scuba

Question 1

Planned exceptional exposure dives shall not be conducted except by specific authorization from whom?

Answer 1

Chief of Naval Operations (N97)

Question 2

Diving supervisors should consider employing an independent back-up air source for dives exceeding what depth?

Answer 2

100fsw

Question 3

What is the Maximum depth for standby SCUBA diver using a fully charged single cylinder with less than 100 SCF air available?

Answer 3

60fsw

Question 4

What is the normal and maximum working limit for SCUBA diving operations?

Answer 4

Normal: 130fsw
Maximum: 190fsw

Question 5

SCUBA diving operations deeper than 130fsw may be made with approval of whom?

Answer 5

The Commanding Officer or Officer-in-Charge

Question 6

Who can approve SCUBA decompression dives?

Answer 6

Commanding Officer or Officer-in-Charge

Question 7

Who designates officers as Officers-in-Charge?

Answer 7

By BUPERS order

Question 8

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?

Answer 8

The Commanding Officer

Question 9

What are the restrictions of USN civilians conducting SCUBA dives?

Answer 9

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.

Question 10

What governs the USN civilian SCUBA diving restrictions?

Answer 10

29 CFR Part 1910

Question 11

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?

Answer 11

1 Hour

Question 12

What is the minimum equipment to conduct SCUBA diving operations?

Answer 12

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

Question 13

What are the principle applications of SCUBA?

Answer 13

Shallow water search
Inspection
Light repair and recovery

Question 14

What are the advantages of SCUBA?

Answer 14

Rapid deployment
Portability
Minimum support requirements
Excellent horizontal and vertical mobility
Minimum bottom disturbances

Question 15

What are the disadvantages of SCUBA?

Answer 15

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)

Question 16

Standby diver must have a minimum of how many SCF of air for dives deeper than 60fsw?

Answer 16

100scf

Question 17

What is maximum current to conduct SCUBA diving operations?

Answer 17

1 knot

Question 18

What is required to conduct SCUBA diving operations in currents greater than 1 knot?

Answer 18

ORM analysis; at a minimum the divers(s) must be tended or have a witness float.

Question 19

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?

Answer 19

Small Craft

Question 20

What is the required number of personnel required for a SCUBA dive with a single diver?

Answer 20

4 personnel: Supervisor, Diver, Dive Tender, Standby Diver

Question 21

What is the required number or personnel required for a SCUBA dive with a buddy pair?

Answer 21

4 personnel: Supervisor, (2) Divers, Standby Diver

Question 22

What can a diving supervisor additionally act as on a SCUBA dive side?

Answer 22

Logs
Standby Diver (if deployed)

Question 23

What may the diving supervisor utilize as manning based upon operation necessity?

Answer 23

3 qualified divers and one non-diver tender

Question 24

What is the single greatest safety practice in Navy SCUBA operations?

Answer 24

The use of the buddy system

Question 25

Never leave a dive partner unless under what circumstances?

Answer 25

The partner has become trapped or entangled and cannot be freed without additional assistance.

Question 26

When may a SCUBA standby diver remove the tanks?

Answer 26

At the discretion of the Diving Supervisor if the hazards of remaining dressed outweigh the need to have standby immediately ready to deploy.

Question 27

What equipment shall the SCUBA standby diver be equipped with?

Answer 27

Need not be equipped with the same equipment as the primary diver, but shall have equivalent depth and operational capabilities.

Question 28

Can you use non-divers as tenders on a SCUBA dive-side?

Answer 28

Yes; the Dive Supervisor shall ensure they are thoroughly instructed in their required duties.

Question 29

How often shall tenders signal the divers with a single line-pull?

Answer 29

Every 2 to 3 minutes

Question 30

If the divers fail to respond to line-pull signals, what action must be taken immediately?

Answer 30

The standby diver must investigate immediately

Question 31

What are the 4 basic open-circuit SCUBA components?

Answer 31

Demand Regulator Assembly One or more air cylinders Cylinder valve and manifold assembly Backpack or harness

Question 32

What is the central component of the open circuit system?

Answer 32

Demand Regulator Assembly

Question 33

The first stage regulator reduces high-pressure air from the cylinder to an intermediate pressure, also called what?

Answer 33

Over-bottom pressure

Question 34

What is the principle disadvantage of the single-hose units?

Answer 34

Increased disadvantages of the single-hose unit | Exhaust of air in front of the diver’s mask

Question 35

What is required when using an AMU approved full-face mask for SCUBA diving operations?

Answer 35

Approved single-hose first-stage regulator with an octopus

Question 36

What is the depth limitation in SCUBA when using an approved full-face mask?

Answer 36

Maximum approved depth of the regulator

Question 37

What is the required length and markings of a SCUBA octopus?

