GEM43
Active member
This has recently been posted on a Scottish sailing group, worthy of duplication here I thought:
Failing anchor chain
- Thread starter GEM43
- Start date
NormanS
Well-known member
That broken weld would be so easily missed. It might have been always or usually in the root of the gypsy.
Full marks to Gael Force.
Full marks to Gael Force.
vyv_cox
Well-known member
Looks like crack two links up also. Did you find many others?
GEM43
Active member
Other than knowing that "multiple links" have failed I can't add anything else.
noelex
Well-known member
Congratulations to Gael Force Marine.
Thanks for the sobering reminder that we need to keep our eyes open and not take anything for granted.
Thanks for the sobering reminder that we need to keep our eyes open and not take anything for granted.
wingcommander
Active member
Well done for spotting it .Not that obvious when caked in mud/ weed .
Neeves
Well-known member
It does not look as if the chain had been welded at all, but maybe I'm misjudging the image.
My guess is the crack was always there, from new. The tension a leisure yacht can place on a chain is insignificant well below WLL. It is unlikely that this issue is limited to Gael Force. If GF have bough this chain there will be multiple deliveries across Europe. No-one would ship one drum from China - its simply uneconomic.
Chains are commonly Proof Tested, that's twice WLL, as an integral part of the process. I would have expected that the fault would have been identified then. This implies that the chain was not Proof Tested, and/or the Proof Test was inadequate. The fact this chain was deemed to meet specification by the manufacturer could suggest other chain, from other batches, might also have slipped through the net. Batches could be 3,000m. Chain is usually chopped up into lengths that fill a 45gal drum.
If this was a branded chain from a 'reputable' supplier, CMP et al, I would have expected the buyers to have paid slightly more and the Chain be marked CMP etc. If its just 'any old (or new) chain' (and they all come from China now) there could be many rode lengths on yachts from the same or similar batches. The problem with much Chinese manufacture is that chains are unusual if they hold a manufacturers mark, they are often not even marked with the grade G3 or G4 - so though there are hundreds of chain makers in China - the chains all look and are marked the same.
Gael Force will know the source, it will be on their documentation, its a pity they have not made mention, maybe they have, as other chandlers in the UK might have chain from the same source.
Its an expensive flaw and could be more expensive than just replacing chain.
I have no idea how quickly chain is sold but I'd extend the doubtfull period from at least August through October. Personally if I'd bought chain from June/July through to November/December 2022 I'd be looking at every link and I'd draw my concerns to the attention of the chandler I had bought from and ask them to confirm it was not the same Chinese manufacturer that supplied Gale Force. Its not an onerous task for 'my' chandler - one phone call.
Jonathan
My guess is the crack was always there, from new. The tension a leisure yacht can place on a chain is insignificant well below WLL. It is unlikely that this issue is limited to Gael Force. If GF have bough this chain there will be multiple deliveries across Europe. No-one would ship one drum from China - its simply uneconomic.
Chains are commonly Proof Tested, that's twice WLL, as an integral part of the process. I would have expected that the fault would have been identified then. This implies that the chain was not Proof Tested, and/or the Proof Test was inadequate. The fact this chain was deemed to meet specification by the manufacturer could suggest other chain, from other batches, might also have slipped through the net. Batches could be 3,000m. Chain is usually chopped up into lengths that fill a 45gal drum.
If this was a branded chain from a 'reputable' supplier, CMP et al, I would have expected the buyers to have paid slightly more and the Chain be marked CMP etc. If its just 'any old (or new) chain' (and they all come from China now) there could be many rode lengths on yachts from the same or similar batches. The problem with much Chinese manufacture is that chains are unusual if they hold a manufacturers mark, they are often not even marked with the grade G3 or G4 - so though there are hundreds of chain makers in China - the chains all look and are marked the same.
Gael Force will know the source, it will be on their documentation, its a pity they have not made mention, maybe they have, as other chandlers in the UK might have chain from the same source.
Its an expensive flaw and could be more expensive than just replacing chain.
I have no idea how quickly chain is sold but I'd extend the doubtfull period from at least August through October. Personally if I'd bought chain from June/July through to November/December 2022 I'd be looking at every link and I'd draw my concerns to the attention of the chandler I had bought from and ask them to confirm it was not the same Chinese manufacturer that supplied Gale Force. Its not an onerous task for 'my' chandler - one phone call.
Jonathan
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Findhorn
Member
Interesting that there is no sign of corrosion at the weld indicating that the failure is very recent or that it was there when the chain was galvanised..hmm
Minerva
Well-known member
that was my chain and my post on Sailing Cruising Scotland.
I usually anchor in Mud (as attested to by the state of the anchor locker, really should have washed that before I took the photo
). On Sun/Mon we anchored in Sand at Eigg. Upon retrieval found a number of broken links - some where the links had come a good 3mm adrift.
I recon on retrieving the 35m I had out I counted in excess of 5 links like those shown.
The chain has had an easy life - one seasons’ worth of anchoring of anround 40 nights and the most wind we saw last season was 30kts in a sheltered Anchorage in Loch Hourn.
