Well, despite the vague nature of the Drive article above, we have all seen the jagged hole at the waterline in the stern of one of these ships. (See Andrea Victory, Bergen, in BBC article above) There was a similar attack a couple of years ago I remember where some craft managed to creep up undetected to a (Japanese?) tanker and hit it mysteriously.
https://www.telegraph.co.uk/news/wor...of-Hormuz.html