Chain plate replacement confusion

[Cheechako]

Originally Posted by chris95040

Lots of good info in your post BUT...

1. The anecdotal '304 is stronger than 316' claim seems overstated to me.

300 Series Stainless Steel Alloys - 302, 304, 316

90,000 vs 95,000 psi? I'd think allowances for a 304 part's corrosion will often surpass that difference in strength. Which brings me to my next point....

2. No one beds a chainplate cover thinking 'I'm gonna make sure this one leaks pretty soon.'. Everyone thinks 'leaks are the other dudes problem, we are more careful than that. ' Water never takes a break, it's always looking for an in... I think it's wise to use 316 for chainplates..

I think you are right but will go further, I think the strength difference and the corrosion difference is very minimal. Passivation and Polishing is the best anti corrosive bang for the buck.

[reed1v]

Originally Posted by Cheechako

I think you are right but will go further, I think the strength difference and the corrosion difference is very minimal. Passivation and Polishing is the best anti corrosive bang for the buck.

Or just go with Monel and be done with it. Will outlast the boat, probably even the planet. Second best would be silicon bronze which is far stronger and more flexible than stainless and will last at least 3000 years(remember the bronze age stuff still hanging around?)

[Cheechako]

Whatever he goes with will last a long time done well. But yeah, bronze or Monel would be super. Too bad Monel isn't used much like it used to be. A lot of people with under deck bad tanks wouldn't be going thru that if they had been made of Monel. The builder saves $100 in material to start and causes thousands of $ repair later.

[Wind River]

Does anyone here have any experience with electro-polishing chain plates and other stainless items? Does electro-polishing produce a mirror like finish?

I have a few parts, like my bow roller bracket, that don't lend themselves well to mechanical polishing. Too many angles and small hard to reach areas. I did have someone try to do a mechanical polish on the bow roller bracket with way less than satisfactory results.

The material used to make it was a pretty rough grade of stainless, no shine at all. I would like to pretty them up a bit while they are off.

[reed1v]

Originally Posted by Cheechako

Whatever he goes with will last a long time done well. But yeah, bronze or Monel would be super. Too bad Monel isn't used much like it used to be. A lot of people with under deck bad tanks wouldn't be going thru that if they had been made of Monel. The builder saves $100 in material to start and causes thousands of $ repair later.

The old Crocker sailboats were built with monel sinks, plates, etc. Good stuff.

[crazyoldboatguy]

Originally Posted by roverhi

Has anyone tried aluminum bronze??? When I needed to change out the chainplates wanted to go with Bronze but couldn't find silicon bronze in flat stock only round. Aluminum Bronze c954 was readily available and seemed to have all the strength and corrosion of Silicon Bronze but couldn't find anything out about it's long term survivability in a marine environment. Didn't want to be a guinea pig so went with 316 stainless.

Don't know that 304 or 316 survives any better against anaerobic corrosion. 316 definitely stays shiny better than 304 but whether it is more resistant to penetrating corrosion is unknown to me. If I had to do it again, would probably go with titanium. It doesn't have the crevice corrosion problems of the 300 series stainless so doesn't need to be polished which is a savings in fabrication and is pretty much a lifetime material if you believe the hype.

Pulled a couple of chainplates from each side of the boat and measured them. Turned out the lower and upper chainplates were the same so just used one as a pattern. Used halyards to support mast as I changed out the chainplates. Didn't do them all at the same time but staggered the replacement from side to side.

Sadly, many folks eschew the bronzes, although I don't know why. I have used both silicon and aluminum bronze in different applications. The former is less expensive but the latter is very strong. Harder to machine tho.

No crevice corrosion worries - no need to passivate. And pretty, too. Will last the life of the boat.

[Cheechako]

Originally Posted by Wind River

Does anyone here have any experience with electro-polishing chain plates and other stainless items? Does electro-polishing produce a mirror like finish?

I have a few parts, like my bow roller bracket, that don't lend themselves well to mechanical polishing. Too many angles and small hard to reach areas. I did have someone try to do a mechanical polish on the bow roller bracket with way less than satisfactory results.

The material used to make it was a pretty rough grade of stainless, no shine at all. I would like to pretty them up a bit while they are off.

Electro polishing is quite commonly used on railings etc. It works well but doesn't produce the mirror like finish of mechanical polishing usually. A lot has to do with the original finish of the stainless though. Some tubing and plate is pretty rough, other has a nice smooth finish to start.

[Schooner Chandlery]

Originally Posted by reed1v

The old Crocker sailboats were built with monel sinks, plates, etc. Good stuff.

Yes, we have one of those Crocker's. Her plans show that she had a German Silver (a close relative to today's Monel) counter and sink. Unfortunately the previous owner removed it.

We're presently in the process of lining up a supplier for Schooner Chandlery to provide Monel sinks and a few other items.

[tinkrman69]

chain plates aren't really that hard a job, done it a few time on different boats. on the shrouds the plates are the same port to strbd...the aft lowers the same, the uppers th same, the fwd lowers the same take one lower fwd, one lower aft and one upper alternating side to side, so the mast stay erect. fasten the jib halyard fwd and the main halyard aft and remove the stem chain plate and the one or two aft stay plates. make duplicates where necessary and you'll be able to have them all done at once, without having to unstep the mast.

