Term
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Definition
| Self Contained Underwater Breathing Apparatus |
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Term
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Definition
| recreational, sport, commercial, technical, skin, free diving (no apparatus) |
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Term
| After certification, you're qualified to dive in... |
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Definition
| conditions similar to those in which you did your open water certification dives. |
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Term
| Additional specialty diving courses |
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Definition
| rescue diving, underwater photography, hunting, collecting, night diving, etc. |
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Term
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Definition
| National Association of Underwater Instructors. Founded in 1960. |
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Term
| As a diver, you must be willing to accept... |
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Definition
| risk of death, injury, and take responsibility for own actions. can be strenuous, especially in cold water/strong currents/beach entries. |
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Term
| Must sign this to accept risk |
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Definition
| Express Assumption of Risk Associated with Diving and Related Activities. also - medical history form. |
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Term
| Misconceptions about diving |
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Definition
1. run out of air - check submersible pressure gauge (SPG), carry additional regulator/air supply.
2. unreliable equipment. care for equipment, more likely to give too much air via regulator than no air.
3. shark attack. rare to see sharks, no interest in humans. |
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Term
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Definition
1. attend, participate in, complete all classroom/open water sessions.
2. finish exams and confined/open water evaluations. even if you pass, instructor can withhold certification.
3. health: heart, lungs, ears, sinuses, diseases, unconsciouness ailments.
4. fitness - swim 200 meters nonstop. best way to stay fit is to dive regularly. take refresher course.
5. drugs/alcohol never used before diving, or prescription drugs not recommended with operating machinery. |
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Term
| medical history form/well-being |
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Definition
| naui instructor can decline training you if you have an absolute contraindication (asthma, diabetes, epilepsy) or pregnancy (no definitive studies done, so can't dive). |
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Term
| Buy equipment local because |
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Definition
| can see/wear before buying, can adjust BCs, can service gear, can rent/loan, fill cylinders |
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Term
| because you wear most pieces of dive gear directly on your body, this is most important |
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Definition
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Term
| four pieces of gear needed for skin diving |
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Definition
| mask fins snorkel flotation device |
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Term
| scuba mask differs from swimming goggles how? |
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Definition
| covers nose, allowing you to equalize pressure inside the mask when you exhale air from your hose. |
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Term
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Definition
| place mask on face, no strap. inhale through nose. if mask sticks even when looking down, good fit. |
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Term
| essential features of a mask |
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Definition
tempered glass lens so it doesn't break.
solid frame to hold lens
adjustable split/wide headstrap
ability to block off nose to help equalize pressure in ears
double featheredge seal to help fit to face. |
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Term
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Definition
side windows, purge valge, prescription.
can clear mask lens lubricant with toothpaste - also helps prevent fogging. |
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Term
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Definition
1. used to conserve energy/air when swimming on the surface.
2. J shaped tube with mouthpiece.
3. can add flecible hosing, purge valve, swivel mouthpiece, baffles to keep air out of top, soft mouthpiece.
4. Should be 30-35 centimeters tall!
5. inside diameter no less than 2 centimeters
6. too wide/tall can make breathing difficult - like breathing through straw, or getting water in top if too short |
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Term
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Definition
1. protection/warmth. shoes while walking.
2. made of neoprene - synthetic rubber injected with gas (usually nitrogen) to make it spongy. covered with nylon. |
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Term
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Definition
1. means of propulsion
2. full-foot (for snorkeling, warm water, entire foot is in foot pocket of fin) vs. heel strap (strap on back, open, must wear booties, any temp water)
3. blade - portion extending from foot. too large can cause cramps. |
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Term
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Definition
1. considered basic gear in many parts of world.
2. protect rom cuts/scrapes, give warmth
3. made from cotton, thin nylon, thin neoprene (cold water)
4. don't touch stuff even when wearing gloves. can injure fish/reefs
5. some places don't allow gloves (cozumel mexico) to prevent touching reefs. |
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Term
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Definition
for snorkeling and skin diving.
inflatable vest, usually slips over head and fastens at waist. |
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Term
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Definition
rinse with fresh water after every diving ay.
don't leave in sun
end of trip- soak overnight in fresh water then rinse
store in cool, dry area |
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Term
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Definition
1. store lots of air in small space. aka bottes/tanks
2. highly compressed, made of aluminum(don't rust but more easily damaged)/steel (less damaged, but if water enters, rusts)
3. usually 10-18 liter, pressure of 150-200 bar. or 63-95 cubic foot with pressure 2475-3000 psi.
