Chainplate Bulkhead Rot Opinions

[SZTZ]

Hello,

This subject has been covered quite a bit, and I've read a bunch of the threads. That said, as someone very new into owning a boat, looking for opinions on the chainplate bulkhead rot I'm trying to resolve without rebuilding the boat.
I've attached a photo... vastly worse that it was pre-winter storage. I've also recently rebedded the chainplates on the deck to fix the leak.
Seems like one of the previous owners had a problem as well and simply replaced a section of the bulkhead with good wood.

I'm not a fan of patchwork though rebuilding the entire bulkhead is not in my toolbox of skills.
A neighbour at the marina advised to add material versus remove as it's structural but given the situation, and fully engulfed in black mold, I'd rather remove at least that section.

Any thoughts or advice would be greatly appreciated.

Stefan

[Don C L]

What kind of boat is this? Unfortunately the integrity of the wood is crucial to the strength of the chainplate's connection to the hull. The wood and its tabbing to the hull must both be intact to be reliable, as you probably already know. On my old boat, mine are still fine, but I have considered moving to two lower shrouds (only one on mine) and bolting to the outside of the hull. Perhaps that may be a solution in your case? In any case, if there is solid, undamaged wood with secure tabbing to the hull, there could be a workable solution, but I suspect there will be some major wood and glass work to be done. How about more photos of the other side too? And it appears that the wood that is rotten is a plywood layer over the bulkhead material itself, which may be different and undamaged. Is that possible? I'd remove the chainplates and that yellow layer and then poke around some more and get more photos too.

Welcome aboard BTW!

[SZTZ]

Thanks Don!
It's a Hughes 26 circa 1980... I'll take some more pics as you suggested once I'm back at the marina Tuesday.
I expected, reluctantly, major glass and wood work. I'll also take the plates off and see if there is any good wood. It appears that the previous owner, one of them, scarfed a section of material to the original bulkhead. Makes sense given the mountain of caulking I had to dig through to get the chainplate covers rebed on the deck. I'm hoping as you mention, it's only plywood added over the original bulkhead with some good wood underneath.

Thanks again.
SZ

[Tillsbury]

There’s not likely to be good wood underneath, otherwise why did the previous owner do that?

As you have worked out, keep removing anything that looks at all flaky or “added” then see what you have. And use decent materials when you do the repair so the same thing doesn’t happen.

Assuming you’re in the galley it doesn’t matter if you don’t get an immaculate finish, as you could always tile the repair you have done.

[TrentePieds]

Hm... That looks a bit nasty! Looks like a previous "repair" was effected by laminating a chunk of plywood to the face of the bulkhead, and that that chunk, like the bulkhead before it, has rotted due to ingress of water where the chain plate comes through the deck.

It looks as if the "chunk" was spiled to fit the contour of the ceilings in order to furnish "extra strength". Conclusion: Whoever did the repair was a little weak on the basic concepts!

IMO the fundamental first step to achieving a solid, durable repair is to remedy the basic weakness of the design, viz that the chain plates are taken through the deck. Your damage is the wages of the designer/builder favouring "pretty" over "functional" in the manner many builders did back when your boat was built. IMO, new chain plates should be fitted to the outside of the hull so that the holes in the deck where the old ones come through can be closed off in a seamanlike fashion This MO seems drastic, but it would prove to be a case of the long way about being the short way home.

Once that has been done, any rot spores in the bulkhead structure can be killed with boric acid or, better still, with pentachlorophenol. Nasty stuff is "penta", so if you use it, be careful! When the rot has been killed the bulkhead can be "sistered" as necessary. This bulkhead takes the thwartships compression forces generated by the rig, even when the chainplates are on the outside of the hull, so the "sisters" need to be ACCURATELY spiled to the inside section of the hull, AFTER any ceilings in way of the sisters have been removed. The sisters should then be glued to the existing bulkhead, and thereafter tabbed with fiberglass tapes to the inside of the hull.

Think this one through carefully and lay a "repair plan" (Scope of Work) before you spend any money.

Best of luck.

TrentePieds

[a64pilot]

If you go to external chain plates, you may need to consider beefing up the hull at that point, you may not, but I think it needs consideration.

[Cheechako]

It's just hard to assess without seeing the details. But that's a mess.
It appears, but not sure that the bulkhead was tabbed into the hull not just relying on contact with the underdeck to counteract the rigging. (?) Some thoughts:
- It's possible with the rotted portion and the loudy patch job removed that the glass ply bond inside the tabbing is no longer adhered. You could then simply dig the old bulkhead out of the tabbing. Insert a new bulkhead (or portion) into the tabbing and use one of today's "thick super glues in a caulking tube" in there. Those glues would be stronger than the original glass/wood bond.
-How far down does the rot go? Under the cabinet or does it stop? You could sister a new bulkhead portion to good bulkhead down there under the cabinet as well. May be a ton of work too though.

Of course in the middle of all this is can you actually get new bulkhead or pieces in place?

[Spot]

Is this the boat and the location of the issue?

