nah ace its all halfmask and a reg on the hose, with an idependant bailout requiring a spare reg to be located from a accessable position on the harness and the inverted tank valve to opened.
the only coms used in the industry is a simplified morse code by the head diver while drifting, by means of two stainless 200lb plastic coated multi strand fishing trace run down the inside on the hose to an inline button at the divers end.
skippers can marks spots of thick shell, sand h***s, turn left/right, speed up or slow down or call the divers up by getting the decky to belt the crap out of the bits/bollards on the stern with a sledge hammer
hahahaha. funny times
the hand signals got pretty imaginative by the end of it. always had the thought that a deaf diver would have a laugh and a half on that job.
u got what u had to do straight before u went in every time and learnt not to rely on asking stupid questions.