4. markings - serial number unique to each cylinder, name of manufacturer, material type, hydrostatic testing date (in us every 5 years).
5. some have boot to protect bottom/stand upright, or netting |
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Term
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Definition
1. holds air in, controls flow out, attachment point for regulator.
2. like water faucet. open by turning handle counterclockwise (from top of handle view)
3. usually K Valve in US, o-ring seal
4. J valve - like K, but has lever "reserve mechanism" - restricts airflow. popular before submersible pressure gauges (spgs) were invented. now rare.
5. DIN valve - large threaded opening, captured o-ring system. common outside of US. is stronger.
6. burst disks - pressure relief disk. allows cylinder to vent extra pressure by bursting disk so doesn't erupt if gets hot. |
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Term
| Cylinder inspection/maintenance |
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Definition
1. internally/externally once/year by certified inspector.
2. look for dents, marring, fire/heat discoloration on outside. corrosion/water/cracks inside.
3. sticker on tank when passed.
4. if cylinder needs to be tumbled to remove oxidation, needs hydrostatic testing. also every 5 years in US. tests for metal fatigue. filled with water, placed with larger cylinder of water. pressurized. if tank increases size then returns to size, okay.
5. store tanks with air/pressure for steel to avoid water getting in. aluminum stored empty. upright where can't be knocked over, cool/dry place. valve open so not fire hazard. lay on side if could fall over. |
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Term
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Definition
1. mechanical device that delivers air on demand.
2. reduces high pressure of tank air to ambient pressure (of body surroundings) so you can breathe it.
3. two parts: first stage and second stage. |
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Term
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Definition
high pressure air from cylinder is reduced to about 10 bar / 150 psi above pressure surrounding the cylinder. fits over post of cylinder valve using yoke/yoke screw. some use DIN threaded fitting.
submersible pressure gauge attached to this port to monitor air supply. might also have power inflator hose, alternate regulator, etc. attached. |
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Term
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Definition
mouthpiece attached.
further reduces the air pressure from approx 10 bar above, to whatever the surrounding pressure is.
so - air you breathe is at same pressure needed by your body, no matter how deep.
high performance options deliver greater volumes of air at deeper depths - good for deep/wreck/cave diving. |
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Term
| regulator alternate air source |
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Definition
octopus regulator.
additional second stage that allows you to share air with another diver.
should be longer 10cm than standard regulator hose.
another option - combo regulator/power inflator for BC that fits on power inflator hose. this way - no extra hose.
also: contingency scuba - true alternate air sources.
pony bottle: small tank with own regulator.
or, smaller cylinder with integrated first/second stage mounted directly on cylinder.
good backup if buddy separated, but bulk and expense. |
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Term
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Definition
tells depth, bottom time, direction, and air supply.
dive console: streamlines gauges into one unit. has submersible pressure gauge, depth gauge, and compass.
submersible pressure gauge SPG: required, shows air pressure remaining in tank. check frequently. reads in bar or pounds per square inch (PSI). full aluminum = 200 bar/3000 psi.
depth gauge: four types: capillary tube (simple, cheap. clear tubing, water enters, compresses air. good for shallow), bourdon tube (pressure straightens curved metal tube) diaphram mechanism (metal diaphragm attached to linkage, attached to needle) electronic depth gauges (attached to dive computers, very accurate).
must have a means of measuring deepest depth. only electronic gauges always record. |
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Term
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Definition
important when low visibility. not essential.
diving compass must be filled with liquid, have a reference line (lubber line) used as direction of travel, and have a bezel to show direction. |
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Term
| maintenance of regulator/air/gauges |
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Definition
replace dust cap over inlet to first stage whenever regulator is off a cylinder. must be dry. often uses an o-ring.
rinse with fresh water, including mouthpiece. never press purge when running water through. soak after dive trip.
get regulator serviced once/year. |
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Term
| additional diving instruments |
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Definition
timing devices - tracks time underwater - watch, computer, etc.
dive computers - measure length of bottom time, depth (max & current), remaining allowable time.
backup instruments |
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Term
| buoyancy compensator (BC) |
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Definition
controls whether you float, hover, or sink. control by adding air/venting from BC.
controls buoyancy.
amount of air it can hold = lift capacity |
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Term
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Definition
overpressure relief valve (prevents damage from too much internal air pressure)
inflator/deflator hose (at east two centimeters diameter. can pull down to open overpressure relief valve/dump valve.)
power-inflator mechanism (attached to first stage. allows adding air to BC using button)
& deflator/oral inflator valve.
mouthpiece to inflate manually.
avoid older BCs with carbon dioxide cartridge inflator mechanisms. |
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Term
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Definition
1. back flotation- whole bladder behind you, leaving front uncluttered. popular for photography. can push you face down.
