Moody 31 MkII Moody 31 Chainplate Leak

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David A Evans

Temporary Member
I'm just about to buy a Moody 31 but the survey states that the chainplates are leaking. The surveyor said that this could cause problems with the balsa core and worse case scenario could cause the rig to fail!!

So question is is leaking shroud chainplates common in Moody 31 and does it cause major problem?. Do other owners cut inspection hatches into deck or cabin joinery to keep an eye on these?

David
 
I lifted and resealed mine when I bought, a couple of years ago.
No indication that they were or are leaking.
I don't have inspection holes yet.
If the core is not already damaged, which I think would be evident?, then it might be enough to reseal them.
If there is confirmed evidence of a leak then it would be prudent to check the bolt integrity and wood plate condition.
This might be more than a visual by endoscopy, and would require access being made, either by cabinet removal or holes being cut.
If you need to repair the wood mount plates, then it's a cabinet out job, and would be worth getting quotes to reduce the purchase price accordingly.
 
Hi David,

The design of chainplate mounting and sealing with dinky little stainless plates screwed onto the deck was common to many Moody models up to the M44. In my view, it is quite adequate as long as the seal remains effective but, as your surveyor says, can cause major problems if leaks persist for any time.

The leaks start as the sealant used to bed the sealing plates hardens with age and cracks. Owners who are aware of this simply lift the plates, dig out the old sealant and reseal from time to time. My preference as sealant is butyl rubber, which will remain flexible far longer than the original sealant used. This simple preventive maintenance will avoid water getting into the deck core around the chainplates or the marine ply part bulkheads to which the chainplates are bolted.

Do a search on this site for chainplates, without specifying the model, and you will find a wealth of information and experience.

Peter.
 
Sounds like the above contributor is referring only to the chainplate deck seals.That is , a plate which is crewed to the deck to surround the chain plate at the bottom of the shrouds. This plate needs to be unscrewed once a year , and the gp where it meets the deck needs to be resealed otherwise water gets in and rots the wooden frame underneath to which the chainplate itself is screwed.
If the wooden frame becomes weak from rot and water ingress, then the wood splits under pressure and stress from the mast flexing and the bolts lose their grip and the whole thing fails, sometimes quite dramatically. You dont want that.
 
Hi Henry,

I was writing about the sealing plates on deck around the chainplate penetrations as that is invariably the cause of failure of the bolted joint between the stainless chainplate and the grp part bulkhead or knee. Annual resealing seems to me a bit over the top - I would expect a seal well made with a modern material such as butyl rubber, which remains flexible, to last 10 years so rejointing every 5 years should be fine, particularly if you take the trouble to chamfer the top edges of the slot and push the sealant well down the slot before fitting the stainless plate on top. and screwing down hard. If the self tapping screws holding the sealing plates have lost their grip on the holes in the deck, you need to drill them out oversize, refill with epoxy then drill the correct size for the screws again to ensure they have a good grip. Modern sealants are designed to remain flexible whereas the original material used 30 - 40 years ago tended to dry out, harden and crack, letting water in.

Looking after the chainplate penetrations in this way will prevent any future deterioration of the part bulkhead and any deck core around the penetration through water ingress. However, it will do nothing to rectify any damage done by water penetration at some time in previous owneship. It's definitely worth taking a look at the condition of the knees to which the chainplates are fastened to ensure they have not gone soggy or started rotting - there are many ways of doing this, including drilling small holes (4mm) and examining the condition of the sawdust that comes out. If the wood is wet, at least the damaged part of the knee should be replaced which requires removal of the cabinetry for access. peter Fleming did a great job of this on his M346, as described here:

https://www.moodyowners.info/resources/moody-346-chainplate-bulkhead-knee-repair.1584/

However, if the knees remain dry and have not become wet at some point in the boat's life, this kind of job should not be necessary as long as you take care to keep the deck penetrations properly sealed. In answer to Ben's question in the OP, yes, we have cur inspection holes in our M425 for all 6 chainplates - they are covered by short lengths of teak decking planks and inside cupboards or bookshelves, so blend in quite well. This year, the rig is due for replacement and our insurers have asked for a professional report on the attachments between the rig and the hull.

Elsewhere on this board, you will find a report of a M376 which lost its mast in the Irish sea through this very problem going undetected.

Peter.
 
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