SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Chain Plate Replacement

10K views 35 replies 12 participants last post by  gtod25 
#1 ·
Planning on replacing my chain plates in next few months.

Current are 316 Stainless. Considering Silicon Bronze but material is almost impossible to find, and all I find is made overseas with questionable quality control.

Also considering Titanium. Apparently can get either overseas made or US (with added cost).

The only company I can find that can sell the material and fabricate to my dimensioins is Allied Titanium. Being able to have one company responsible for all seems to be a big plus.

Internet searches finds no company able to do this-
Do you know of others?
Thoughts?
 
#2 ·
Casey,

I work for Allied Titanium, so my advice is going to be prejudiced. But we make very affordable parts. Every now and then I have been underbid, but generally only if someone else is using remnants they just need to use up where we are using virgin metal.

You could look at a local machine shop, and there are a number of places on line that will do custom fabrication as well. But none of those shops deal with the volume of titanium that we do, or carry everything from the plates, to the nuts and bolts (unless they buy the fasteners from either us or Tico titanium).

The one thing I will mention is that depending on the size and cost of your plates it very well may be worth having a NA redesign titanium plates to meet the actual loads your boat experiences. Stainless plates are typically massively overbuilt to give a corrosion allowance, meaning a titanium chainplate can be a fraction the size. This results in lighter, stronger, and in some cases cheaper parts than going stainless.

For example, if you are using 1/2 wire, we could probably get away with a titanium bar 1/4" x 3/4 x leingth. Where a typical stainless plate may be 1/2x 1". I don't recommend this without a NA making the changes though. Which typically costs $100-$200.
 
#3 ·
Do you have any knowledge of titanium being used for chain plates? I wouldn't think you could use the same dimensions as steel and get equal strengths and then there is the problem of titanium "work hardening", which could result in catastrophic failure. Work hardening could be minimized if everthing was very precise and no stress risers introduced by any of the components - clevis pins, bolts, etc.
I would certainly want an engineer experienced in titanium applications to design and specify your new chain plates.
 
#6 · (Edited)
This could be done but the cost would be about 2.5 times the same chainplate in 316 ss and not really any stronger depending the type of titanium you use. Grade 3 is about the same strength or maybe a bit less. grade 5 is a lot stronger but about 6 times the price of 316 ss. yes it will weigh less and it will not corrode but the 316 ss will last another 25 years and most will not keep their all ready 25 year old boat that long. the advantage of using the higher strength Ti alloys is you can engineer it to be the required strength with less material. therefore saving both weight and cost. the problem with that is the total cost will not be less due to the extra cost of re-engineering.
the chainplates are sized based on the hole size and width that is needed for the clevis. and if you choose a smaller size it may not support the clevis pin and it will wear excessively (point loading)
are you ready to tell your insurance company that you guess the engineer must have gotten it wrong and you think they should pay for a new mast.
 
#7 ·
CC,

We make a lot of chainplates, and I have a good deal of experience with them. But as I frequently mention I am not a designer, and have no engineering degree, so the best I can do is point people to the answers, and help them find the right experts.

316 stainless is so much weaker than titanium, there really is an issue of overbuilding. While we do our best to drive the prices down, the raw material cost still adds up, and so if a NA can redesign (this is normally just a resizing issue) a chainplate and shave more than half the material from the part, well that is often worth more than his bill.

As an example:

The yield strength of 316 stainless is 32,000psi. While the yield for G5 titanium is 128,000psi. What this means is that a 1" cross section stainless bar will distort at the same point that a 32/128= 1/4" sectional area titanium bar will distort. So you build in a massive amount of additional strength. Combine this with the fact that most chainplates are so overbuild in the first place and you can realistically see titanium chainplates that are 20 times stronger than they need to be.

So how strong should a chainplate be? Well ONLY a NA can tell you, but a good place to start is with the size of your shrouds, since they transmit the load the chainplates need to carry. If we said someone has 1/2" shrouds with a breaking strength of 19,000 pounds, then chainplates any stronger than this are redundant because the wire will break first. Which would put us in the range of a 1/8" sectional area titanium plate. Of course this makes the rest of the system hard to work with, so in reality you have to upsize the titanium a little to fit tangs and bolt holes.

So why do designers overbuild chainplates in the first place? The simple answer is that they know that localized corrosion is the single biggest cause of chainplate failure, and the only way to delay it is by making the plates much larger than need be. This is called corrosion allowance, and is a good engineering tool. However, since titanium doesn't need a corrosion allowance when used for chainplates, there is no need to maintain these massive corrosion allowances.
 
#10 ·
I love the idea of using Titanium but I just can't see how to justify the cost for material. about a year ago I helped an friend change some chain plates. I bought 6' of 1.5" x 3/16" 316L stainless steel flat bar for less then a $100 . I priced G5 Titanium 6' of 1.5" by 1/8" with several suppliers and the best price I was given was $ 596 about 6 times as much. boat is sailing just fine on the 316L chainplates and $500 of beer and steaks.
 
