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Old 04-02-2011, 16:55   #16
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think she means crap exteriour grade ply ..........

in yot speek.....
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Old 04-02-2011, 17:07   #17
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If you Google "replacing Chainplates" you will find lots of information and pictures of what you are likely to find when you start digging.
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Old 04-02-2011, 17:41   #18
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I think he means CPES, which is absolutely worthless on plywood, oh and if you didn't know ISN'T waterproof. In fact, straight polyester resin is more waterproof then CPES. This is a marketing dream product (penetrating epoxies). It's a diluted epoxy, typically with solvents, often many conflicting solvents, though admittedly some brands do employ non-reactive modifiers, which is the correct way to control epoxy resin viscosity.

Picture this, a product that is diluted with inexpensive solvents by as much as 70% (CPES is about 67% solvents) and sold at a higher value then if you'd just bought the straight resin. They sell you 30% epoxy for the cost of 100%, what a dream come true. So much of a marketing dream that the very formulators that have tested these products and debunked the myths surrounding them, still offer a similar product, just to capitalize on the folks that don't keep up with industry testing.

This debate has gone on for some time, but the jury has been in now for about a decade and the penetrating epoxy guru's just haven't kept up or still think it's the mother of all bombs.

The bottom line and testing confirms it, penetration is meaningless unless the goo is waterproof, which diluted epoxy isn't. A thin surface coating of a waterproof goo is more effective at preventing moisture vapor ingress then a well penetrated goo that isn't waterproof.

In short, he's right this is a common repair, though most professionals look to inert materials in these applications, again such as G-10, metals or ultra high modulus plastics. It removes rot from the equation, though bedding is still and issue.
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Old 04-02-2011, 18:03   #19
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Originally Posted by jobi View Post
a blade will only go thru the first lawar of plywood...bacteria (black mold) from condensation make it look worst then it is. all wood is dry now...the water came in via chainplate top, needs rebeding.
bolts have been epoxyed and no water has passed thru bolt holes...under chainplate wood is solid
ps Iv remouved the chainplate alredy
Seems, jobi, that you've chosen to do a thorough job in accordance with the advice of the good posts that followed your entry above.

But for the record, I don't agree. From what I could see, it seemed that water had been leaking down the chainplate with showers/spray and the alternate wet and dry had had lifted the top layer of ply. My solution would have been to stop the leak, peel off the top damaged layer and, given that the remaining wood was good (as since indicated), apply a good paint and then simply reset the bolts.

There is no suggestion of rot - it's just lifted ply - and the loss of that one layer of ply over that small section of the bulkhead would have resulted in a loss of strength so small as to be effectively zero. In any case, all boat scantlings are overspecified and such minor losses are of absolutely no consequence. And any suggestion that the chainplate could "pullout" are wrong imo - provided it was adequate in the first place.

On a more general note: I know most don't agree with me but I always advise against overkill in repairs - unless you're headed off across oceans. Day and coastal cruising is what 90% of boats are used for and most rarely venture out in severe conditions. Further, boats are designed and constructed with ample redundancy. Rarely are vessel structural failures the cause of boating problems or tragedies.

Thus my approach is to discourage sailing folk from treating their vessel like an icebreaker, cut unnecessary costs and work, and instead go out and find the wind shifts.
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Old 05-02-2011, 01:57   #20
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[QUOTE=At sea;612157]Seems, jobi, that you've chosen to do a thorough job in accordance with the advice of the good posts that followed your entry above.

But for the record, I don't agree. From what I could see, it seemed that water had been leaking down the chainplate with showers/spray and the alternate wet and dry had had lifted the top layer of ply. My solution would have been to stop the leak, peel off the top damaged layer and, given that the remaining wood was good (as since indicated), apply a good paint and then simply reset the bolts.

There is no suggestion of rot - it's just lifted ply - and the loss of that one layer of ply over that small section of the bulkhead would have resulted in a loss of strength so small as to be effectively zero. In any case, all boat scantlings are overspecified and such minor losses are of absolutely no consequence. And any suggestion that the chainplate could "pullout" are wrong imo - provided it was adequate in the first place.

On a more general note: I know most don't agree with me but I always advise against overkill in repairs - unless you're headed off across oceans. Day and coastal cruising is what 90% of boats are used for and most rarely venture out in severe conditions. Further, boats are designed and constructed with ample redundancy. Rarely are vessel structural failures the cause of boating problems or tragedies.

Thus my approach is to discourage sailing folk from treating their vessel like an icebreaker, cut unnecessary costs and work, and instead go out and find the wind shifts. [/QUOT


you and I have preaty much the same views on this mater...I agree these boats where built over kill...and thats is what I like about them.

if I was to sail this boat weekends, id slit an opening inject epoxy under the first lawer and be done with it, not even touching the chainplate.

however my first sail will be ils de la madelaine...then crossing to azures...this is my preparation sail to my Asian voyage where I will spend severald years island hopping from the mollucans to the salomons.
therfor I want this boat rock solid...and why I ask so many questions even if I have my own views on the matter...always open to better ideas.

kind regards
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Old 05-02-2011, 04:43   #21
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externalize yur chainplates and keep them outside and replace the bulkhead with cpe'd ply and fiberglass--it does have a movement there from the boat--must maintain that grace or have further problem. LOOKS LIKE THE CHAINPLATE IS THE SOURCE OF THE LEAK-- remove the chainplate and place backing plates inside the boat anf plates outside .... epoxy it then caulk the crapouttadem. bulkhead-- cut away the bad stuff and place a cpe'd bit of marine grade ply and glass it in. done. veneer it for beauty. dont forget to angle the bulkhead end at the overhead for movement.
to externalize my chainplates would be optimal...especialy sins they are near the hull anyway...it would be an easy fix?

