Excellent "Travelogue" APS. I wasn't aware the Sunfish had foam inside that absorbs water. One thing that can't be ignored...If the boat is WET, it has a LEAK and there is absolutely no sense in
Drying Out the boat if you are not going to fix the leak.
Before I read the travelogue I would have been inclined to pull the deck off the boat and renew the deck to hull SEAL**...which no one in the travelogue suggested, that I noticed. Most were even reluctant to pull off the rub rail....never mind the deck.
IF..and a BIG IF.. the leak is as simple as a screw hole needing new bedding under some hardware.... I thought about the bailer as well, maybe all is not lost. I would NOT pay someone to take on this job. It will be a money pit in a 1977 boat.

NB
**Note: Is the
Deck To Hull Joint glassed, epoxied, or 5200..?? Hopefully ...
None Of The Above.