CHAPTER 8 Surface-Supplied Air Diving Operations
Change A 8-29
Before leaving the descent line or stage, ensure that the umbilical is not fouled.
Loop one turn of the lifeline and air hose over an arm; this acts as a buffer
against a sudden surge or pull on the lines.
Proceed slowly and cautiously to increase safety and to conserve energy.
If obstructions are encountered, adjust buoyancy to pass over the obstruction
(not under or around). If you pass around an obstruction, you must return by
the same side to avoid fouling lines.
When using buoyancy adjustments to aid in movement, avoid bouncing along
the bottom; all diver movements are controlled.
If the current is strong, stoop or crawl to reduce body area exposed to the cur-
rent. Adjust the inflation of the dress to compensate for any change in depth,
even if the change is only a few feet.
When moving on a rocky or coral bottom, make sure lines do not become
fouled on outcroppings, guarding against tripping and getting feet caught in
crevices. Watch for sharp projections that can cut hoses, diving dress or unpro-
tected hands. The tender is particularly careful to take up any slack in the
divers umbilical to avoid fouling.
Guard against slipping and falling on gravel bottoms, especially on slopes.
Avoid unnecessary movements that stir up the bottom and impair visibility.
Avoid overinflation and be aware of the possibility of blowup when
breaking loose from mud. It is better to call for aid from the standby
diver than to risk blowup.
Mud and silt may not be solid enough to support your weight. Many hours
may be spent working under mud without unreasonable risk. The primary haz-
ard with mud bottoms comes from the concealment of obstacles and
Searching on the Bottom. If appropriate electronic searching equipment is not
available, it may be necessary to use unaided divers to conduct the search. Proce-
dures for searching on the bottom with unaided divers are:
A diver search of the bottom can be accomplished with a circling line, using
the descent line as the base point of the search. The first sweep is made with
the circling line held taut at a point determined by the range of visibility. If
possible, the descent line should be in sight or, if visibility is limited, within
reach. The starting point is established by a marker, a line orientation with the
current or the light, signals from topside, or a wrist compass. After a full 360-
degree sweep has been made, the diver moves out along the circling line