Info

Stage Depth (fsw): 244'

Decompression Procedure: Emergency SWR -V

Max Depth (fsw): 24.9'

Divers' Condition: ^^

Diving Remarks:

Figure 14-5. HeO2 Diving Chart.

Figure 14-5. HeO2 Diving Chart.

Figure 14-6. Emergency Surface Decompression Dive Profile for a 249 fsw/:18 Dive.

3. Surface the diver from 20 fsw when it is confirmed that the diver is breathing air.

Example. A diver intends to dive to 300 fsw. Five minutes is spent at 20 fsw shifting from air to an 88 percent helium/12 percent oxygen mixture. Descent is then begun at 60 fsw/min, but at 80 fsw the diver signals for a hold because he is unable to clear. After 2 minutes at 80 fsw, the dive is aborted. The bottom time is 3 minutes: 1 minute for the descent and 2 minutes at 80 fsw. The corrected bottom time is 8 minutes: 5 minutes at 20 fsw and 3 minutes of bottom time. The table shows an 80 fsw dive for 8 minutes is well within the no-decompression limit of 25 minutes. The diver should ascend to 20 fsw at 30 fsw/min, shift to air, ventilate, and then ascend directly to the surface.

Example. A diver intends to dive to 200 fsw on an 84 percent helium/16 percent oxygen mixture. The diver descends from the surface to 60 fsw at 60 fsw/min. No time is spent at 20 fsw shifting gases. At 60 fsw the diver signals for a hold and after 3 minutes at 60 fsw, the dive is aborted. The bottom time and the corrected bottom time are both 4 minutes: zero minutes at 20 fsw, 1 minute for descent, and 3 minutes at depth. The table shows a 60 fsw dive for 4 minutes is well within the no-decompression limit of 40 minutes. This diver may ascend directly to the surface at 30 fsw/min.

Example. A diver intends to dive to 300 fsw. Eight minutes is spent at 20 fsw shifting from air to an 88 percent helium/12 percent oxygen mixture. Descent is begun at 60 fsw/min but at 140 fsw the diver signals for a hold. After 2 minutes at 140 fsw the dive is aborted. The corrected bottom time is 12 minutes: 8 minutes at 20 fsw, 2 minutes of descent time from 20 fsw to 140 fsw and 2 minutes at 140 fsw. Decompression would take place on the 140-fsw/20-minute schedule.

14-3.10 Variation in Rate of Ascent. The rate of ascent to the first stop and between subsequent stops is 30 fsw/minute. Minor variations in the rate of travel between 20 and 40 fsw/minute are acceptable.

14-3.10.1 Early Arrival at the First Stop. If the divers arrive early at the first stop:

1. Begin timing the first stop when the required travel time has been completed.

2. If the first stop is 50 or 40 fsw and arrival at the stop is early, shift to oxygen and begin stop time when the required travel time has been completed.

14-3.10.2 Delays in Arriving at the First Stop.

■ Delay less than 1 minute. Delays in arrival at the first stop of less than 1 minute may be ignored.

■ Delay in excess of 1 minute. For delays in excess of 1 minute: 1. Add the total delay to the bottom time.

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