Norwegian Shipping Company Bans Electrified Vehicles over Fire Fears
carscoops.com
carscoops.com
THIS. I used to know the Chief Engineer on a large bulk carrier (cargo ship). If there was a fire - then he, his tiny crew, and the equipment they had on board was it. No "second alarm", no "mutual aid from neighboring city", no nothing. Fire-fighting training was in-depth, and very specific to the types of fires they might face. Ditto their equipment.
Unless the company running car ferries has crews which are train / equipped / certified to deal with an electrical vehicle fire (and marine insurance to back that up), then it is a very reasonable business decision to say "no electrical vehicles". Ditto for anything powered by propane, hydrogen, etc.
Lithium batteries are scary when they're damaged though. Can't imagine wanting to be on-board in the case of a fire, either.