DOH !
At reload of the game the battleship is on the surface and I did not get 'credit' for the sinking.
Oh well.. might as well reload from before the task force being encountered.. now I'm just going through the pain of a 6 hour depth charge for no reason.
You guys are awesome for helping me though.
Ducimus.. please give suggestion though anyway; so I learn and can try what you say next time.