2. jacket-style - most popular. wraps around, comfy.
3. Horse collars- older, encircles neck. works for skin diving too.don it separately from cylinder.
integrated weight systems - (not on horse collars) - can have weight direclty on BC, no weight belt. add with velcro, can drop the pockets in emergency. but instructor can't tell how much weight you're carrying. |
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Term
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Definition
| rince internally and externally after each diving day. gets water in it every time you bleed air, can cause damage. fill with water through oral inflator mouthpiece, slosh around, drain through same mouthpiece. power inflator inspected yearly. |
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Term
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Definition
wear lead to offset buoyancy of body/wetsuit/gear. can be molded to fit hips, or bullet weights with hole in middle.
soft weight - lead shot sewn into pouches, are comfy, cause less damage when dropped.
belt - nylon belt, weight keepers keep lead from shifting. some have pockets, some one continuous compartment.
weight harnesses - usually with dry suits. supports via shoulders.
good feature of weight belts - compensate for wetsuit compression as you descend, so doesn't slip down.
quick release - necessary, with one hand. |
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Term
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Definition
must wear right thermal protection. get cold, aren't performing at best. fatigue fast.
amount of insulation depends on water temp, activity level, build, body fat, etc.
in warm tropical, maybe just skin suit. cold needs wetsuit, coldest needs dry suit.
also protects from injuries. |
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Term
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Definition
dive skins - thin, one piece, protects from injury.
usually lycra (minimal thermal, but can combo with polypropylene/insulators. no wind protection) and polartec (combo of lycra and velour fleece lining. warm and less weights needed)
wetsuits-foam neoprene. good insulation, widely used. fits snugly. thicker = better insulation but also awkward. can adjust warmth by layering. can have custom made.
dry suits- for colder water. expensive, keeps you dry. can layer underwear to adjust insulation.neoprene/nylon. seals at edges. control air in dry suit with inflator valve. similar to BC. use bc for surface flotation only, and backup. need to take specialty classes for using dry suits. |
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Term
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Definition
hoods for cold water - lose most heat from head, hands, chest, armpits, groin.
personal decision - some people colder than others. 80degrees+ skin suit, 55-75 full wetsuit. 35-55 full dry suit. colder than 35- special training. |
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Term
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Definition
| rince with fresh water, in and out. store on wide hangers or unfolded. dry suit - rinse outside only, occasionally clean inside. |
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Term
| diving accessory equipment |
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Definition
clips - keeps gauges off of bottom so don't damage marine life or be damaged. clip to bc.
knives - cuts line/nets if you get tangled. not weapons. underwater hunter wants thin sharp blade, wreck diver wants heavy knife with blunt tip for prying. keep sharp, in sheath. keep on inside of calf or BC pocket.
gear bags - transport gear to dive site. nylon best, or canvas.
dive flags/floats - let others know you're underwater. US is red with white diagonal stripe. take down when out of water. international flap - alpha flag. if shore diving, just need a surface support station like an inner tube.
logbooks - record of experience. record all info. shows varied experiences, documented. hours underwater, dives done.
first aid kits- add to standard kit.
underwater slate - communicate with buddy.
goodie bag - hold artifacts.
light - night diving.
marker buoy, spare parts. |
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Term
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Definition
snorkel on left
do site survey and dive plan FIRST.
booties and feet must both be either wet or dry.
figure four position when donning fins. walk backwards or side step.
mask/snorkel last. |
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Term
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Definition
flutter kick most common - legs broomsticks, kick from hip.
kick slow, deliberate, wide. don't bend knees much.
on surface - keep fins in water. shorten stroke. have air in BC to float.
also - dolphin kick. legs together, knees relaxed. |
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Term
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Definition
weight neutrally buoyant at surface.
get as much of body out of water as possible to help push you beneath surface.
