The 330 I just had surveyed the surveyor pulled both rear vents out and showed me no sealant and bare wood. This boat had 400 hours over 17 years and kept under cover so there was no moisture issue. He told me to pull them out when I get it home and paint the entire area with resin to seal the wood then some 4200 and reinstall the vents.
He also recommended trying to check all the thru hulls. I was planning on pulling rub rail midship back and resealing. I will also be resealing or glassing the transom cap when I repower.
These are all areas I have seen gradys leak