replacing interior wall

[chuckg5]

gotta older taiwanese sailboat with some rotten walls from decks leaks.
i'm cutting them out but what to replace with. i'm thinking of 3/4" plastic board but where to find it and what is it called? plywood would do the same rotting eventually. can not find anything in the home improvement shops.

[SailingHarmonie]

Bulkheads (“walls”)on a boat are an essential part of the structure. You can not replace plywood with plastic. If you are worried about plywood rotting then fix the damn leaks!

[chuckg5]

these are mysterious leaks.. leaky teakies

[Bill O]

Originally Posted by SailingHarmonie

Bulkheads (“walls”)on a boat are an essential part of the structure. You can not replace plywood with plastic.

^^^^Agree.

Depending on the amount of rot could section them or better is to replace the whole thing. Marine plywood would most likely be the least expensive to make the proper repair, but if you still have leaks you could use Coosa (urethane composite). Coosa is as strong as ply, but ~1/3rd the weight and doesn't absorb water.

[Tupaia]

It's called Polycore, Polypropylene honey comb with scrim on either side. Available in many DIY stores mainly in Asia but also Europe. It needs to be laid up with glass and epoxy on both sides (Polyester does not adhere). With the right layup it can be made very strong and retain it's lightness although the core is easily crushed, so is not good for high traffic areas like decks and being springy can delaminate. There are other honeycombs that would also be suitable Nomex, aluminium honeycomb and Phenolic paper honeycomb.

All would be OK as bulkheads provided the correct layup and and tabbing was used. They are all considerably more expensive than Marine Ply.

[boatpoker]

Originally Posted by chuckg5

gotta older taiwanese sailboat with some rotten walls from decks leaks.
i'm cutting them out but what to replace with. i'm thinking of 3/4" plastic board but where to find it and what is it called? plywood would do the same rotting eventually. can not find anything in the home improvement shops.

Teak decks ? How many rotten "walls". ? Anything other than Home Depot plywood is gonna cost you thousands. How much are you willing to spend and what is your skill level with carpentry, epoxy and/or more exotic materials ? How much time is in your budget ?

[Moosemiester]

Easier to replace whole walls, rebuild cabins, etc than to scarf in new wood,

See my You Tube video “How to restore a trawler for the Great Loop” - I scarfed the salon, and choose to rebuild the forward house from scratch.

Tearing the whole house off and rebuilding was so much easier…

[chuckg5]

many good replies. thank you. i'm now think'in marine ply. available here in the states and affordable. thanks again for the input.

[Fore and Aft]

Chuckg5 I had a rotten spot about the size of a dinner plate on a bulkhead on an old yacht I owned. I had some old polyester resin and glass cloth laying around, so I cut out the rot, ground a scarph on the bulkhead and just layered 12mm of glass into the hole. Five years later the repair was still invisible and holding up well. Another client of mine with a boat hardly worth fixing cut out the rotten sections of plywood bulkhead, scarphed in some new plywood then glassed the whole bulkhead with chop strand mat and coated it with flo coat. It was a quick and dirty repair but last time I surveyed the boat the bulkheads still looked good.
Cheers

[psk125]

Originally Posted by chuckg5

many good replies. thank you. i'm now think'in marine ply. available here in the states and affordable. thanks again for the input.

Many builders coat their plywood with epoxy resin to keep water from getting in and rotting the wood. Each piece needs to be coated after it is cut or shaped, especially on the end grain, before it is installed. Screw holes in the plywood can also be treated the same way to avoid water getting into the wood.

[chrisr]

if you find marine ply is too expensive, and if you don't need a nice timber veneer (ie going to paint or skin with eg formica) then concrete formwork ply is a really good alternative

much cheaper and every bit as strong & waterproof (perhaps more so). just need to grind off the black finish before glueing

cheers,

[Spot]

Hi Chuck, is this your boat?
https://sailboatdata.com/sailboat/vagabond-42/

Do the chainplates that hold the stays/shrouds attach to the bulkheads in need of repair?

[lornolsen]

Aircraft Ply is about twice as good as boat ply. Go to aircraftspruce.com to buy it and to read about it.

[boatpoker]

Originally Posted by lornolsen

Aircraft Ply is about twice as good as boat ply. Go to aircraftspruce.com to buy it and to read about it.

I know nothing about it. What is better about it ?

[Nicholson58]

Originally Posted by SailingHarmonie

Bulkheads (“walls”)on a boat are an essential part of the structure. You can not replace plywood with plastic. If you are worried about plywood rotting then fix the damn leaks!

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