scuba Flashcards
Planned exceptional exposure dives shall not be conducted except by specific authorization from whom?
Chief of Naval Operations (N97)
Diving supervisors should consider employing an independent back-up air source for dives exceeding what depth?
100fsw
What is the Maximum depth for standby SCUBA diver using a fully charged single cylinder with less than 100 SCF air available?
60fsw
What is the normal and maximum working limit for SCUBA diving operations?
Normal: 130fsw
Maximum: 190fsw
SCUBA diving operations deeper than 130fsw may be made with approval of whom?
The Commanding Officer or Officer-in-Charge
Who can approve SCUBA decompression dives?
Commanding Officer or Officer-in-Charge
Who designates officers as Officers-in-Charge?
By BUPERS order
Officers not designated by BUPERS as OICs are serving under the authority of the Commanding Officer and may not exceed depth or no decompression limits without specific authority delegated from whom?
The Commanding Officer
What are the restrictions of USN civilians conducting SCUBA dives?
Depths deeper than 100fsw or outside no-decompression, requires a recompression chamber that is available within 5 minutes of the dive location.
Cylinder manifold must be equipped with a manual reserve (J valve), or an independent reserve cylinder gas supply with a separate regulator.
A submersible pressure gauge must be worn by each diver.
What governs the USN civilian SCUBA diving restrictions?
29 CFR Part 1910
How long shall USN Civilian divers remain at the location of the recompression chamber after surfacing for all dives that require a recompression chamber to be available within 5 minutes of the dive location?
1 Hour
What is the minimum equipment to conduct SCUBA diving operations?
Open-circuit SCUBA with J-valve or submersible pressure gauge Life preserver/buoyancy compensator Weight belt (if required) Dive knife Face mask Swim fins Submersible wrist watch Depth gauge Submersible Pressure Gauge
What are the principle applications of SCUBA?
Shallow water search
Inspection
Light repair and recovery
What are the advantages of SCUBA?
Rapid deployment Portability Minimum support requirements Excellent horizontal and vertical mobility Minimum bottom disturbances
What are the disadvantages of SCUBA?
Limited endurance (depth and duration)
Limited physical protection
Influenced by current
Lack of voice communication (unless equipped with a through-water communications system or full face mask)
Standby diver must have a minimum of how many SCF of air for dives deeper than 60fsw?
100scf
What is maximum current to conduct SCUBA diving operations?
1 knot
What is required to conduct SCUBA diving operations in currents greater than 1 knot?
ORM analysis; at a minimum the divers(s) must be tended or have a witness float.
What is mandatory for diver recovery during open-ocean diving when diving off of a large platform or when the diver is untended and may be displaced from dive site?
Small Craft
What is the required number of personnel required for a SCUBA dive with a single diver?
4 personnel: Supervisor, Diver, Dive Tender, Standby Diver
What is the required number or personnel required for a SCUBA dive with a buddy pair?
4 personnel: Supervisor, (2) Divers, Standby Diver
What can a diving supervisor additionally act as on a SCUBA dive side?
Logs Standby Diver (if deployed)
What may the diving supervisor utilize as manning based upon operation necessity?
3 qualified divers and one non-diver tender
What is the single greatest safety practice in Navy SCUBA operations?
The use of the buddy system
Never leave a dive partner unless under what circumstances?
The partner has become trapped or entangled and cannot be freed without additional assistance.
When may a SCUBA standby diver remove the tanks?
At the discretion of the Diving Supervisor if the hazards of remaining dressed outweigh the need to have standby immediately ready to deploy.
What equipment shall the SCUBA standby diver be equipped with?
Need not be equipped with the same equipment as the primary diver, but shall have equivalent depth and operational capabilities.
Can you use non-divers as tenders on a SCUBA dive-side?
Yes; the Dive Supervisor shall ensure they are thoroughly instructed in their required duties.
How often shall tenders signal the divers with a single line-pull?
Every 2 to 3 minutes
If the divers fail to respond to line-pull signals, what action must be taken immediately?
The standby diver must investigate immediately
What are the 4 basic open-circuit SCUBA components?
Demand Regulator Assembly
One or more air cylinders
Cylinder valve and manifold assembly
Backpack or harness
What is the central component of the open circuit system?
Demand Regulator Assembly
The first stage regulator reduces high-pressure air from the cylinder to an intermediate pressure, also called what?
Over-bottom pressure
What is the principle disadvantage of the single-hose units?
