Anyone ever broken an anchor chain?

[oldvarnish]

Just wondered. I've been reading the very authoritative posts in the other threads about anchor chain where strength is being much discussed.

But does anyone ever get to the stage where there is a possibility their chain might break?

 

[prv]

There's a bit in Heavy Weather Sailing where a large yacht anchored to avoid being blown ashore in a gale; a lifeboat took the crew off as they assumed the anchor wouldn't hold for long. In fact it did and they were able to go back out to the yacht in the morning, where they found that the chain had been stretched so that the links no longer pivoted through each other and it had turned into a rigid bar.

I don't remember ever reading an account of a chain breaking though.

Pete

 

[Roberto]

Just wondered. I've been reading the very authoritative posts in the other threads about anchor chain where strength is being much discussed.

But does anyone ever get to the stage where there is a possibility their chain might break?

Not exactly the same aspect, but in France there has been a worrying number of reports of broken chains during a period of a few years, in every case it was due to a manufacturing fault: one link was not correctly soldered and it split open in lightish winds. Most probably a bad batch, though using all the informations from the various users it was difficult to go back to a single manufacturer.

I personally have not seen broken chain, but permanently deformed chain which had worked slightly behind its elastic limits. The links were somehow stretched, very difficult to realize visually by their shape but the chain had become "stiffer", imagine holding a vertical length of chain by one link, slightly moving the link caused the whole of the chain to oscillate a lot more than with a proper chain; it crearly looked like the various links had "seated" against each other.
It was on a fellow boat, it happened with a stuck anchor and the chain being pulled tight vertically, I suppose with wave action.

edit just seen prv talks about the same phenomenon

 

[J Neeves]

I asked the same question, for the same sort of reasons, and drew something of blank.

I had one reply from a member of this Forum whose G40 failed as a result of a bad weld. He had anchored in shallowish water to take the dog ashore but was interrupted by the violent waving of the arms of his wife, he swam back to discover the chain had parted in fairly benign conditions. He recovered the anchor, chain and broken link and the link was identified, by the chain maker, to have failed as result of corrosion in a poor weld. The chain maker quietly replaced the chain.

I was a bit twtchy about this as I had this idea if one weld was poor - so might others from that batch - but there was no mention of a recall.

Basically that was it!

Historically there were anecdotal stories of Chinese chains failing - but not one person came forward (and Vyv's tests contradict the idea).

Basically chain being sold by someone with a reputation to protect seems one of the most reliable bits of yachting kit. G30 seems perfectly safe. I'm guessing its 'over specified' which is no bad thing.

I would not advocate complacency and requesting a test certificate seems prudent and might keep the vendors on their toes.

The major characteristic of which people do complain is poor galvanising - and this is less easy for 'us' to check - and the life of the gal determines the life of the chain. Roughly - The thicker the gal the longer the gal will last.

Based on my searches: Swivels fail (for a whole variety of reasons - but primarily bad design), anchors bend (and rust), shackles fail (often because they were poor shackles in the first place) - but chain is reliable.

I'm interested to see if anyone alters my conclusions.

Jonathan

 

[doug748]

This link was straightened out on a mooring pick up chain, it is 5/16th, of unknown quality.

The 30ft boat had been brought down very hard by the bow, by a riser trapped under the mooring sinker. Passing wash probably caused the failure:

 

[Roberto]

I have found one picture that was shown at the time of the "French" chains which were breaking, a number of persons recognized their broken chain had the same appearance.
In many cases it was brand new chain, which means that at least in these cases a tested chain would have avoided the problem

regards

 

[Resolution]

I would hazard a guess that it is far more common for deck cleats to be pulled out, or even the odd samson post, than for the chain to break.

 

[charles_reed]

There's a bit in Heavy Weather Sailing where a large yacht anchored to avoid being blown ashore in a gale; a lifeboat took the crew off as they assumed the anchor wouldn't hold for long. In fact it did and they were able to go back out to the yacht in the morning, where they found that the chain had been stretched so that the links no longer pivoted through each other and it had turned into a rigid bar.

