When we are in the great boat we can swim for the key at the other side of the ship,but poor indy dies on the way back because the airproblem, who knows how to get trough this. We are trying it for days but without any results.
don't swim directly to the key. instead turn right before you reach the cargo hold. Next left and up. Use the rosty hammer to open the lock. now the distance to get the key is much smaller...
check also my walkthrough at
www.cyberjunkie.com/rayon) (
http://www.cyberjunkie.com/rayon)