CHAPTER 9 — Air Decompression
Change A 9-3
9-3.7
Equivalent Single Dive Bottom Time. The equivalent single dive bottom time is
the time used to select a schedule for a single repetitive dive. This time is
expressed in minutes.
9-3.8
Unlimited/No-Decompression (No “D”) Limit. The maximum time that can be
spent at a given depth that safe ascent can be made directly to the surface at a
prescribed travel rate with no decompression stops is the unlimited/no-decompres-
sion or No “D” limit (Table 9-6).
9-3.9
Repetitive Dive. A repetitive dive is any dive conducted within 12 hours of a
previous dive.
9-3.10
Repetitive Group Designation. The repetitive group designation is a letter used to
indicate the amount of residual nitrogen remaining in a diver’s body following a
previous dive.
9-3.11
Residual Nitrogen. Residual nitrogen is the nitrogen gas still dissolved in a
diver’s tissues after surfacing.
9-3.12
Residual Nitrogen Time. Residual nitrogen time is the time that must be 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. Residual nitrogen time is expressed in
minutes.
9-3.13
Single Dive. A single dive refers to any dive conducted more than 12 hours after a
previous dive.
9-3.14
Single Repetitive Dive. A single repetitive dive is a dive for which the bottom
time used to select the decompression schedule is the sum of the residual nitrogen
time and the actual bottom time of the dive.
9-3.15
Surface Interval. The surface interval is the time a diver has spent on the surface
following a dive. It begins as soon as the diver surfaces and ends as soon as he
starts his next descent.
9-4
DIVE RECORDING
Chapter 5 provides information for maintaining a Command Diving Log and
personal diving log and reporting individual dives to the Naval Safety Center. In
addition to these records, every Navy air dive may be recorded on a diving chart
similar to Figure 9-1. The diving chart is a convenient means of collecting the dive
data, which in turn will be transcribed in the dive log. Diving Record abbrevia-
tions that may be used in the Command Diving Log are:
LS - Left Surface
RB - Reached Bottom
LB - Left Bottom
