Us Navy Dive Manual Ch.9 Rev-6

Front 1

What are the benefits of using oxygen during decompression?

Back 1

The use of oxygen helps accelerate elimination of excess nitrogen from the body.

Front 2

What two things directly effect nitrogen absorption in the body?

Back 2

Depth and time at depth.

Front 3

When if ever can you deviate from established decompression procedures?

Back 3

Only in an emergency and with guidance and recommendation from the MDO & with the CO or OIC's approval.

Front 4

Describe Decent Time.

Back 4

The total time elapsed from the time the diver leaves the surface to the time he reaches the bottom. Always round up to the next whole minute.

Front 5

Describe Bottom Time.

Back 5

The total time from when the diver leaves the surface to when he leaves the bottom. Always round up to the next whole minute.

Front 6

Describe Total Decompression Time (TDT).

Back 6

Total time from when the diver leaves the bottom to the time he arrives on the surface.

Front 7

Describe Total time of Dive (TTD).

Back 7

The total elapsed time from the time the diver leaves the surface to arriving back on the surface.

Front 8

Describe Deepest Depth.

Back 8

The deepest depth recorded on the depth gauge during the dive.

Front 9

Describe Maximum depth.

Back 9

The deepest depth obtained plus the pneumofathometer correction factor.

Front 10

Describe Stage Depth.

Back 10

The pneumofathometer reading taken when the diver are on the stage just prior to leaving the bottom.

Front 11

What is the stage depth used for?

Back 11

To compute the distance and travel time to the first stop or the surface?

Front 12

How do you compute maximum depth for a SCUBA diver?

Back 12

Use the divers depth gauge, maximum depth is the deepest depth gauge reading.

Front 13

What are Decompression Tables?

Back 13

A structured set of decompression schedule, or time limits, usually organized in order of increasing bottom times and depths.

Front 14

Describe Decompression Schedules.

Back 14

A specific decompression procedure for a given combination of depth and time. Indicated as feet/minutes.

Front 15

What is a Decompression Stop?

Back 15

A specific depth where a diver must remain for a specific length of time during ascent.

Front 16

What is the No-Decompression (No"D") Limit?

Back 16

The maximum time a diver can spend at a given depth and still ascend directly to the surface without taking decompression stops.

Front 17

Describe a No-Decompression Dive.

Back 17

A dive that will not require a diver to take decompression stops during ascent to the surface.

Front 18

Describe a Decompression Dive.

Back 18

A dive that requires a diver to take decompression stops during ascent to the surface.

Front 19

Describe Surface Interval for repet dives.

Back 19

The time spent on the surface between dives. It begins when the diver reaches surface and end as soon as he starts his next descent.

Front 20

Describe Surface Interval for Surface Decompression.

Back 20

The total elapsed time from when the diver leaves the 40' water stop to when he arrives at 50' in the chamber.

Front 21

Describe Residual Nitrogen.

Back 21

The excess nitrogen gas still dissolved in a diver's tissues after surfacing.

Front 22

Why must Residual Nitrogen be concidered when computing repet dives?

Back 22

Residual Nitrogen still in the tissues must be accounted for when computing decompression requirements for the next dive.

Front 23

What is a single dive?

Back 23

A dive conducted after all of the residual nitrogen from prior dives has been eliminated from the tissues.

Front 24

What is a Repetitive (Repet) Dive?

Back 24

Any dive conducted while the diver still has some Residual Nitrogen in his tissues from a prior dive.

Front 25

Describe Repetitive Group Designator.

Back 25

A letter used to indicate the amount of residual nitrogen remaining in the diver's body following a previous dive.

Front 26

What is Residual Nitrogen Time?

Back 26

Time that must ge added to the bottom time of a repetitive dive to compensate for the nitrogen still in solution in a diver's tissues from a previous dive.

Front 27

What is an Equivalent Single Dive?

Back 27

A repet dive is converted to a single dive equivalent before entering the decompression tables to determine the decompression requirements.

Front 28

How would you determine the depth for repet dives

Back 28

The depth of an Equivalent Single Dive is equal to the depth of the repet dive.

