between atria. See ASD. A shunt between the right and left side of the heart that allows some blood to circulate back through the body without going to the lungs first. This means that micro-bubbles don't get removed from the blood stream by the lungs efficiently, making DCS more likely. 1in 4 people have a PFO.

 Paul Bert Effect

 CNS O₂ toxicity

NOAA - CNS oxygen toxicity exposure limits
ppO2 (Bar)	Exposure Limit per dive (min)	Exposure Limit per day (min)
1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.7	45 120 150 180 210 240 300 360 570	150 180 180 210 240 270 300 360 570

PDC

Personal Dive Computer (British)

persuader

Any large crowbar, pipe wrench or sledge hammer used for souvenir hunting

pony bottle

15 to 30 cu. ft. tank, typically worn beside main tank, as a fully redundant emergency air supply. See discussion of ponies and Spare Air in rec.scuba FAQ.

pp

Partial Pressure. The total pressure of a gas mixture is the sum of the partial pressures of the component gases.

ppHe

Partial Pressure of Helium

ppO₂

Partial Pressure of Oxygen. Don't go over 1.4 ATA while diving, or over 1.6 ATA while decompressing.

ppN₂

Partial Pressure of Nitrogen

pretzel

as in bent as a pretzel. Very bent, doubled over in agony.

primary

In a Hogarth rig, the regulator with the long hose, wrapped around the canister light on the right of your harness belt, up to the left of your head, around your neck and into your mouth.

psi

pounds per square inch. psi / 14.50377 = bar.

P weight

Weight designed to fit in the gully of a standard backplate.

Q

R

reduce the signal-to-noise ratio

Write useless verbiage (noise), thereby reducing the proportion of useful postings (signal) to useless postings (noise).

RIB

Rigid Inflatable Boat, solid keel and large inflated tubes. (British)

riding the hook

Hooking up to a wreck by handing a diver the anchor and chain and said diver jumping over and riding it down to the wreck. Used for small/low-profile wrecks.

rolling a tank

Tumbling a tank to remove internal corrosion.

Rule #1

Don't dive with strokes. (Hogarthian)

Rule #2

Don't listen to strokes. (Hogarthian)

Rule of Thirds

Air - a third to get there, a third to get back, and last third belongs to your buddy.

S

SAA

Sub Aqua Association.

The thorn in BSAC's side, and the only thing stopping them from gaining world domination (well, err...in the UK at least).

SAC

Surface Air Consumption.

SAC =

At Depth Air Consumption

At Depth Absolute Pressure

See Estimating Gas Consumption, by Larry "Harris" Taylor, Ph.D.

S.A.F.E.

PADI training acronym: "Slowly Ascend From Every dive". Alt: "Submerge And Forget Everything".

safe second

Octopus.

SAR team

Search and Rescue Team

Scooter

DPV.

SCUBA

Self Contained Underwater Breathing Apparatus. Contrast with SCBA, used by firefighters, which is similar but not intended for use underwater. Also compare with surface supplied air. Scuba is generally used to mean open circuit scuba, as opposed to closed or semi-closed circuit rebreathers.

SD

Short for "Spare Death", a slur on the brand name Spare Air. A can of air that is too small to get you to the surface in a real emergency. See discussion of ponies and Spare Air in rec.scuba FAQ.

sea lice

Yucky rash, actually caused by larvae of thimble jellyfish larva, getting trapped in bathing costume/lycra etc. and stinging. The larvae almost invisibly small. Sea Lice or Seabather's Eruption, according to which "any rash needs a thorough evaluation to rule out possible communicable causes", which also has detailed instructions for treatment.

second

In a Hogarth rig, the regulator under your chin.

serious bandwidth-damage

Posting of lots of stupid messages.

set the hook

To make sure that the wreckhook is securely fastened to the wreck. Usually done by the first person down.

shoot a bag

To send a liftbag up with a line attached for a floating deco.

silt-out

Complete loss of vision caused by silt being disturbed, typically by careless finning.

SI

Surface Interval (between dives)

six-pack/fast boat

Small, open diveboat. Passengers generally limited to not more than six - ergo 6 pack.

