We have a house rule that big ships sink for 1 turn. Meaning when its hit for the final time, we leave it in its last position, turn it upside down and leave it like that for 1 turn. At the end of the next turn we remove it. It not only feels more realistic that big ships do not just "disappear", it also forces nearby ships to try to maneuver to avoid the wreck.
Just mentioning it if someone wants to add a bit of more realism to the game.