Coated chainplates

[elkscout]

I've read about chainplates and associated hardware corroding from saltwater and how one type of stainless steel is more resistant than another, and they appear to be the foundation for a boat's rigging. Just like the foundation of a house, it's pertinent to have a strong "healthy" one.

So, are there such things as coated chainplates and hardware? It seems if they were at least powdercoated, then they would be more resistant to corrosion. Assuming they exist, I haven't seen much talk of them.

[JohnRPollard]

Originally Posted by elkscout

I've read about chainplates and associated hardware corroding from saltwater and how one type of stainless steel is more resistant than another, and they appear to be the foundation for a boat's rigging. Just like the foundation of a house, it's pertinent to have a strong "healthy" one.

So, are there such things as coated chainplates and hardware? It seems if they were at least powdercoated, then they would be more resistant to corrosion. Assuming they exist, I haven't seen much talk of them.

I'm not a metallurgist, but....

The vast majority of chainplates are made from stainless steel. There are different grades of stainless. Some are stronger, some are more resistant to corrosion. Some builders emphasize one attribute over another, which explains the different choices.

But all stainless needs to "breathe", or be exposed to oxygen. Otherwise it loses it's corrosion-resistant properties. So powdercoating stainless chainplates would be a big no-no, and would make things much worse.

As it is, properly sized and fitted stainless chainplates are reliable pieces of hardware offering great longevity, typically providing decades of service. You're more likely to run into issues with how they're bedded/attached.

[elkscout]

Thanks for the reply John,
It seems with technology so advanced, there would be a substitute for stainless where it wouldn't have to breathe and could be coated to resist the corrosion/cracking, and hopefully last longer.
Most of the readings I've come across as made it sound like 15 to 20 years life expectancy out of the various kinds of stainless hardware, not decades.

[CaptainForce]

Here's a stainless chainplate on a saltwater boat given no maintenance beyond washing and cleaning for 38 years.





Here's the same chainplate after a DIY removal, polishing & inspection.






Of course this is not as easy a task on an embedded chainplate, but it does support the idea of exposed stainless functioning well. 'take care and joy, Aythya crew

[tager]

I am a fan of galvanized stuff. If I ever replace my chainplates, they will be galvanized or bronze. Either of these are very easy to inspect, and last just as long as stainless.

[sailingdog]

Good chainplates, made of 316L Stainless Steel, should be fine for a long time. One problem that is fairly common is when 304 Stainless was used, since it is far more prone to crevice corrosion issues. Another common cause of problems is when the chain plates are encapsulated in fiberglass and the sealant at the deck goes bad, allowing water into the fiberglass surrounding the chainplate. The water leads to crevice corrosion. 304 is also prone to chloride ion stress cracking.

Galvanized steel was used previously, but has issues. While galvanized steel will generally give warning prior to failure, which stainless steel often will not, it takes more work to keep it in good condition, and will often bleed rust on to the surrounding boat.

[QUOTE=elkscout;575837]I've read about chainplates and associated hardware corroding from saltwater and how one type of stainless steel is more resistant than another, and they appear to be the foundation for a boat's rigging. Just like the foundation of a house, it's pertinent to have a strong "healthy" one.

So, are there such things as

[elkscout]

CaptainForce, you're pictures didn't come through, but I think you're suggesting some degree of PM to prevent a bigger repair job later. I guess I'm mostly thinking of what you're calling embedded chainplates or similar devices anchoring through the deck, and not so much as those fastened on the side of the hull.

[CaptainForce]

Originally Posted by elkscout

CaptainForce, you're pictures didn't come through, but I think you're suggesting some degree of PM to prevent a bigger repair job later. I guess I'm mostly thinking of what you're calling embedded chainplates or similar devices anchoring through the deck, and not so much as those fastened on the side of the hull.

I restored the photos to the post and my intent is to show that good stainless steel can function for decades (38 years on this vessel) on a saltwater cruiser with minimal care. By "embedded" chainplates I was referring to those that are encapsulated in fiberglass, not just passing through the deck. I don't see alternatives to easily accessed stainless steel any where near as reliable. 'take care and joy, Aythya crew

[Waltthesalt]

I think coating is irrelavent to stainless steel applications. It's commonly used on commercial marine applications to reduce corrosion on mild steel components. 304 stainless can have chlioride stress corrosion at any stresspoint so all it would take is for the powder coat to have some cracking anywhere. I haven't heard about 304 stainless cracking in chainplates, it's more common in things like nicopress fittings. Chainpalates just don't see that kinda stress. The more common internal chain plate issue is that they're mils steel and they just rust away. If you're in a position to pick your chain plate material 316 stainless has better stress corrosion resistance than 304 ans will have adequate streinght as well. Make sure you do the calculations. Any stainelss needs to be thicker than the mild steel component to have comparable streinght.