Long or Short Link 10mm Chain

[Frayed Knot]

As part of the ongoing refurbishment of my sailing cruiser I shall be replacing both windlass and chain this year (large ball of rust, anybody?)
As this presents me with a blank canvas I’m wondering whether, other than a very slight weight difference, there are any pros/cons regarding 10x28 vs. 10x30, particularly with how they stow in the locker.
I do experience problems with the current chain sometimes piling up and jamming but that may be due to the rusty surfaces.

 

[Praxinoscope]

Never had a windlass on any of my boats, but surely windlass chain needs to be calibrated to work? In which case surely you are stuck with short link?

 

[RichardS]

Never had a windlass on any of my boats, but surely windlass chain needs to be calibrated to work? In which case surely you are stuck with short link?

But since he's replacing his windlass he could start again with either short or long link. I doubt whether 2mm will make any difference in how it stows but that doesn't help much.

I have a feeling that the one I have is slightly harder to find in Croatia than the other but I can't remember which I actually have. Short link I think.

Richard

 

[vyv_cox]

Slight nomenclature problem in the post. You are asking about the difference between DIN 766 and ISO 4565. Full details on the website. I have never heard of any performance difference between them. For 8 and 12 mm chain the dimensions are the same but not for 10 mm.

Long link chain is what it says. The links are considerably longer, e.g about two inches for 8 mm chain. This is not anchor chain.

 

[Norman_E]

It may depend where you are and what local stockists have. My old chain was on an ISO gypsy but was probably American 3/8 inch chain as it always ran badly. ISO chain would fit on the well worn gypsy, but was considerably more expensive to buy in Turkey, and when I went to get some none of the stockists in Marmaris had a long enough length in stock. All were selling Chinese DIN766 chain of varying quality, some of it as good as any I have seen, but some with rough galvanising (which I avoided). I ended up buying DIN766 chain and having a new gypsy made locally which cost no more in total than 60 metres of ISI chain would have cost, had it been available.

 

[Neeves]

You have a blank sheet of paper - use it

Do you actually need 10mm chain, or was the previous owner a catenary fanatic and bought oversized chain in the first place. If your yacht is 'in between' 8mm and 10mm I'd be inclined to seriously consider 8mm G40 and start to use a decent snubber.

Don't be 'sold' into G43 because its 'stronger' - its an imperial link size, not an issue - you can get a gypsy to suit - but the 'extra' strength is because it has a different safety factor and most of the strength improvement is arithmetic.

If 8mm G40 or 8mm G70 would do the job, think about it.

If you can use smaller chain you will have more room in the locker and towering will thus be less frequent.-

Can you afford Duplex chain, you could downsize to 8mm (if 10mm is the correct size) and stainless will better 'flow'.

Most new windlass can be option with 'almost' any gypsy you like, so you can buy a windlass and the gypsy could be 8mm, 10mm or 12mm (or any of the imperial equivalent) and for 10mm could be either ISO or DIN. I don't know which chain specification (ISO or DIN is the more popular - buy the popular one its going to be marginally easier to source). Imperial will be more difficult to source in Europe and metric more difficult in America (and it markets).

I, like Vyv, have never heard of a performance difference between ISO and Din - they should be made from the same steel, using the same weld and galvanised the same way - so the difference in link length seems unlikely to impact any characteristic - except its fit on the gypsy.

I'd tend to buy the windlass and the chain from the same chandler and then if someone makes a real cockup - you only have one person to blame! (yourself or the chandler).

10mm chain is very heavy, as you will find when you remove it from the locker - consider where you want the new chain delivered and how you are going to move it. If the old windlass is a pile of rust - it may need to be cut out of the locker - think angle grinder.

 

[Frayed Knot]

Many thanks for the advice/opinions. As it seems there’s little or no difference in performance I’ll probably just look for the best deal available.

 

[Graham376]

Many thanks for the advice/opinions. As it seems there’s little or no difference in performance I’ll probably just look for the best deal available.

