Use of G40 chain

[Neeves]

Maggi, who seem to be one of the few anchor chain makers left in Europe make G40 and G70 chain. Chinese chain appears to be made as a G30 chain. In America you can buy, in imperial sizes, G30, G43 and G70.

Reports of chain failure over the last few years are non-existent. I do recall one failure, it was a poor weld - but its really the only failure I have heard of - with a decent and reliable description.

There are stories of chain breaking and stretching from years ago, ill-defined when, but the reports seldom have any detail - and might be of chain 30 years old.

In America there is a trend toward G43. If you buy Maggi chain it would commonly be their G40. I wonder why - as there are no reports of G30 failure. Vyv's testing of G30 chain from China show it to be actually made to near a G40 strength (some is over G40 strength).

The fact there are no failures suggest that the sizing spreadsheets, assuming they are based on G30 chain, are about right and that the safety factor (whatever it is) is more than adequate. I'm assuming that some yachts might use undersized chain - but even they do not report of any failure.


So how many buy G40 chain - and why.

Or are there more chain failure/stretching than I recall.

Jonathan

 

[geem]

Maggi, who seem to be one of the few anchor chain makers left in Europe make G40 and G70 chain. Chinese chain appears to be made as a G30 chain. In America you can buy, in imperial sizes, G30, G43 and G70.

Reports of chain failure over the last few years are non-existent. I do recall one failure, it was a poor weld - but its really the only failure I have heard of - with a decent and reliable description.

There are stories of chain breaking and stretching from years ago, ill-defined when, but the reports seldom have any detail - and might be of chain 30 years old.

In America there is a trend toward G43. If you buy Maggi chain it would commonly be their G40. I wonder why - as there are no reports of G30 failure. Vyv's testing of G30 chain from China show it to be actually made to near a G40 strength (some is over G40 strength).

The fact there are no failures suggest that the sizing spreadsheets, assuming they are based on G30 chain, are about right and that the safety factor (whatever it is) is more than adequate. I'm assuming that some yachts might use undersized chain - but even they do not report of any failure.


So how many buy G40 chain - and why.

Or are there more chain failure/stretching than I recall.

Jonathan

We have G32/40 chain manufactured by Chaineries Limousines in France. The manufacturer seems to recently have gone through a change of certification of their chain as the chain was quoted as G32 when we started our enquiries and it was G40 by the time we purchased it. The G32 version of the spec said it exceeded G32 spec by 25% which actually equalled G40 spec. The chain is described as having a unique process for galvanising that gives it a thicker coating than normal. The chain was purchased in Martinique earlier this year. We will see how long the galvanising lasts. The links are stamped every five with the manufacturers mark. May be worth investigating their webiste

 

[JumbleDuck]

When I needed new chain I just went to my friendly local chandlers and said "Can you get me 30m of 8mm chain?" "Yes", said Jane "it will be here in a week" and that was that. I have no idea what grade it is and I don't really care, because I agree with the OP that there seems to be no significant issue with anchor chains breaking.

 

[iTom]

I am just short of buying exactly the same chain in Martinique. I am highly interested in your experience after some time and use.

 

[Neeves]

Chaineries Limousines were bought by Pewag 10 years ago. Pewag is one of the top chain makers in Europe, another is Rud. They have an enviable reputation in the lifting industry (for both quality and innovation). 10 years is enough time for Pewag to have their OC systems etc imposed on Chaineries and I'd have no hesitation in buying their product in terms of 'chain' quality. The only area that I might look at carefully is galvanising (as Pewag would not normally sell galvanised chain - lifting chain commonly does not need it) - and I would wait for Geem to comment and if possible I would conduct Vyv's bent link test for gal integrity, see his website (cut link at centre of one long edge, twist to form an 'S' observe if the gal flakes - post comments and see how Vyv reacts. As indication - Maggi's chain flaked badly and had a poor gal life (both G40 and G70).

I would not be beguiled by the G40 quality - I think it unnecessary (many might disagree) unless you are torn between whether you need G30 8mm or 10mm - then I'd say buy G40 x 8mm. Chain life is determined by the quality of the gal. Reports or threads on regalvanising are common place - find me anyone who has retired the chain because of doubts over chain integrity.

Geoff might contribute - and will add a more professional comment to mine - but - gal life is determined by the thickness of the coating - more gal longer life. But there is a limit to the thickness beyond which the actually coating integrity suffers (and it flakes or peels, it can also flake because the chain/steel was not 'cleaned' properly) - but Vyv's test should be indicative. If they are claiming thicker coating - I'd be asking for some indication of this excellence (like how thick is the coating and have they done any abrasion tests- otherwise its all fluff).

