Connecting anchor to chain?

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I have alway connected an anchor to a chain by passing the eye of the shackle through the anchor slot and the pin through the last chain link. What is the opinion of two shackles back to back i.e. one pin through the anchor eye and one pin through the the last chain link. I could use a swivel connerctor but they are an expensive complication and maybe less reliable than a simple shackle.
 
pvb said:
What's the benefit of the second shackle?
Click to expand...

First, it should be the bow through the anchor. This is why the hole is oblong.

The reason for 2 shackles is most often G43 or better chain; the shackle that fits the chain is sometimes too small to fit the anchor. Thus, there are two shackles of two different sizes. This is not needed for G30 chain.
 
Really no benefit, just to acomodate an anchor with a hole too small to take a shackle eye rather than a large slot which is more normal.
 
The best shackles, relatively easily available from Tecni in the UK, are Crosby's G209A. Their smallest size is a 3/8th" which will fit a 8mm chain. They do not make smaller shackles of this strength. The 3/8th" shackle has a WLL of 2t. The fall back are CMPs Black pin shackles that come in smaller sizes (and larger) but have a WLL of 1.6t or 1.8t (don't remember - but it is on their website under their Titan brand) for a 3.8th shackle - so not as strong as a Crosby shackle. I think CMP Black pin shackles are freely available in the UK - but I recommend the Crosby shackles for obvious reasons. Do not use the Titan Yellow Pin shackles, they are 50% weaker - they are not worth the savings.

The reason for having such a large WLL in comparison to that of the chain is that if the shackle locks up in the anchor shank and tension is applied at 90 degrees (on the shackle) the WLL is reduced by 50%, so that 2t WLL drops to 1t. I've tested this and can confirm that shackles loaded at 90 degrees do fail at half rated strength.

Crosby shackles are individually Proof Tested to 1,5 x WLL (and the requirement is that effectively they do not bend under a load of 1.5 x WLL - you still have much wriggle room!) I don't recall if CMP Titan Black pin shackles are individually Proof Tested, I doubt it - but check the website.

I would be quite happy using the appropriately sized Crosby shackle with G43, or G40, chain. The shackles have a 4.5:1 safety factor the chain (G43) is only 3:1 and G40 is a more conventional 4:1. Realise that the safety factor for G43 is for Transport Chain - its a mathematical fudge (as might they all be - we don't know the basis of the safety factors) - it looks great, but is not much different to G40 chain.

Don't use stainless shackles - they bend too easily.

There is nothing wrong with 2 shackles if they are correctly moused and if they are of the appropriate quality. Except - if you have the pin through the slot of the anchor the shackle will not articulate, the length of the shank is effectively increased and the longer lever arm may damage a weak shackle (and there are lots of them in stores and on yachts) or bend the shank end - especially if the shank is on an undersized anchor or if it is of nefarious origin.

I have never heard of a Crosby shackle failing. Shackles I know that failed were all of dubious and usually totally unknown origin. If the shackle is not embossed - do not buy it (unless you need it to chain up your dog).

What anchor are you using that will not take the, appropriate, shackle eye?

Jonathan

edit

coincidentally see post #6

http://www.cruisersforum.com/forums...hor-shackle-for-a-40-rocna-anchor-202003.html

close edit
 
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Neeves said:
The best shackles, relatively easily available from Tecni in the UK, are Crosby's G209A. Their smallest size is a 3/8th" which will fit a 8mm chain. They do not make smaller shackles of this strength. The 3/8th" shackle has a WLL of 2t. The fall back are CMPs Black pin shackles that come in smaller sizes (and larger) but have a WLL of 1.6t or 1.8t (don't remember - but it is on their website under their Titan brand) for a 3.8th shackle - so not as strong as a Crosby shackle. I think CMP Black pin shackles are freely available in the UK - but I recommend the Crosby shackles for obvious reasons. Do not use the Titan Yellow Pin shackles, they are 50% weaker - they are not worth the savings.

