CHAPTER 8 Surface-Supplied Air Diving Operations
Change A 8-31
breathing. Tests of the air in the enclosed space shall be conducted
hourly. Testing shall be done in accordance with NSTM 074, Volume 3,
Gas Free Engineering (S9086-CH-STM-030/CH-074) for forces afloat, and
NAVSEA S-6470-AA-SAF-010 for shore-based facilities. If the divers
smell any unusual odors they shall immediately don their EGS.
If the diving equipment should fail, the diver shall immediately switch to
the EGS and abort the dive.
Working Around Corners. When working around corners where the umbilical is
likely to become fouled or line-pull signals may be dissipated, a second diver
(tending diver) may be sent down to tend the lines of the first diver at the obstruc-
tion and to pass along any line-pull signals. Line-pull signals are used when audio
communications are lost, and are passed on the first divers lines; the tending diver
uses his own lines only for signals directly pertaining to his own situation.
Working Inside a Wreck. When working inside a wreck, the same procedure of
deploying tending divers is followed. This technique applies to the tending divers
as well: every diver who penetrates a deck level has another tending diver at that
level, or levels, above. Ultimately, the number of tending divers deployed depends
on the situation and the good judgment of the Diving Officer, Master Diver, or
Diving Supervisor on the site. Obviously, an operation requiring penetration
through multiple deck levels requires detailed advanced planning in order to
provide for the proper support of the number of divers required. MK 21 MOD 1
and MK 20 MOD 0 are the only equipment approved for working inside a wreck.
The diver enters a wreck feet first and never uses force to gain entry through an
Working With or Near Lines or Moorings. When working with or near lines or
moorings, observe the following rules:
Stay away from lines under strain.
Avoid passing under lines or moorings if at all possible; avoid brushing
against lines or moorings that have become encrusted with barnacles.
If a line or mooring is to be shifted, the diver is brought to the surface and, if
not removed from the water, moved to a position well clear of any hazard.
If a diver must work with several lines (messengers, float lines, lifting lines,
etc.) each should be distinct in character (size or material) or marking (color
codes, tags, wrapping).
Never cut a line unless the line is positively identified.
When preparing to lift heavy weights from the bottom, the lines selected must
be strong enough and the surface platform must be positioned directly over the
object to be raised. Prior to the lift, make sure the diver is clear of the lift area
or leaves the water.