Looking for and old chainplate

colind3782

colind3782

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One of the chainplates on my 1988 Furia 332 has developed some fine cracks. Any ideas where I can look for a replacement? A pair would be better as the port side is starting to look suspect too. Last resort is to take it off and get the cracks ground out and rewelded but that will involve tricing the mast while it's off. Not ideal if it gets windy!
Chainplate.jpg
 
Instead of taking them off and getting welded, ask the guys who you would weld them for a price to make some new as this would be easy for them to do
 
Daverw said:
Instead of taking them off and getting welded, ask the guys who you would weld them for a price to make some new as this would be easy for them to do
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That's a possible but I would still probably have to take it off for a pattern. What you see in the picture is the deck fitting. Somehow it attaches to a bar which goes down to the hull plates. I will have to strip away loads of sealant to see how that attaches to the deck fitting. These boatbuilders don't make anything simple do they?
 
vyv_cox said:
Are the cracks in the deck plate or in the vertical part? The deck plate does not do much, so cracks in that could perhaps be left for a more convenient time.
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Thanks Vyv. The minute cracks which are only visible if you are really looking hard are just in the deck plate and I'm not worried about them at all, we don't race and only do gentle coastal cruising here in the Gulf of Roses. However, I have an insurance survey due in the next 12 months and I know he will pick up on them.

Edit: Did you mean the vertical part of the deck plate or the rod which goes through to the hull plate? I'll try to clear it out and get a better picture of what's going on below the deck.
 
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I had some chain plates like that on my old boat and welding like that does concern me as all the load is taken by the weld and bending in the plate bolted to the deck.

To me a better design is would be with the vertical piece passing through the deck and welded under the deck which would allow filet plates and welding on both sides, The top plate then becomes a cover/sealing plate which doesn't take any rigging load and the clamp bolts also don't take any rigging load.

The underside plate can then be bigger to distribute the load over a greater deck area.

The existing cracks how fatigue loading and could be a stress raiser resulting in crack propagation to ultimate failure.
 
colind3782 said:
Edit: Did you mean the vertical part of the deck plate or the rod which goes through to the hull plate? I'll try to clear it out and get a better picture of what's going on below the deck.
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I was assuming them to be similar to mine, shown here Sadler 34 lower and cap chainplates If they are not like that but more like these Westerly Oceanmaster 48 chainplates then it's a different matter and they need attention now. I was assuming from your initial post that yours were more like mine.
 
vyv_cox said:
I was assuming them to be similar to mine, shown here Sadler 34 lower and cap chainplates If they are not like that but more like these Westerly Oceanmaster 48 chainplates then it's a different matter and they need attention now. I was assuming from your initial post that yours were more like mine.
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Vyv yours are very much how they should be designed taking the boat into a bulkhead which is part of the structure of the boat.

The Westerly design is just designed to break away and leak as shown in your link.
 
The deck plates look more like the Westerly but a lot more substantial. I have to go and pick a friend up from the airport now but I'll pick this up tomorrow when I can expose more of the below deck part. Thanks to all so far...
 
Vyv, that OceanMaster engineering looks horrible. I have just been helping with a similar prob to the OPs, except that the bulkhead was rotting from the leaks. Short fix, was to make some plates to pick up on the lower bolts and fasten lower down, where the ply was good. The long term is going at the moment. Cutting back the ply to good wood, chamfering the edges and laying up epoxy glass to replace the wood. Leaving the 'short fix' plates too, as not visible after the trim is back.
The through deck bolts serve no purpose, though the deck is a bit flexible, so they help the mastic to stay in touch.
 
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Looking below decks, that seems to be where the strength is and looks quite over engineered. The hull plate is 8mm by 60mm flat bar doubled over and bolted through the attachment point. From there an 18mm diameter round bar goes up to the deck plate. I've scraped away as much sealant as possible but I still can't quite make out how it attached to the deck late, whether welded or screwed in somehow. I wonder if the deck plate can be welded in situ?
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The me it looks like the 18mm round bar is welded to the underside of the plate bolted to the top of the deck.

Still not a great design IMHO a design where the round bar passes through the deck plate at the rigging load is taken directly by the round bar and not be the upper and lower welds.
 
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