The possibilities are so varied that maybe better to give a few possible scenarios. However, before getting into this boat you should get a really, really good survey
. Find someone that is experienced with wet decks and a moisture meter and a good ear with a rubber mallet and do not commit until you know what you're getting into. Testing and interpreting moisture in a core
with a meter takes some knowledge and experience to do accurately so make sure the surveyor
knows what he/she is doing.
It is unlikely that the moisture has not spread and worst case scenario you could be looking at repairs
costing far more than the value of the boat. On the other hand, if the damage is limited and you get a good deal on the boat you could come out well.
On other comment, the cost will depend a LOT on where you are. Paying a yard in New England
will be about double what it would cost in VA or north FL for example.
1. I think very unlikely but IF there is only 1 sq ft that is wet and delaminated AND you can and want to do the cheapest, fastest repair, the area could be dried out without taking apart the deck
by drilling holes, heating
and ventilating for some time and finished by injecting epoxy
into the holes it could be done for a $100 if you DIY or a few hundred in a yard.
2. Better repair is to open up the deck and remove the wet core
. If the deck is really soft then the core is probably rotten, at least in part, and should be replaced and the structure glassed back together. If you have to do this to only a 1 sq ft area and pay a yard it could be $1000 or so.
3. Skipping several intermediate possibilities and going to the worst case scenario with lots of moisture, rot
and spreading delamination
requiring replacement of most or all of the deck it will be many thousands or even tens of thousands of dollars. Again depends on where you have it done and how fancy you want to get with the repair.