That was lucky then! I don't know your name other than your sign-in, but let me know if you're with me and you too will be cancelled forthwith!
But exactly, accidents can happen... but in your case, if a claim had come in against you, was there any negligence on your part? Very probably not, so again, the insurance would defend you, but with a view to regrettably declining the boat-owner's claim. That may seem harsh, but as I say, it's all about who is legally liable, if anyone; and usually, nobody is actually at fault, so nothing comes of the claim; but at least you don't have to deal with it on your own.