#11 ·
Overboard,

I wouldn't begin to try and compete with the price of free labor. And the prices you saw are on the high end for retail titanium, when we buy it in 500lbs blocks from the mill we don't pay quite that much.

If you have a machinist friend who can take the raw stainless bar and make chainplates, that will almost certainly be the cheapest option. If you start to pay for machine time and labor rates titanium starts to look much better. If you redesign the original plates for the new material, titanium can actually be cheaper (I am looking at you Formosa owners).
 
#12 ·
I am trying to under stand how adding labor rates will make it seem cheaper. labor rate to machine Ti are higher. tool costs are higher and polishing costs are higher. if you are talking about 1/2" thick 316 Vs 1/4" thick Ti then maybe a bit less to cut and drill but most shops have a higher rate when working with Ti. if they make a mistake it gets expensive real fast. it is no doubt Ti is a great material and I have made many part out of it, but while owning a machine shop for the last 37 years I have never found a reason to use it because it is the cheaper way to go. I am still hoping that day will come.
 
#13 ·
Interesting discussion but I have to wonder why bother with the cost and trouble of titanium. Ok sure its better but it seems a bit over kill to me. Stainless easily will last 30 years or more as long as you keep them sealed from moisture where they go through the deck. This is something that needs to be done even with titanium as you do not want deck leaks or core issues. As a surveyor I have seen a few chainplate failures but without exception it was due to poor maintenance and long time leaks. I think the biggest problem is owners feel like or do not know that you need to check your chainplate installations from time to. This is important for leaks and the bolts as well. Like many things you just have to check them from time to time just like you have to check the rest of your rigging, this would be the case no matter what the material. I just finished a article about chainplate maintenance I posted on my web site but I cannot post it here so pm me if you would like to read it, I will send the link.

Capt. Wayne Canning, AMS
 
#15 ·
Wayne,

The typical person I deal with is either replacing chainplates due to failure (rig coming down, or identified corrosion), or the OEM who are exploring it for production purposes. They have very different concerns, so I will only address the replacement side here.

By the time an owner pulls the rig, removes whatever internal structures are necessary to access the chainplates, and hires someone to do the job or replacing them, the marginal cost difference between 316L chainplates, and titanium is very small as a percentage of the job. But it means that the job will never need to be done again.

Much for the same reason once you have pulled an engine out of a boat you might as well replace the engine mounts. Even if they are fine, but 20 years old, it would be foolish to not spend the $20 to have them replaced while you have easy access to them.
 
#16 ·
The thing I like about Allied Titanium is that I could send them a drawing, pay them and then get a quality (I hope) part back.

I cannot find any other company that will do this in stainless or silicon bronze- and I have made a lot of calls.

So option is I buy the material, then shop around for a machine shop to do the work. Small shops may not have the skills, and large shops either cost a lot or do not want to bother with a small job.

I like what Allied Titanium is offering.
 
#17 ·
If the price of titanium can come down (and maybe we are almost there), I could see say in 20 years nearly all stainless on a boat to be replaced with Titanium.

Never really understand why boating industry moved from bronze to stainless (other than stainless is shiny). Stainless is really a poor material to be used around salt water. But bronze is hard to get now and is nearly the cost of titanium.
 
#20 ·
If the price of titanium can come down (and maybe we are almost there), I could see say in 20 years nearly all stainless on a boat to be replaced with Titanium.

Never really understand why boating industry moved from bronze to stainless (other than stainless is shiny). Stainless is really a poor material to be used around salt water. But bronze is hard to get now and is nearly the cost of titanium.
The price for titanium has actually dropped by I think 90% in the last 10 years, while the cost of stainless has gone up. We have crossed the point where life cycle costs in the marine market are favoring titanium, and are getting close to the point that titanium is actually the same price (ok this is a bit of an exaggeration, but we are getting there).
 
#18 ·
Casey,

We will even pay to have your drawing converted into a CAD file, assuming you allow us to resell the parts to other people.

As for quality, just look at some of our customers.

Colligio Marine
Boeing - yes we meet FAA requirements for QC and QA for use in passenger airplanes (if you buy bolts from us they come from the same lots actually)
McMaster Carr
 
#19 ·
Casey,

We will even pay to have your drawing converted into a CAD file, assuming you allow us to resell the parts to other people.

As for quality, just look at some of our customers.

Colligio Marine
Boeing - yes we meet FAA requirements for QC and QA for use in passenger airplanes (if you buy bolts from us they come from the same lots actually)
McMaster Carr
I do hope your company does well. I think you can offer the boating community a great service- making our boats safer. I plan to measure my existing chain plates in a few days and will contact you.
Regards
 
#21 ·
I have had a couple of people ask for the link to my article but the restrictions here will not allow me to posts links or reply to PMs till I have 15 posts. So if you are interested just google project boat zen and you will find it. Sorry about that but best I can do. And to the mods i really am not here to spam but as I run a board too I completely understand. I'm just here to help when i can.

