Anchor chain joiners

[Screen Saver]

Has anyone had any first hand experience with anchor chain joiners failing, or anyone used them for a year or two and happy with them.

My 10mm chain has a couple of spots at the 30m mark that are worn and I believe it is responsible for making the chain jump on Gypsy which will in turn damage the Gypsy.
I am contemplating buying 50m of new chain, cutting out the worn section out/off and adding the old last 30m, but good looking section to the end of new chain.

My concern is the joiner and there reliability or how long they last.

 

[Captain Larry-DH]

I used a Crosby G-335 Missing Link "c-link" for about 3 years. Worked fine, and went through the gypsy without any issues. I did not peen the two halves together (I should have) but used 3M 4200 adhesive to hold them together when not under load (the chain pulling on each side pulls the halves together when under load).
I found that the joining nubs/pins stand a bit "proud" if they aren't peened with a hammer, and those pins can catch on the adjacent chain links to cause a kink as the chain comes up out of the locker. We were out cruising at the time I discovered that, and I didn't have ready access to a heavy sledge, anvil, and terra-firma to properly peen it (it would require heavy blows from a heavy hammer... not something I'd do on deck). So, my quick fix was to grind the tips of the nubs flush with a rotary tool and cutting wheel. Worked fine after that, and the only ill effects were some small spots without galvanizing. (That was mitigated with some spray-on galvanizing at the end of the season.)

 

[Screen Saver]

Good points and all noted thankyou very much. I had not considered peening and how I would do it on board. So I probably need to be in a marina and get the chain off the boat. A point I had not considered. Thanks

 

[Captain Larry-DH]

Good points and all noted thankyou very much. I had not considered peening and how I would do it on board. So I probably need to be in a marina and get the chain off the boat. A point I had not considered. Thanks

Peening is "proper" but I don't think it is necessary, if you do as I did.

 

[dLj]

I used a Crosby G-335 Missing Link "c-link" for about 3 years.

That's a great reference!

If you're "living on the hook" though, I'd definitely peen those rivets.

dj

 

[thinwater]

Oh dear.

There is a HUGE difference in shear strength between 5200 and a rivet. When the chain approaches full load, the two joiner halves begin to straighten, like a carabiner, and like the gate of a carabiner, it is the rivets that keep it from opening up and failing. You REALLY need to peen the rivets, but you won't see the difference until the middle of a real storm.

Compare the open and closed gate strength of a carabiner (the only difference is whether the gate is latched--a fraction of an inch). In this case, which is typical, the difference is 22 KN vs. 7 KN (4950 pounds vs. 1575 pounds breaking strength). I have snapped carabiners when the gate was pressed open just a fraction such that the gate rivet did not engage.

You should be able to peen them on the dock if you haul something out to serve as an anvil, and a plank for a foundation. Better yet, get a slip on a shore side bulkhead.

Granted, the rivets are engauged, and they would have to bend, but they can. You're giving the maker a heart attack.

 

[Captain Larry-DH]

Granted, the rivets are engauged, and they would have to bend, but they can. You're giving the maker a heart attack.

When under load they are engaged (as you noted) but don't do anything more to hold the sides together. The holding together is being done by the chain links on each side which are shaped in a way that would prevent the C-links from separating enough to slip off the peening nubs. If they'd slip when unpeened, I believe they'd also slip if peened.

 

[Captain Larry-DH]

Here are some interesting threads, some of the posts include noteworthy world cruisers. Evans Estarzinger has notably done extensive high latitude circumnavigations and anchored under the most extreme conditions in Pategonia and the Arctic regions. Joining Chain - Cruisers & Sailing Forums
Here he describes using a C-link glued by 5200 in combination with Dyneema lashings as backup in case the c-link broke. Elsewhere he wrote more about this. He also described using lashings without a C-Link, noting that metal components experince more chafe between segments than Dyneema, but Dyneema is less cut resistant. The Dyneema was probably stronger than the chain, the lashings went through the gypsy well, and neither the C-Link nor the lashings ever failed, independently or together. whoops... there goes the chain! - Page 4 - Cruisers & Sailing Forums

 

[All U Get]

To peen the rivets you need to get the link over a piece of heavy metal, like an anchor that has a groove like your windlass. I’ve tried on the corner of a square anvil and squashed my thumb when the link jumped while being struck. I used a 3-pound hammer and it hurts for days.

 

[thinwater]

When under load they are engaged (as you noted) but don't do anything more to hold the sides together. The holding together is being done by the chain links on each side which are shaped in a way that would prevent the C-links from separating enough to slip off the peening nubs. If they'd slip when unpeened, I believe they'd also slip if peened.

Yes, people have done other things. I think they will also tell you that the chain most likely never saw more than 20% breaking strength, so the ultimate strength was never tested. You could just use smaller chain. You could just shorten the chain and rely on the rope tail. Most things don't fail because even those that have used them for years probably never saw the worst case scenario. Hopefully none of us will.

Do what you like. That is not how they are designed. But I just don't see why pulling the boat up to a bulkhead and peening the rivets properly is any kind of big deal. I've done it. Not doing it is just a shortcut.

 

[Screen Saver]

Yep thanks guys all understood and I think smart suggestions. I typically do 7000-10000 nm a year, 99% in Asia and Pacific 2500 in last 12 months thanks to Covid. So yep I want to do it properly and peening on my oversized anchor on the dock sounds like a great idea. I doubt 3M 4200 is in this country and to be honest I’m not sure what the difference is between that and 5200, but I will find out. No one has mentioned whether there are different manufactures or quality in the C-links, so Im assuming that Crosby -335 for example is a trusted manufacture, but does anyone have another good or bad ? Keep in mind Im in Asia there is bound to be bad ones here.

Also I haven’t checked yet but I will need to try to match the pitch etc. I only learned about 5 years ago that 10mm short link is not all the same.. My yacht sails a lot on anchor so I only get about 5 years out of the 30m mark, usually I replace it all, but apart from probably 5-maybe 10m around the 30m mark the rest looks very good.

Am I being a miser or you all replace yours in my situation ?

 

[Captain Larry-DH]

@Screen Saver you have a big boat, and only you can be the judge. Replacing chain is not cheap, but its cheaper than replacing the boat. I think a quality c-link backed by 5 or 6mm Dyneema lashing (looped many turns) is a pretty safe bet, if done right.
Not sure of the brands you have down under, or in Asia. I’d look for Crosby or Acco or Chicago (US brands) or a reputable European brand that’s stamped with a load rating for tensile strength to match your chain. As I wrote above, a proper Dyneema lashing is probably higher strength than the steel chain It‘s joining. Combined, you get strength plus cut resistance.
ps. 4200 is considerably weaker than 5200. Both have sealing and adhesive properties.