Is it viable to extend an anchor chain

[vyv_cox]

Why would you want a hardened and tempered link in a chain that is not itself hardened and tempered? If I got one like that I would anneal it until I could work it.

On the assumption that this was a serious comment, I will explain. A C-link is inevitably weaker than a solid link by virtue of its construction. My testing of many mild steel ones, as sold in chandleries, suggests that for the same material a C-link has about half the strength of a chain link. Stainless steel ones are slightly stronger than carbon steel ones but still little better than 50% of chain strength. The logical answer is to make the C-link from a stronger metal, typically a hardened and tempered steel, which is exactly what Crosby and a couple of others have done. The result is a link that is somewhat stronger than good quality Grade 30 chain and even Grade 40 if made up well.

Some chandlery suppliers have been suggesting that C-links should be welded once assembled, to 'improve' their strength. The reality of course is that welding will anneal them, resulting in a strength reduction.

 

[vyv_cox]

Why on earth would I want to cut corners by having some bodged-up anchor cable when I can have the proper thing for such a small amount? The price of half a dozen dinners. It makes no sense to me at all.

The lifting and hoisting industry is, quite correctly, very conservative. C-links made by Crosby and others are approved for this industry, which undoubtedly makes them perfectly safe for use in anchoring, where the maximum loads to be expected are considerably less than the strength of either the chain or any links. Before I knew as much as I do now about C-links I had used chandlery-bought ones for many years without any problems. Crosby links are about twice as strong as these.

 

[lw395]

The lifting and hoisting industry is, quite correctly, very conservative. C-links made by Crosby and others are approved for this industry, ...

The Crosby website says otherwise.

 

[Pye_End]

A couple of photos of C links that I cut off after several years of service.

They were unbranded, but I think rather better than the ones I replaced them with at the time.

Whilst the outside was quite corroded, the inside still had plenty of fresh metal, and you have to look pretty carefully to see the line of the join.

 

[Neeves]

The Crosby website says otherwise.

It merits mention G30 and G40 chain is not approved in the lifting industry. Our anchor chains have the same safety factor as lifting chain 4:1, they have the same Proof Load test, 2 x WLL. They have the same UTC as a smaller, say G80. it is recommended when using lifting chain, or any chain, not to shock load - yet our anchor chain should not be used for lifting.

A major difference is yield point, much lower in our chain, which does indicate when you have overstressed you chain - but to stretch your chain and notice it - the loads are huge.

I suspect that you would stretch G30 or G40 before you will approach damaging a good brand name 'C' link - but this opinion is simply based on the characteristics of our chain and those of a Q&T steel similar to that of the 'C' link (which could easily be tested).

The biggest issue of a 'C' link is operator error in installation - which is, obviously, outside the control of the supplier.

Jonathan

 

[vyv_cox]

The Crosby website says otherwise.

C-links are listed under Crosby Lifting Products. The Expert Comment is: Simple chain repair is achieved by linking the two ends of the chain with the "Missing Link" and then peening the rivets over with a hammer.
Not Suitable for use with Grade 80 or Grade 100 chain and chain slings used in overhead lifting.

Maybe I am assuming something but the implication is that C-links are perfectly OK for lesser grades than 80.

 

[vyv_cox]

A couple of photos of C links that I cut off after several years of service.

They were unbranded, but I think rather better than the ones I replaced them with at the time.

Whilst the outside was quite corroded, the inside still had plenty of fresh metal, and you have to look pretty carefully to see the line of the join.

What size are these?

 

[Pye_End]

8mm

 

[Poignard]

If, as the 'Test Results' reproduced on the Cox Engineering website* appear to show, a 5/16" Crosby G-335 C-link has a 'Mean SWL Measured' of 1,040kg and 8mm chain has a 'Mean SWL Measured' of 1,230kg, doesn't this suggest that the Crosby link was 15% weaker than the chain it joined? Or am I misunderstanding what I read there?

*( https://coxengineering.sharepoint.com/Pages/Clinks.aspx )

 

[Neeves]

Chain measured strengths tend to be significantly, and reassuringly, higher than specification.

One reason NOT to use Crosby 'C' links with G80 and G100 chain is very simple - they are significantly weaker than the chain and would be the weak link - and thus should not be used for lifting with G80 or G100 chains (as they de-rate the chain). It seems pretty obvious when you look at the specs. 'C' links specification minimum strength is higher than the correctly sized G30 or G40 chain - as long as attached, installed, correctly.