The reason for having such a large WLL in comparison to that of the chain is that if the shackle locks up in the anchor shank and tension is applied at 90 degrees (on the shackle) the WLL is reduced by 50%, so that 2t WLL drops to 1t. I've tested this and can confirm that shackles loaded at 90 degrees do fail at half rated strength.

Crosby shackles are individually Proof Tested to 1,5 x WLL (and the requirement is that effectively they do not bend under a load of 1.5 x WLL - you still have much wriggle room!) I don't recall if CMP Titan Black pin shackles are individually Proof Tested, I doubt it - but check the website.

I would be quite happy using the appropriately sized Crosby shackle with G43, or G40, chain. The shackles have a 4.5:1 safety factor the chain (G43) is only 3:1 and G40 is a more conventional 4:1. Realise that the safety factor for G43 is for Transport Chain - its a mathematical fudge (as might they all be - we don't know the basis of the safety factors) - it looks great, but is not much different to G40 chain.

Don't use stainless shackles - they bend too easily.

There is nothing wrong with 2 shackles if they are correctly moused and if they are of the appropriate quality. Except - if you have the pin through the slot of the anchor the shackle will not articulate, the length of the shank is effectively increased and the longer lever arm may damage a weak shackle (and there are lots of them in stores and on yachts) or bend the shank end - especially if the shank is on an undersized anchor or if it is of nefarious origin.

I have never heard of a Crosby shackle failing. Shackles I know that failed were all of dubious and usually totally unknown origin. If the shackle is not embossed - do not buy it (unless you need it to chain up your dog).

What anchor are you using that will not take the, appropriate, shackle eye?

Jonathan

edit

coincidentally see post #6

http://www.cruisersforum.com/forums...hor-shackle-for-a-40-rocna-anchor-202003.html

close edit[/QUO

Thanks for that info Neeves. The anchor is a 13Kg Knox. I can find G209 Crosby Shackles - is G209A different?
keith
Click to expand...
 
Dougal said:
I've been using single stainless shackles for almost 40 years. Never had one bend, nor even deform a thread. Even when anchored in hurricane conditions off northwestern Mexico.
Click to expand...

I have 8mm stainless shackles holding down the end of my bowsprit and due to the angle of the attachment there is an element of twisting the shackle and one has bent. The bowsprit is pretty agricultural and strong (100mm square stainless box section 3mm thick) with 2/3 on deck so I was not expecting it to lift much as calculated wind pressure loads should not exceed 300 lbs and the lift should be much less. The force involved here are far less than anchoring which is why I am interested in the Crosby Shackles with their possibly greater resistance to side forces. I have only been sailing UK for 20 years but have anchored a lot and like you have never had an anchor shackle bend even in marginal anchoring conditions.
Howver it is not consistent to get the best anchor you can afford and link it with a shackle of unknown provenance to save a few quid.
 
I must admit to not understanding the logic of introducing a lower spec stainless steel shackle between a galvanised chain and a galvanised anchor. Why? A single rated galvanised bow shackle does me between 10mm chain and. 15kg Rocna.
 
Its what people have lying around, that fits, when they come to attach anchor to chain. They buy a new anchor, usually bigger, the old shackle will not fit the new anchor - it the easy option. Not many people have spare rated gal shackles. And a surprising number of people think, beautiful looking and commonly more expensive stainless is stronger than grotty looking galvanised shackles.

As you mention not unusual to see stainless to connect anchor to rode and almost as common to see one small shackle and one larger shackle.

It is very common to see an overly large NG anchor with a big shackle, the big shackle is needed to fit the new anchor. The old chain, usually original, looks undernourished against the anchor and it is joined to the big shackle with a decidedly emaciated looking stainless shackle (it the only shackle to owner had whose pin would fit the chain. The owner buy the big anchor because - it stands to reason - it will give him more hold - which might be more than the hold the chain is rated for. Its all very contradictory.