I suspect in Martinique you don't have much choice for metric chain

Jonathan

 

[BobnLesley]

We bought 70m of 10mm/DIN766 Maggi G40 chain in the USA (Ft Lauderdale) in July 2015.
Full time livaboards, so it's probably been deployed 300+ days a year ever since and we've been very pleased with it; whilst it's probably 'good for another year' we're about to get it re-galvanised whilst we're in NZ, but there's no noticeable wear on any of the links - I was checking it all just two days ago.

 

[skipmac]

When I needed new chain I spent hours and hours researching the different grades and sizes. It turned out to be a lot more complicated that it initially seemed. Since I am over here I'll use US units.

First if you have a windlass you must get the right size for the gypsy. Not all 3/8" chain is created equal. That measurement is of course the diameter of the metal that makes each link. However, the critical spec for fitting a gypsy is the number of links per foot. 3/8" BBB (a G30 grade) has almost the same number of links/ft as 5/16" G40 (also called HT and G43 but all the same specs) and I can use either in my windlass. But I cannot use 3/8 HT in my windlass as the links are longer that 3/8" BBB so jumps the pockets. When in doubt get a 1-2' sample and see how it fits the windlass.

Since I could use 3/8" BBB or 5/16" HT G43 I compared the two. The 5/16" HT is lighter, higher load rated AND cheaper so was a no brainer until I found a deal on like new used chain that was 3/8 BBB so ended up with that.

 

[Neeves]

As Skipmac implies Imperial chain is a night mare. Historically Americans used what they call BBB, which was a G30 chain (strength) and had its own sizing. More recently they use a simple G30 classification (but its a different size (same strength as BBB). G43 is an (old?) transport chain and is a different size again. US galvanised G70 is also a transport chain, but can be slight different size (again) to G43 but is not a G70 quality (more like a G55 quality). Except for Maggi G70 which in imperial sizes is a true, or near a true, G70 strength and made to the same size as American galvanised G70 (they make metric sizes also to a true G70 strength). American G43, as is implied, is slightly stronger specification than metric G40 but G43 appears to have become the default quality supplied on new yachts (I'm not sure why - maybe G43 steel wire, from the which the chain is made is cheaper, plenty of production - or Americans are twitchy about chain integrity - don't know.)

There are there fore gypsies (chain wheels) made by most manufacturers of windlass that accept each of these different grades in the various sizes, 1/4"; 5/16th" etc. Some chain wheels will accept chain for which they are not designed, this is fortuitous.

None of this matters to anyone using metric chain as the links size for 6mm (8mm, 10mm etc) is the same whether its G30 through to G120. Except there are 2 sizes of link for 10mm, ISO and DIN. Also some (or all) G120 chain is made with a funny wire size, slightly bigger or square - though totally irrelevant for anyone looking at anchor chain.

Just be very grateful for sensible European standards!

If you have imperial chain the answer is - take, buy, borrow 300mm of chain and try it on your gypsy. For metric chain if it says 8mm it will accept any 8mm chain (G30, G40, G70 or Duplex G60) - just watch for 10mm - your gypsy will be marked DIN or ISO.

Chain wheels are expensive - so be very careful.

If you buy an American yacht second hand - in America - it will probably have imperial chain which you might find difficult to replace if you come back to Europe.

Chain failure used to be, more, common, but the history of the chain was never defined - so it could be people were using chain that was 25 years old.

Chain today is continually tested during to production to Proof Strengths, 2 x WLL (except for chain made to a 1:3 safety factor and then Prop Load is 1.5 x WLL), and will not stretch, yield below this level. American chain is, again, different and use safety factors of 4:1 (as all metric chain is defined) but also 3:1 and Maggi selll their G70 at a 5:1 safety factor. Selling with a 3:1 safety factor 'arithmetically' makes the chain, or the WLL, better - but its a fudge. G43 looks really good, because its WLL is so high compared to our metric G40 or their G30 - but the Minimum Tensile Strength better reflects quality.

In Oz and NZ we, bizarrely, call our G30 chain Grade L

American do mark their chain, I think all American chain makers have agreed to this and it is commonly marked with the Grade and manufacturers 'name', 'C' for Campbell, - hence C4 or C7. CMP also mark their chain, the chain I have seen, very clearly. Many Chinese manufacturers did not mark their chain - it then become, another, lottery.


I find it increasingly odd that the life of chain is governed by the galvanising quality but there is no 'advertised', specification to which companies coat their chain - its a lottery - the buyer has no idea - hence the value of Vyv's simple test.

Galvanising is harder than the underlying steel. If the gal has gone the underlying steel will wear more quickly. Tensile strength, those 'G' numbers reflect, roughly, hardness (and the harder the steel, gal, the slower is abrades - so G30 will wear more quickly than G43 (or G40). If you 'catch' the chain just as the links 'start' to show corrosion - you should be well and good.

