They're attacking exclusively sailboats, which are silent. Granted, not many motor yachts are transiting the straits and those that do tend to be larger than 40

They're attacking exclusively sailboats, which are silent. Granted, not many motor yachts are transiting the straits and those that do tend to be larger than 40 feet, but some do. Their method of attack (disable the rudder) is also only effective on sailboats (the rudder is much, much larger and consequently easier to break.) I'm really not sure that's the reason. Someone else in this thread had an idea that they were trying to replicate a prior result (obtaining something desirable from a disabled yacht) but I'm inclined to believe they're just being dicks. And why not? We hunt for sport. And we know that orcas engage in play, even quite cruel play with cornered seals. It could be adolescent orcas challenging each other, like pelagic ding dong ditch. EDIT: The boat in the article was motoring, not under sail. So strike the word "silent" for "a lot quieter than a motorboat."