1. headfirst: pike dive, tuck dive (less splash, scare less fish)
2. feet first: good for skin divers. upright in water, starfish arms/legs outwards then kick together, arms overhead while head goes underwater. then clear ears, tuck, face down, descent. |
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Term
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Definition
when free diving, breathe in & out deeply a few times before taking deep breath of air. don't hyperventilate - too much carbon dioxide in body, not enough oxygen. usually happens close to surface upon ascent.
breathe in and out deeply twice, then third breath do dive. |
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Term
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Definition
blast clear: exhale air forcefully as you surface.
displacement clear: look up as ascend, exhale slowly. look down as head breaks surface, breathe normally. |
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Term
| assembling scuba equipment - who's responsible? |
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Definition
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Term
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Definition
10% of your body weight pus 5 pounds. for salt water.
distribute evenly on each side! |
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Term
| acronym for series of steps to plan dive/check equipment |
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Definition
SEABAG:
site survey
emergency planning
activity planning
buoyancy - buddy check weights, easy release. bc, power inflation, orally inflate, deflate
air - cylinder turned, regulator works, spg full, straps secure
gear & go - mask, snorkel, fins. hoses free, secure. accessories ready. |
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Term
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Definition
bc partially inflated
hold mask, breathe from regulator
make sure area is clear and deep
1. giant stride - from boat where distance to water is less than 6 ft. keeps you near surface.
2. back roll - small boat
3. seated side - pool, ledge at water level, boat dock. from water's edge, sit at edge with legs in water, turn & lower. |
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Term
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Definition
calm water - walk in, shuffle feet to detect holes/rocks. don fins when waist-deep, maybe inflate BC and float on back. if lose balance, don't stand up. crawl and swim.
surf- special training. bc deflated so you can easily get underwater.
rock jetties or breakwaters - special training. sit on rock, push off. |
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Term
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Definition
evaluate area first. check equipment in place. think out steps. keep fins on while in water.
1. ladder - stay out of way until your turn.hold ladder, remove fins using figure 4 position. fin straps over wrists, climb ladder.
2. boat transom platform - coordinate wave action to help lift you. remove weight belt/items, scuba unit. place hands on platform, kick legs, push up, swivel. remove fins. |
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Term
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Definition
depends on conditions.
calm water - swim until waist deep. stand and use buddy to remove fins. walk out.
surf- keep regulator in, hold mask on. swim until can crawl. roll over, remove fins.
rock jetties/breakwaters - reverse entry procedure. |
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Term
| clear water from regulator - two methods |
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Definition
blast clear - breathe out
purge clear - push button |
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Term
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Definition
note time you leave surface
deflate BC.
equalize ears
exhale, begin feet-first descent
stay with buddy
not rapid!! 75 FEET PER MINUTE TOPS
first descent will be controlled descent - along a line.
once more comforatble, will do free descents virtically in open water without a line. |
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Term
| neutral buoyancy during dive |
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Definition
neither sink nor float when at rest.
add air to BC when deeper to offset ewtsuit compression.
as ascending, vent air from BC to maintain neutral buoyancy. |
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Term
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Definition
secure accessories
find power inflator hose, hold above head
give buddy up signal
swim up, look up
control buoyancy by venting BC air
DON'T ASCEND MORE THAN 30 FT/MINUTE. 6 inches per second.
slow ascent when get to 30 feet, stop at 15 feet for 3 minutes for precautionary decompression stop.
go to surface, inflate bc, switch to snorkel if desired, record time. |
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Term
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Definition
ripple marks in sand form parallel to the shore! closer to shore, closer together.
sun/shadows.
surge - back/forth movement of water close to shore. |
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Term
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Definition
dead reckoning. compass shows directions, depth gauge tells you your vertical position in water.
keep compas lubber line aligned with centerline of body. point lubber line to shore, mark index marks on bezel to mark position of needle.
reciprocal course - halfway through dive, make 180 degree turn to return. |
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Term
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Definition
| combined weight of air and water |
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Term
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Definition
mass of an element per unit of volume. compressed air is more dense.
density of gas depends on its pressure and temperature.
density of liquid like water is constant no matter temp or pressure.
air has weight. |
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Term
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Definition
one liter of air = 1.25 grams
or- .08 pounds per one cubic foot of air, in imperial measurement system. |
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Term
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Definition
one lier fresh water weighs 1 kilogram.
one liter salt water weighs 1.025 kilograms - bc of dissolved salts/minerals.
in imperial system- water is 62.4 pounds per cubic foot for freshwater, 64 pounds salt water |
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Term
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Definition
mix of gases.
colorless, odorless, tasteless.