Vyv quantified the strength of a number of chains from different sources and illustrated the 'over-specification' of G30 and G40 chain from UK sources. The same is true of American and Australian made chain. The thought is that there are huge volumes of the steel qualities being used for other industries, construction?, and we are simply benefitting from scale of production. Whether this situation continues - we don't know.

None of us know the strength of our chain, one reason being - no-one asks. Chain is commonly delivered to the importer and sometimes distributor with a test certificate for the batch. In the absence of knowing actual characteristics most reply on the specification of the chain, as one does with a 'C' link. The chain being better than specification is fortuitous.

One danger - that has already occurred - because G30 can be of G40 quality some suppliers are selling G30 as G40. The exceptional strengths, that we have unwittingly enjoyed, suddenly disappear - to allow a distributor/importer to sell to a higher specification.

Jonathan

 

[BelleSerene]

https://www.practical-sailor.com/issues/44_6/psadvisory/Reliable-Chain-Connections_12426-1.html

 

[RichardS]

https://www.practical-sailor.com/issues/44_6/psadvisory/Reliable-Chain-Connections_12426-1.html

Our friend Jonathan. I've never heard of some of those joining devices.

Richard

 

[GTom]

I was playing with the idea of adding 15'/5m heavier chain for the bottom part. My current chain is 8mm, probably could go with 12mm for the bottom section.

 

[atol]

i always cut open one side of a link with a hacksaw ,then put it in a vice and open up the now cut link with a large adjustable spanner, open opposite sides at 45 degrees to each other,,untill you have a gap big enough to put the first links of the 2 chains you are joining into,then close the open link with the spanner again,then fully weld with a welder(MIG if possible) ,wire brush then coat weld with galvanising spray.
super strong

 

[vyv_cox]

I was playing with the idea of adding 15'/5m heavier chain for the bottom part. My current chain is 8mm, probably could go with 12mm for the bottom section.

ACCO/Peerless and Crosby make an oval C-link for exactly this purpose. The Crosby one is the 334 Crosby® 335 Galvanized "Missing Link" Replacement Links - The Crosby Group I do not know a UK supplier of the Peerless C-links.

 

[RichardS]

I was playing with the idea of adding 15'/5m heavier chain for the bottom part. My current chain is 8mm, probably could go with 12mm for the bottom section.

I haven't read the old posts .... but does your chain not have to run over a windlass gypsy?

Richard

 

[GTom]

ACCO/Peerless and Crosby make an oval C-link for exactly this purpose. The Crosby one is the 334 Crosby® 335 Galvanized "Missing Link" Replacement Links - The Crosby Group I do not know a UK supplier of the Peerless C-links.

So far only found it in a book, called pear link: Mooring System Engineering for Offshore Structures

I haven't read the old posts .... but does your chain not have to run over a windlass gypsy?

It does indeed, I have yet to figure if there is an alternative. I usually pull the chain by hand but the gypsy does help if I take a few seconds break. While anchoring, the gypsy would only see the 8mm part as I never let out less than 5m.

 

[RJJ]

My current chain, from a British manufacturer Griff Ltd, cost me around £300 for a single length of 65 metres with enlarged links at each end. My boat is insured for £22,500. The chain cost less than 1.5% of the value of the boat; and that's just the monetary value. Why on earth would I want to cut corners by having some bodged-up anchor cable when I can have the proper thing for such a small amount? The price of half a dozen dinners. It makes no sense to me at all.

Because first of all if you add up all the hundreds of things that are "just" a fraction of the value of the boat, and take the most expensive approach to all of them adds up to a significant sum. If there's a cost saving alternative it's good to explore if it's workable.

Also because many of us don't like disposing of things that are well within serviceable life, even if they can be recycled.

Finally because even if it can be recycled, shifting your anchor chain around from boat to dock to car to recipient is a pain in the neck. And then doing same in reverse with the new. Sounds as though adding the C-link may be quicker on its own merits.

 

[vyv_cox]

So far only found it in a book, called pear link: Mooring System Engineering for Offshore Structures

Somewhat larger than you will be needing I think ACCO/Peerless are a USA company, although their equipment is made in Taiwan I think. They do not seem to be represented in UK.

 

[Neeves]

Our friend Jonathan. I've never heard of some of those joining devices.

Richard

I hope it has been useful, knowledge is better shared.

We have been using Omega links now for 3-4 years, with out issue, and have recently, 12 months, started using hammerlocks. There are many ways to skin a cat (or build a rode).

Jonathan