Chain plate replacement confusion

[Stumble]

Originally Posted by Sulaire

Apologies to op if this is off topic, but maybe useful too;

Our chain plates are through deck and then visible on the inside of cabin, some one told me not to put sikaflex or any other sealing/bedding compound on the bolts themselves as stainless is best left to breath, good advice?

I would have thought a small gasket of sealant round the outside head of the bolt would be ok to stop water ingress?

The sealant is great up to the first time the seal breaks. Then it all goes sideways. The sealant acts to trap water against the stainless and prevent oxygen from getting to it. Which accelerates corrosion. It's the same reason coated wire lifelines are so dangerous, they can look good from the outside and be rotten away inside.

[Schooner Chandlery]

Originally Posted by Stumble

The sealant is great up to the first time the seal breaks. Then it all goes sideways. The sealant acts to trap water against the stainless and prevent oxygen from getting to it. Which accelerates corrosion. It's the same reason coated wire lifelines are so dangerous, they can look good from the outside and be rotten away inside.

And exactly the reason why we love our bronze chainplates as well as bronze bolts and other fasteners aboard the boat. They last longer, safer, than does stainless.

[crazyoldboatguy]

Originally Posted by Schooner Chandlery

And exactly the reason why we love our bronze chainplates as well as bronze bolts and other fasteners aboard the boat. They last longer, safer, than does stainless.

I use bronze - won't use anything else for chainplates.

But you won't get much of a response on that old fashioned material here.

[Stumble]

Originally Posted by Schooner Chandlery

And exactly the reason why we love our bronze chainplates as well as bronze bolts and other fasteners aboard the boat. They last longer, safer, than does stainless.

No question stainless is a terrible metal onboard. It's only saving grace is the rest are worse. Good bronze or titanium is absolutely the way to go.

[Sulaire]

Forgive my ignorance, but why are chainplates mostly made from stainless? Is it cost?

I like the idea of bronze and possibly titanium, can you get titanium bolts?

My rigging is all stainless, how would the interface from stainless rigging to bronze or titanium stand up dissimilar metals and all that?

[Schooner Chandlery]

Originally Posted by Sulaire

Forgive my ignorance, but why are chainplates mostly made from stainless? Is it cost?

I like the idea of bronze and possibly titanium, can you get titanium bolts?

My rigging is all stainless, how would the interface from stainless rigging to bronze or titanium stand up dissimilar metals and all that?

Marketing and herd mentality.

They used to be bronze or they were galvanized steel. You can still get either one of those.

Bronze and stainless play well together above the waterline.

[Cheechako]

Originally Posted by Sulaire

Apologies to op if this is off topic, but maybe useful too;

Our chain plates are through deck and then visible on the inside of cabin, some one told me not to put sikaflex or any other sealing/bedding compound on the bolts themselves as stainless is best left to breath, good advice?

I would have thought a small gasket of sealant round the outside head of the bolt would be ok to stop water ingress?

That a tough one I think. Personally I would seal them tight. The problem is, that a minimum open amount wont help at all. (like a bolt thru a hole drilled in fiberglass) It will just trap moisture. If you can keep the moisture out in the first place... better. JMHO

[Maka]

Love this thread as we are discussing chain plate replacement for my
Bruce Roberts 40.
Any one with specifics for a Roberts 40, Id appreciate it.

Mahalo

[HBWT]

Originally Posted by barnakiel

BTW On the design front, I could consider any bolts that pass thru a backing that thick to be possibly sub-optimal choice. Given the hull thickness you mentioned the backing block is possibly not necessary and should definitely not be made in any material that could catch rot. And I do not believe the material they used in your boat was solid grp!

There are this many ways to build things.

b.

Agree there are many ways to skin a cat but I think the backing blocks are a must unless I switch to external chain plates in which case I would have had a much bigger project. For a Hans Christian 43 the plates pass through the deck. The curvature of the deck and hull creates a void between the hull and the chain plate. This backing block is a must to take up the space unless I bend the chain plate to take up the void. This would create a much bigger issue of counter forces against the bulwarks that are currently dispersed to the hull. Is there simpler ways more cost effective ways to make a chain plate, Yes. Will it be a bigger project to make work, Oh Yes. Besides, I think Harwood Ives did a great job at designing our boat and like a classic car, I take pride in trying to keep as original as possible.

[chris95040]

Originally Posted by Sulaire

Apologies to op if this is off topic, but maybe useful too;

Our chain plates are through deck and then visible on the inside of cabin, some one told me not to put sikaflex or any other sealing/bedding compound on the bolts themselves as stainless is best left to breath, good advice?

I would have thought a small gasket of sealant round the outside head of the bolt would be ok to stop water ingress?

What water? The chainplates are sealed up on deck. I think as long as you periodically check for signs of that failing, you are fine to avoid any compound on the bolts themselves inside the boat. Thats just going to be additional hassle every time you pop and inspect your chainplates.