Ideas Needed for Re-sealing Pulpit and Fore Deck

[Boatsb]

Or just use Coosa

No way is coosa the best way to go.

Its a closed cell foam core that can be ordered in different densities depending on your needs. It's coated with a bonding agent for the polyester resin and is lighter than plywood and easier to work. Where would the challenge be?

[bobk]

Agree, as a foam, Coosa will be more compressable than mahogony or a laminate. That is part of the leak issues we all have.... the cores are under compression and eventually allow the sealant to start to leak as the wood cores compress.

Bobk

[34Hatt]

Coosa is a direct replacement to plywood

[Boatsb]

No it's not. It's lighter and better for use as a core. However as a structural component it differs from plywood and different densities of the coosa are better suited for different applications

[bobk]

Here are pictures of the underside of the pulpit area. The damage is quite localized and seems largely due to the compression of the core by the winch bolts.

The underside area will be covered with a 1/8" fiberglass panel, filled with thickened epoxy, re-drilled etc. There will be no compressible core remaining where there are bolts. Heavy backing plates for bolts etc. And I'm having flanged SS pipes made up for the chain and rope falls so any potential leaks will be directed into the locker without touching wood.

Is there supposed to be a seal to keep water from running down the Galley Maid windlass shaft?

Bobk

[Boatsb]

Here are pictures of the underside of the pulpit area. The damage is quite localized and seems largely due to the compression of the core by the winch bolts.

The underside area will be covered with a 1/8" fiberglass panel, filled with thickened epoxy, re-drilled etc. There will be no compressible core remaining where there are bolts. Heavy backing plates for bolts etc. And I'm having flanged SS pipes made up for the chain and rope falls so any potential leaks will be directed into the locker without touching wood.

Is there supposed to be a seal to keep water from running down the Galley Maid windlass shaft?

Bobk

That looks like the backing was inadequate when it was installed. Was it a factory install? I see people doing things like that thinking a fender washer is enough backing for a windless when they really need a 1/4" plate ( alum or stainless ) to spread the stress over a much larger area.

My fighting chair mount has more backing than that and had much less stress on it.

[bobk]

That looks like the backing was inadequate when it was installed. Was it a factory install? I see people doing things like that thinking a fender washer is enough backing for a windless when they really need a 1/4" plate ( alum or stainless ) to spread the stress over a much larger area.

My fighting chair mount has more backing than that and had much less stress on it.

This was indeed a factory install. The backing, which I didn't post a picture of, was a two inch thick mahogony disc. But no matter the backing, there is too much compressive stress on the balsa core.

Note also the darkened fiberglass in the damaged areas. The resin seems to have dissolved. Looks like an ortho resin with no hydrolysis resistance. And it is very thin!

Bobk

[spindrift]

Gents:I had a similar coring failure problem on a 40 foot sailboat I use to own and race. A good solution that the project manager at the yard came up with was to replace the coring with high-density PVC. The boat had an aluminum toe rail so we actually removed all of the through bolts securing the toe rail to the deck, dry fit a piece of masonite to bridge the entire triangle on the forward underside of the deck. Then we used the template to cut the HD PVC, dry fit it, then bonded with West System and mechanically secured with through bolts. The key is to use one of the excellent 3M sealers to bed the through bolts (rail to deck) through.

While the configuration of most Hatts is a bit different up forward, you do have the pulpit, winch bolts etc. that could add a mechanical fastening to the HD PVC which is on the underside of the deck.

Like others have stated earlier in this thread, there are two key factors that created the leaks in the first place. The first, is core compression (substitution with HD PVC) will address that issue. The second is leaks that appear through all through deck penetrations over time (windlass bolts, pulpit bolts etc.). What we have seen up in the northeast is that many of the older boats (pre 1990s used a dolphinite type of bedding compound that dries out over time. The new flexible sealers (notably good 3 M products) have much better longevity.

The reality is, that on a periodic basis deck hardware has to be pulled, cleaned, re-sealed. However, while a pain the tushy this is far less costly and a less messy job than getting into core-replacement.

Spin

[Triskele]

BobK,
I did th same thing on Little Skooch. I removed with a trim router 2 foot squares from the underside in the Vee and locker area. Cleaned out the bad core and dried it out. Then with straight unthickened West System I made 2 foot sandwitch 3/4 inch thick of glass and balsa. Then I pushed it up with a tall scissors jack and plywood covered with a plastic trash bag. Let it cure over night. Then removed the jack and bag moved on to the next 2 foot patch. Anything bigger was too hard to handle by myself. I think if you had two people you could get much bigger patches which would help a great deal.

Very strong, very messy, did not cost much but terrible job over all. And guess what? I get to do it again with Big Skooch. I can't wait.

Skooch
New Bern NC

How did you make the 3/4" glass and balsa "sandwich"? Did you glass over the balsa to create a core that would then be layed between the deck skins?