20.9 oxygen, 78% nitrogen, 1.1% misc gases like argon and carbon dioxide.
most important is oxygen, but can only breathe pure for limited periods.
nitrogen is a metabolically inert gas - doesn't react in our bodies, but is present.
to dive with mixtures of gases, need special training. |
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Term
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Definition
easily compressed. add pressure to volume of air, can be forced to occupy smaller area.
the air around earth at sea level is compressed by the weight of the air above it.
not so with water - can't be compressed, so density is always the same, but pressure is greater bc of weight of water above it. |
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Term
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Definition
eye designed to focus light through air. mask puts air space in front of your eyes.
refraction - light rays slow down and bend from air to water. makes objects seem 1/3 closer, larger than in air.
colors different. color absorbed- first red, then orange, then yellow green blue indigo violet.
depths - can only see blue/purple |
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Term
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Definition
| greater density of water= sound waves travel faster. difficult to determine source of sound. |
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Term
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Definition
water absorbs heat w/o affecting its temp. heat conducted out of your body 25 times faster than by air.
water resists movement - drag. sleeker/more compact equipment makes easier swimming. horizontal position also helps. |
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Term
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Definition
an object in a fluid is buoyed up/lifted by a force equal to the weight of the fluid it displaces
if object displaces amount of water that weighs more than it does, it floats. |
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Term
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Definition
buoyancy is always an upward force causing you to float/rise/hover/sink less quickly.
if float, object displaces water weighing more than object. object is less dense than the water.
weight and volume affect buoyancy. |
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Term
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Definition
impossible to sink in wetsuit due to nitrogen gas bubbles in the neoprene material. need weights.
as descend, bubbles compress, wetsuit displaces less water, loses some buoyancy. so - add air to BC to increase volume.
ascend- bubbles expand. so, vent air. |
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Term
| salt vs fresh water buoyancy |
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Definition
salt water 2.5% denser than fresh water bc of weight of minerals in it. displace more weight in salt water, so greater buoyancy.
if neutral in salt water, will sink in fresh water. |
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Term
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Definition
the force from the weight of the air and water above you. measured in bar or pounds per square inch (psi).
column 1 in. by 1 in. extending to top of atmosphere, weighs 14.7 pounds (per square inch). aka. 1 bar.
same for water - column of fresh water 34 feet tall, exerts same pressure of 1 bar. water not compressible, transmits pressure freely. pressure increases at contant rate and is cumulative. 34 ft of fresh water is 1 atmosphere, 68 ft is 2, etc.
salt water 33 ft tall - 1 bar. |
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Term
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Definition
absolute- air pressure + pressure under water. if go 33 feet deep in alt water, you're doubling the pressure on your body. must understand how pressure affects volume of air spaces underwater.
gauge - ignores the 1 atmosphere from the air above the water, bc this is constant. |
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Term
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Definition
when pressure increases, volume decreases, if it can.
and vice versa. if take bucket to bottom of ocean, then fill with air, and bring it up, the air would overflow when gets to top. |
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Term
| effects of boyle's law on open/closed system |
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Definition
open - like turning a bucket upside down and pushing air inside it to bottom/top of ocean. to bottom - volume of air decreases. take to bottom, fill with air, then bring to top - overflows.
closed-more dramatic. sealed plastic bag-gets smaller at bottom. bring to top after adding air at bottom - bag will burst. only way to prevent is to vent excess air from bag during ascent.
same thing could happen to lungs if hold breath! never hold breath! |
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Term
| how pressure affects density |
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Definition
increasing pressure affects volume of air. also affects density - compresses to be smaller. so - when deep, lungs contain 2x, 3x air in same space, doesn't flow as easily - is compressed, denser than air you breathe on surface.
more resistance in flow through regulator hose, your air passages, etc. limits how you can exert yourself.
also shows importance to equalize pressure underwater to keep pressure in body air spaces equal to pressure outside body.
rate at which you consume air in cylinder is directly proportional to the depth of dive. consume air twice as fast at 33 ft.
also - physical activity effects air consumption. |
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Term
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Definition
lungs, sinuses, middle ears.
