While watching the Cousteau Odyssey collection, I've noticed that the deep divers (down to 370FSW where diving with 3 tanks of heliox and each had what looks like white balloons attached to the manifold. I wonder if anyone on this board knows the reason for these. The support crew (down to the bell @180FSW) didn't have these.
Today, the requirements to dive the Britannic are far different than they were back in the 70's when Cousteau discovered the wreck's location. It is well worth the time to watch the Cousteau Odyssey program if you can get a copy of it.
https://www.youtube.com/watch?v=L-ShLUtrj2s