I'd have the dealer take a look first - my guess engine isn't toast - but who knows, most boat engines are run somewhat too cold most of the time, figure that most 350 small block chevies in cars run 190-210 as standard range.
Biggest issue with this in boats is that the open loop cooling system will boil at the same temp as water on the stove, the antifreeze with a pressure cap in a truck will keep the boil down.
So if the coolant boiled out in the heads, and particularly in aluminum heads - that can give you some issues, but then again... depends.
I've seen "boat" specialty guys screw up hulls, guy on our lake had an MC with a repair after a skeg strike - boat never skied properly again. They basically made a step in the hull.