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Author Topic: C34 mark 2 chain plates leaking - Chainplate flix  (Read 14588 times)

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Stu Jackson

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Re: C34 mark 2 chain plates leaking - Chainplates flix
« Reply #15 on: December 28, 2012, 10:04:38 PM »

...but left the excess where the chainplate  penetrates the top plate. I tried to form it into a fillet. Is that how others handle that joint? 

Maine Sail's now-famous butyl tape topic discusses how to do it:
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

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Craig Illman

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Re: C34 mark 2 chain plates leaking - Chainplates flix
« Reply #16 on: December 29, 2012, 09:11:30 AM »

Electric impact wrench, also works on those stubborn bolts holding the pulley to the rudder post. Good enough for occasional use, like rotating your tires.

You'll need some impact sockets too.



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Re: C34 mark 2 chain plates leaking - Chainplates flix
« Reply #17 on: December 29, 2012, 09:24:17 AM »

I pored over that tutorial before jumping in and it did not quite explain the issue. I wish I had photographed the process... In "normal" bedding, with one piece of hardware and screws  (eg a cleat), the butyl is placed between say the hardware and the deck, wrapped around the screw heads. It squeezes out as the screws are tightened. This squeeze out can be easily trimmed after tightening.

The case of the chainplate is different. It is much more like Mainesail's example of the NFM metals port light installation. The butyl has to be forced into the crack around the chainplate and built up in that area (as seen in Stu's photos). It is also put on the base of the top plate (in Mainesail's NFM tutorial he actually used sealant on the trim ring equivalent) also as Stu showed. When the top plate is screwed to the deck, butyl squeezes out in three places (I'm ignoring the deck through bolts in this example)- the screw heads, the perimeter of the top plate and between the top plate and chain plate. It is easy to remove the excess around the first two, but between the top plate and the chainplate you can't simply trim away the excess butyl because it is part of the seal. Furthermore, that butyl will be exposed to sunlight. In the NFM tutorial, Mainesail does not explain how to finish that part of it. In fact it kind of appears that he leaves it alone. I'm tempted to trim that portion back and hit that joint with polysulfide over the butyl to finish it. This would protect the butyl from sunlight and provide a seal over that joint which is not under any pressure from fasteners.

ps Thanks Craig- Will dig up one of those 20% off coupons

edit 12/30: Just noticed in this link,6202.0.html
where cmainprize finished the top plate much the way I did, and is not concerned about sunlight exposure
« Last Edit: December 30, 2012, 11:31:13 AM by 2ndwish »


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Re: C34 mark 2 chain plates leaking - Chainplates flix
« Reply #18 on: January 07, 2013, 07:41:55 PM »

With regards to sunlight and the butyl tape - the stuff is very tough and holds up well to UV degradation. I've left a small ball outside on a dock piling for the past 1.5 years just see what would happen and can report that its still rubbery.

What's perhaps more of problem aesthetically, is that some dust and grim can stick to it.  But frankly I have found that this simply helps it blend in. I don't think you really need to do anything more to it.

Gaulois #579 C34 Tall Rig - CYC West River, MD


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Re: C34 mark 2 chain plates leaking - Chainplate flix
« Reply #19 on: June 03, 2021, 12:35:14 PM »

Thanks @stu for showing the picture with the rod removed.  A good hint that I wish I would have done was to disconnect the bar below the deck as shown in Stu's picture.  That way the sequencing of tightening the chain plates first to seat the butyl THEN the rods.  Otherwise the rods tension raced against the plate tension,

See rod tensioning post regarding also:
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