Boats are crunchy on the outside with a gooey middle.
In seriousness, it sounds like they are just being bullies.
Time to knock them down a peg.
Older killer whale (in aquatic Foghorn Leghorn voice) “Now son,lemme show you how it’s done heeya. FIRST, we sink the boat, then those land varmints end up in the water, but we don’t eat then right away ya see. Ya gotta, Ah say ya gotta swim around ‘em some first”
Younger killer whale: “why’s that Papa?”
Older killer whale: “Ya wanna scare, I say frighten, the inside stuff...the ugly stuff that is, out first. They taste better that way”
I'm thinking that a flash-bang over the side would have the desired effect with out hurting them.
But Europeans are not to smart.