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Chainplates and Bulkhead - replace?

CaptDan

Member III
I had the same issue on my boat - minus the chainplate fissure - and successfully scarfed in a new section, which through periodic inspection, has proven sound. Knock on 'wood.':rolleyes:

Fortunately, the rotted part was only the girth of the salon chainplate covering box, so I didn't have to worry about doing the job 'pretty.'
Here are the cliff notes:

First, I had to dismantle the forward part of the bulkhead in the head - removing the shelf above the sink, and the chainplate covering board.

Then, I ground out the old fiberglass tabbing, making note of how it was attached around the hull area so I could duplicate it later.

After cutting a fairly square section out of the rotted bulkhead, I carved a 3/4" piece of marine grade mahogany plywood, shaping it as close to the cut section as I could, then using West Systems thickened with the 'structural grade' powder, fit the piece in.

After that part cured, I sanded and faired the repair (took a full day; that epoxy mixture is TOUGH stuff). Satisfied the area was as fair as I could manage (it wasn't), I filled in the rough parts with West thickened with colloidal silica, then laid another coat over the entire area, allowing it to go slightly beyond the corners - just within the dimension of the covering box.

Next, after fairing the previous work, I laid a couple of layers of biaxial glass over everything, tabbing it up to the hull corners as noted before. Then I did the same in the forward section in the head.

Then I sanded that part down, drilled new holes for the chainplate bolts, and reattached the chainplate with new stainless hardware. Now - the hardest part of the process: re-installing the head shelf and covering board.

Because the rot extended into the aft section of the shelf, it was necessary to cut about an inch off the shelf fiddle in order to get it to fit back in. Plus, the new scarfed section was ever so slightly askew, creating a need to surgically alter the shelf and fiddle. Even then, I had to fill in some gaps using West and that structural powder. (I used the brown variety which helped it blend in with the teak fiddle.)

I followed a suggestion from a wise E35II dude (John Moses) : instead of reattaching the chainplate boxes with screws, I used 3/8" diameter dowling instead. That allows quick disengagement of the box for easy inspection - should any new leaks develop.

Finally I re-caulked/bedded the chainplate where it penetrates the deck. Thankfully, there was no core delamination there. The soundness of the deck is what prevented the mast from going by the board, because I'd been sailing the boat for about a year before I realized my folly.:)

Certainly replacing the entire bulkhead is the preferred way to go. But - in my opinion, and in some cases - it's not the only way.

Hope this helps. Good luck.

Capt Dan G>E35II "Kunu"
 
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gareth harris

Sustaining Member
I have only just noticed this thread; it is one of the first jobs I did, exactly ten years ago now, bck when I was daft enough to cut a lovely piece of mahogony and then realise it would not fit in through the hatch.

One of the cosmetic probems is that the mahogony available in the early 70s came from rainforests that have been cut down by now, so the colour tends to be less rich these days. A stain may help that.

The other thing I have not seen anyone else mention is the importance of not fitting the plywood right up to the hull, instead having a small piece of foam in between. The point is to not have a hard point on the glass of the hull, which would damage even the thick glass during the buffeting of a boat in motion;, but spread the load across the fibreglass tabbing, which has a certain amount of spring.

Gareth
Freyja E35 £241 1972
 

CaptDan

Member III
I have only just noticed this thread; it is one of
The other thing I have not seen anyone else mention is the importance of not fitting the plywood right up to the hull, instead having a small piece of foam in between.


Hi Gareth,

That's a good point, but I'd offer this elaboration:

From what I can determine from my vintage E35, (1977) the bulkhead corners 'floated' between the hull via the fiberglass tabbing. In other words they were not bonded 'tight' in those places. I assume the same is true for the upper edges, but can't say for certain.

Obviously this was done for the very reason you say - to allow the units to 'work' in a seaway without creating stress. Seems to me that would be accomodated by simply duplicating the cloth tabbing, making sure about 1/2" of space is allowed between the bulkhead (or scarfed piece) and the inner section of the hull. I'm not sure a piece of foam is necessary, but it doesn't sound like a bad idea either.

For what it's worth.

Capt Dan G>E35II "Kunu"
 

gareth harris

Sustaining Member
[ Seems to me that would be accomodated by simply duplicating the cloth tabbing, making sure about 1/2" of space is allowed between the bulkhead (or scarfed piece) and the inner section of the hull. I'm not sure a piece of foam is necessary, but it doesn't sound like a bad idea either.

Capt Dan G>E35II "Kunu"

The foam is just so you have something to rest the bulkhead on while you do the glasswork, I suspect our original foam has disintegrated by now.

I have cut my new bulkheads with 1/2" foam, using a table saw to cut it at a 45 degree angle so the glass does not make a sharp 90 degree turn. It may be overkill.

Gareth
Freyja E35 #241 1972
 

CaptDan

Member III
The foam is just so you have something to rest the bulkhead on while you do the glasswork, I suspect our original foam has disintegrated by now.

I have cut my new bulkheads with 1/2" foam, using a table saw to cut it at a 45 degree angle so the glass does not make a sharp 90 degree turn. It may be overkill.

Gareth
Freyja E35 #241 1972

Or - not. If ever I were to replace the entire bulkhead, I'd do the same thing.
Thanks for the tip.

Capt Dan G>E35II "Kunu"
 

John Bouchard

Member II
Bulkhead Replacement...

I've been away for a while - PC problems... but now... I'm baaacckk!

Just noticed this thread - and without looking too deeply... did anyone mention or look into the archive threads on this subject?

It was of great assistance to me, and I attached a few pictures of the bulkhead replacement project on my 1971 E32. I think it was winter of '03-'04. I actually replaced both sides of the main bulkhead 3/4 inch ply - , and also the starboard forward bulkhead - 1/2 ply - all at the same time.