Purchased as ISO & DIN certified chain so I expected acceptable standards.
Gaelforce have been exemplary with their dealing of this and showed great concern and gratitude when I highlighted the issue and sent through photos. 5* to them!
I usually anchor in Mud (as attested to by the state of the anchor locker, really should have washed that before I took the photo
). On Sun/Mon we anchored in Sand at Eigg. Upon retrieval found a number of broken links - some where the links had come a good 3mm adrift. I recon on retrieving the 35m I had out I counted in excess of 5 links like those shown.
The chain has had an easy life - one seasons’ worth of anchoring of anround 40 nights and the most wind we saw last season was 30kts in a sheltered Anchorage in Loch Hourn.
Purchased as ISO & DIN certified chain so I expected acceptable standards.
Gaelforce have been exemplary with their dealing of this and showed great concern and gratitude when I highlighted the issue and sent through photos. 5* to them!
RunAgroundHard
Well-known member
This is interesting because I have noticed a few times now, a smell of H2S (hydrogen sulphide, rotten egg gas) when I recovered my anchor chain. The TreadMaster on my deck, which is dirty, has been bleached clean from the mud after my last suspected H2S even which was quite noticeable. Plain steel will become black in H2S, but not galvanised steel.
Hydrogen sulphide causes embrittlement of steel and especially in welds that have not been heat treated, where the hardness is greater than 22 Rockwell C, or 237 Brinell Hardness. Hence if the QA of the chain failed and welds were not post weld heat treated, the hard steel could be susceptible to sulphide stress cracking.
H2S is commonly produced in shallower muds due to rotting organic matter and warmer conditions, compared to deeper water. Many of us will not recognise it because it washes away from the mud as chain is hauled in, or is in very low concentrations and dissipates. I have significant experience of H2S in oil and gas operations and have witnessed equipment destroyed rapidly when exposed to H2S. Maintaining steel hardness below the specified results is a key factor in preventing embrittlement.
Anyway, just a guess.
Supertramp
Well-known member
Thanks for sharing.
I am no expert but it does look like a straightforward manufacturing defect. Hope the same chain is not supplied for lifting work.....
I considered replacing my 20yr+ chain this season and decided not to (cost priorities). Your story is making me hesitate even more. Is it better to stick with old, rusty in places chain that is time and load proved than replace with an unknown? I suspect the answer will be to buy a higher grade or quality of chain at considerably more cost than for "standard".
NormanS
Well-known member
That is really interesting. Many years ago, I had a newly laid mooring fail where "high spec" chain was used. Maybe, in spite of all the encouragement coming from certain quarters to use smaller sized, higher grade anchor chain, ordinary bog standard G30 mild steel chain of a suitable size is actually better.
Ref the blackening of chain: we mostly anchor in mud, often of the smelly variety, and the (galvanized) chain goes black. When I left my chain to be regalvanized, a couple of years ago, they looked at it and thought that it had been painted black
, and proceeded to grit blast it, before galvanizing it. I objected to the extra charge, which was subsequently waived. (Thanks Geoff).
vyv_cox
Well-known member
237 Brinell is not possible in a steel with carbon content of less than 0.22, which applies to all grades below grade 70. Sulphide stress corrosion cracking is most unlikely but has a branched appearance completely different from what is seen here. There seems little doubt that the welds have not been made correctly due to poor voltage control.
Humblebee
Well-known member
Interesting and somewhat worrying. Thanks for sharing Minerva, and for the helpful comments from Jonathan, Vyv and others.
I'll be inspecting my chain link by link before anchoring again!
PS a second endorsement for Gael Force, great folk to deal with.
Chris
I'll be inspecting my chain link by link before anchoring again!
PS a second endorsement for Gael Force, great folk to deal with.
Chris
Neeves
Well-known member
Ref the blackening of chain: we mostly anchor in mud, often of the smelly variety, and the (galvanized) chain goes black. When I left my chain to be regalvanized, a couple of years ago, they looked at it and thought that it had been painted black
We have had a similar experience in mud. The chain went black overnight or rather the galvanising went black. With use later in sand the chain was polished and looked like 'black' stainless - all shiny but black. A short exposure, overnight, is not a real issue - long term its a problem.
Its apparently a common problem in acid, smelly, mud - as found in slow moving rivers and old harbour locations with no through flow. Its also a problem in sewage works - where they might not bother with galvanised chain at all and simply use 'black' chain as the black paint (which wears due to abrasion) and the galvanising (which wears due to sitting in acidic water) have much the same short lifespan.
With a more careful look at the picture I can see the joint has been welded, I can see the slight thickening on either side of the joint - but there looks little penetration and the edges of the link are clean, sharp edges on both sides of the joint. I'd have exp[ected to see some gal on one edge - I can see nothing 'inside' the joint - though I'd not be categorical without having the link itself.
