If you get hit, just nosedive your boat into the bottom, climb up to the rear torpedo tube (if equipped) or cut a hole through the hull, and get out, it's really not that deep:
http://www.bbc.co.uk/kent/news/stori...2/tanker.shtml
and yes, never trust us Brits, we are all underhand sneaky b*st*rds that skillfully mask it behind a 'terribly posh' accent.

Chock