The drain plug is metal in the bottom of the cockpit. It's a Sunfish. I do have duct tape! I was hoping to loosen it, got very afraid then the whole device started turning....
I have no experience with the metal bailer; however, I'd expect the metal bailer can be removed and replaced with a new bailer made of plastic. ($42.)
Douse the metal threads with Kroil®, P-Blaster®, WD-40®, or CRC 666®, then rotate top and bottom parts to loosen and remove. Check that the inside and outside of that cockpit and bottom remain bonded together; otherwise, check this thread: http://sailingforums.com/threads/bailer-opening.30935/#post-141918
I have Phantom bailers for $10 each. Includes shipping. Just need to fill in hole and drill smaller 3/4" dia hole. Then put parts together with three screws. cjo1023 at yahoo dot com.