so far this tragedy seems to have been caused by a fire on the car deck of the ferry. whether malicious or not is not known at this point, but what I would ask is this.... your cargo is vehicles, things that have electricity, petrol, friction, fire etc so there is a quite big risk of fire. You are a ship and this cargo is in your belly, so wouldn't you have lots of smoke detectors, and a fantastically good sprinkler system? cars and lorries are designed to be wet, you have the sea as your source... simply soak the car deck at the slightest whiff of smoke surely?
PS if you're about to post a reply and your response is going to be negative, improper, average, odd, obtuse, irrational, an argument, might change the focus, going off at a tangent or just mean ... go and find a maths forum to post on instead, they'll love you !!