Chapter 9 Usn Dive Manual Rev. 6

Front 1

Why do some tissues ongas faster than others

Back 1

The amount of blood flow. The faster the blood flow, the faster the on and off gasing.

Front 2

Deviations from established decompression procedures are not permitted except

Back 2

in an emergency and with the guidance and recommendation of a Diving Medical Officer (DMO) with the Commanding Officer or Officer-in-Charge’s approval.

Front 3

Surface Interval during Sur D's is calculated from

Back 3

Time the diver leaves 40' in-water to the time the diver reaches 50' in the chamber.

Front 4

What are the characteristics of an exceptional exposure dive?

Back 4

one 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 5

Planned exceptional exposure diving needs approval from?

Back 5

The CNO

Front 6

What are the 6 tables required for any spectrum of air dives?

Back 6

No-Decompression Limits and 1)Repetitive Group Designation Table for No-Decompression Air Dives.
2)Air Decompression Table
3)Residual Nitrogen Timetable for Repetitive Air Dives
4)Sea Level Equivalent Depth Table
5)Repetitive Groups Associated with Initial Ascent to Altitude Table
6)Required Surface Interval Before Ascent to Altitude After Diving

Front 7

Pnuemo correction factor from 0-100 fsw

Back 7

1 fsw

Front 8

Pnuemo correction factor from
101-200 fsw

Back 8

2 fsw

Front 9

Pnuemo correction factor from
201-300 fsw

Back 9

4 fsw

Front 10

Pnuemo correction factor from 301-400 fsw

Back 10

7 fsw

Front 11

Minor variations in ascent between ......... are permitted

Back 11

20-40 ft./min

Front 12

Decompression stops except for the first one start when..

Back 12

...leaving the last stop to leaving the current stop.

Front 13

The first decompression stop starts when...

Back 13

....arriving at the first stop to leaving the first stop.

Front 14

What depth is the last in-water decompression stop?

Back 14

20 fsw

Front 15

Diver/s are eligble for Sur D' after completing what stop?

Back 15

40 fsw

Front 16

The optional 'shallow water no decompression table' is located in ....

Back 16

Appendix 2A

Front 17

Name the modes of decompression

Back 17

1) In-water D using air
2) In-water D using air/O2
3) Sur D O2

Front 18

During in-water decompression on O2; what is the maximum time spent on O2 before an air break must be taken, unless total time is less than :35

Back 18

30 min.

Front 19

When using a FADS III, LWDS, or DSM what assembly is needed to deliver O2 in-water to the divers

Back 19

Oxygen Regulated Console Assembly (ORCA)

Front 20

FMGS is what?

Back 20

Fly-away Mixed Gas Diving System

Front 21

When switching from air to O2 during in-water decompression what is the ventilation time for each or both divers?

Back 21

20 seconds

Front 22

What are the advantages to Sur D O2's?

Back 22

1)Shorter exposure time in the water keeps divers from chilling to a dangerous level when diving in cold water.
2)Inside the recompression chamber, the divers can be maintained at a constant pressure, unaffected by the surface conditions of the sea. 3)Once divers have been recovered into the recompression chamber, a second dive team can begin descent, provided the recompression chamber and the surface-supplied diving system have separate air supplies. This greatly speeds up operations.

Front 23

To be Sur D O2 eligable what depth stop must be completed?

Back 23

40'

Front 24

During Sur D' O2's how long is an O2 period? and half periods?

Back 24

30 min./ 15 min.

Front 25

During a normal surface interval, how much time is spent in the chamber at 50FSW?

Back 25

15min

Front 26

During the Sur D O2 procedure, what is the rate of ascent from 40FSW to the surface?

Back 26

40FT./Min.

Front 27

During the Sur D O2 procedure what is the approximate time the tenders have for the undress tme and assist the diver to chamber?

Back 27

3 1/2 min.

Front 28

During Sur D O2's chamber phase an inside tender is not needed when?

Back 28

If there are two divers and the supervisor elects not too.

Front 29

During the chamber phase of Sur D O2's the descent rate is not to exceed?