Part of the problem is self inflicted - we expect the chandler to sell product of merchantable quality and he relies on a certificate from the manufacturer. Nobody checks the chain except the manufacturer (who is meant to check the chain and issue a test certificate). None of us ask to see a certificate (which would have the suppliers name on it). Because most local chain makers have given up on making anchor chain we are left with little choice. Vyv has mentioned a UK chain maker who now imports from China (Babbage??) - they might test their chain. CMP has a reputation to protect and they should test their chain (also made at their own factory in China), sold under their Titan brand (same people who market the Rocna anchor). There is a chain maker in France...Chaineries Limoges or something similar - they may still make anchor chain. Some in Italy, sold by Jimmy Green - again it may be made in Italy - or not.
I hate to make mention but buying European lifting chain, which will have been Proof tested continuously, and then having it galvanised is the only foolproof but desperately laborious way to have a degree of certainty. I don't recommend the idea - just mention in passing.
We have to hope most Chinese chain makers are honest.
Jonatha
Looking at chain in a chandler - it will all look good - the gal will hide anything.
Neeves
Well-known member
This is what chain looks like after a few years normal use on a roving live aboard yacht and then 9 months in the Paraiba River acidic mud.
The chain is 6mm G100 and then Armorgalv coated, aka Thermal Diffusion Galvanising (TDG). This was a chain I had had processed for the owner in Australia. The original galvanised coating was 100 microns, thick - a good HDG coating might be 70 microns and the US Marine's spec for TDG is 80 microns. Neither the chain nor the galvanised coating can withstand 9 months immersion in an acid environment. Hot Dipped Galvanising, HDG, would be no better, well it might be better, who knows, but it would not be sufficiently better.
A recommendation for a similar environment might be Dyneema and constant attention to any metal components.
I have actually heard, but never really believed it, that anchoring in or at the mouth of Thai rivers, low oxygen, high nutrient contents, for a short time will remove the galvanising.
There are apparently anaerobic marine organisms that can survive without oxygen in high nutrient content salt water that excrete sulphur containing compound that convert to sulphuric acid.
Jonathan
The chain is 6mm G100 and then Armorgalv coated, aka Thermal Diffusion Galvanising (TDG). This was a chain I had had processed for the owner in Australia. The original galvanised coating was 100 microns, thick - a good HDG coating might be 70 microns and the US Marine's spec for TDG is 80 microns. Neither the chain nor the galvanised coating can withstand 9 months immersion in an acid environment. Hot Dipped Galvanising, HDG, would be no better, well it might be better, who knows, but it would not be sufficiently better.
A recommendation for a similar environment might be Dyneema and constant attention to any metal components.
I have actually heard, but never really believed it, that anchoring in or at the mouth of Thai rivers, low oxygen, high nutrient contents, for a short time will remove the galvanising.
There are apparently anaerobic marine organisms that can survive without oxygen in high nutrient content salt water that excrete sulphur containing compound that convert to sulphuric acid.
Jonathan
rotrax
Well-known member
As an experienced welder, albeit of old fashioned methods by todays equipment, that was my though exactly. No penetration visible at the join.
vyv_cox
Well-known member
William Hackett and Bainbridge import chain into UK from China, they both batch test but I do not know the frequency. They sell.to chandlers in drums, each of which has a certificate that can be seen by customers.
A company in Southampton import chain, batch test and mostly sell on to boat builders. Unfortunately I no longer have their name, although I have had quite a lot of correspondence with their owner
(Edit: they are named Rigmasters)
My little twisting quality test, often referred to by Neeves, would have found this problem. One of the chains I bought for the YM test looked not unlike this one. It failed the tensile test, the only one that did, and it failed my twist test. Chain
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Neeves
Well-known member
The NACM, NACM Welded Steel Chain Specifications, Welded Chain Grades seems to describe the accepted method for chain testing - it is hardly onerous. A few links from a batch and a batch can be huge.
If you look at Vyv's list there appear to be a few importers who are known to conduct their own batch testing - which is a start. So define from whom the chandler obtains their chain. We don't know how much of a batch is tested. However if you simply took a link and tested that link using Vyv's twisted link test and on finding integrity bought from that drum you are being as careful as possible.
You can conduct Vyv's test in the chandler's car park - you just need a decent vice to allow you to hold the link when you cut the link with an angle grinder. You can use the same vice to retain the link when you bend it, use a big adjustable spanner. The weld should always be stronger than the link.
Any and all chandlers should not object to your activity - and it would be in their interest to encourage the test - better than selling duff chain.
It would help us all if those that choose to conduct the test report here.
Jonathan
If you look at Vyv's list there appear to be a few importers who are known to conduct their own batch testing - which is a start. So define from whom the chandler obtains their chain. We don't know how much of a batch is tested. However if you simply took a link and tested that link using Vyv's twisted link test and on finding integrity bought from that drum you are being as careful as possible.
You can conduct Vyv's test in the chandler's car park - you just need a decent vice to allow you to hold the link when you cut the link with an angle grinder. You can use the same vice to retain the link when you bend it, use a big adjustable spanner. The weld should always be stronger than the link.
Any and all chandlers should not object to your activity - and it would be in their interest to encourage the test - better than selling duff chain.
It would help us all if those that choose to conduct the test report here.
Jonathan
NormanS
Well-known member
I'm not sure how many chandler's car parks have decent vices.
