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repairing the chain plate attachment area

TS Farley

Member II
Hi,

Would there be anyone that could help with a bit of advice on repairing a small section of rotten bulkhead?

In replacing the standing rigging and inspecting the chain plates in my 1975 35 MK II, the typical bulkhead rot came to light. Previous threads on this topic are quite informative and I'm thinking I may be able to tackle this myself with perhaps a few pointers from the knowledgeable folks on this site.

There is just a small section of wood rot, about the top 5 inches under the fbg tab. The area below that seem sound, but I'll find out when I start pulling it apart. I understand that just the rotten area, rather than the whole bulkhead, could be replaced, preferably with mahogany or ironwood, scarfed by beveling the existing bulkhead with sanding and then layering fbg cloth/epoxy? Then the repaired area should be reattached/glassed to the hull to be contiguous with the existing fiberglass tab? When the chain plate is reattached, the addition of a new back plate forward of the bulkhead seems to be a good suggestion. The area should be just about within the wooden cover piece. Does this sound about right?

Under the port outer shroud chain plate.jpg
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
It occurs to me that this repair often comes with the need to finish it off with a new layer of veneer to cover the old-and-new work.
If so, then there is no need to install a scarfed-in piece of plywood ("wood" being the part best avoided). I would use G10 glass composite and a long scarf @ the recommended 12 to 1 slope. You could even add a layer of biax over the whole repaired surface, fair it out, and then put the lovely and concealing new veneer on top.

Confession: I have not done a repair of that size/complexity, so my advice is tainted by conjecture. :rolleyes:

Loren
 
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kapnkd

kapnkd
Hi,

Would there be anyone that could help with a bit of advice on repairing a small section of rotten bulkhead?

In replacing the standing rigging and inspecting the chain plates in my 1975 35 MK II, the typical bulkhead rot came to light. Previous threads on this topic are quite informative and I'm thinking I may be able to tackle this myself with perhaps a few pointers from the knowledgeable folks on this site.

There is just a small section of wood rot, about the top 5 inches under the fbg tab. The area below that seem sound, but I'll find out when I start pulling it apart. I understand that just the rotten area, rather than the whole bulkhead, could be replaced, preferably with mahogany or ironwood, scarfed by beveling the existing bulkhead with sanding and then layering fbg cloth/epoxy? Then the repaired area should be reattached/glassed to the hull to be contiguous with the existing fiberglass tab? When the chain plate is reattached, the addition of a new back plate forward of the bulkhead seems to be a good suggestion. The area should be just about within the wooden cover piece. Does this sound about right?

View attachment 16138[On my 73 E-32 II ....I first replaced a section similar to yours by cutting out the bad wood and scarfing in a new section. I then bought some mahogany veneer and refinished the entire bulkhead for esthetic reasons.

Years later, we found the starboard forward lower had similar problems in the forward berth. At that point, we decided it was time for a major refit and have replaced ALL the bulkheads with marine grade plywood. Templates were made, checked and rechecked for proper fit before cutting the panels. Panel ends were first coated with epoxy to seal the ends and then were tabbed in place with multiple layers of glass and roving. It's a LOT of work but the old gal is really strong now!!! (Including the cabin top around the mast support. ...check out the photos on my profile page.)

I don't envy you the work having "been there and done it"!!! ...Good luck and fair winds!
-kerry
 

Shelman

Member III
Blogs Author
I have done some plywood scarfing and I have worked with both mahogany and ironwood bonding with epoxy. I would chose a good marine plywood over the hardwoods because no matter which way you orient the grain in the wood they will split quite easily with the stress of the chain-plate and the flexing that a bulkhead receives, and also ironwood can be rather difficult to get the epoxy to stick well to because the epoxy must either soak in (ironwood doesn't soak much) or bond to a rough enough surface to grab a hold of. (ironwood is inherently smooth even when roughened)
I would probably add the extra layer of plywood backing to the backside over-reaching the repair as well, although a really perfect scarf is stronger than the original piece, its nice to have the added piece of mind and strength.
A 3/4" 4x8 sheet of true marine plywood made from khaya or meranti (mahogany) will cost about $125.00 but the pieces left over always seem to find a home around my house.
Depending on how vested you are in this particular boat and the difficulty in fully removing the bulkhead I agree that the best option is to replace the full bulkhead with marine plywood.
 

TS Farley

Member II
Hmm. The veneer is pretty beaten up, I am highly invested in this anthropormorphized dear old friend and would like to have the best structural repair with esthetics a close second. I have a couple weeks off coming up..........maybe replacing the entire bulkhead would be the way to go and doing it with the mast out would be the best time. The $125 per sheet is not bad, it's the hourly shop rate when I find I'm over my head that is worrisome!

Getting the template exact would be rather critical. Any pointers on drawing up the template?

In considering how to prevent water seepage and a repeat of the same problem, the rigger pointed out something helpful about the deck fittings which are welded to a couple of the chain plates. He said it would be better to have them separate so they can be simply lifted to reseal rather than having to remove the whole chain plate to reseal.

