Rotten Deck Core Surrounding Chainplate!

[Tim Good]

So I’ve pulled my Ubolt chainplates to replace after one snapped. Inside is the plywood core is rotten.

There are plenty of threads on this so I’ll refer to those but why don’t yacht builders fill the area around hainllates with solid Epoxy? At least the are where the bolts go through so that any water would never make it into the wooden core?

Seem crazy how so many people have suffer with the same problem.

 

[Boathook]

Costs money (time) to do that, and if they did, a very good chance that voids would be left for the water to pass through.

 

[savageseadog]

So I’ve pulled my Ubolt chainplates to replace after one snapped. Inside is the plywood core is rotten.

There are plenty of threads on this so I’ll refer to those but why don’t yacht builders fill the area around hainllates with solid Epoxy? At least the are where the bolts go through so that any water would never make it into the wooden core?

Seem crazy how so many people have suffer with the same problem.

Yes, a common problem. It's the same on many boats with most deck fittings as well. The issue with the chain plates is the forces involved and the movement created.

 

[Blueboatman]

Some of it is simply down to attention to detail when the deck mould is built I think .

A chain plate sitting on a raised plate of deck moulding is obv less of a water ‘sump’ collector than one plonked onto a flat deck.. they may still leak ??but less over time .

But yes, I agree, if you are building a production line of boat decks , once you’ve got all the holes and hardware worked out after the prototypes tested, why not bond solid grp plates into the laminate in way of all apertures instead of mush-to-be plywood ?

Oh if only all boatbuilders were so organised , perhaps ??

 

[geem]

How do the chain plates connect to a structural point? Do they go to a bulkhead? If they go to a bulkhead then the deck is taking no load. There may be some deflection at the deck if the chainplate doesnt point in the direction of the load. This can cause leaks as the load on the chainplate changes causing slight movement. Whatever the chainplate passes through at deck level has to deal with that movement without causing a leak. It may be worth excavating the core and filling with epoxy and glass strands. You may need to use Sikaflex around the chainplate to ultimately seal against leaks and allow for some movement. Good luck

 

[savageseadog]

Some of it is simply down to attention to detail when the deck mould is built I think .

A chain plate sitting on a raised plate of deck moulding is obv less of a water ‘sump’ collector than one plonked onto a flat deck.. they may still leak ??but less over time .

But yes, I agree, if you are building a production line of boat decks , once you’ve got all the holes and hardware worked out after the prototypes tested, why not bond solid grp plates into the laminate in way of all apertures instead of mush-to-be plywood ?

Oh if only all boatbuilders were so organised , perhaps ??

I know the issue is prevalent in the smaller scale boat builders but do the large scale CIM boat builders like Jeanneau and Beneteau engineer this stuff in?

 

[Ammonite]

It works (to a point), its cheap and by the time it turns to mush it won't be their problem.

 

[TernVI]

In the 90s, when I was looking at boats, it was common advice to regard u-bolt or 'hairpin' chainplates with a great deal of suspicion and for surveyors to insist they should be re-bedded at least on boats more than a few years old.

 

[jwilson]

Putting ply sections in on load areas of cored deck was for many years, and for some builders still is, pretty much standard with most production boats, though there are exceptions. As others have said, it's cheap, it works fine if water never gets in, and if it does get wet and eventually rot it's probably a long time on from new and not the builder's problem.

 

[PetiteFleur]

And also the U bolts could suffer from corrosion in the deck area so check carefully and replace if necessary. Found out on a Jaguar 27 - replaced with Wichard U bolts.

 

[chris-s]

Have just done a similar repair on our little Pegasus where the ubolts go thru a narrow strip of ply with nothing more than the fro deck and underside to support it.