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E35-2 repair to chainplate bulkhead anchoring

steven

Sustaining Member
while tracing wiring I found damage on the bulkhead where starb uppers are anchored.
image is the nut side. The other side is the ss chain plate (which is easily accessible)

anchoring for top two bolts is rotted out.
All the other bolts are undamaged.
Is there a recommended repair ?

Could I just extend the chainplate by say 2" wide by 1/4 thick ss at the bottom ?


thanks

--Steve
 

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Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Well, the chainplate is pulling on the bulkhead and the bolts spread the force. But the critical piece is the bulkhead itself. Let's assume the bulkhead is fine and the hardware undamaged.

I'd make a mahogany backing plate to cover the old holes, maybe 3-4" wide, and epoxy it to the bulkhead. (fill the old holes with thickened epoxy first, plan to re-drill them)., Might need a backing plate on the other side too, but probably not if the chainplate did its job. Varnished, a backing plate would look fine and dandy. It would regain the contact between wood and steel.

Actually, if the damage is only to the top few holes, I might well just pack in some epoxy filler, re-drill the holes, replace with bigger washers and not worry about it.

Looks to me like some water got in there. Fix that leak first. And assure yourself the rigging is set up right and the chainplate isn't wiggling around, although that doesn;t look like the cause of the enlarged holes.

Amateur opinion, I'm not a surveyor or designer.
 

steven

Sustaining Member
Christian,

thanks for reply. no other damage is evident. everything tight and no leaks.
Only top two holes. The other 4 are sound, as is the wood around them.
So this is probably old damage that was not noticed (by me or my surveyor).

For solution 1, will epoxying a plate into the existing plywood (which is 1/2") be strong enough ? Do you think I would need to lap the ply to some extent? I am not concerend with cosmetics (it is in a closet). Just strength.

--Steve
 

gabriel

Live free or die hard
I completely replaced my bulkhead...

I also added a backing plate on the nut side to spread the load...this makes the clamping force hold the chain plate in addition to the sheer force of the bolts through the holes. It’s stronger than just using the nuts and washers in my opinion.

As mentioned above I would definitely fix a leak first.
 

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  • 905EC0D2-AD75-4C86-84EC-8BAD9D6C7303.jpeg
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kapnkd

kapnkd
while tracing wiring I found damage on the bulkhead where starb uppers are anchored.
image is the nut side. The other side is the ss chain plate (which is easily accessible)

anchoring for top two bolts is rotted out.
All the other bolts are undamaged.
Is there a recommended repair ?

Could I just extend the chainplate by say 2" wide by 1/4 thick ss at the bottom ?


thanks

--Steve

Short of replacing the complete bulkhead (for cosmetic reasons), you could/should at least splice in a new section of bulkhead wood that will completely butt back up against the cabin top to better handle and distribute the upward pressures placed on your rig under loads.

We replaced ALL our bulkheads during our refit and did it with veneered marine grade ply. In addition, we sealed the top edge with epoxy as well as oversizing the bolt holes, epoxy filling and redrilling to insure any future water has less chance of permeating into the wood.
 

Brad Johnson

Member III
I would remove the other nuts and washers ,Remove bolts, fill all the holes with thickened epoxy, re drill holes, ,fabricate a backing plate larger than the damaged area in width and bolt back together.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
While this model and many others with ss chainplates that go thru the deck and bolt to bulkheads can have this problem, remember that the current "problem to be fixed" started many years earlier.
i.e. one or more prior owners did not seal the deck against: 1) moisture getting into the balsa coring, and 2) moisture next running down the chainplate and rotting that bulkhead (and corroding the SS plate faster).
Whatever it takes to repair the current bulkhead problem, DO pull the chainplate out and do the vital "over-drill, undercut, epoxy-fill, and re-drill " regimen.
And considering the age of the boat and the SS chainplates, just have new ones fabricated.
They are relatively cheap, and extraordinarily vital.
 

garryh

Member III
there is no strength left in that wood and I think it would be a really bad plan to fill the holes in rotten wood and redrill. While not as critical as the main shroud/chainplate/bulkhead assembly, the forward lower does take a lot of strain and keeping the mast vertical (and in tune) is important. At some point, that chainplate will tear right out and this will not happen on a calm day.
The top of the bulkhead is so rotten it is missing; and you can see the staining all the way down to the last bolt. The water has been transmitting downwards through the plies for many years and if you poke an awl into that wood you will find it punky all the way down (possibly even past the last bolt). To the extent that the wood is compromised, it needs to be cut out and replaced.
Replacing the entire bulkhead is painful, it is more the disassembly of the boat/cabinetry/overhead than the actual bulkhead replacement. As a patch fix, I would recommend cutting out all rotten wood in a clean trapezoidal shape maybe 6" wide at the bottom and 4" or so at the top (only as wide as you need to in order to remove all rotten wood; trapezoidal so the upward stress 'jams' the patch). Insert a new piece of plywood of matching thickness which closely fits the removed shape (use a cardboard template for both). Soak edges of patch piece and edges of cutout with epoxy and then fill joint with thickened epoxy when installing. Use temporary backing to keep the planes in line (covered with poly to eliminate epoxy adhesion). The patch should be tabbed at top like the original.
One side of this bulkhead (or both?) is inside the hanging locker and this will be the repair side for aesthetics. Make up a plate from 5/8 or 3/4 plywood copying the upper 'third' or so of the bulkhead; down to 4-6" below the patch. Once the epoxy is kicked and patch in place, paint the plate and existing bulkhead (stripped of finish) with epoxy, apply a layer of matt to the back of the plate (matt for adhesion more than strength) and install against the existing bulkead. Use 1 1/4" screws to keep in place and in fact numerous screws over the plate surface will only strengthen the repair. Tab the plate to the hull and deck.
On the 'clean' side of the repair you can simply dress out with a piece of 1/8" ply or luan. There is just no percentage in patching holes on rotted wood for chainplates; a proper repair is required
As Loren mentioned, chainplates are cheap and should be replaced after 40 years (or way sooner). Ericson welded the 'sealing plate' to the forward chainplates; to me this is really dumb idea and pretty much guarantees leaking. Attaching the sealing plate to the constantly stressed and destressed chainplate makes an effective seal very very difficult. It is also a gigantic pain to regularly rebed the fixture as should be done every 5 years or so. I am replacing all my chainplates as part of my new bulkhead project and I will be replacing the forward lowers without the attached plate; I will make a separate plate for bedding. This just makes way more sense. Guy Stevens in a thread here recommended making the plates out of fiberglass with no screws vs metal which I though was a point well taken, fg plates expand and shrink at the same rate as the hull which promotes a better seal (cannot find the thread... Guy..?)
And to reiterate from above, you have to stop the leak; installing a proper sealing plate will help. Dollars to doughnuts though, you will have core rot in that area- it has been leaking for years. This will need to be addressed before installing and sealing chainplates as it might be extensive and it is simply impossible to seal a chainplate against rotted soft deck.
 

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garryh

Member III
addendum: also as mentioned above, a backing plate would add to the strength of the assembly. If replacing the chainplate, have the top cut off the old one and use it as a backing plate. Obviously the holes would have to match up exactly but easily done when being duplicated in a shop. Having them cut out by water jet eliminates and issues from heating the stainless while machining.
And if having one fabricated, would be a good time to have them all done. Mission creep.... : )
 
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