deck repair

[john]

The bow section on my ODay 22 is quite spongy and is suffering from delamination. I need to cut open the deck and replace the core. My question is since the new core is going to be completely sealed do I need to use marine grade plywood? how aout standard exterior grade? Any advice concerning this type of repair by someone whos been through this would be greatly appreciated

 

[Dave]

Plywood

The difference between exterior grade and marine plywood is that in the marine plywood all of the defects from knots have been punched out and filled with patches so the wood has no voids in it. Regular plywood often has a perfect outer layer of the laminate but the inner layers have defects. dave

 

[Jim A]

I would use

The best rated wood for the job. I think they use Balsa wood for the core. The amount of labor your going to invest in the job out weights using cheap. This is a labor of love for your boat!

 

[John Dawson]

Core values

The assumption that water will never find its way into a core seems flawed; it did once already and any stress crack may admit it again. Why not deter it with good materials? I've always thought marine plywood was made with more water-resistant glue also. Not true?Nevertheless, things happen. Ever drop the end of the spinnaker pole in a gybe? Have a clumsy crew drop the anchor? Drop a tool from aloft? Dislodge a stanchion in a collision or deck accident? Seat a handrail or toerail imperfectly? Murphy's law applies to boats too.

 

[Dave]

Same glue

I also thought marine plywood was different glue, but I read somewhere that it is not. The only difference is no defects. Regardless the glue may be fine but the wood between the glue is not protected. Thats why when building plywood boats you have to seal the end grain with epoxy.

 

[Kevin]

plywood core

Whatever the grade you choose, simply coat the plywood in epoxy. This will add weight,however, I doubt this will be a concern to you. Seal both sides and the edges.good luck