Increased disadvantages of the single-hose unit
Exhaust of air in front of the diver’s mask
What is required when using an AMU approved full-face mask for SCUBA diving operations?
Approved single-hose first-stage regulator with an octopus
What is the depth limitation in SCUBA when using an approved full-face mask?
Maximum approved depth of the regulator
What is the required length and markings of a SCUBA octopus?
Length and designation markings are at the discretion of the diving unit
When is an octopus required?
Standby Diver
Diving with a full-face mask
Ice Diving
What is the preferred method of buddy breathing during SCUBA diving operations?
Buddy breathing with an octopus
What is the most common length of SCUBA intermediate hoses?
2 to 3 feet
When diving without a reserve, the dive shall be terminated when the cylinder pressure reaches what psi?
500 psi for a single cylinder or 250 psi for twin manifold cylinders
What specifications must all seamless steel or aluminum cylinders meet in order to be approved for use in the Navy?
Department of Transportation (DOT) specifications
The volume of a cylinder, expressed in actual cubic feet or cubic inches, is a measurement of what?
Internal volume of the cylinder
The capacity of a cylinder, expressed in standard cubic feet or liters, is an expression of what?
The amount of gas (measured at surface conditions) that the cylinder holds when charged to its rated pressure.
When shall open-circuit SCUBA cylinders be visually inspected?
At least once every 12 months
Every time water or particulate matter is suspected in the cylinder
How often shall SCUBA cylinders be hydrostatically tested?
At least every 5 years
What shall SCUBA cylinders be hydrostatically in accordance with?
DOT regulations
Compressed Gas Association (CGA) pamphlets C-1 and C-6
What is the minimum size SCUBA cylinder authorized as a primary air source?
50cuft
What NSTM provides “Guidelines for Handling Cylinders”?
NSTM Chapter 550
Cylinder valves that employ what, are preferred when diving in zero visibility where a gauge may not be able to be read because the J-valve will provide a warning that air is low?
A built in air reserve mechanism (J valve)
Safety burst discs must be rated at what percent over the maximum cylinder pressure or at the manufacturer’s recommended pressure?
10 percent
What must all straps have on them for a backpack or harness that holds the SCUBA on the diver’s back?
Quick-release features easily operated by either hand, so that the diver can remove the cylinder and leave it behind in an emergency.
What shall all SCUBA mask faceplates be constructed of?
Tempered or shatterproof safety glass
Why are plastic faceplates generally unsuitable?
They fog too easily and are easily scratched
What is the principle function of a life preserver?
Assist a diver in rising to the surface in an emergency and to keep the diver on the surface in a face up position
What are the requirements of an AMU approved life preserver?
Have a low pressure inflation device (CO2).
Have a manual inflation device.
Have an overpressure valve (OPV) to prevent rupture of the life preserver on ascent. Have sufficient volume to raise an unconscious diver safely from the maximum dive depth to the surface.
Be sturdy enough to resist normal wear and tear.
What are the requirements of all buoyancy compensators used in the Navy?
Provide a minimum of 10 pounds of positive buoyancy at the maximum depth.
Have jettison-able weights if integrated into the vest.
Have a power inflator.
Have an alternate source of inflation (oral).
Have an over-pressure relief valve.
What are the requirements of a weight belt?
Buckle must have a quick-release feature, easily operated by either hand
Weights (normally made of lead) should have smooth edges so as not to chafe the diver’s skin or damage any protective clothing.
Belt should be made of rot- and mildew-resistant fabric, such as nylon webbing.
What are variable volume dry suits usually constructed of?
1/4-inch closed-cell neoprene with nylon backing on both sides
How many cubic feet is usually required for the inflation of a variable volume dry suit?
0.2 actual cubic feet
What is the preferred waterproof flare used by divers?
MK 99 MOD 3
What color smoke does the MK 99 MOD 3 flare have for day and night operations?
Day: Orange
Night: Brilliant Red
How long and at what depth can the MK 99 MOD 3 be used?
45 Seconds
200 fsw
How is the flare and smoke each identified on the MK 99 MOD 3?
Smoke: hexagon shaped end cap marked smoke
Flare: round shaped end cap with eight grooves marked flare
What additional flares can be used for day and night diving operations?
Day: MK 131 MOD 0
Night: MK 132 MOD 0
For safety, each diver should carry a maximum of how many flares?
2 flares
When should a lifeline be used?
When it is necessary to exchange signals, keep track of the diver’s location, or operate in limited visibility.
What are the 3 basic types of lifelines?