Back 29

100 ft/min

Front 30

At what point of the Sur D' O2 process does the diver go on O2?

Back 30

At the arrival of 50FSW

Front 31

During the Sur D' O2 process period 2-4 are completed at what depth?

Back 31

40FSW

Front 32

During Sur D' O2's if more than 4 periods are required, what depth are they completed at?

Back 32

30FSW

Front 33

During Sur D' O2's chamber phase what is the rate of ascent after O2 periods are complete?

Back 33

30FSW/Min.

Front 34

While at 30 or 20 FSW in-water decompression when may the supervisor elect to use Sur D' O2?

Back 34

At any point; but has the option to take credit for time already spent on O2. or complete all the prescribed O2 periods.

Front 35

During in-water decompression the supervisor decides to move to Sur D O2. With 38min. left of O2 still to complete how many O2 periods will be done in the chamber?

Back 35

1.5; Mulitiply remaining in-water (38) by 1.1 and divide by 30, then round up to the nearest half.

Front 36

During in-water decompression on air at 30 FSW the supervisor decides to use Sur D O2. How does the conversion work for this process?

Back 36

For a diver at 30 fsw: First compute the air/oxygen trading ratio at 30 fsw by dividing the 30 fsw air stop time listed in the table by the 30-fsw oxygen time. Next divide the remaining air time at 30 fsw by the air/oxygen trading ratio to determine the equivalent remaining oxygen time at 30 fsw. Add the oxygen time shown in the table at 20 fsw to the equivalent remaining oxygen time at 30 fsw to obtain the total remaining oxygen time. Compute the number of chamber oxygen periods required by multiplying the remaining oxygen time at the stops by 1.1, dividing the total by 30 minutes, then rounding the result up to the next highest half period. One half period (15 minutes at 50 fsw) is the minimum requirement.

Front 37

For dives that do not require more than 15 min. of decompression; what type of decompression is most suitable?

Back 37

In-water decompression on air

Front 38

In-water decompression on air and oxygen is most suitable for dives that do not require more than

Back 38

90 min of total air and oxygen time in the water. Longer times increase the risk of CNS oxygen toxicity and exposure to the element

Front 39

If the total air/oxygen decompression time in the water is greater than 90 min, surface decompression on oxygen is required unless

Back 39

CNO permission to conduct exceptional exposure dives is obtained.

Front 40

To use the repetitive dive procedure described below, the interval on the surface between dives must be at least ____

Back 40

10 minutes

Front 41

In the Repetitive Dive Procedure: If the surface interval between dives is less than 10 minutes,

Back 41

add the bottom time of the two dives and enter the decompression table at the deeper of the two depths

Front 42

RNT Exception rule

Back 42

-Plan deepest dive first.
1)Firgure RNT using the Table 9-8
2)Combine both bottom times and calculate ESDT
This gives the option in which to use either method for least amount of decompression

Front 43

Is it possible to perform a repetitive dive on air following either a MK 16 MOD 0 or a MK 16 MOD 1 nitrogen-oxygen dive using the existing tables?

Back 43

Yes. To perform a repetitive dive on air following a nitrogen-oxygen dive on either the MK 16 MOD 0 or MOD 1, use the steps outlined starting on page 9-29 in the NDM.

Front 44

Exceptional exposure is intended for emergency use only; for what emergency?

Back 44

To save a trapped diver and/or a life.

Front 45

In order to to plan an exceptional exposure dive; the dive must be what?

Back 45

The Commanding Officer must carefully assess the need for planned exceptional exposure diving and prior CNO approval for such diving is required.

Front 46

Name 3 types of dives that are considered exceptional exposure.

Back 46

1)Any dive deeper than 190 fsw.
-2)Any in-water decompression dive with a total decompression time on air or air/oxygen greater than 90 minutes.
3) Any SurDO2 dive with a chamber oxygen time greater than 120 minutes (4 oxygen periods).

Front 47

State the variations of ascent.

Back 47

20-40fsw

Front 48

If Travel Rate is Exceeded you should..

