CHAPTER 13 Mixed Gas Operational Planning
Change A 13-5
mixed gas diving until complete rewarming of the diver has taken place, as shown
by sweating, normal pulse, and return of normal core temperature. Subjective
thermal comfort does not accurately indicate adequate rewarming.
Mobility. Some diving operations may dictate the use of a diving method that is
selected as a result of special mobility requirements in addition to depth, bottom
time and logistical requirements. The MK 21 MOD 1 is the preferred method
when operations require mobility in the water column (see Figure 13-1).
For missions where mobility is an essential operating element and depth and
bottom time requirements are great, closed circuit diving may be the only avail-
able option. Such diving is frequently required by special warfare and/or explosive
ordnance disposal (EOD) personnel.
Equipment Selection. Equipment and supplies available for mixed gas diving
operations by U.S. Navy personnel have been tested under stringent conditions to
ensure that they will perform according to design specifications under the most
difficult conditions that may be encountered. Several types of equipment are avail-
able for mixed gas operations. Equipment selection is based upon the chosen
diving method, depth of the dive and the operation to be performed. Table 13-3
outlines the differences between equipment configurations.
The UBA MK 21 MOD 0 is an open circuit, demand-regulated diving helmet
designed for saturation, mixed gas diving at depths in excess of 300 fsw and as
Figure 13-1. Searching Through Aircraft Debris on the Ocean Floor.