Answer 37

Length and designation markings are at the discretion of the diving unit

Question 38

When is an octopus required?

Answer 38

Standby Diver Diving with a full-face mask Ice Diving

Question 39

What is the preferred method of buddy breathing during SCUBA diving operations?

Answer 39

Buddy breathing with an octopus

Question 40

What is the most common length of SCUBA intermediate hoses?

Answer 40

2 to 3 feet

Question 41

When diving without a reserve, the dive shall be terminated when the cylinder pressure reaches what psi?

Answer 41

500 psi for a single cylinder or 250 psi for twin manifold cylinders

Question 42

What specifications must all seamless steel or aluminum cylinders meet in order to be approved for use in the Navy?

Answer 42

Department of Transportation (DOT) specifications

Question 43

The volume of a cylinder, expressed in actual cubic feet or cubic inches, is a measurement of what?

Answer 43

Internal volume of the cylinder

Question 44

The capacity of a cylinder, expressed in standard cubic feet or liters, is an expression of what?

Answer 44

The amount of gas (measured at surface conditions) that the cylinder holds when charged to its rated pressure.

Question 45

When shall open-circuit SCUBA cylinders be visually inspected?

Answer 45

At least once every 12 months | Every time water or particulate matter is suspected in the cylinder

Question 46

How often shall SCUBA cylinders be hydrostatically tested?

Answer 46

At least every 5 years

Question 47

What shall SCUBA cylinders be hydrostatically in accordance with?

Answer 47

DOT regulations | Compressed Gas Association (CGA) pamphlets C-1 and C-6

Question 48

What is the minimum size SCUBA cylinder authorized as a primary air source?

Answer 48

50cuft

Question 49

What NSTM provides “Guidelines for Handling Cylinders”?

Answer 49

NSTM Chapter 550

Question 50

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?

Answer 50

A built in air reserve mechanism (J valve)

Question 51

Safety burst discs must be rated at what percent over the maximum cylinder pressure or at the manufacturer’s recommended pressure?

Answer 51

10 percent

Question 52

What must all straps have on them for a backpack or harness that holds the SCUBA on the diver’s back?

Answer 52

Quick-release features easily operated by either hand, so that the diver can remove the cylinder and leave it behind in an emergency.

Question 53

What shall all SCUBA mask faceplates be constructed of?

Answer 53

Tempered or shatterproof safety glass

Question 54

Why are plastic faceplates generally unsuitable?

Answer 54

They fog too easily and are easily scratched

Question 55

What is the principle function of a life preserver?

Answer 55

Assist a diver in rising to the surface in an emergency and to keep the diver on the surface in a face up position

Question 56

What are the requirements of an AMU approved life preserver?

Answer 56

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.

Question 57

What are the requirements of all buoyancy compensators used in the Navy?

Answer 57

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.

Question 58

What are the requirements of a weight belt?

Answer 58

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.

Question 59

What are variable volume dry suits usually constructed of?

Answer 59

1/4-inch closed-cell neoprene with nylon backing on both sides

Question 60

How many cubic feet is usually required for the inflation of a variable volume dry suit?

Answer 60

0.2 actual cubic feet

Question 61

What is the preferred waterproof flare used by divers?

Answer 61

MK 99 MOD 3

Question 62

What color smoke does the MK 99 MOD 3 flare have for day and night operations?

Answer 62

Day: Orange Night: Brilliant Red

Question 63

How long and at what depth can the MK 99 MOD 3 be used?

Answer 63

45 Seconds | 200 fsw

Question 64

How is the flare and smoke each identified on the MK 99 MOD 3?

Answer 64

Smoke: hexagon shaped end cap marked smoke Flare: round shaped end cap with eight grooves marked flare

Question 65

What additional flares can be used for day and night diving operations?

Answer 65

Day: MK 131 MOD 0 Night: MK 132 MOD 0

Question 66

For safety, each diver should carry a maximum of how many flares?

Answer 66

2 flares

Question 67

When should a lifeline be used?

Answer 67

When it is necessary to exchange signals, keep track of the diver’s location, or operate in limited visibility.

Question 68

What are the 3 basic types of lifelines?

Answer 68

Tending Line Float Line Buddy Line

Question 69

When may a float line be used?

Answer 69

May be used instead of a tending line only when direct access to the surface is available.

Question 70

What are the requirements of a float line?

Answer 70

Should be no smaller than an 11 inch inflatable buoy | Brightly colored to be easily visible in open seas (international orange is recommended).

Question 71

What is the required length of a buddy line?

Answer 71

6 to 10 feet

Question 72

What are suitable materials for a life line?