I've shipped some out to shops a coupe times as the owner requested and made my own, for myself and others. You don't need any "special" tools, just hand tools, even for a radius or bevel on the edges and polishing. For drilling the holes by hand you'll need to step the hole size up little by little till you reach the required diameter hole. in 1/4 inch stock to say a 1/2 hole you'll need at least 5 deferent size drill bits to get a clean hole and not damage any tools or body parts.

Good luck

[Schooner Chandlery]

Originally Posted by crazyoldboatguy

Sadly, many folks eschew the bronzes, although I don't know why. I have used both silicon and aluminum bronze in different applications. The former is less expensive but the latter is very strong. Harder to machine tho.

No crevice corrosion worries - no need to passivate. And pretty, too. Will last the life of the boat.

Our boat had Tobin Bronze (it's really a brass with up to 5% Tin added) which has similar strength to Silicon Bronze but is less costly to boot. Her original chain plates lasted from 1931 until we replaced them, in kind, during our rebuild (08 timeframe) so that was a good long while. The chainplates were still functional but did have numerous pink spots indicating the zinc and tin were coming out of the alloy leaving brittle copper behind in those spots. Still 75 or so years is a good long time. If the boat had been properly maintained, the plates likely wouldn't have gotten so wet and probably would have been good far longer.

Two of the running backstay chain plates were cast manganese bronze and we reused them as they were in perfect shape. They had been installed in 1953, so...65 years old and still in use today.

I would not use stainless steel. Nor would I use aluminium bronze simply because I haven't seen it used in chainplates like I've seen other bronzes and brasses used: I would go for silicon bronze, tobin bronze, manganese bronze (if cast), or even certain alloys of naval brass.

We have a fellow in the Schooner Chandlery who custom makes chainplates of bronze for folks. Feel free to follow up via the site contact form https://schoonerchandlery.com/contact/

[HBWT]

Originally Posted by bletso

What was so special about the bolts? Yes, 316 bolts are dear, but $1800.00. Fastenal is probably 4 X or more the cost from McMaster Carr.

Nothing special, but when they have to custom make the bolts, it gets expensive. These are 316 5/8 2" Wide Round Flat Slotted X 5-8" long. If I could find it cheaper, I would have.

Mcmaster Carr was more expensive. Also quotes with Tacoma Screw, National Bolt, and Champion. Even tried ordering direct with Hans Christian and they have moved to Carriage.

[Schooner Chandlery]

Originally Posted by HBWT

Nothing special, but when they have to custom make the bolts, it gets expensive. These are 316 5/8 2" Wide Round Flat Slotted X 5-8" long. If I could find it cheaper, I would have.

Mcmaster Carr was more expensive. Also quotes with Tacoma Screw, National Bolt, and Champion. Even tried ordering direct with Hans Christian and they have moved to Carriage.

So 5/8" thick x 2" wide chainplates in 316 stainless and the bolts were (also 5/8" diameter?) 5 to 8 inches in length?

Did they plate and/or mechanically polish the chain plates and bolts (e.g. they're visible inside the boat) ...?

[HBWT]

Originally Posted by zeehag

1800 usd for bolts--sucker born every minuet--

Yep, you got me. I am a sucker because I decided to replace my chain plate bolts with 316 stainless with original spec dimensions. Unlike you, I want the next owner to get another 30 years out of our boat that we have the pleasure of owning." You have a leaky teaky FORMOSA and expect your deck plates not to leak with 304. I guess you are right that the next owner will salvage your boat... Good luck. Yes, I called almost every local supplier for a quote and Fastenal came back with the lowest price with shipping. If that makes me a sucker.... sign me up.

[HBWT]

Originally Posted by Schooner Chandlery

So 5/8" thick x 2" wide chainplates in 316 stainless and the bolts were (also 5/8" diameter?) 5 to 8 inches in length?

Did they plate and/or mechanically polish the chain plates and bolts (e.g. they're visible inside the boat) ...?

That is the bolt dimensions.

The Shroud Chain Plate were ( If memory serves me well) 316 1/2 flat bar stock 4.25-5" Wide by 22-28 inches long. 8 Shroud,

Yes they are visible inside the boat and NW Railmakers Electro Polished and Passivized.

[Wind River]

Originally Posted by HBWT

Nothing special, but when they have to custom make the bolts, it gets expensive. These are 316 5/8 2" Wide Round Flat Slotted X 5-8" long. If I could find it cheaper, I would have.

Mcmaster Carr was more expensive. Also quotes with Tacoma Screw, National Bolt, and Champion. Even tried ordering direct with Hans Christian and they have moved to Carriage.

I am in the process of checking all my chain plates and replacing the bolts. I had a hard time finding bolts also. What I decided to do was change to carriage bolts. The holes in my chain plates are exactly the right size to broach to a square hole. McMaster-Carr sells the broach for about $200 that can be used on a hydraulic press or and arbor press. I should have about $450 into the bolts (about 50 of them), broach and shipping plus my time to broach the holes.

What got me thinking was a close look at my old bolts. They appeared to be carriage bolts with the square shank machined off. It seemed it would be a lot easier to make the hole square than make the square round!

McMaster-Carr