I don't remember ever reading an account of a chain breaking though.

Pete

Adlard Coles "Heavy Weather Sailing", Tilly Whin surfed ashore on Portland Bill, got a badly injured crew ashore, expecting to come back to a wrecked boat - instead found an elongated anchor chain and a refloatable boat.

I've only heard of chain failure due to a sub-standard link - shouldn't happen with certified chain which is all I've ever bought.
Rumour hath it that recent failures have been with Italian-sourced chain. (Aqua)

 

[jsl]

I've seen it happen: small mobo anchored close to beach, ferry passed along channel, mobo was at exact focus of wave sweeping along beach from both ends, mobo lifted several feet vertically, chain snapped. I do think it was the chain and not the shackle, but no one bothered to do any close examining.

 

[rob2]

To snap a chain due to wash in an open anchorage suggests that not enough scope was veered. With sufficient scope the change in depth should be accomodated by the adjustment in the catenary curve. It amuses me that the term "catenary" derives from the Italian for chain.

Rob.

 

[KellysEye]

The only broken chain I know of was a stainless steel chain on a boat anchored in Chaguaramas, Trinidad. It had been anchored for seven months on sand and that had caused crevice corrosion. The only boats I've seen on the rocks were four charter boats in Greece the reason being their anchor swivels had failed.

 

[Stemar]

I've seen it happen: small mobo anchored close to beach, ferry passed along channel, mobo was at exact focus of wave sweeping along beach from both ends, mobo lifted several feet vertically, chain snapped. I do think it was the chain and not the shackle, but no one bothered to do any close examining.

To snap a chain due to wash in an open anchorage suggests that not enough scope was veered. With sufficient scope the change in depth should be accomodated by the adjustment in the catenary curve. It amuses me that the term "catenary" derives from the Italian for chain.

Rob.

I'm struggling to imagine how this could happen, even with an inadequate scope. The boat lifting is little different from an anchor recovery, albeit a rather brutal one.

 

[prv]

I'm struggling to imagine how this could happen, even with an inadequate scope. The boat lifting is little different from an anchor recovery, albeit a rather brutal one.

Exactly - too brutal for the chain.

Pete

 

[jsl]

I'm struggling to imagine how this could happen, even with an inadequate scope. The boat lifting is little different from an anchor recovery, albeit a rather brutal one.

Yes, the scope was tiny and the lift was really impressive in height and speed. I would have expected the anchor to be yanked out of the ground, but that isn't what happened. My daughter paddled around and found the anchor, slightly to the bemusement of the owner.

 

[vyv_cox]

Both of the photos above show brittle type fractures due to a problem at the weld. I found that several failed in this way when tested, although almost all were up to specification strength. The one exception is shown towards the bottom of this page http://coxengineering.sharepoint.com/Pages/Chaindefinitions.aspx I subsequently thought up the one-link test and the one from the defective chain failed in exactly the same way. The strength of this one was about half what it should have been

Ideally, and it happened in about half the cases I tested, the fracture will be ductile and occur at the point of minimum radius, like this one. The lack of articulation referred to by several posters above is the precursor of this type of failure, when the links begin to extend plastically. With the typical fairly mild steel of anchor chain this will be at about 60% of UTS.

 

[J Neeves]

The failure I quoted in #4 was a French chain, but the owner of the chain did not divulge the manufacturer. The chain was newish and the picture I saw looked new chain as the gal looked intact. A number of other posts suggest maybe there was a complete batch with poor welds. Batches can be 1,000m. I note that there is an anecdotal comment of poor Italian chain, Aqua - which is Maggi and Jimmy Green. As mentioned these failures should be picked up, I think, if the chain was Proof Tested which is common conducted as part of the production process. And if Proof Testing is part of the production process it does seem one cheap way of ensuring the chain you buy meets some of its specified attributes. The other cheap way is to follow Vyv's one link test.