Gareth's right about the "look" - I used two or three stains mixed together to "match up" the color on the other cabinetry. It came out fairly good, imo.

I had a knowledgeable boat guy helping me, and he advised to tab the bulkhead into place on just one side (forward or aft) at first. Then, we filled the void with one of the West System's fillers. Finally, tabbed in the other side. Believe me, I asked several times about that solid filling... and he insisted no problem. I've sailed the boat fairly hard for the last four seasons, and there is no problem that I can see/find/notice!

DO seal the top edges of the bulkheads with epoxy, but not the bottom. Let gravity work to remove any moisture in there...

While I had the cabinetry removed, I installed cedar strips in the hanging closet using a method the boat guy also suggested. It looks great, but more importantly it smells like a cedar chest in there (don't laugh - this is my wife's domain on the boat, and she likes it...).

I have a ton of pictures of this work in process, if anyone is interested. But read the original threads that go back a little - great information in there!

John B.:confused:
 

John Bouchard

Member II
Further on the bulkhead replacement...

I just noticed that the pics were posted relative to another question - which was the maststep reinforcement. It was posted in January of 2004.
 

John Bouchard

Member II
Bulkhead Replacement and Maststep support

That's it! Thanks, Loren. I found it, but was unsure how to paste it in a reply. Now I know!

John B.:egrin:
 

tenders

Innocent Bystander
So, my '69 E32 finally needed the PORT side forward bulkhead to be patched, and I did it myself.

Photo 1: bulkhead viewed from the V-berth, chainplate removed. That smudge to the right of the uppermost bolt hole is a hole that I poked all the way through the bulkhead with my finger.
Photo 2: bulkhead after trapezoidal-shape area is cut out using Makita handheld saw. The bottom part of the trapezoid is perfectly fine wood. The top of it was almost entirely rotten and de-plyed.
Photo 3: bulkhead viewed from the head after trapezoid removed
Photo 4: bulkhead after sanding. Sanding was done on both sides of the bulkhead. You can see how it's tapered; where the wood changes color is a different ply.
Photo 5: where I left it today. I carefully cut a piece of 1/4" G10 to replace the trapezoid shape I cut out of the original plywood. There are four layers of glass of increasing size on both sides of that G10 holding it into the bulkhead. I will reinstall the original chainplate, and on the V-berth side add a chainplate extension made of more 1/4" G10. This will extend one more bolt's spacing deeper down into the original bulkhead, and will also add two more holes to the right and left of the bottom bolts of the original chainplate. More photos to follow on this once I get it done.
 

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tenders

Innocent Bystander
The bulkhead is repaired except for a cosmetic laminate I want to put over everything but that will wait until next winter.

What you're looking at here is the hole, filled with a 1/4" G10 plate tabbed with 4 layers of fiberglass cloth on each side, and almost completely faired with several steps of West System (white cotton and brown microballoon additives) so that the chainplate lies as flush to the wood as possible. This was done to minimize the bending force as the chainplate is tightened down.

The first three photos are the forward side of the port bulkhead, taken from within the v-berth; the last is the aft side of the port bulkhead, taken from within the head area. The photos don't show the final fairing, but you get the idea. Now that it's done, except for the difference in texture between the wood and the epoxy, you can barely tell there's a patch there when you rub your hand over it.

I ended up having to do this on the other (starboard) bulkhead too, where the horizontal plywood the sink fits into allowed water leaking from somewhere to penetrate the vertical bulkhead. This was a less complicated repair because there isn't a chainplate bolted through there but it did require some woodwork removal and fairing to get it looking OK.

So far, it seems to be holding.
 

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Guy Stevens

Moderator
Moderator
BEfore you extend that chainplate

Make sure that you go over it well with a hand held microscope. If it is the original 1969 chainplate, it is almost certainly a victim of crevice corrosion. The leaking that caused the rot also deprives the chainplate of free oxygen, and causes crevice corrosion where the chainplate penetrates the deck.

I would have a new chainplate made longer than the current one, as a matter of fact as long as possible, get it well below the current patch to the bulkhead.

The number 1 cause of dismastings according to Boat US insurance...

Chain plate failure.

40+ year old chainplates.......

Guy
:)
 

jarnold67

Member II
Looking for cracks in stainless steel

Guy,
That is good advice to look for crevice corrosion and cracking in the chain plate.

While a good visual examination can find most stuff, a liquid (dye) penetrant can find the tight cracking that often is the scourge of stainless steel. While I use the MagnaFlux brand stuff for work, they are a bit pricey and I don't know if you can find a small (and cheap) kit. I did find this link on a auto racing site - http://www.pegasusautoracing.com/productdetails.asp?RecID=1207. Note, I have no experience with this supplier - YMMV.

Doing this type of examination isn't that difficult - just read the directions, clean the area real good and if cracks are there, they'll pop out at you.

Safe journeys,
John (E26 - "Pickle")
 

jarnold67

Member II
regarding crack inspection

Good stuff at McMaster/Carr - just remember that Magnetic-Particle Flaw Detection Kits only work on magnetic materials. :egrin:
 

jag3man

New Member
Very impressive Jason

As long as you can bond well to the hull and then spread the load to the existing original bulkhead piece you are going to be fine. My Mk II had a completely separated hull deck joint covering two thirds of the length of the boat on both sides. Lots of grinding, west system, and through bolts later she is still doing fine (25+ yrs). Unfortunately for me the forward port lower had the same issues as your upper and I lost every bit of wood in the head!!! I've got a few cabinets and bulkheads to rebuild myself. It's all very relative and seeing your job is inspiring me to just get er done. Good luck.
 
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