Back 48

stop the ascent, allow the watches to catch up, and then continue ascent.

Front 49

If the divers arrive early at the first decompression stop:

Back 49

1. Begin timing the first stop when the required travel time has been completed.
2. If the first stop is an oxygen stop, shift the divers to oxygen upon arrival at the stop. Begin stop time when the divers are confirmed on oxygen and the required travel time has been completed

Front 50

If there is a delay up to 1 minute in reaching the first decompression stop you..

Back 50

A delay of up to one minute in reaching the first decompression stop can be ignored.

Front 51

Delay greater than 1 minute, deeper than 50 fsw:

Back 51

Round up the delay time to the next whole minute and add it to the bottom time. Recompute the decompression schedule. If no change in schedule is required, continue on the planned decompression. If a change in schedule is required and the new schedule calls for a decompression stop deeper than the diver’s current depth, perform any missed deeper stops at the diver’s current depth. Do not go deeper

Front 52

Delay greater than 1 minute, shallower than 50 fsw:

Back 52

If a delay in ascent greater than 1 minute occurs shallower than 50 fsw, round the delay time up to the next whole minute and add the delay time to the diver’s first decompression stop.

Front 53

Delay less than 1 minute leaving an air stop:

Back 53

When the delay in leaving an air stop is less than 1 minute, disregard the delay. Resume the normal decompression when the delay is over.

Front 54

Delay less than 1 minute between air stops:

Back 54

If the delay between stops is less than 1 minute, disregard the delay.

Front 55

Delay greater than 1 minute leaving an air stop or between air stops deeper than 50 fsw:

Back 55

Add the delay to the bottom time and recalculate the required decompression. If a new schedule is required, pick up the new schedule at the present stop or subsequent stop if delay occurs between stops. Ignore any missed stops or time deeper than the depth at which the delay occurred.

Front 56

Delay greater than 1 minute leaving an air stop or between air stops shallower than 50 fsw:

Back 56

Ignore the delay. Resume the normal schedule upon completion of the delay.

Front 57

Delay leaving an oxygen stop at 30 fsw or delay between oxygen stops at 30 and 20 fsw:

Back 57

Subtract any delay in leaving the 30 fsw oxygen stop or any delay during travel from 30 to 20 fsw on oxygen from the subsequent 20-fsw oxygen stop time. If the delay causes the total time on oxygen deeper than 20 fsw to exceed 30 minutes, shift the diver to air at the 30-minute mark. When the problem has been resolved, shift the diver back to oxygen and resume decompression. Ignore any time spent on air

Front 58

Delay in leaving the 20-fsw oxygen stop:

Back 58

Delays leaving the 20-fsw oxygen stop can be ignored. However, do not leave divers on oxygen longer than 30 minutes as described in paragraph 9-8.2.2. Shift the divers to air and remain on air until travel to the surface is possible.

Front 59

Delay in Travel from 40 fsw to the Surface for Surface Decompression:

Back 59

Disregard any delays in travel from 40 fsw to the surface during surface decompression unless the diver exceeds the allowed 5-minute surface interval. If the diver exceeds the 5-minute surface interval, follow the guidance in paragraph 9-12.6.

Front 60

In rare instances bottom time may exceed the longest bottom time listed in the table for the diver’s depth. In this case the protocal is:

Back 60

immediately contact the Navy Experimental Diving Unit for advice on how to decompress.
2)If available, use the U.S. Navy Thalmann Algorithm Dive Planner to compute the decompression requirement
3)Read down to deeper depths in the Air Decompression Table until a depth is found that has a schedule that is equal to or longer than the bottom time. The Air Decompression Table contains longer schedules at various depths especially for this purpose

Front 61

Loss of O2 supply in the water before reaching the 30FSW or 20FSW:

Back 61

1)Have the diver continue to breathe air while the problem is investigated.
2). If the problem can be corrected quickly, ventilate the diver with oxygen as soon as the gas supply is restored. Consider any time spent on air as dead time. Remain on oxygen at the stop for the full stop time listed in the table.
3. If the problem cannot be corrected, initiate surface decompression or continue decompression in the water on air. In this situation, the surface interval for surface decompression is the time from leaving the in-water stop to reaching the 50-fsw stop in the recompression chamber