I've had both types on the same boat but obviously had to change the gypsy. No difference in performance whatsoever.

 

[TQA]

The 10 28 fits a Lofrans 3/8th windlass.

It was Italian chain I bought for my cruising boat. I had to replace it after 18 months. Went back to US made 3/8th BBB chain.

 

[maggie2]

had a few windlass in rhe past years and have never used long linck chain this is mostly use for decorative purpuses but go for the size and pitch the windlass maker says.maggie2

 

[RichardS]

had a few windlass in rhe past years and have never used long linck chain this is mostly use for decorative purpuses but go for the size and pitch the windlass maker says.maggie2

There are two versions of calibrated 10mm anchor chain, with only a 2mm difference in the link length. These are the "long" and "short" under discussion. Long link chain is, as you suggest, something completely different as described above.

Richard

 

[Boo2]

...Long link chain is what it says. The links are considerably longer, e.g about two inches for 8 mm chain. This is not anchor chain.

Can I ask whether long link chain is of a different strength than short link chain made from the same material ?

Boo2

 

[jdc]

Can I ask whether long link chain is of a different strength than short link chain made from the same material ?

Boo2

The figures are all a bit suspiciously rounded numbers, but Hackett chains say of their grade 3 chains:

10mm ISO short link MBL = 6 tonnes
10mm DIN short link MBL = 5 tonnes
9.5mm long link MBL = 4 tonnes

The reduction from 10 to 9.5 should reduce the strength from 5 to 4.5 tonnes (5 * 0.95^2) so it seems that long link is indeed weaker by construction. Why there is a difference between ISO and DIN I can't explain, and it may just be a specification or testing method difference rather than a real one. But Hackett use the same safety factor in all cases, so the same proportionate differences exist in their SWL specs (1.5 and 1.25 tonnes).

See https://www.williamhackett.co.uk/en...s/bulk_chain/grade_3_long_link_chain/p-107148 for example

 

[vyv_cox]

The only difference I am aware of between DIN766 and ISO 4565 is one of tolerance. Thus it may be that the allowable strength differs whereas the actual strength is exactly the same. So far as long link.is concerned, no idea, but strength of two times wire diameter cannot be a lt different regardless of its link length.

 

[Neeves]

My understanding (admittedly of American wire) is that the G30, or G40 refers to the strength of the wire rather than the chain, though obviously as the chain is made from the wire there is a relationship. The 'G' number is the minimum strength of the wire used. The minimum specification of the chain is then 'simply' an arithmetic calculation based on the wire diameter. This then dictates that the weld must be at least as strong as the chain, or wire, and is usually stronger (in fact chain that fails at the weld is commonly suspect (I've tested lots of chain and apart for some special tests where I inadvertently stressed the weld - the welds have never failed).

As specification is an arithmetic calculation based on an agreed min strength specification for the wire and its diameter then the specifications should be identical.

What has happened is that wire usage, or sourcing, has been advantageous for the customer over the last few years and both G30 and G40 chains have had strengths well above specification. This was noted by Vyv in his testing of chain some years ago (I'm sure its on his website) and reported in YM. I have found exactly the same and it does not matter if you buy chain from Peerless in America, someone in the UK, Maggi, CMP or many Chinese manufacturers - but G30 is near a G40 strength and G40 also much higher than specification. Conjecture is that the wire benefits, or benefitted, from a glut of wire for construction (which has a higher strength than would be needed for G30/40 chain) and the glut resulted in lower prices for the steel or wire.

This then raises an opportunity and I did hear of one supplier/manufacturer who thought to relabel their G30 as G40 - but this is anecdotal and might be the marine equivalent of waking up in Thailand minus a kidney!

But there is a 'danger' that if the 'glut' story is true than when the glut finishes something might change, chain gets more expensive and/or strengths fall to near specification (or worse).