Answer 72

Nylon, Dacron, and Polypropylene

Question 73

Submersible wrist compasses, watches, and depth gauges covered by what instruction?

Answer 73

NAVSUPINST 5101.6 (series) | Controlled by the Nuclear Regulatory Commission

Question 74

How often submersible are wrist compasses, watches and depth gauges required for leak testing and reporting?

Answer 74

Every 6 months

Question 75

In particularly hazardous dives and dives deeper than 100fsw, Dive Supervisors should consider outfitting each diver with what?

Answer 75

Independent secondary air source (with AMU approved first and second stage regulator)

Question 76

An independent air source is a DOT specification type 3AA or 3AL cylinder with a minimum capacity of what?

Answer 76

19scf

Question 77

What capacity is the range of an independent air source?

Answer 77

19scf to 50scf

Question 78

The duration of the air supply of any given cylinder or combination of cylinders depends upon what factors?

Answer 78

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

Question 79

What are the three things you must calculate to determine how long a divers air supply will last?

Answer 79

Consumption Rate Available Air Capacity Duration

Question 80

How do you calculate consumption rate?

Answer 80

C = D +33 / 33 X RMV

Question 81

How do you calculate available air capacity?

Answer 81

Va = Pc – Pm / 14.7 X FV X N

Question 82

How do you calculate duration?

Answer 82

Duration = Va / C

Question 83

What are the 2 methods of charging SCUBA cylinders?

Answer 83

Cascading | HP Compressor

Question 84

What is the fastest and most efficient method of charging?

Answer 84

Cascading

Question 85

SCUBA charging lines shall be fabricated using what type of hose for 3,000 psi and 5,000 psi service?

Answer 85

3,000 psi = SAE 100R7 | 5,000 psi = SAE 100R8

Question 86

The service pressure of the SCUBA charging lines shall be no greater than what?

Answer 86

The working pressure of the hose used

Question 87

How is the working pressure of a hose determined?

Answer 87

One-fourth of its burst pressure

Question 88

What materials are acceptable to be used for strain reliefs on a charging hose?

Answer 88

Cable Chain 21-thread 3/8-inch nylon

Question 89

At what minimum interval shall strain reliefs be married?

Answer 89

Every 18 inches | At the end of the hose

Question 90

What material is required for marrying cord?

Answer 90

1/8-inch nylon or material of equivalent strength

Question 91

What materials are not authorized for marrying?

Answer 91

Tie wraps, tape, and marlin

Question 92

What is the allowed charging rate for SCUBA cylinders wet and dry?

Answer 92

200 psi/min (Dry) | 400 psi/min (Wet)

Question 93

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?

Answer 93

50 psi or greater

Question 94

What is the minimum over-bottom pressure of a SCUBA first stag regulator?

Answer 94

135 psig

Question 95

What entry method is best used from a stable platform?

Answer 95

Front step

Question 96

What entry method is preferred for entering the water from a small boat because it is the most stable for the diver?

Answer 96

Rear roll

Question 97

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?

Answer 97

Front roll

Question 98

What is the minimum length of a circling line of a lost diver buoy?

Answer 98

25 feet

Question 99

Compressor should be secured in the diving craft and not subject to operating angles exceeding how many degrees?

Answer 99

15 degrees

Question 100

What are the two types of through water communication systems?

Answer 100

``` Amplitude Modulated (AM) Single Sideband (SSB) ```

Question 101

What are the benefits of AM and SSB communication systems?

Answer 101

AM: provides a stronger signal and better intelligibility, but are restricted to line-of-sight use. SSB: provides superior performance in and around obstacles

Question 102

What is required when using externally powered tools with SCUBA?

Answer 102

Diver must have voice communications with the Diving Supervisor.

Question 103

How many feet above a muddy bottom should a SCUBA diver stay?

Answer 103

2 to 3 feet

Question 104

What is the minimum size of the lost diver buoy?

Answer 104

Sufficient size to avoid being pulled underwater (minimum 11 inch buoy)

Question 105

What are some common factors in the majority of recovered lost divers?

Answer 105

Nitrogen narcosis or other complications involving the breathing mixture, which can result in confusion, dizziness, anxiety, or panic.

Question 106

The first and most important action that a trapped diver can take is to do what?

Answer 106

Stop and think; panic and overexertion are the greatest dangers to the trapped diver.

Question 107

What is required in SCUBA if diving directly under the hull of a ship?

Answer 107

Tending Line: required when there is no free ascent to the surface

Question 108

What are SCUBA dives normally planned as?

Answer 108

No decompression dives

Question 109

What is required to conduct open circuit SCUBA dives requiring decompression?

Answer 109

Considered absolutely necessary Authorized by the Commanding Officer or Officer in Charge (OIC)