heavier, yes. But, if a whale attacks a steel boat then the odds are good that the whale is going to be hurting more than the boat. You can't say that about wood or plastic boats.

While the sample size is relatively small and incomplete - dead men tell no tales, after all - when whales attack they seem to attack wooden boats the most. Never heard of a steel or aluminum boat being attacked. Perhaps this is because the whales can use their 'sonar' to detect a difference in composition? Just speculation.

btw, if you are are grounded, a steel boat has great advantages - especially over a plastic boat. A relatively small impact with a rock can do extensive - and expensive - damage to a glass boat but ....

Jerry