Front 62

Procedure for loss of O2 while at the 30FSW and 20FSW stops:

Back 62

Shift the diver back to air.
2. If the problem can be corrected quickly, re-ventilate the diver with oxygen and resume the schedule at the point of interruption. Consider any time spent on air as dead time.
3. If the problem cannot be corrected and a recompression chamber is available on the dive station, initiate surface decompression. Compute the number of chamber oxygen periods required by multiplying the remaining oxygen time at the stops by 1.1, dividing the total by 30 minutes, then rounding the result up to the next highest half period. One half period (15 minutes at 50 fsw) is the minimum requirement.
If the problem cannot be corrected and a recompression chamber is not available on the dive station, continue decompression on air in the water. Compute the remaining stop time on air at the depth of the loss by multiplying the remaining stop time on oxygen at that depth by the ratio of the air stop time to the oxygen time at that depth.
If the shift to air occurs at 30 fsw, compute the remaining stop time on air at 30 fsw as shown above, then take the full 20-fsw air stop as prescribed in the Air Decompression Table.

Front 63

Contamination of Oxygen Supply with Air; If the operator discovers that the ORCA is improperly lined up, take the following action:

Back 63

1. Align the ORCA properly.
2. Re-ventilate each diver with oxygen for 20 seconds.
3. Restart oxygen time. Consider any time spent on contaminated oxygen as dead time.

Front 64

CNS Oxygen Toxicity Symptoms (Non-convulsive) at 30 or 20 fsw Water Stop; where will it most likely occur and what is the most likely symptom?

Back 64

At the end of the 20ft stop and the SX will most likely be nausea.

Front 65

If the diver develops symptoms of CNS toxicity at the 30- or 20-fsw water stops, take the following action with a chamber available:

Back 65

If a recompression chamber is available on the dive station, initiate surface decompression. Shift the console to air during travel to the surface. Compute the number of chamber oxygen periods required by multiplying the remaining oxygen time at the stops by 1.1, dividing the total by 30 minutes, then rounding the result up to the next highest half period. One half period (15 minutes at 50 fsw) is the minimum requirement

Front 66

If the diver develops symptoms of CNS toxicity at the 30 fsw water stop, take the following action, chamber not available:

Back 66

If a recompression chamber is not available on the dive station and the event occurs at 30 fsw, bring the divers up 10 fsw and shift to air to reduce the partial pressure of oxygen. Shift the console as the divers are traveling to 20 fsw. Ventilate both divers with air upon arrival at 20 fsw. Ventilate the affected diver first. Complete the decompression on air at 20 fsw. Compute the 20-fsw stop time as follows: Multiply the missed stop time on oxygen at 30 fsw by the ratio of the air to oxygen stop time at 30 fsw to obtain the equivalent missed air time at 30 fsw. Add this time to the 20-fsw air stop time shown in the Air Decompression Table.

Front 67

If the diver develops symptoms of CNS toxicity at the 20 fsw water stop, take the following action, chamber not available:

Back 67

Shift the console to air, ventilate both divers, affected diver first, and complete the decompression in the water at 20 fsw on air. Compute the remaining stop time on air at 20 fsw by multiplying the remaining stop time on oxygen at 20 fsw by the ratio of the air stop time to the oxygen time at 20 fsw

Front 68

Oxygen Convulsion at the 30- or 20-fsw Water Stop:

Back 68

1. Shift both divers to air if this action has not already been taken.
2. Have the unaffected diver ventilate himself and then ventilate the stricken diver.
3. If only one diver is in the water, launch the standby diver immediately and have him ventilate the stricken diver.
CHAPTER 9—Air Decompression 9-39
4. Hold the divers at depth until the tonic-clonic phase of the convulsion has subsided. The tonic-clonic phase of a convulsion generally lasts 1–2 minutes.
5. At the end of the tonic-clonic phase, have the dive partner or standby diver ascertain whether the diver is breathing. The presence or absence of breath sounds will usually be audible over the diver communication system.If the diver appears not to be breathing, have the dive partner or standby diver attempt to reposition the head to open the airway. Airway obstruction will be the most common reason why an unconscious diver fails to breathe.
7. If the diver is breathing, hold him at depth until he is stable, then surface decompress. Compute the number of chamber oxygen periods required by multiplying the remaining oxygen time at the stops by 1.1, dividing the total by 30 min, then rounding the result up to the next highest half period. One half period (15 minutes at 50 fsw) is the minimum requirement.
8. If surface decompression is not feasible, continue decompression on air in the water. Compute the remaining stop time on air at the depth of the incident by multiplying the remaining stop time on oxygen at that depth by the ratio of the air stop time to the oxygen time at that depth. If the shift to air occurs at 30 fsw, compute the remaining stop time on air at 30 fsw, then take the full 20-fsw air stop as prescribed in the Air Decompression Table.
9. If it is not possible to verify that the affected diver is breathing, leave the unaffected diver at the stop to complete decompression, and surface the affected diver and the standby diver at 30 fsw/min. The standby diver should attempt to maintain an open airway on the stricken diver during ascent. On the surface, the affected diver should receive any necessary airway support and be immediately recompressed and treated for arterial gas embolism in accordance with Figure 20-1.

Front 69

If the time from leaving 40 fsw in the water to the time of arrival at 50 fsw in the chamber during surface decompression exceeds 5 minutes, take the following action:

Back 69

If the surface interval is more than 5 minutes but less than or equal to 7 minutes, increase the time on oxygen at 50 fsw from 15 to 30 minutes

Front 70

If the time from leaving 40 fsw in the water to the time of arrival at 50 fsw in the chamber during surface decompression exceeds 7 minutes, take the following action:

Back 70

If the surface interval is greater than 7 minutes, continue compression to a depth of 60 fsw. Treat the divers on Treatment Table 5 if the original schedule required 2 or fewer oxygen periods in the chamber. Treat the divers on Treatment Table 6 if the original schedule required 2.5 or more oxygen periods in the chamber

Front 71

Describe the "safe way out" procedure.

Back 71

Compress the diver to the deepest depth he can attain initially. This will usually be less than 20 fsw. Begin oxygen breathing at that depth. Continue attempts to gradually compress the diver deeper. If the in-water air or air/oxygen decompression schedule required only a 20-fsw water stop, attempt to compress the diver to 20 fsw. If the in-water air or air/oxygen decompression schedule required a 30-fsw water stop, attempt to compress the diver to 30 fsw.
Oxygen time starts when the diver initially goes on oxygen. Interrupt oxygen breathing every 60 minutes with a 15-min air break.

Front 72

Describe the DCS Type I during surface interval protocol:
(relieved at 50 fsw in the chamber)

Back 72

Press to 50 fsw, do a neuro once on O2; if resolved and surfac interval was less than :05 add an additional :15 to the 50fsw stop.

Front 73

Describe the DCS Type I during surface interval protocol:
(not relieved at 50 fsw stop)

Back 73

If not relieved at the initial :15 and 2 or fewer O2 periods are due press to 60 fsw and complete a TT5. If more than 2 O2 periods were required complete a TT6.

Front 74

Describe the DCS Type II during surface interval protocol.

Back 74

If any DCS type II sx occurs press to 60 fsw and complete a TT6.

Front 75

Protocol for surface interval :05 or less/ symptomatic diver

Back 75

Increase O2 time from :15 to :30 min at 50 FSW

Front 76

Asymptomatic omitted D
No stop missed. any surface interval (blowup)

Back 76

Observe on surface for 1 hour

Front 77

Asymptomatic omitted D
Stop missed at 20fsw or 30fsw,
Surface Interval less than a minute.

Back 77

Return to depth of stop. Increase stop time by 1 min. Resume decompression according to original schedule.

