Blowing ballast

Originally Posted by BettingUrlife

Ok Fab, that makes sense, but then wouldn't the opposite (i.e. submerging) mean they blow the tank's air out? Then if that is the case, there is still no bubbles from our subs in SH3 I sincerely hope you aren't going to tell that they suck the air from the ballast tanks back into the sub? It's just that I'd hate to be wrong twice in a day

Not really; most of the time, the tanks keep the boat at more or less neutral bouyancy. They'll suck in a little water to help the dive, but by and large, the ballast tanks don;t play as much a role in diving as the planes and engines do (hence why diving when stationary takes quite a bit longer).