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jim767 · 27-12-2010, 14:27

Comments on bronze vs stainless for chainplates please.

**Pblais** · 27-12-2010, 14:44

What boat?

When you get into replacing the chain plates it's the removal of the old ones that cost blood, sweat, and tears. The new super stainless alloys are unbeatable compared to anything. The cost of the material is not much compared to the cost of the machining and removal of the old ones. You can install poor plates as easy as really good ones too. I have a bronze stem fitting but it connects to a stainless plate.

The funny thing is if you could remove the plates and x-ray them you would know for sure if they needed replacing but the cost of doing the testing it isn't worth the effort once removed from the boat,

DeepFrz · 27-12-2010, 14:45

Look right at the bottom of this page and there is a list of threads on this topic that should help you.

Noname1 · 27-12-2010, 14:51

I of course am ultimately responsible for my mistakes and loosing my boat but one I will never make again is to trust a SS chainplate. Bronze or titanium for ever more.

simonmd · 27-12-2010, 15:19

Idealy, Bronze.

Next?

**Pblais** · 27-12-2010, 15:29

Quote:

I will never make again is to trust a SS chainplate.

It's why they need to be replaced and I assume the point of this original post in the first place is to replace them. Is that your point? It's not always possible to know all the details of a failure and regrettable to have to experience one. Choices made beforehand often are proven wrong but more often not proven at all.

Most boats come with 316 SS plates but if you could afford Titanium it would be a good choice. It's not the most friendly metal to work so carries a rather large premium. The new super stainless plates are a much better choice than 316 for replacement since they would be of similar size and shape and far more resistant to crevice corrosion. Well made 316 plates as replacement could assure a long life as well.

Metal alloys are all different just as bronze is an alloy and so is steel. They both have a huge spectrum of variances and alloys and all with a purpose. Not all stainless steel is even close to the same when it comes to corrosion resistance. There are alternatives better than just 316. 316 has tight tolerances for the fabrication and that step can be a cause of failure.

Bronze is not entirely superior in all applications else it would be used exclusively. An alternative stainless plate would require no engineering modification to the design of the plates nor the attachment. It would improve the result without modification to the design.

Material is but one element in the total functional package and it would be a mistake to assume all other elements are not significant and could remain the same.

cal40john · 27-12-2010, 16:09

I'm guessing that price is the reason you see stainless steel used most of the time. My old boat has everything bronze except for the forward lower chainplates. I have no idea what the history of my chainplates are and so I priced new ones. I was told that if I wanted bronze replacements for the bronze main chainplates they were going to be 25% over the cost of SS.

John

Noname1 · 27-12-2010, 16:25

Paul I'm sorry if I sounded critical of your post. If I did you have my apology. I don't ever want to hear that bang again. Nor would I want anyone else to do so. Especially as it is not necessary. I researched the subject in depth and also talked to the designer of my boat and high silicone bronze (C65500 Silicon Bronze) will outlast the hull by many centuries. You can get bronze water-jet cut to spec and need little additional work and the cost is to my mind not unreasonable. My research suggests titanium is not particularly difficult to work if you do your homework and buy the correct drills.

SS is shiny and cheap. What sailor can resist that? Bronze is neither. One can now get titanium thru-hulls for example and would be about invulnerable.

Jim asked for comments. These are mine. YMMV.

**Pblais** · 27-12-2010, 16:45

Water cutting is the way to go no matter what you use. It makes the polishing easier as well as stressing the metal far less. It's easier to get it done in the Pacific NW as that cutting is used in the aircraft industry a lot. You just need a shop that can do it. Local small shops is where most of this work gets done so access to materials and the familiarity is what you need. The cost of the material isn't as important as the huge labor ripping the old ones out. If you have an older boat and you replace the plates with even 316 done well it still should last a long time. Being able to outlast the rest of the rig isn't much of an advantage.

Should there be a rig failure you could overload one plate and break it even with it being perfectly fine. Cascade failures are almost impossible to go back and figure out in the case of a rig. Chain plates really are just one part in a big list. Replacement based on time is the standard for wire, fittings, as well as plates. With an old boat you can't tell by just looking.

Sailorman375 · 27-12-2010, 17:03

I work in the offshore oil and gas insudstry and supply valves. The choice of materials for sea water service in this industry is interesting to me as normally either nickle aluminum bronze, super duplex stainless, or titanium are what is specified by all the major oil companies. I never see any othe these alloys discussed in regard to yachts? Is it just the cost?

cal40john · 27-12-2010, 17:10

Quote:

Originally Posted by Pblais

Water cutting is the way to go no matter what you use. It makes the polishing easier as well as stressing the metal far less. It's easier to get it done in the Pacific NW as that cutting is used in the aircraft industry a lot. You just need a shop that can do it. Local small shops is where most of this work gets done so access to materials and the familiarity is what you need. The cost of the material isn't as important as the huge labor ripping the old ones out. If you have an older boat and you replace the plates with even 316 done well it still should last a long time. Being able to outlast the rest of the rig isn't much of an advantage.

Should there be a rig failure you could overload one plate and break it even with it being perfectly fine. Cascade failures are almost impossible to go back and figure out in the case of a rig. Chain plates really are just one part in a big list. Replacement based on time is the standard for wire, fittings, as well as plates. With an old boat you can't tell by just looking.

You say there is huge labor in replacing chainplates compared to the rest of the rigging then say the chainplates outlasting the rest of the rig isn't an advantage.

I'd prefer to take the path never having to dis-assemble the cabin for chainplate replacement and replace the rest of the rigging as needed over doing chainplates nearly as often as the rest of the rigging.

John

Noname1 · 27-12-2010, 18:06

Quote:

Originally Posted by cal40john

You say there is huge labor in replacing chainplates compared to the rest of the rigging then say the chainplates outlasting the rest of the rig isn't an advantage.

I'd prefer to take the path never having to dis-assemble the cabin for chainplate replacement and replace the rest of the rigging as needed over doing chainplates nearly as often as the rest of the rigging.

John

Thank you for saying more plainly what was in my mind.
One less thing to worry about. One less major project on the horizon. I'm 58 and my ignorance cost me a great boat and a lot of $$ let alone the thrill of being rescued at sea by the Coasties. Assuming we are able to get another boat each repair will be made with the goal of outlasting us. And yes I know that's not likely but still a worthy goal. My dad burned into me do it right once wherever possible. Had things gone a little differently the boat would be wearing bronze chainplates today.

markpierce · 27-12-2010, 18:33

Go stainless steel. That's the "norm." Bronze is more susceptible to failure. Like when the bronze tiller-to-rudder-shaft casting failed on my Dad's boat in the 1960s, causing the use of a crescent wrench to steer the boat home. The quarter-inch-thick stainless-steel replacement fitting never failed. Let's say this: would you rather be armed with a steel sword or one of bronze?

Noname1 · 27-12-2010, 18:58

Quote:

Originally Posted by markpierce

Go stainless steel. That's the "norm." Bronze is more susceptible to failure. Like when the bronze tiller-to-rudder-shaft casting failed on my Dad's boat in the 1960s, causing the use of a crescent wrench to steer the boat home. The quarter-inch-thick stainless-steel replacement fitting never failed. Let's say this: would you rather be armed with a steel sword or one of bronze?

Actually I prefer a Fortress anchor, and a shotgun lubed with cetol.