Front 78

Asymptomatic omitted D, stop missed at 20fsw or 30fsw, surface interval between 1-5 min. CHAMBER AVAILABLE

Back 78

SUR Decompress

Front 79

Asymptomatic omitted D, stop missed at 20fsw or 30fsw, surface interval between over 7min. CHAMBER AVAILABLE

Back 79

Sur Decompress add :15 at 50'

Front 80

Asymptomatic omitted D, stop missed at 20fsw or 30fsw, surface interval between 1-7 min. CHAMBER NOT AVAILABLE

Back 80

Return to depth of stop. Multiply 30 and/or 20 fsw air
or O2 stop times by 1.5.

Front 81

Management of Asymptomatic Omitted Decompression, Deeper than 30 fsw, CHAMBER AVAILABLE

Back 81

Treatment Table 6

Front 82

Management of Asymptomatic Omitted Decompression, Deeper than 30 fsw, CHAMBER NOT AVAILABLE

Back 82

Descend to depth of first stop. Follow the schedule to 30 fsw. Switch to O2 at 30 fsw if available. Multiply 30 and 20 fsw air or O2 stops by 1.5.

Front 83

Management of Asymptomatic Omitted Decompression, Deeper than 50 fsw, CHAMBER NOT AVAILABLE

Back 83

Return to depth of first stop and follow the schedule to 30'. At the 30' and 20' ft stop multiply air or o2 time by 1.5.

Front 84

In-water DCS is most likely to occur..

Back 84

in shallow water depths

Front 85

For in-water DCS, when the diver feels he can stay in the water and the diver is already at 30fsw or 20fsw diver should be breathing what, if not already?

Back 85

100% O2

Front 86

In water DCS diver is at 30' on O2 and no relief of symptoms. What should be done?

Back 86

Have the diver descend 10 fsw. If significant relief of symptoms is not obtained, have the diver descend an additional 10 fsw, but no deeper than 40 fsw if the diver is on oxygen. Remain at treatment depth for at least :30

Front 87

In water DCS diver is at 30' on air and no relief of symptoms. What should be done?

Back 87

Have the diver descend 10 fsw. If significant relief of symptoms is not obtained, have the diver descend an additional 10 fsw, If the diver is on air, resume decompression from treatment depth by multiplying subsequent air or oxygen stop times in the Air Decompression Table by 1.5. If recompression went deeper than the depth of the first stop on the original air decompression schedule, insert intervening stops in 10 fsw increments between the treatment depth and the original first stop depth equal to 1.5 times the original first stop time.

Front 88

For altitude diving what is the correction of dive depth formula

Back 88

Equivalent Depth (fsw)= Altitude Depth x pressure at sea level / pressure at altitude

Front 89

What is the correction factor for dives shallower than 300fsw?

Back 89

None

Front 90

At altitudes between 300 and 1000 feet, correction is required for dives deeper than..

Back 90

145 fsw (actual depth)

Front 91

At altitudes above 1000 feet, correction is required for..

Back 91

All dives

Front 92

What should be done to the depth gauges at altitude prior to diving?

Back 92

Guages should be zeroed; no further correction is needed.

Front 93

A correction factor of _____ for every 1000 feet of altitude should be added to the reading of a sealed reference gauge before entering

Back 93

1ft.

Front 94

How many hours at altitude is required at altitude before a diver is considiered acclimatized?

Back 94

12 hrs.

Front 95

What table gives the repetitive group associated with an initial ascent to altitude.

Back 95

Table 9-8

Front 96

What table gives the surface interval (hours:minutes) required before making a further ascent to altitude?

Back 96

Table 9-6

Front 97

Before ascent to altitude after an excpetional exposure dive the diver/s need to wait how long?

Back 97

48 hours

Front 98

Maximum ascent to altitude after a dive is?

Back 98

10,000 ft

Front 99

Normal altitude used to compute for commercial flights is?

Back 99

8,000ft.

Front 100

Ascent to altitude after a No-D heli-ox dive requires a wait time of how many hours?

Back 100

12 hours

Front 101

Ascent to altitude after a Decompression heli-ox dive requires a wait time of how many hours?

Back 101

24 hrs.