Annual Diving Report - Divers Alert Network

2.4 Dive Profiles
2. PROJECT DIVE EXPLORATION
Section 2.4 describes the breathing gases, repetitive dive status, number of days in the dive
series, number of dives in the series, maximum dive depths, deepest and last dives in the series,
maximum depth for each day of multi-day series, dive planning methods, decompression stops,
and altitude exposure.
The breathing gas was reported as air in 69 percent of PDE dives, nitrox (a nitrogen-oxygen mix
with greater than 21 percent oxygen) in 30 percent, and a mix containing helium in one percent.
Fifty-eight percent of the dive series were multi-day, 25 percent were single-day repetitive, and 17
percent were single dives (Figure 2.4-1). Dive profiles from liveaboards were predominately
repetitive and multi-day. About 40 percent of all dive series occurred in one day. Dive series with
2-4 dives made up over one-quarter of all dives and were collected mainly from beach and
dayboat divers (Figure 2.4-2). Forty-seven percent made 5-29 dives in a series (Figure 2.4-3).
The typical diving pattern for from liveaboards was 10-19 dives over six days. Series with more
than 30 dives over seven or more days diving were contributed, for the most part, by recreational
dive professionals.
Twenty percent of the dives were deeper than 90 fsw/27 msw (Figure 2.4-4), and the last dives of
the series were to lesser depths than the deepest dives (Figure 2.4-5). During multi-day diving,
the mean average depth decreased progressively from 73 fsw (22 msw) on the first day to 19 fsw
(6 msw) by the tenth day (Figure 2.4-6). Thirty-five percent of Scapa Flow dives and 25 percent of
beach and dayboat dives were deeper than 90 fsw (27 msw) whereas only 10-13 percent of
liveaboard and RDP were this deep (Figure 2.4-7).
Dive computers were used for 81 percent of the PDE dives while in 17 percent, another diver was
followed (Figure 2.4-8). Only about one percent of PDE divers used tables. Ninety-eight percent
of Scapa Flow divers used dive computers (Table 2.4-1) and did the most dives with required
decompression stops (some using oxygen-rich gas mixes) while liveaboard divers did the most
safety stops (Table 2.4-2). At least 30 percent of PDE divers reported flying after diving (Figure
2.4-9).
60
50
40
30
20
10
0
Single Dive One Day-Repetitive
Diving
Multi-day Diving
Figure 2.4-1 Single, repetitive, and multi-day dive series (n = 3,265).
18 Annual Diving Report: 2006 Edition