NAUI Master Diver Scuba Final
DIVE EQUIPMENT Open-circuit demand scuba is most commonly used by
recreationals divers, closed-circuit and semi-closed rebreathers now available -
ANS-True
DO NOT GET MOISTURE INTO THE CYLINDER. Water will cause corrosion by
combining with high pressure oxygen inside the cylinder. - ANS-True
^^ Prolonged storage of air in a steel cylinder containing water can be bad. Oxidation
process will consum some of the oxygen in the air, leaving higher nitrogen concentration
- ANS-True
Always keep 300 psi of pressurized air in cylinder to prevent moisture accum. Bad if
slosh heard, whitish mist or odor. IF COROSSION IN CYLINDER THIS CAN BE
CLEANED BY TUMBLING - so fill it with aluminum oxide chips or abrasive materials
and rotate for many hours removing rust - ANS-True
Hydrostatic filled to 5000 psi or five thirds of the rated pressure of the cylinder, fill
300-500 psi per minute - ANS-True
Standard on-off cylinder in usa is k-valve, low air warning mech. is j-valve (two sides).
This valve lever should be fully up to reserve air if they forget or if diving eliminates that
can be turned down but air will release quick without warning - ANS-True
dual valves like Y-valves or H-valves allow diver to mount two regulator systems on
single cylinder for deep or enclosed dives - ANS-True
First stage in regulators reduces cylinder pressure to intermediate or low pressure
around 90-150 psi - ANS-True
Upstream valves rare, downstream more resistant to operate as cylinder prerssure
decreases b/c failure in closed position. Third valve is balanced valve - ANS-True
First stage includes diaphragm and piston. - ANS-True
Intermediate pressure remains at a constant above ambient pressure as diver descends
or acends - ANS-True
, the main valve of a pilot valve regulator is opened and clsoed w/ air pressure rather
than mechanical leverage - ANS-True
First stage coloring: green is corrosion, red is rust, black is carbon dust - ANS-True
Modern regulator performance is defined in terms of maximum resipiratory work level or
breathing work - ANS-True
pressure gauges: surface cylinder pressure gauge to check air in a cylinder above water
w/ bleed valve. and sumbmersible - ANS-True
If water is visible in cylinder pressure gauge don't use it till repaired and tested -
ANS-True
Open bourdon gauge least expensive but most problems w/ corrosion - the small one.
sealed "" basically the same but more protection. Oil filled "" oil filled case, avoid leaving
in sun due to leakage and expansion - ANS-true
two basic types of computers - tissue baed and table based. If a computer fails ascend
w/ safety stop - ANS-true
air compressors operate under Boyles law - p and v - ANS-True
DIVE ENVIRONMENT wavelength is the horizontal distance between successsive
crests, period is the time required for two successive crests to pass a given point. Fetch
is the distance the wnid blows overthe water - ANS-true
Spilling breakers waves break far from shore and all the way back to beach. Plunging
breakers waves steepen quicly and break suddenly, most hazardous. - ANS-true
Spring tides high, neap low. Diurnal one high and low tide every 24 hrs and 50 minutes.
semi-diurnal two "" change every six hours. mixed combination. swim perpendicular to
shore if caught - ANS-true
currents are waves approaching shore at an angle that flows parallel to shore.
Longshore currents move you down the beach, can often be detected. Four types of rip
currents: permanent, fixed, flash, traveling. The set and drift of a current refer to
currents directions and velocity. Always begin a dive against a current unless trained -
ANS-True
DIVE EQUIPMENT Open-circuit demand scuba is most commonly used by
recreationals divers, closed-circuit and semi-closed rebreathers now available -
ANS-True
DO NOT GET MOISTURE INTO THE CYLINDER. Water will cause corrosion by
combining with high pressure oxygen inside the cylinder. - ANS-True
^^ Prolonged storage of air in a steel cylinder containing water can be bad. Oxidation
process will consum some of the oxygen in the air, leaving higher nitrogen concentration
- ANS-True
Always keep 300 psi of pressurized air in cylinder to prevent moisture accum. Bad if
slosh heard, whitish mist or odor. IF COROSSION IN CYLINDER THIS CAN BE
CLEANED BY TUMBLING - so fill it with aluminum oxide chips or abrasive materials
and rotate for many hours removing rust - ANS-True
Hydrostatic filled to 5000 psi or five thirds of the rated pressure of the cylinder, fill
300-500 psi per minute - ANS-True
Standard on-off cylinder in usa is k-valve, low air warning mech. is j-valve (two sides).
This valve lever should be fully up to reserve air if they forget or if diving eliminates that
can be turned down but air will release quick without warning - ANS-True
dual valves like Y-valves or H-valves allow diver to mount two regulator systems on
single cylinder for deep or enclosed dives - ANS-True
First stage in regulators reduces cylinder pressure to intermediate or low pressure
around 90-150 psi - ANS-True
Upstream valves rare, downstream more resistant to operate as cylinder prerssure
decreases b/c failure in closed position. Third valve is balanced valve - ANS-True
First stage includes diaphragm and piston. - ANS-True
Intermediate pressure remains at a constant above ambient pressure as diver descends
or acends - ANS-True
, the main valve of a pilot valve regulator is opened and clsoed w/ air pressure rather
than mechanical leverage - ANS-True
First stage coloring: green is corrosion, red is rust, black is carbon dust - ANS-True
Modern regulator performance is defined in terms of maximum resipiratory work level or
breathing work - ANS-True
pressure gauges: surface cylinder pressure gauge to check air in a cylinder above water
w/ bleed valve. and sumbmersible - ANS-True
If water is visible in cylinder pressure gauge don't use it till repaired and tested -
ANS-True
Open bourdon gauge least expensive but most problems w/ corrosion - the small one.
sealed "" basically the same but more protection. Oil filled "" oil filled case, avoid leaving
in sun due to leakage and expansion - ANS-true
two basic types of computers - tissue baed and table based. If a computer fails ascend
w/ safety stop - ANS-true
air compressors operate under Boyles law - p and v - ANS-True
DIVE ENVIRONMENT wavelength is the horizontal distance between successsive
crests, period is the time required for two successive crests to pass a given point. Fetch
is the distance the wnid blows overthe water - ANS-true
Spilling breakers waves break far from shore and all the way back to beach. Plunging
breakers waves steepen quicly and break suddenly, most hazardous. - ANS-true
Spring tides high, neap low. Diurnal one high and low tide every 24 hrs and 50 minutes.
semi-diurnal two "" change every six hours. mixed combination. swim perpendicular to
shore if caught - ANS-true
currents are waves approaching shore at an angle that flows parallel to shore.
Longshore currents move you down the beach, can often be detected. Four types of rip
currents: permanent, fixed, flash, traveling. The set and drift of a current refer to
currents directions and velocity. Always begin a dive against a current unless trained -
ANS-True