Mud is, sorry - can be, anaerobic but the organisms living in the mud exude sulphur compounds which convert to sulphuric acids (that bad egg smell) which will strip your chain of gal quite quickly - wash your chain copiously - the gal determines life and chemical wear is quicker than abrasion. Chain also suffers from 'white rust' (Mr Google will explain) - I know it sounds daft - keep you chain dry and wash with fresh water - when you can. The white rust is your gal being eaten away. If its raining (and you are at anchor), open the chain locker hatch, let the rain rinse the chain and the open hatch will air the contents.

Jonathan

Apologies if I rambled, again!

Know how: Ground Tackle

 

[Zing]

We have G32/40 chain manufactured by Chaineries Limousines in France. The manufacturer seems to recently have gone through a change of certification of their chain as the chain was quoted as G32 when we started our enquiries and it was G40 by the time we purchased it. The G32 version of the spec said it exceeded G32 spec by 25% which actually equalled G40 spec. The chain is described as having a unique process for galvanising that gives it a thicker coating than normal. The chain was purchased in Martinique earlier this year. We will see how long the galvanising lasts. The links are stamped every five with the manufacturers mark. May be worth investigating their webiste

Which supplier did you buy from? I will need some of this soon.

 

[dunedin]

When I needed new chain I just went to my friendly local chandlers and said "Can you get me 30m of 8mm chain?" "Yes", said Jane "it will be here in a week" and that was that. I have no idea what grade it is and I don't really care, because I agree with the OP that there seems to be no significant issue with anchor chains breaking.

But I think the point is that nowadays many on here would recommend getting 50m of 6mm G40 chain instead - as reportedly same strength for much less weight.

 

[Neeves]

But I think the point is that nowadays many on here would recommend getting 50m of 6mm G40 chain instead - as reportedly same strength for much less weight.
[/QUOTE]

Except they don't - they buy the same size (and weight) of chain - because they don't want to buy a new gypsy by going smaller. So they increase the safety margin (no bad thing) though given the reliability of G30, unnecessary. Obviously if G40 costs the same, nothing wrong at all, but it does seem a waste of money if you pay more for the G40. If you are buying a new windlass and a new chain, or a new yacht, then you have the option to downsize with no additional cost (in fact the new windlass with the smaller gypsy might be cheaper). But you really need to look to G70 before you can 'safely' swap from G30, say 8mm to 6mm, and enjoy the same strength and gain the weight and volume savings. You also need to rethink your snubber/bridle as you have sacrificed some catenary. You need to be careful of your connectors (shackles) as finding a shackle that fits 6mm chain and is of an acceptable strength is not easy - in fact I see many G40 chains with totally inadequate shackles - which defies any logic at all.

To me the marketing of G40 and G7- chain is contradictory - the chandler will sell you the chain - but seldom has shackles to match. So the customer buys an understrength shackle - making it (the £10 shackle) the weak link in a £1,000 rode.

Having used 'G70' for 3 years now I would recommend the switch (for weight sensitive yachts) - but there are caveats.

Jonathan

 

[jdc]

When I needed new chain I just went to my friendly local chandlers and said "Can you get me 30m of 8mm chain?" "Yes", said Jane "it will be here in a week" and that was that. I have no idea what grade it is and I don't really care, because I agree with the OP that there seems to be no significant issue with anchor chains breaking.

I have some sympathy with this. Certainly I have never been worried by strength but I have had some dreadfully poor quality galvanising, one chain lasted about 2 years of relatively light use whereas my more recent chain's galvanising lasted >5 with very heavy use. So I feel that quality of galvanising should be specified, and it is worth ensuring you get good quality (but not, as I said earlier, for strength reasons).

 

[Neeves]

jdc and a post from Roger (Shaw) raises an interesting point:

Without exception people who have their chain regalvanised all comment that the second galvanising results in a better coating than the original. No-one has explained why, whether when you have it regalvanised the galvaniser takes more care, or a second galvanising (somehow) results in a better coating.

Whatever

You can buy 'raw' (ie uncoated) metric G30 chain. Instead of buying 'special' galvanised anchor chain from the chandler, which is no different to the G30 uncoated chain you can buy (except it has no coating) and have it galvanised - maybe your galvanised coating would last longer......or not. Roger seems happy buying 'odd' lengths of chain, welding them together (or welding links to join them together) and having the whole galvanised.

Its obviously a bit of a faff - and might not make economic sense (except Roger seems happy). There is also the doubt as to the quality of uncoated G30 chain - does the market for which it is intended worry about strength?

And maybe Geoff might be supportive

Just a thought.

And you can obviously do the same with G40 chain.

Jonathan