my questions are can i mont both upper and lower shrouds on same chainplate side by side...at present they are one in front of the other on same chainplate...not a big diference but still needs more spacing inbetween for ajusters...wonder if such a small pull would afect the mast??
pearson tritons have 3 outside chainplates so that the lower shrouds are balanced.
rgds
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Old 05-02-2011, 05:01   #22
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Quick thought on externalized.
You will change the way the load is distributed. So you would need to add something inside to distribute that change. Not sure on your boat but it could be Angle brackets bolted back to the bulkhead or a carbon fiber build up and backer plates.
Without my eyes on it I would probably replace what you have in kind. laminate in new wood and Over tab the area with heavy glass on both sides replace the chain plates with new. Use bedding plates above deck. Do not set the bedding plates down tight. instead leave them a few MM off the deck while the bedding dries and after the bedding is rubbery then tension them a little more to press the caulk against the chain plate.
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Old 05-02-2011, 05:24   #23
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looks like only the top lawer of plywood is afected...need opinions on a solid way to fix?

I wanted to cut away the afected erea and aply panatrating epoxy, then level with thikened epoxy and finalise with a lawar of fiberglass...and also add a backing plate as the original has none, in fact the bolts have carved in the plywood.

thanks for any opinion
rgds

ps thats the only problem chianplate...all others are ok
The fix will depend on what it looks like after you start digging around - given your intended use I would start from the position that it will need complete replacement, even if you keep your fingers crossed it don't. Not a quick job by any means, but when dealing with "new" it does save a lot of messing around.

I would be very surprised if once you start digging into the delam Plywood that it doesn't extend more than one layer - that looks longterm damage. I would also be looking very carefully at the tabbing onto the hull and coachroof - especially in the bilge as any delam their will probably be (my) decider on complete replacement.

Having said all that I would be tempted to dig out to solid wood, fill with epoxy (not for strength - just as filler / for compression) and then on top of that flat surface add a new bulkhead (both sides?), epoxied on and bolted through..........could maybe even get away with that even if digging out to solid wood reaches fresh air in places .......and then paint . Don't shoot me
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Old 05-02-2011, 07:01   #24
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... Use bedding plates above deck. Do not set the bedding plates down tight. instead leave them a few MM off the deck while the bedding dries and after the bedding is rubbery then tension them a little more to press the caulk against the chain plate.
This good advice recognizes that chainplates WILL move a little, hence the bedding acts less like an adhesive caulk, and more as a gasket.
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Old 05-02-2011, 07:23   #25
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This good advice recognizes that chainplates WILL move a little, hence the bedding acts less like an adhesive caulk, and more as a gasket.
for this reason I use butyl for portlights, stanchions, chainplates
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Old 26-02-2011, 10:16   #26
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Re: Bulkhead Water Damage at Chianplate . . .

is it normal for this chainplate to have a bend?
should I make a thicker and larger chainplate...I dont know to me it looks small and fragile??
its only 1/4in thick
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Old 26-02-2011, 16:29   #27
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Re: Bulkhead Water Damage at Chianplate . . .

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is it normal for this chainplate to have a bend?
should I make a thicker and larger chainplate...I dont know to me it looks small and fragile??
its only 1/4in thick
A quarter inch is well adequate for that size craft imo. And yes, sometimes chainplates are bent like that by design. Without knowing the boat, but knowing it's 1/4" stainless plate, I'd say that is the case here. Put it back and don't worry is my suggestion.
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Old 26-02-2011, 17:18   #28
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Re: Bulkhead Water Damage at Chianplate . . .

Had this problem and wound up completely replacing one bulkhead. The way I did it worked out very well so if you would like details, will write it up in a subsequent post. Instead of even screwing with replacing the plates as they were, I moved all the chainplates outboard and beefed them up considerably from 1 1/2" to 2". My old Alberg 35 has 1/2"+ solid glass in the hull adjacent to the plates, so attachment through hull was pretty straightforward and I believe stronger than bolted through plywood bulkheads. I don't know why boat builders do the deck penetration thing other than to avoid seeing the chainplates on the side of the boat. There is really no way to make them watertight and once moisture gets into the end grain of plywood, you're dead. Some folks raise the area around the plates which probably helps somewhat with a small amt. of water running down the decks but does nothing when the rail is underwater or being flooded in heavy seas.
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Old 26-02-2011, 17:52   #29
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Re: Bulkhead Water Damage at Chianplate . . .

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...I don't know why boat builders do the deck penetration thing other than to avoid seeing the chainplates on the side of the boat. There is really no way to make them watertight and once moisture gets into the end grain of plywood, you're dead. Some folks raise the area around the plates which probably helps somewhat with a small amt. of water running down the decks but does nothing when the rail is underwater or being flooded in heavy seas.
They did/do the "deck penetration thing" because it provides a potential 1/16 knot extra overall through better point performance. Nobody wants a slow boat.

But more than that - it's also fashion and what buyers expect and have come to see as normal. Nobody does outside chainplates these days except boats designed for the traditional ship market.

But to say there's no way to make them watertight I don't think is correct; it just requires extra maintenance making sure the silicon (or something fancier) is still doing the job.

And not to be forgotten, outside chainplates also provide structurally superior support for the stick too. Should be more of it imo.
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Old 26-02-2011, 20:26   #30
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Re: Bulkhead Water Damage at Chianplate . . .

Our chainplates hold capshroud, intermediate and lower stay. They have a neoprene gasket, 10 bolts, solid fiberglass area of the hull (instead of balsa core) and a partial bulkhead across the center of the plate on the inside. No backing plate, just monster fender washers (these are 1" bolts).

Completely leak free. The only maintenance has been removal for inspection.

cheers,
Nick.
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