There was a reference somewhere higher up this thread to a ship being captured when grounded. This ocurred during the Enlish Civil war when a ship was capured by a cavalry troop at Blue Anchor in the Bristol Channel, between Watchet and Minehead.

I would sugest that the cabin boy's best course of action would be to try to board the enemy ship unnoticed, creep down to the bilges and bore holes from the inside. Drilling several holes in a circle, each most of the way through and then break the whole area out and run!