Why does nobody talk about the shift from steel to aluminum tanks for deep salvage?

I worked a big wreck job in the Gulf six years ago where we all used heavy steel 120s, but last month on a similar job, every diver had switched to aluminum 80s. The lighter weight cut our surface intervals by almost half, but some guys say the buoyancy swing is a safety risk. Do you think the trade-off is worth it for deep commercial work?

3 comments

3 Comments

xenar143mo ago

Watch a diver chase their tank across the deck because they forgot it was half empty and now it's a balloon. Sure, you save time on the surface, but you spend it all doing math at depth. Seems like a great way to turn a salvage job into a game of underwater ping-pong.

the_simon1mo ago

Call out @xenar14 all you want but on my last deep job the aluminum tanks meant we could get an extra diver in the boat and finish the shift before the current turned nasty. Buoyancy swing is just another thing to account for, like current or depth, not some impossible math problem.

sagesingh3mo ago

The real problem is the thermal conductivity. Aluminum pulls heat from you way faster than steel in those cold deep layers. You burn through your gas trying to stay warm, which messes up all your planned run times and deco stops. The weight saving gets eaten by the extra gas you need.