I recall 10 years ago, maybe more, reports of chain failure were evident - though it was never entirely clear if this was operator abuse or poor chain (and I did hear of one owner (on this forum) who had a weld fail, 10-15 years ago). But in general I don't recall hearing of chain failure recently -but I stand to be corrected. Chain seems to be good quality, see later, and safety factors seem right (if not too stringent) and the spread sheets of chain strength vs vessel size look reliable - if not overly cautious.

The major rate determining factor for life of chain is the quality of galvanising - and that's a real can of worms.

And why the final comment - chain is sold 'galvanised' with no mention of quality (of the gal). There are specifications but they are never quoted nor is any mention made off the thickness of gal achieved. So chain appears strong enough but the life, which is dictated by the gal is a variable feast - that can of worms.

Life of gal is a function of how clean the steel was prior to galvanising and the thickness of the gal achieved.

In my opinion - we should 'monitor' strength to check its being kept upto, or exceeding spec - but we should concentrate on getting gal quality more consistent (and better) - though how we do that, more difficult.

I am fascinated by the oft heard comment that people who regalvanise think their 'recycled' chain galvanising is better than the original - this is a fairly consistent comment and if its true = what's special about sending it off for a second coating - that results in it being better. Or is it all psychological. Sadly we are prone to making bald and bold statements that on even cursory examination don't stand scrutiny - but in this case it does not matter too much - its just (not too much) money, not lives.

It would be nice if it were true and could be replicated to 'our' advantage - might chain subject to seawater and sand abrasion hold gal better?? etc etc

Jonathan

 

[vyv_cox]

Jonathan, I have not tested any G40 chain so am interested in your statement that its strength is greater than spec. My thinking was that G30 composition is virtually nothing but iron and a little carbon, whereas G40 composition has some minor alloying elements. This is close to the steel used for construction, RSJs, welded bridges, etc., of which there must be vast quantitiesavailable everywhere, whereas the G30 stuff could be expensive to source. However, I am not sure why nominally G40 would be any stronger as this would require the addition of carbon, chromium and nickel, which seems unlikely for the application.

 

[Neeves]

This is a link to G30 and G70 chain, where effectively the results on G30 reflect those found by Vyv.

https://www.practical-sailor.com/issues/37_42/features/Looking-into-High-Test-Myth_11416-1.html

I'm having a quick look where the G40 result are quoted.

Jonathan

This includes the first G40 I tested, supplied by Maggi. I tested a 1m length

Not spectacularly over strength but enough to be comfortable

https://www.practical-sailor.com/issues/37_51/features/Armorgalv-vs-Hot-Dipped_11637-1.html

I later bought 8mm x 300mm of G70 and G40 from Jimmy Green and disappointingly received 2 x 300mm of G40 one of which I tested for strength (UTS), 4,330kg and the other I used for abrasion testing. I have not written an article where this most recent test, 2 years ago now, would be relevant (I actually bought the samples to conduct abrasion testing when gal wear became a prominent issue). My guess was the 2 samples of G40 came from the same length.

My testing of G40 is hardly statistically sound, not much market here, if any.


I confess not to have tested for UTS any G30, or G40 recently and I don't know if there has been any significant changes - none of this testing is cheap. I have done a number of tests on galvanised G80 and G100 - but that is significant thread drift.


Apologies:

I thought I might add - in America the default anchor chain increasingly being supplied on new yachts and this determines the gypsy is G43. G43 is a different link size to historically more common G30 or BBB. Americans appear to be embracing G43, which is stronger than metric G40. This move to a stronger chain is 'unusual' as there are no current safety concerns with regard to G30 - G30 is considered adequate in Europe and Oz. Commonly the same sized chain is replacing the old standard. One major difference is that G43 is sold with a 3:1 safety factor but G30 (and metric chain) is sold to a 4:1 safety factor so WLL is arithmetically higher for G43 than G30 - making G43 look exceptional. There is nothing wrong with increasing the strength of a rode - but yacht owners are historically parsimonious and it seems an unusual trend. Interestingly last time I heard Lofrens were selling G40 chain, but not G30, and Maggi have never sold a G30.