can also be in stomach, intestines, teeth.
outside body - mask, dry suit |
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Term
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Definition
pressure on body increases at .1 bar per meter, or .5 psi per foot of depth.
wen pressure outside air space is greater than pressure inside air space, it's a squeeze. can cause damage. barotrauma - pressure injury.
avoid by using equalization techniques. |
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Term
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Definition
opposite of a squeeze.
pressure inside air space is greater than the surrounding pressure.
can occur during ascent. air trapped inside a space, tries to expand as surrounding pressure decreases. |
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Term
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Definition
outer ear- canal
middle ear-eardrum separates from outer. flexible membrane, vibrates when sound waves hit it. 3 small bones that transmit sound waves to auditory nerves of inner ear. also has airway linked to back of throat, eustachian tube.
inner ear- body's balance mechanism. sudden change of pressure/temp in one ear and not other, get dizzy/vertigo. |
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Term
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Definition
air/water presser in outer ear is greater than in middle ear.
equalize middle ear by moving air from throat through eustachian tube into middle ear. if cannot equalize, must end dive and return to surface.
if pressure increases on outer ear (as you descend) and not equalized, pain, eardrum flexes to help equalize pressure. can rupture to allow water to flow into middle ear to equalize.
equalize BEFORE feel pressure in ears.
pressure can hold eustachian tube closed, and you can't do anything about it. must ascend a few feet to reduce pressure difference and try again. never force it. |
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Term
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Definition
| wiggling jaw, tilting head side to side, putting tongue to roof of mouth & compress trapped air with tounge. |
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Term
| injuries to eardrum/head colds |
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Definition
if rupture eardrum, water will enter middle ear and cause vertigo. surface and see doctor, can't dive until heals.
head cold - can't dive, can force bacteria into middle ear space when equalizing. decongestants aren't answer, never use earplugs. no way to equalize trapped air between ti and eardrum. |
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Term
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Definition
| reverse block - ascend, ear hurts & feels full. stop ascent and descend until feeling goes away. |
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Term
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Definition
sinuses = air cavities lined with mucous membranes - four sets. if sick, air trapped in sinuses. descend - soft tissue will be pushed into the sinus, is painful, can cause blood to flow into sinus to fill it. when ascend, air of sinus will try to expand but cannot bc of fluid. might have blood forced out into nose/mouth/mask.
don't dive when sick!
decongestants not meant for underwater. can wear off, cause drowsiness, etc. |
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Term
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Definition
don't eat gassy foods
teeth - air can be in filling, can compress and cause pain, cause fractures.
mas space- add air to mask. exhale through nose.
dry suit - addd air to suit when descending. |
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Term
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Definition
when breath in, they inflate, exhale, deflate.
consist of millions of tiny air sacs called alveoli, surrounded by capillaries - tiny blood vessels. |
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Term
| lung overexpansion injuries |
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Definition
| breathe compressed air under pressure - risk. don't hold breath. more likely at shallow depths. breathe normally. |
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Term
| three types of lung overexpansion injuries |
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Definition
1. air embolism: plug of air in bloodstream. will block flow of blood to brain. most serious.
2. pneumothorax: lung ruptures, escaping air gets into pleural lining surrounding the lungs. can cause this condition - collapsed lung. not fatal, is painful.
3. tissue emphysema - air from ruptured lung escapes into chest cavity beow breastbone - causes mediastinal emphysema - air in the middle tissue. air is around heart, expansion of air will cause pressure on heart. subcutaneous emphysema - air from ruptured lung collects under skin, usually neck, causing swelliing. |
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Term
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Definition
for arterial gas embolism.
aka recompression chamber.
pressurized to reduce bubble size and restore blood circulation.
pressure in chamber released slowly, allowing gas to move from bloodstream and out of body with each exhalation. |
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Term
| carbon dioxide & breathing |
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Definition
breathing rate is controlled by carbon dioxide in bloodstream - not amount of oxygen. more carbon dioxide, more you want to breathe.
breathe deeply to get carbon dioxide out o lungs. exhale fully.
don't hyperventilate - lowers body's carbon dioxide level.
skip breathing - dangerous. don't hold breath. builds up carbon dioxide.
air starvation - avoid overexertion. you're breathing through a restriction. stop, rest, breathe slowly/deeply until recover. |
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Term
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Definition
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