Tending Line
Float Line
Buddy Line
When may a float line be used?
May be used instead of a tending line only when direct access to the surface is available.
What are the requirements of a float line?
Should be no smaller than an 11 inch inflatable buoy
Brightly colored to be easily visible in open seas (international orange is recommended).
What is the required length of a buddy line?
6 to 10 feet
What are suitable materials for a life line?
Nylon, Dacron, and Polypropylene
Submersible wrist compasses, watches, and depth gauges covered by what instruction?
NAVSUPINST 5101.6 (series)
Controlled by the Nuclear Regulatory Commission
How often submersible are wrist compasses, watches and depth gauges required for leak testing and reporting?
Every 6 months
In particularly hazardous dives and dives deeper than 100fsw, Dive Supervisors should consider outfitting each diver with what?
Independent secondary air source (with AMU approved first and second stage regulator)
An independent air source is a DOT specification type 3AA or 3AL cylinder with a minimum capacity of what?
19scf
What capacity is the range of an independent air source?
19scf to 50scf
The duration of the air supply of any given cylinder or combination of cylinders depends upon what factors?
Diver’s consumption rate (which varies with the diver’s work rate)
Depth of the dive.
Capacity and pressure of the cylinder(s).
Surface to bottom temperature differential
What are the three things you must calculate to determine how long a divers air supply will last?
Consumption Rate
Available Air Capacity
Duration
How do you calculate consumption rate?
C = D +33 / 33 X RMV
How do you calculate available air capacity?
Va = Pc – Pm / 14.7 X FV X N
How do you calculate duration?
Duration = Va / C
What are the 2 methods of charging SCUBA cylinders?
Cascading
HP Compressor
What is the fastest and most efficient method of charging?
Cascading
SCUBA charging lines shall be fabricated using what type of hose for 3,000 psi and 5,000 psi service?
3,000 psi = SAE 100R7
5,000 psi = SAE 100R8
The service pressure of the SCUBA charging lines shall be no greater than what?
The working pressure of the hose used
How is the working pressure of a hose determined?
One-fourth of its burst pressure
What materials are acceptable to be used for strain reliefs on a charging hose?
Cable
Chain
21-thread
3/8-inch nylon
At what minimum interval shall strain reliefs be married?
Every 18 inches
At the end of the hose
What material is required for marrying cord?
1/8-inch nylon or material of equivalent strength
What materials are not authorized for marrying?
Tie wraps, tape, and marlin
What is the allowed charging rate for SCUBA cylinders wet and dry?
200 psi/min (Dry)
400 psi/min (Wet)
If the pressure in cylinders is what psi or greater over rating, open the cylinder on/ off valve to bleed off excess and re-gauge the cylinder?
50 psi or greater
What is the minimum over-bottom pressure of a SCUBA first stag regulator?
135 psig
What entry method is best used from a stable platform?
Front step
What entry method is preferred for entering the water from a small boat because it is the most stable for the diver?
Rear roll
What entry method is only appropriate when the freeboard of the platform is minimal, and should not be performed if there is more than one or two feet of distance between the platform and the water surface?
Front roll
What is the minimum length of a circling line of a lost diver buoy?
25 feet
Compressor should be secured in the diving craft and not subject to operating angles exceeding how many degrees?
15 degrees
What are the two types of through water communication systems?
Amplitude Modulated (AM) Single Sideband (SSB)
What are the benefits of AM and SSB communication systems?
AM: provides a stronger signal and better intelligibility, but are restricted to line-of-sight use.
SSB: provides superior performance in and around obstacles
What is required when using externally powered tools with SCUBA?
Diver must have voice communications with the Diving Supervisor.
How many feet above a muddy bottom should a SCUBA diver stay?
2 to 3 feet
What is the minimum size of the lost diver buoy?
Sufficient size to avoid being pulled underwater (minimum 11 inch buoy)
What are some common factors in the majority of recovered lost divers?
Nitrogen narcosis or other complications involving the breathing mixture, which can result in confusion, dizziness, anxiety, or panic.
The first and most important action that a trapped diver can take is to do what?
Stop and think; panic and overexertion are the greatest dangers to the trapped diver.
What is required in SCUBA if diving directly under the hull of a ship?
Tending Line: required when there is no free ascent to the surface
What are SCUBA dives normally planned as?
No decompression dives
What is required to conduct open circuit SCUBA dives requiring decompression?
Considered absolutely necessary
Authorized by the Commanding Officer or
Officer in Charge (OIC)
