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48 Cards in this Set
- Front
- Back
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What is the maximum working depth for air diving ops using the MK 21 MOD 1? |
The maximum working depth for air diving operations using the MK 21 MOD 1 system is 190 fsw.
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Describe the MK 21 MOD 1.
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The MK 21 MOD 1 is an open circuit, demand, diving helmet.
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When is an EGS mandatory for the MK21 MOD 1?
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An EGS is mandatory at depths deeper than 60 fsw and when diving inside a wreck or enclosed space.
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Whose approval is needed to dive deeper than 190' on air?
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Planned air dives below
190 fsw require CNO approval. |
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How is the EGS carried when working in an enclosed space?
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The EGS can be man-carried or located outside the space and connected to the diver using a 50' to 150' whip.
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For the EGS what is considered an adequately charged ANU approved scuba cylinder?
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An adequately charged cylinder has enough air to bring the diver to his first decompression stop or the surface.
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What is the relief valve set at on the first stage regulator for your EGS?
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The relief valve is set at 180 ± 5 psig over bottom pressure.
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Why is the relief valve set at 180 +or- 5 on the 1st stage regulator?
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To prevent rupture of the low pressure hose should the first stage regulator fail.
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What is the pressure for the first stage regultor set at on the MK21 EGS?
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The first stage regulator is set at manufacturer’s recommended pressure, not lower than 135 psig.
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Which valve can you use on the MK21 EGS cylinder?
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Either a K- or J- valve (with reserve turned down)
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When will your first stage regulator be set at 150 psig?
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If the EGS cylinder is topside, the first stage regulator will be set at 150 psig.
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To calculate the EGS cylinder pressure, you must first determine what two things?
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1, Determine the amount of gas required to get back to the stage and leave bottom.
2, The gas required for ascent to the first decompression stop. |
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What is the formula used to determine the required EGS cylnder pressure?
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Depth + 33, divided by 33,
multiplied by 1.4, multiplied by time (in minuets) |
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What is the flow requirements for the MK 21 MOD 1?
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The air supply system must be able to provide an average sustained flow of 1.4 acfm to the diver.
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How much acfm is used in the MK 21 MOD 1 in free flow mode?
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When used in a free-flow mode, greater than eight acfm is consumed.
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How much acfm is consumed in the MK 21 MOD 1 in demand mode?
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The air consumption varies between 0.75 and 1.5 acfm when used in demand mode
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When planning a dive with the MK21 MOD 1 what acfm is used for calculations?
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When planning a dive, calculations are based on 1.4 acfm.
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When diving the MK 21 Mod 1 if a system is not capable of sustaining 165 psi overbottom due to design limitations, is 135 psi overbottom acceptable?
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Yes, for systems not capable of sustaining 165 psi overbottom due to design limitations, 135 psi overbottom is acceptable.
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When diving the MK 21 MOD 1 what are the minimum over bottom pressure requirments for various depths?
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0 to 60' 90 psi
61' to 130' 135 psi 131' to 190' 165 psi |
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When diving the MK 21 MOD 1 with the double exhust kit installed what is the minimum overbottom pressure required?
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A minimum of 135 psig over bottom.
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When diving the MK 21 MOD 1 what is the formula for determining minimum manifold pressure?
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Depth times .445 plus overbottom pressure.
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What is the formula for calculating standard cubic feet (scf) of air available?
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-Add minimum flask pressure and MMP.
-Subtract that from the total flask pressure. -Divide by 14.7 -Multiply by Floodable Volume of flask. -Multiply by number of flasks. |
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What are minimum flask pressures for air and O2?
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Minimum flaks pressure for are is 200 psi, and for O2 is 100 psi?
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What are the depth limits for the MK 20 MOD 0?
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The MK 20 MOD 0 is authorized to 60' with surface-supplied air and 130' when used with SCUBA.
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When diving the MK 20 MOD 0 with the EGS bottle topside what is the 1st stage regulator set at?
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When leaving the EGS topside, adjust the first stage regulator to 150 psig.
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What are the required gas flow rates and overbottom pressures for the MK 20 MOD 0
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The MK 20 MOD 0 requires a breathing gas flow of 1.4
acfm and an overbottom pressure of 90 psig. |
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What are the depth restrictions for the EXO band mask?
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The EXO is authorized to 190' with air and 140' with nitrox.
130' when diving SCUBA mode. |
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What is the floodable volume & "scf" of one MK 3 MOD 0 Lightweight Dive System flask when jammed to 3000 psi?
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.935 cu ft floodable volume & each flask holds 191 scf of compressed air at 3,000 psi.
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What are the depth limits for each configurations of the MK 3 MOD 0 LWDS? (3)
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configuration 1 - 60' configuration 2 - 130' configuration 3 - 190'
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What is the MK3 MOD 0 in configuration 1?
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Primary air supplied by a medium-pressure diesel compressor, with secondary air supplied by one air-rack assembly
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What is the MK3 MOD 0 in configuration 2?
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Primary air is supplied using 3 flask racks & secondary air using one flask rack.
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What is the MK3 MOD 0 in configuration 3?
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Primary air is supplied using 3 flask racks & secondary air using two flask racks.
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What is the difference between the MK3 MOD 0 and the MK3 MOD1
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The systems are identical except the MK3 mod 1 control console and volume tank have been modified to support 5,000 psi operations for use with the Flyaway Dive System (FADS)
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What is a lead line used for?
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The lead line is used to measure depth.
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What type of line is recommened for the divers decesnt line?
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A 3-inch double-braid line is recommended.
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What are the minumum requirments for a divers stage line?
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The stage line is to be 3-inch
double braid, or 3/8-inch wire rope minimum, |
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How often are air samples taken?
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Every 6 months not to exceed 8 months.
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Where will you normally find the compressor rating?
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Normally, compressors have their rating stamped on the manufacturer’s identification
plate. |
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What types of oil is used for divers air compressors?
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2190 TEP for normal operations, or 2135 TH for cold weather operations.
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What is considered a high-pressure air cylinders or flasks?
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HP air cylinders or flasks are vessels designed for pressures over 600 psi.
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What are the three line-pull signals that are not answered immediately.
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1) 4 pulls from diver to tender - “Haul me up”
2) 4-4-4 pulls from diver to tender - “Haul me up immediately.” 3) 4 pulls from tender to diver - "Come up" (This signal is not acknowledged until the diver is ready to leave the bottom.) |
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When surface supplied diving what current requires the dives to wear additional weight?
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More than 1.5 knots
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What is the maximum allowable rate of descent, by any method?
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Descent shall not exceed 75
feet per minute (fpm). |
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When a diver is working in an enclosed or confined space the diver must be tended by another diver at the access opening. What is the exception to this rule?
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When a diver is working in a submarine ballast tank.
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What must be worn for enclosed space diving?
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During enclosed space diving, all divers shall be outfitted with a MK 21 MOD 1, MK 20 MOD 0, or EXO BR MS
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What are the requirements for divers to remove their dive helmet inside a submarine ballast tank?
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-The atmosphere must be flushed twice with air from a
source meeting the requirements of Chapter 4 of the Navy Dive Manual. -Initially tested in accordance with NSTM 074, Vol. 3 to confirm safe for breathing. -Additional tests conducted hourly. -If divers smell any unusual odors they immediately don their EGS. |
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What 3 things are mandatory for divers to dive in an enclosed space?
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1)diver-to-diver communications
2)diver-to-topside communications 3)EGS for the diver inside the space. |
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When can you use a steel cable or a chain as a descent line?
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Only with the Diving Officer's permission.
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