Capt. Wayne
 
#22 · (Edited)
FYI,
Over weekend starting pulling my chain plates.

The lower forward shroud chain plate always has some rust staining on the deck so wanted to take a look.

Here are pics what I found. Seems to be a stress corrosion crack at the rusty area. The crack occurs where the chain plate has a sligth bend for alingment to the wire (shop made bend). This chain plate is about 6 years old and has about 30,000 miles on it.

One of the attached pics has another chain plate next to the existing (this was taken after I polished the existing plate some to clean it up). This old chain plate with no wire attached was on the boat when I bought her (in storage). You can see some corrosion, and there is a small crack running width of the chain plate. There is an indentation near the crack- indent was made when bend was done by shop, probaly while on the break machine. Seems both crevice corrosion and stress corriosion happened on the old chain plate that was stored on the boat. All the corrosion is occuring in the deck penetration area (where water could collect).

almost certain the chain plates are 316 ss.

Plan to replace all my chain plates.
 

Attachments

#24 ·
#27 ·
The C76200 is a VERY heat temper dependent metal, with yield strengths ranging from 21,000psi to 110,000psi. This makes is non-suitable for use as a structual metal, unless a huge amount of engineering is done. The upside is that the lower limit is similar to aluminium, so you could borrow a lot from aluminium design. But the price premium would be huge.
 
#30 ·
I'd go with titanium, but I would avoid AlliedTitanium. I went with them and placed an order which took a month for them to tell me was not started. Since I had to remove them to measure, I was stuck unable to sail on their word they would be done in 15days. Bleh!

I ended up finding a local place that will have them to me in two days.

If you want the long drawn out version:
http://www.sailnet.com/forums/showthread.php?t=99707&highlight=alliedtitanium
 
#32 ·
I just finished drilling the holes in my new chainplates. I went with aluminum bronze. The alloy is called C61400. I purchased it from Atlas Bronze.
After talking to Tom Smith, who is the owner I think, I was convinced that this was the best bronze to use.
It wasn't cheap. But I don't believe I will ever have to change out chainplates again.
I am doing all the fabricating myself, but since they had to cut the material from plate, I had them cut to length. So all I have to do is grind, drill, polish and bend them a little. :eek:
I also upsized them. From 1/4" x 1.5" to 3/8" x 1.5. Way bigger than I needed, but I don't want them to be the weak link.
My boat can handle the extra weight.

The address for Atlas Bronze is 445 Bunting Ave. Trenton NJ 08611 and the phone is 800 478 0887.

I have no affiliation with them other than this recent purchase, but I will say that they are very helpful and nice to deal with.

Since I wanted to use the same alloy for the bolts but couldn't find any. I am purchasing round stock from them and am going to make my own bolts by threading both ends. They will all be made the exact length.
The bolts on most of the chainplates are visible inside the boat so I am going to use acorn nuts on the inside so that they all are uniform. The outside will be regular silicon bronze nuts.

http://www.atlasbronze.com/

Edit: The total cost of the material is around $675.00 including the round stock, but not the nuts.
 
#33 ·
Hey thanks for the input. I have decide to purchase silicon bronze bar stock and drill to make up my own chain plates. A lot cheaper that Ti and I will be in charge of the work and schedule. I plan to use US made silicon bronze bolts as well. Plates should be good for a long long time after that.
Regards
 
#34 ·
Hi

I must have missed the start of this discussion but I know I contributed to an earlier one. I have installed Ti chain-plates on my Whitby 42 and am well pleased. I have jokingly posted the following on my blog but it has an element of truth;

Titanium Chain-plates are a no-brainer for the following;

1. Rich people.
2. New boat build (especially where the chain-plates are buried - Listen up IPY.)
3. People who have to pay a "professional" $70+ an hour to remove and install the chain-plates.
4. Neurotics like me.

They are not recommended for;

1. Any boat with Baggywrinkles.
2. Any production boat under 30 ft.
3. Cruisers who price their time at 25Cents an hour and spend hours sorting old screws and dubious SS fittings into little boxes (Jim, you know who you are).

http://theincrediblehull.blogspot.com/search/label/chainplates

 
#35 ·
One advantage of titanium over stainless is that apparently polishing of ti is not necessary except for cosmetic purposes.

Do people really polish their SS themselves, and if so how long does it take and what is the process?
If it takes long enough some extra money for the ti may be worth something.
 
#36 ·
One advantage of titanium over stainless is that apparently polishing of ti is not necessary except for cosmetic purposes.
From my blog; "I ordered Grade 5 (Ti-6Al-4V) Titanium with sand blasted finish. Interestingly someone suggested that the polished finish is too shiny while the blasted finish is cheaper and holds the deck sealant better."

Gerry

ps. Sandblasted Ti is cheaper than polished.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top