In the USA a licensed captain can operate a boat carrying up to 6 paying passengers without the boat undergoing the rigorous inspection required of vessels that carry more passengers. Most dive boats tend to be either six packs less than 25 feet long or cattle boats of more than 40 feet. The six packs still have to be seaworthy and must carry certain safety gear, they just don't have to meet all the requirements that cruise ships do.

skin

Lycra for warm-water wimps.

sled

Wooden board you hold onto while being dragged by a boat.

sling [bottle]

Stage bottle.

slobitus

DCS skin hit (called that because it originates in fatty tissues).

sloppy

Snotty (New York/New Jersey).

snotty

Rough sea conditions. In the Northeast, this means 14 foot seas. In Cozumel, it means 2 inch seas.

SMB

Surface Marker Buoy. Buoy with flag (on a line to diver). (British)

SOB

Same Ocean Buddy

shot line

A weight with line and buoy attached to mark the location of a wreck. Used primarily by european divers.

'sorb

Stuff in a rebreather to absorb the carbon dioxide you breathe out. Adsorbent.

souvenir

To remove items from a wreck.

SPG

Submersible Pressure Guage

spring straps

Stainless steel springs used to hold your fins on your feet.

square dive

A dive where you stay at the deepest point for the duration of the dive.

stab

stabilizer jacket, or BC (British).

stage bottle

A separate gas supply which is detachable from the diver.

steel 72

Somewhat old-fashioned tank. Nominal capacity 72 cu. ft.

stop

if it weren't for the honor of the thing, the safety stop would be a deco stop

stroke (1)

diver who's so clueless that he/she is a danger to him/herself and anyone nearby. Often considered an accident looking for a place to happen.

stroke (2)

Diver who refuses to learn even when shown a better way.

stroke (3)

Favorite insult of Hogarthian divers at WKPP.

stroke mix

WKPP divers believe that 80/20 is a bad idea, and refer to it as "stroke mix".

strokery

The practices of a stroke.

squidgie

A RIB. (British)

suicide clips

A type of brass clip with a springed gate notorious for trapping lines and killing divers.

T

tag line

Granny line.

tank

bottle

tech

also tek, tekkie, techie, and cowboy

Techdiver Salute

A raised fore-finger indicating all is well.

thermocline

Boundary between layers of water of different temperatures.

tie in

To attach the wreck hook to the wreck with a separate line.

top-to-bottom

Underwater vis so good you can see the wreck from the surface.

towfish

Side-scan sonar transducer. Towed in water behind boat.

tox

Slang for central nervous system oxygen toxicity that can happen when diving too deep on air or diving deeper than you should on an enriched air (nitrox) mixture. Also called the Paul Bert Effect, but tox is easier to remember and lots easier to type.

travel mix

Mix such as 50/50 used to travel to or from the bottom. Travel gas is used to get down to the point where depth indicates that you must change to your bottom mix, and then to get up from that point to where you can switch to your deco mix(es).

trimix

Breathing mix of three gases, typically oxygen, helium, and nitrogen. Composition is quoted as percentage of oxygen / percentage of helium, e.g. 17/50 is a trimix with 17% oxygen, 50% helium, balance (33%) nitrogen.

tumble

Clean tanks of internal corrosion, by filling them with an abrasive such as ceramic chips or aluminum oxide, and leaving on a machine that rotates them for several hours.

 TUP

 Transfer Under Pressure. A TUP system mates a portable compression chamber to another chamber to transfer a person under pressure from one chamber to the other.

Tupperware

Large plastic containers wreck divers use to haul all their gear.

U

undeserved hit

DCS occuring despite staying within table or computer limits.

V

vaporware

Software that has been announced, but does not yet exist. Often pre-announced for marketing reasons, to discourage users from purchasing a real, shipping, competitive product.

VIP

Visual Inspection Program. Testing tank for integrity by visual inspection of insides.

viz

Visibility. As in "viz was great - 15 to 20 feet" (North East wreck diver), or "viz was disgusting - 50 feet" (Florida tourist diver).

V weight

V-shaped lead weight designed to fit between your tanks behind your backplate.

W

wah-wahs

Extreme form of nitrogen narcosis (and possibly oxygen toxicity), described in Cautionary Tales.

weight retainer

Small metal or plastic device used to keep lead weights from sliding, among other things.

wet

Means more to us than just moisture present.

whip

Adapter to fill tanks from O₂ or He bottles.

WKPP

Woodsville-Karst Plains Project

WPB

West Palm Beach

wreck hook

An anchor with bendable tines, also called a grappling hook.

X

Y

y valve

Tank valve with two outlets.

Z

zodiac

A RIB.