Front 29

How would you determine the bottom time of an Equivalent Single Dive?

Back 29

Add the residual nitrogen time and the actual bottom time of the repet dive.

Front 30

What is an Equivalent Single Dive Time used for?

Back 30

It is used to select the decompression schedule for a repet dive.

Front 31

What is an exceptional exposure dive?

Back 31

A dive in which the risk of decompression sickness, oxygen toxicity, and/or exposure to the elements is substantially greater than on a normal working dive.

Front 32

What are the 6 tables used for air decompression?

Back 32

1) No-Decompression limits & Reptet Group Designatoin Table for No"D" Air Dives.
2) Air Decompression Table.
3)Residual Nitrogen. Timetables for Repet Air Dives.
4)Sea Level Equivalent Depth Table.
5)Repet Groups Associated w/ Initial Ascent to Altitude Table.
6) Required Surface Interval Before Ascent to Altitude After Diving.

Front 33

What is the No-Decompression Limits & Reptet Group Designation Table for No"D" Air Dives used for?

Back 33

This give the No-"D" Limits and Repet Group Designators for N0"D" Dives.

Front 34

What is the Air Decompression Table used for?

Back 34

This gives the Decompression Scheduals and Dive Group Designators for dives that require Decompression Stops.

Front 35

What is the Residual Nitrogen Timetables for Repet Air Dives Table used for?

Back 35

This allows the diver to deternime his Residual Nitrogen Time when doing Repet Dives.

Front 36

What is the Sea Level Equivalent Depth Table used for?

Back 36

It allows the diver to correct the Sea Level Decompression Tables for use at Altitude.

Front 37

What is the Repet Groups Associated w/ Initial Ascent to Altitude Table used for?

Back 37

It allows the Diver to adjust his decompression if he is not yet fully equiliberated to altitude.

Front 38

Required Surface Interval Before Ascent to Altitude After Diving Table is used to...?

Back 38

To tell the diver when it is safe to fly or ascend to higher altitude after a dive.

Front 39

Where should the pneumofathometer located on the diver?

Back 39

At mid-chest level.

Front 40

What are the Pneumofathometer Correction Factors for 0-100, 101-200, 201-300, and 301-400 feet of sea water?

Back 40

0-100 +1
101-200 +2
201-300 +4
301-400 +7

Front 41

What is the descent rate on an air dive?

Back 41

Not to exceed 75 feet per minute.

Front 42

What is the ascent rate from the bottom to the first decompression stop?

Back 42

30 fsw per minute.

Front 43

What is the ascent rate between decompression stops?

Back 43

30 fsw per minute.

Front 44

What is the ascent rate from the last decompression stop to the surface? (No"D")

Back 44

30 fsw per minute.

Front 45

What is the ascent rate from the 40' stop to the surface for surface decompression?

Back 45

40 fsw per minute.

Front 46

For in-water decompression on air when does the time for the first decompression stop begin? When dose the stop time end?

Back 46

For the first stop the time starts upon arrival and ends when he leaves the stop.

Front 47

For all decompression stops during Air Decompression EXCEPT for the 1st stop when does the stop time start?

Back 47

Stop times start when you leave your last stop.

Front 48

True or False; the ascent time between stops (for Air Decompression)is included in the next stop time?

Back 48

True

Front 49

When does stop time begin for the first O2 stop?

Back 49

When all divers are confermed on O2.

Front 50

Where is the last water stop for all in-water decompression?

Back 50

At 20 feet.

Front 51

When is a diver eligile for Surface Decompression?

Back 51

Upon completion of the 40 foot stop. (if no 40' stop ascend directly to the surface and start Sur"D")

Front 52

What is another name for the No-Decompression Table?

Back 52

The "no-stop" table.

Front 53

At depths of ____ feet or shallower there is no limit to the amount of time that can be spent at depth.

Back 53

20 feet

Front 54

Do you need a repetitive group designator following a No"D" dive?

Back 54

Yes, even though you had no decompression stops you still have residual nitrogen in your tissues that must be accounted for if you dive again.

Front 55

What are the acceptable variations in ascent?