Most stainless shackles will bend like spaghetti. You need to spend real money and search to get a decent stainlesss shackle

Jonathan
 
C08 said:
[I can find G209 Crosby Shackles - is G209A different?
keith
Click to expand...
209a is different metal, wll specs from memory show twice as strong as same sized 209 but factor of safety is 4.5:1 for 209a against 6:1 for 209. Either one you won't go far wrong with, Crosby are industry standard for rigging accessories
 
If the OP's Knox is like mine there is no slot, just a hole. In that case he will have to use two shackles, or possible a double-jointed swivel. I am testing one at the moment and it seems that arrangement is OK.
 
Buy the 209A. The difference in price is not significant.

All of the reputable shackle makers, say, without exception, that side loading shackles at 45 degrees will reduce WLL by 25% and side landing at 90 degree will reduce WLL by 50%. Shackles can lock up in the slot in the anchor - they can then be side loaded. I confess never to have heard of a Crosby G209A to have failed due to side loading but I have examples where lower specification shackles have failed (and the anchors lost). I have tested shackles, side loaded, and the reduction in strength is correct. I have tested Crosby shackles and they do meet their own specification - which is more than be said for some other suppliers. Shackles are meant to be used in a straight line pull and usually are in industry - as they can check, and check again. Unless you dive on your anchor every time you leave the angle of loading to chance. The anchor is worth stg400 or more, the yacht is worth 10s or 100s of thousands - the difference in price between a shackle from your local DIY shop, a 209 and the 209A is peanuts - buy the 209A - its not a difficult decision.

There must be other sources but I buy, based in Australia, my Crosby shackles (G209A) from Tecni in the UK. They are efficient and send cheapest possible air parcel.

And if anyone suggests, because I constantly suggest Tecni - that I have an interest - get real! (I simply do not know anyone else - and I'm a happy customer).

edit

As GHA says '209' from Crosby is an industry standard - so much so that if you look at 'Alibaba' or 'Made in China' you will find many Chinese shackle suppliers defining their shackles as '209'. Its become a bit like 'Hoover' - a generic name. Be careful if you see 209 shackles in your local DIY - they might not be Crosby. Crosby mark, emboss, their shackles with the word Crosby in clear letters + WLL and size (imperial). From memory Crosby shackles are 'painted' silver and come off their Platinum series of components. Most shackle makers paint the shackle pin 'their' colour, Crosby's for this range is silver, Campbell's are orange, Peerless are blue - but there are limited colours so there is a lot of overlap. Just specify G209A, Crosby and check the embossing. Campbell's part of Apex Tools, in America) is another supplier of recommended shackle - but I simply don't know a source. The last batch of Peerless shackles I tested did not meet specification - and I have not tested since.

close edit.

Jonathan
 
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Stainless shackles

I am interested in individual positive comments - but I've tested a number, I cannot endorse them. I have not tested Duplex shackles - they are simply too expensive to buy and test - if anyone wants to send me one - I'm happy to test it. I have also not tested Witchard's high tensile stainless shackles - similarly, no incentive.

If anyone can provide me quantitative, technical reasons why a stainless shackle is better than a Grade B, rated, Proof Tested, named, WLL defined, galvanised shackle - of the quality of a Crosby G209A or a Campbell Orange pin shackle (and cheap, relatively speaking) - I'll include them in my recommendations.

Interestingly few of the lifting companies offer stainless shackles, excepting very niche applications - I wonder why.

In the meantime I discourage use of stainless shackles in the anchor rode - I'm sure there are lots of examples of successful usage. The risks are too high - when there is a simple alternative.

Jonathan
 
Neeves said:
Buy the 209A. The difference in price is not significant.

