ive gotten through gibralta before, just keep your distance from the destroyers and weave around them, use flank when possible to move the ball down field, stay close to africa, but remain in deep water,and then slip around to ceuta and hide, once your through. You can recharge when stationary btw (perhaps a bug, I asked whether this was the case in reality on this forum in a past post) just go all stop and use compression and wahch you battery recahrge
its alot of fun down there, my favorite place in the game. good luck!