Thru Hull Backer Blocks / 35.5

[Fred Miller]

On my 1992 35.5 I noticed some of the thru hull fitting backer blocks were plywood which is beginning to delaminate on the top ply layer. Is this a potentially dangerouis situation? Should I pour expoxy over the wood like West System to reinforce the plywood? Am I over reacting consdering that the fitting is probably installed with 5200 sealant under the block?Fred M.

 

[Steve Dion]

What is it going to hurt?

Fred:Cannot imagine what it would hurt to do that. I would hope that they had not used 5200 for these backers. If you have 5200 or you use epoxy on them now, will you be able to remove them to replace them? I would suggest that you replace them on your next haul out.I am wondering if some poly board (cutting board stuff) would not be a good alternative for these in the future. If thsi stuff is kept OUT of the sun, it will last for ever. Water/moisture will not effect it either.Anyone out there have any experience doing them this way?

 

[Ed Schenck]

Glass first, then install.

On my H37C the blocks were glassed before the thru-hulls were inserted and "bolted" down. Don't know if it is original but think that it is. I plan to oversize with true seacocks and will install that way. But I think some delamination of your block is probably cosmetic. Does it look like it could rot out from under the nut? Then I agree with Steve, replace it.