Back 55

20 to 40 feet per minute.

Front 56

What is the depth ranges on the Optional Shallow Water No-Decopmression Table?

Back 56

30 to 50 feet in one foot increments.

Front 57

What is the purpose of the Optional Shallow Water No-Decopmression Table?

Back 57

To maximize no-decompression times.

Front 58

What are the 3 modes of the Air Decompression Tables?

Back 58

(1) In-water decompression using air.
(2) In-water decompression using on air & O2.
(3) Surface decompression on O2.

Front 59

If there is no Repet Group Designator listed for an in-water decompression dive, can you repet a diver?

Back 59

No, you must wait 18 hours to repet this diver

Front 60

At what depths are the in-water O2 stop made?

Back 60

At 30 and/or 20 foot.

Front 61

How are O2 stop times designated on the in-water decompression tables?

Back 61

The Oxygen stop times are in bold print.

Front 62

True or False; The Repet Group Designator for air decompression and air/O2 decompression are the same

Back 62

True, they are the same for both.

Front 63

Explain air breaks for in-water decompression using O2.

Back 63

A 5 minute air break must be taken for every 30 on O2.

Front 64

Travel/shift/vent time for the first O2 stop shuold take no more than ____ minutes?

Back 64

:03

Front 65

Explain Air Breaks for the 30' and 20' O2 stops. What are the exceptions, if any?

Back 65

A :05 minute air break is taken for ever :30 minutes on O2. If the last O2 stop is :35 minutes or less the :05 air break at :30 minutes is not required.

Front 66

True or False; Before leaving the 20' or 30' O2 stop, you must switch the divers to air.

Back 66

False. Surface the divers on 100% O2 upon completion of the O2 stop.

Front 67

What is required to dive a second dive team when you have divers decompressing in the chamber?

Back 67

The chamber and surface-supplied diving system must have separate air supplies.

Front 68

Can you have a planned Sur-D on air?

Back 68

No, all Surface Decompression is on O2.

Front 69

When do you start your Surface Interval time for a Sur-D dive?

Back 69

When the diver leaves the 40' stop, or when the diver passes 40' on ascent.

Front 70

What is the ascent rate from 40' to the surface during a Sur-D?

Back 70

40' per minute.

Front 71

How long are the O2 period for Sur-Ds?

Back 71

:30 minute periods or :15 minute half periods.

Front 72

At what depth is the first chamber O2 period performed during a Sur-D? How long is it?

Back 72

At 50' for :15.

Front 73

True or False the repet group designator for a Sur-D dive will be the same as the repet group designator for a air decompression dive?

Back 73

True, the repet group designator for both is found in the last column of the table.

Front 74

What is required in the chamber if you are decompressing only one diver?

Back 74

You must have an inside tender to monitor the diver.
(With two divers they monitor each other.)

Front 75

What is the max descent rate to 50' in the chamber when doing a Sur-D?

Back 75

100' per minute.

Front 76

What are the depths and length of O2 stops in the chamber diring a Sur-D O2?

Back 76

1):15 at 50' 5):30 at 30'
2):30 at 40' 6):30 at 30'
3):30 at 40'
4):30 at 40'

Front 77

Travel from 40' to 30' in the chamber durring a Sur-D O2 should be taken durring the _____ _____?

Back 77

Air Break

Front 78

Can you Sur"D" a diver from his 30' or 20' inwater decompression stops?

Back 78

Yes, you can Sur"D" after completing the 40' stop.

Front 79

When Sur"D" is elected before the diver has been shifted to O2, how do you compute chamber O2 periods?

Back 79

Complete the full number of O2 periods prescribed by the table.

Front 80

What is your course of action if you decide to Sur"D" your diver while he is at his 30'or 20' O2 stop in-water decompression stop?

Back 80

Multiply all remaining in-water O2 time 1.1, divide the total by 30, then round up the results to the next highest half period. (:15)

Front 81

If you decide to Sur"D" while the diver is decompressing on air at 30' or 20', what is the first thing you do?

Back 81

Convert the remaining air time to equivalent remaining O2 time.