Thanks for the pointers and encouragement.
 

Shelman

Member III
Blogs Author
The only easy way I know of to get the template right is to use the old bulkhead as a pattern and fill in the missing bits by eye, then just insert the template into place to double check before cutting the marine plywood.
 

Macgyro

Amazingly Still Afloat
Blogs Author
Bulkhead repair instead of replacement

http://www.ericsonyachts.org/infoexchange/entry.php?176-Ericson-32-Bullkhead-Repair

Here's the description on how I fixed mine with a similar problem. I didn't want to have to take down the mast to repair the entire bulkhead, so I left the mast support in, and cut around it. My water damage went all the way to the bottom.

I haven't done the veneer yet, I'm still working on other structural and operational problems before getting back into aesthetics.

Good Luck!

Dean
 

TS Farley

Member II
Right, I'm inspired to attempt to replace the entire bulkhead. Hopefully there will be some time left over to go sailing!

Thanks again for the advice and photos.
 

TS Farley

Member II
Of the 6 removed, only 2 needed replacing because of some minor pitting of the interior sections. They were the lower aft plates, not where the obvious bulkhead rot is, which is another reason that the entire bulkhead should likely be replaced....there is probably more damage than is clearly visible. The bow looks good and I elected not to cut out and inspect the embedded stern plate. Have to leave something for next year! All the standing rigging is being replaced. It looks not too bad but there are areas where the twist is uneven, sections more proud, which I am told is a sign of wear. The insulated back stay is of indeterminate age and I'd hate to lose the SSB, not to mention getting demasted, so that is being replaced as well. The collection of old boats parts destined for the future grandchildren's treehouse is growing!
 

TS Farley

Member II
Of possible interest to others, and something that makes me feel a bit better about going through the time and expense of the standing rigging maintenance, is that the plates of the attachment of the shrouds at the mast head, on both sides, were just crumbling away. They were the consistency of an aspirin tablet. They were pieces of some type of metal, not SS, that were welded to the mast. The ends of the spreaders were in a similar shape but were repaired a couple of years ago. I'll post some photos when the mast work is done.
 

TS Farley

Member II
Footrope, your question about the state of the chain plate hardware seems to have disappeared.

Loren, thanks for the advice about the G10, biaxial and scarf joints and the thread you referenced by Martin King on painted bulkheads was interesting. I was thinking that replacing the entire bulkhead would avoid having a joint but I see that the full bulkhead will not fit through the companionway. Since a joint is unavoidable, replacing the entire bulkhead still seems the best plan, regardless of the extent of the rot, because the scarf joint could then be cut more accurately. I can't see (me) getting a perfectly fitting/smooth 6" scarf joint by sanding the remaining piece of bulkhead in place. Removing the entire bulkhead will also provide better access for installing the new Ronco holding tank. Yikes, the work is increasing exponentially.

Shelman, Macgyro and Kapnkd, thanks! Your previous threads have answered a lot of questions. Someone, somewhere also mentioned doing the work while in the water which seems invaluable advice.
 

footrope

Contributing Partner
Blogs Author
Footrope, your question about the state of the chain plate hardware seems to have disappeared.

Yes, I deleted it. I fired that question out there before reading Macgyro's linked post and matching the photos with yours. Good luck with your bulkhead repair.

Craig
 

TS Farley

Member II
Done!

The bulkhead repair is done and the riggers gave it a thumbs up. On close inspection the bulkhead was completely sound everywhere else so I only repaired under the chain plate. The rotted part was ground out, the adjacent good part feathered and 1/8" of good wood was left on the solid fbg hull tab on the head side to build on. Rather than shape/scarf a piece of G10 I just layered the entire thickness with biaxial 1708. Using pieces of wax paper to wet and apply really simplified the procedure, many thanks to the person that posted that. The hard part was finding the biax. None of the chandleries in Victoria and Sidney had even heard of it. I ended up getting getting some scraps from someone in the industry. I brought a sample back to one of the chandleries and they said that 3 people came in after me asking for it as well. Maybe they will start stocking it now.

The wooden deck core (balsa?) had rotten back about an inch so that will get dried out and filled with epoxy. As I mentioned before, the deck plates that were weldeded onto the chainplates were detached and will be slipped back on and rebedded as separate entities. This way we can reseal them without having to tap the chainplates up.
 

Macgyro

Amazingly Still Afloat
Blogs Author
Fiberglass supplier online

Just so people reading have the link to a good online fiberglass supplier:

http://www.uscomposites.com/specialty.html

I ordered a roll of biaxial from them and still have most of it. I don't know much about fiberglass quality, but it looks fine, and has held up well so far.

-Dean


The hard part was finding the biax. None of the chandleries in Victoria and Sidney had even heard of it. I ended up getting getting some scraps from someone in the industry. I brought a sample back to one of the chandleries and they said that 3 people came in after me asking for it as well. Maybe they will start stocking it now.
 
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