Kamaji speculates:
"At what point will insurance carriers start making exceptions/exclusions for fires caused by EVs?"
I would think after one or two more "at sea" fires on ocean-going vessels that carry autos.
Either the insurers will demand as a condition of underwriting that NO electric vehicles be carried at all, or they may include some kind of stipulation (may or may not be enforceable) that if EV's are carried, and if it can be shown that a ship was damaged or lost as a result of an EV-generated fire, that the policy wouldn't pay.