All of the reputable shackle makers, say, without exception, that side loading shackles at 45 degrees will reduce WLL by 25% and side landing at 90 degree will reduce WLL by 50%. Shackles can lock up in the slot in the anchor - they can then be side loaded. I confess never to have heard of a Crosby G209A to have failed due to side loading but I have examples where lower specification shackles have failed (and the anchors lost). I have tested shackles, side loaded, and the reduction in strength is correct. I have tested Crosby shackles and they do meet their own specification - which is more than be said for some other suppliers. Shackles are meant to be used in a straight line pull and usually are in industry - as they can check, and check again. Unless you dive on your anchor every time you leave the angle of loading to chance. The anchor is worth stg400 or more, the yacht is worth 10s or 100s of thousands - the difference in price between a shackle from your local DIY shop, a 209 and the 209A is peanuts - buy the 209A - its not a difficult decision.
Click to expand...
All good advice.

It is almost never mentioned, but it is worthwhile testing the shackle and anchor shank combination with various directions of pull to see how easily it can jam or lock up with some sideways pull.

Some combinations can lock up quite firmly and with a change in direction of pull the shackle can create an unfair pull that will unbalance the anchor and increase the risk that it will break out or not reset. This is rare, but can affect the anchor’s performance significantly. I suspect it is the cause of some reports of atypical anchor behaviour.

Unfortunately, this is not something you can predict before buying the shackle. The shackle can otherwise fit quite well but still have a tendency to jam easily. Often a slightly different design from another manufacturer will solve the problem and not show the same tendency to lock in place.

It is something to check.
 
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vyv_cox said:
If the OP's Knox is like mine there is no slot, just a hole. In that case he will have to use two shackles, or possible a double-jointed swivel. I am testing one at the moment and it seems that arrangement is OK.
Click to expand...

Bizarre!

I had to double check. Ours has a slot, which will accept the eye pf the (appropriate) shackle. But the slot is too narrow and with the bow in the slot the appropriate shackle can lock up. A smaller one would not lock up but then you risk damaging the smaller shackle (because it will be weaker and this is a common issue). This will lead to potential damage to the shackle - if its not man enough. The shackle will bend before the shank - the shank (or mine) is bomb proof! Knox Anchor know my views - the slot needs to be wider.

In the interim Vyv's suggestion seems best (I'm not keen on the swivel - there are too many options - a few swivels are excellent, and cost, most are a failure waiting to happen). I'd use 2 shackles - both rated etc etc. The major fear of using the pin through a hole is that you increase the lever arm length of the shank - and it might bend. The Knox shank is the strongest around and this fear is unfounded in their case - I'd be more than happy to use the shackle pin through a hole and another to connect to the chain - but 2 rated shackles, both Crosby G209A or equivalent.

Vyv - can you define

'I am testing one at the moment and it seems that arrangement is OK' - which arrangement? the 2 shackles or the double jointed swivel - and if the latter which swivel.

Jonathan
 
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Neeves said:
Its what people have lying around, that fits, when they come to attach anchor to chain. They buy a new anchor, usually bigger, the old shackle will not fit the new anchor - it the easy option. Not many people have spare rated gal shackles. And a surprising number of people think, beautiful looking and commonly more expensive stainless is stronger than grotty looking galvanised shackles.


Jonathan
Click to expand...

That's exactly what I did. Got a new anchor and found a nice shiny stainless steel shackle in my bits box which fitted and am using that!
Thanks very much for your thoughts and advice. As I do a lot of anchoring I've just ordered a Crosby.
Mike
 
There are not enough rated shackles from different manufacturers to allow a consumer to test and chop and change. Moreover most chandlers, are there any? do not stock Crosby shackles and the only alternative, of shackles 'our size' would be Campbell Orange Pin shackles and I only know of them available in America.

Basically unless you live near a Crosby distributor, and I only know of Tecni - there must be others and also maybe stockists for Campbell - you cannot try before you buy.

I'd like to see anchor suppliers sell shackles that match their anchors. If people asked, demanded (even) we would not have this issue.

Its not rocket science to stock decent shackles nor know which clevis pin fits metric chain. Shackles are not that expensive - stock costs would not be high.

if you don't ask - it will not happen.

Every anchor needs a shackle - who best to ensure they fit - but the anchor maker.

Jonathan
 
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