Soft, soggy fuel-tank lids are pretty common w/these boats...and yer right about the source of water intrusion...Wellcraft saw no need to seal the edge of the holes cut thru the lid for the inspection hatches...the two wooden supports were in mine also and I suspect were standard issue..not sure of their purpose...they seem to be held in place only by the foam around the tank and are well below the bottom of the hatch lid...
Here's mine when 1st opened
I had just talked to Spare about some things he had done w/a router...found a bit that worked and ran it around the edge
after the router did it's thing, bottom peeled back like an orange
Flatbar and this wide chisel cleaned off the remaining tiles
Here's the newly cored lid...not perfect, but came out OK for my 1st fiberglass job...SHOULD have beveled off the edges of the plywood so glass mat would lay down better...really had to work the stuff for it to make a 90* turn around the edges
Biggest problem reinstalling was several of the screw holes either were too big or just weren't there...cobbled different solutions to this and put it back in place...recaulked w/4200...
Oh yeah...edges of inspection hatch holes are now glassed over and properly SEALED...if water gets back in, it won't be thru there...