[Qayaq]

Had a similiar problem. Bulkhead was teak faced ply. The teak didnt rot. Attacked with a chiesel then angle grinder until I had good wood on the bulkhead but left the last slither of teak on one side and the old tabbbing on 1 side only. Laid 15mm foam into the back of the remaining tab then laid up west laminate into the scarfed bulkhead. Bogged the middle then more laminate then faired and painted. Vd out the deck and put plenty of sika to seal the chain plate. No leaks yet and you wouldnt know it was done. Also had to replace all knees for the rest of the chain plates. Take good care of sealing the chain plates and encaptulate the wood in epoxy including the bolt holes so when it eventually starts leaking again it doesnt kill the wood quite so easily.

[Don C L]

So looking at the design it looks like the chainplate is close enough to the rail to put on chainplates out on the hull. There are a few possible negatives: jib sheeting angle a minor loss, minor angle change on shroud at spreader, strength of hull for those new chainplate locations. Another possibility to consider is to repair the wood inside but get a longer chainplate made that will reach down farther to solid wood in bulkhead/hull connection. And I am curious why we see two chainplates coming down through the deck. It should be one I think. Is that part of an old repair?

[AndyEss]

Originally Posted by Don C L

So looking at the design it looks like the chainplate is close enough to the rail to put on chainplates out on the hull. There are a few possible negatives: jib sheeting angle a minor loss, minor angle change on shroud at spreader, strength of hull for those new chainplate locations. Another possibility to consider is to repair the wood inside but get a longer chainplate made that will reach down farther to solid wood in bulkhead/hull connection. And I am curious why we see two chainplates coming down through the deck. It should be one I think. Is that part of an old repair?

The photo isn't too clear but I see one thru deck chainplate (outboard) and another plate that ends well below the deck.
Backing plate for another chainplate on the other side of the bulhead?

[gmakhs]

God I love my well designed chain plates (being on fiberglass bukhead(-stringer).
Now checking your problem.it.might not be too serious, you need to remove the old repair and see how bad the bulkhead has rott you may be lucky .
After that the options are 2 .
Either replace the bulkhead (very hard job in my.opinion )or repair the bulkhead and reinforce it with a fiberglass or epoxy patch big enough to distribute the streess.
The sink near the bulkhead is a bad idea as well .


External chain plates are another option but they leak and without proper stringer system to distribute the stress they are not a good idea .

I believe we have the same thickness on the hull (my boat is 26 f)and I wouldn't trust mine for chain plates

[elandra65]

The cause is the leaky Chainplate through the deck. This will have to be attended to to avoid future problems. Looks like the previous owner just did a dodgy repair and ignored the cause. You will have to cut the entire section of bulkhead out and scarf a new piece to the good bulkhead and tab it it to the hull side. This is a structural problem and must be done properly otherwise you may lose the entire rig and rip out your cabin top. It is not that big a job if you know basic woodwork and can fibreglass with epoxy. Otherwise get a pro to do it. Don't compromise on this.

Andrew

[SZTZ]

Originally Posted by Spot

Is this the boat and the location of the issue?

Thanks for all the input. Much appreciated.
Spot, that's the boat and it's exactly where the issue is.
I've attached a few more pics of the back of the bulkhead as well as close ups of the front.
At present, I've rebedded the chainplate deck plates, and the leak seems to have stopped. It seemed that one of the previous owners decided that leaks get fixed with an anthill of caulking over deck hardware.
Don, there are indeed two chainplates that attach to two shrouds, one shroud per chainplate.
Did some more "digging" today, and the water damage is largely isolated to the section that the pictures show in addition to a portion at the bottom of the bulkhead. At the galley countertop, working downward towards the bildge, the bulkhead is sandwiched between glass for the v berth and glass for galley lower cabinets. (if that makes any sense) So all I can see is black mold at the very bottom of the bulkhead, then a section of what seems ok, then the water damaged area as in the pics. God knows what the wood is like where it's sandwiched between glass.
The boat is suppose to go in the water on Monday as I'm blocking a bunch of other boats from getting back in. Is this something that can be solved in the water or should I make other arrangements?
Apologies for any terminology mistakes, I'm new to this, and again I appreciate everyone's time in responding.
SZ

[SZTZ]

Originally Posted by Cheechako

It's just hard to assess without seeing the details. But that's a mess.
It appears, but not sure that the bulkhead was tabbed into the hull not just relying on contact with the underdeck to counteract the rigging. (?) Some thoughts:
- It's possible with the rotted portion and the loudy patch job removed that the glass ply bond inside the tabbing is no longer adhered. You could then simply dig the old bulkhead out of the tabbing. Insert a new bulkhead (or portion) into the tabbing and use one of today's "thick super glues in a caulking tube" in there. Those glues would be stronger than the original glass/wood bond.
-How far down does the rot go? Under the cabinet or does it stop? You could sister a new bulkhead portion to good bulkhead down there under the cabinet as well. May be a ton of work too though.

Of course in the middle of all this is can you actually get new bulkhead or pieces in place?

This is the solution I'm considering, replacing a portion of bulkhead. I think if I end up keeping this boat long term, the entire bulkhead will need replacing, but as a stop gap for the summer... this may be the answer.
Note: I cringe at writing stop gap when it comes to structural but here we are.
SZ