To stretch chain such that the links lock, or will not pass through the gypsy implies you are well within 40% of minimal break strength. Typically chains will stretch, permanently, about 15% at failure. But you would need to load to 60% of break strength before the chain starts to stretch, which for 8mm G30 is about 1.5t. To stretch and lock you need to be very near failure. I'm not sure how much stretch will result in gypsy incompatibility.

On the basis a chain is good you really need a very significant load to stretch a chain.

The Americans have an industry standard, G30, G43 and G70, for total stretch of chain at failure of 15%. Interestingly, given its reputation for being brittle, they have another standard for G80, G100 and G120 of 20%.

Jonathan

 

[JumbleDuck]

I asked the same question, for the same sort of reasons, and drew something of blank.

I had one reply from a member of this Forum whose G40 failed as a result of a bad weld. ...

Basically that was it!

You have forgotten our correspondence on the matter, then, in which I told you about my 8mm (may have been 5/16") chain breaking a few years back on the Firth of Clyde. You'll maybe recall that I offered to send you a surviving bit for testing.

For the OP, and anyone who cares, it was in Lowlandman's Bay on the north of Bute. Wind was 25kt constant, with extended gusts of 40kt and occasional blasts of 50kt. Sheltered, so very little by way of waves. I don't have the broken link but I do have about 5m of the chain. It's oldish, but looks in reasonable nick and has no clearly horrible looking rust. Maybe just one bad link?

 

[J Neeves]

Jumbleduck - I had not forgotten! but had restricted my quote or post, with no disrespect, to newish chain. Old chain of indeterminate origin might fail simply because it is old or because it is of indeterminate origin and I think to lump old chain failing with newish chain is unfair, on newish chain. I'd love to test your chain, but its a bit expensive to get it here. But the main deterrent is that if I test it then the information is not of much use as we do not know where it came from (manufacturer) nor do we know how old it is nor how it was used. I recall we do not even know what quality, Grade, it is.

Its a bit like testing (and buying) Chinese chain - some might be fantastic and some might be a bit average but unless you have real confidence in the supplier I would not recommend it. You simply do not know if a supplier swaps source, based for example on price. We have 2 large suppliers of Chinese Chain in Oz (neither supply to a spec - its simply short link chain - but it is for sale in a chandlers alongside anchors), one of the chains would be excellent if you have a large dog, but I would not use it to secure much else. The quality of the other chain is truly excellent, better than any G40 or G43 I tested. It also had good galvanising. Importantly it was cheap. It was so good I spoke to the importer 3 times with a view to their divulging the source or their branding it and supplying a certificate - they were not in the least bit interested, suggesting to me that maybe they were not very confident of continuity of supply. This is not the fault of the Chinese - but, to me, a fault of the importer. But it all makes me wary of unbranded Chinese chain, not backed by a reputable supplier who will offer some form of certification.

Jonathan

 

[JumbleDuck]

But it all makes me wary of unbranded Chinese chain, not backed by a reputable supplier who will offer some form of certification.

I think you worry unnecessarily. As you have said, there is no evidence of an epidemic of chain failures and Vyv Cox, who is actually qualified in such things, doesn't seem to have anything against Chinese chain.

 

[J Neeves]

JumbleDuck,

I am sure you are correct and I have noted Vyv's articles and website information. My caution is not directed at the quality Chinese chain makers but is directed against the importers and those that are not lucky enough to read Vyv's analysis (and these posts). When I am given a choice of a certificated purchase of chain (at 'market' price) or an uncertificated purchase of chain (at much less than 'market' price, or even at 'market' price) I would choose the more expensive product and I would question why, for such a critical item of kit, no certification was available. I would say this for chain manufactured in the EC, USA, China - or anywhere. I think it reasonable to request a certificate and totally unreasonable for it not to be available, for every batch being sold. If everyone who bought chain asked for a certificate - the importers and manufacturers would soon get the message.

I'm in no way saying this is infallible - but then your yacht ends up on the beach your insurance company will have little to argue about if you produce your chain test certificate.

Jonathan