Thanks for the report, GPSRider.
You found the solution to the problem yourself: Lord Rat had trashed down to so few cards, that it doesn't actually have a deck or discard pile, it has all cards it has in its hand. So if you use the "attack mode" of Pirate Ship, no cards will be revealed, as there simply are no cards to be revealed! The log shows what happened, and nothing happened, so it doesn't show anything special.
I know that this is counterintuitive in some cases, like this one. Maybe it would be helpfull if in such a case a small info was posted into the log.