swimmer_spe
Contributor
Just ran it on V-planner for giggles. Using 0.5% Oxygen 99.5% Helium for a bottom gas (still a pretty high PO2 of 1.82 at the bottom) and having 20 deco mixes in 5% increments of oxygen for the ascent. You would use a total of 1,310,924 cubic feet of gas, spend 310 hours (about 13 days) coming up and be at 64 times the recomended limit CNS oxygen exposure. And that is if you only spend 60 seconds on the Titanic.
So, about 11000 steel 120s. That is if they can support the pressure.