Connecting anchor to chain?

[noelex]

Before anyone gets excited - check the costs! Been there, done that

The Petersen shackles look excellent, as strong or perhaps even slightly stronger than the Crosby 209A. The flush pin would be a useful option for many alhough I prefer to mouse the shackle myself.

What is the cost? I cannot see it listed.

 

[vyv_cox]

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

As you know, we have our own reasons for using a swivel and in the many years since we first bought a Kong we have yet to find a reason not to use one. Following my poor experience with the Osculati cranked swivel I wanted to try something other than our Kong plus three chain links. In a chandlery in Piraeus I found a double-jointed swivel by Marine Town, rated at 850 kg, same as the Kong, although it uses interscrews rather than the clever Kong method. We have used it with the Knox on about a dozen occasions so far and not had any problems with this swivel design.

If time allows we may try the back to back shackles method but experience so far is that the Knox comes up back to front just as well as the Rocna does

 

[GHA]

The Petersen shackles look excellent, as strong or perhaps even slightly stronger than the Crosby 209A. The flush pin would be a useful option for many alhough I prefer to mouse the shackle myself.

What is the cost? I cannot see it listed.

Looks like Jimmy Green do them, not pennies but not too crazy when you just need one..

https://jimmygreen.com/stainless-st...127mm_pin/4329-shackle_type-d_with_socket_pin

 

[noelex]

Looks like Jimmy Green do them, not pennies but not too crazy when you just need one..

Thanks for the link, GHA.

So the 10mm (12.6mm pin) recessed screw, stainless steel Petersen shackle from Jimmy Green is £33.60.

The 11mm (12.6mm pin) galvanised Crosby 209A from Tecnilift is £14.56.

I don’t think this is an unreasonable cost difference if you want a stainless steel shackle, especially as the galvanised Crosby shackle is likely to need more frequent replacement. If anyone wants to buy one a bow shackle is often a better choice although surprisingly the Petersen shackle is slightly less strong in this configuration.

 

[GHA]

.....although surprisingly the Petersen shackle is slightly less strong in this configuration.

Back to the lower FOS for the 209A of 4.5:1 as opposed to 6:1 for the stainless (& 209) . Wonder why that is?

MBS looks similar calced from FOS & WLL.

Stay within the WLL shouldn't be a problem though.

Certainly prettier in stainless

 

[Neeves]

Thanks for the link, GHA.

So the 10mm (12.6mm pin) recessed screw, stainless steel Petersen shackle from Jimmy Green is £33.60.

The 11mm (12.6mm pin) galvanised Crosby 209A from Tecnilift is £14.56.

I don’t think this is an unreasonable cost difference if you want a stainless steel shackle, especially as the galvanised Crosby shackle is likely to need more frequent replacement. If anyone wants to buy one a bow shackle is often a better choice although surprisingly the Petersen shackle is slightly less strong in this configuration.

Duplex shackles are made to match G50 or G60, don't recall which (at those prices with galvanised chain they are simply a waste of money - offering no strength advantage). I would buy them if I was very, very rich and had a stainless anchor and Duplex chain.. Crosby's, 209A, shackle are made to match G80 - considerably stronger (which is why, as Noelex noticed, the galvanised shackle is stronger).

Safety Factor are meant to reflect usage and failure. But how they are calculated - no idea. It merits note that the safety factors are derived from the application in which they are used, primarily lifting. Use in lifting is very different to use in an anchor rode. Imperial G43 chain is sold to a 3:1 safety factor (its primary application i transport), metric chain to 4:1 safety factor - G43 WLL looks good against G40 - but their UTS is similar. From memory some Harken shackles are sold to a 2:1 safety factor - so they have excellent WLL - but questionable if used in the rode.

Just be cautious, read the small print - particularly check the warning about side loading. This latter is an unlikely event - but it happens (I have one side loaded failed shackle, not mine - I was given it, and know the new anchor was lost) and the extra cost of a G209A over a 209 is peanuts.

The key is a decent G209A costs peanuts the anchor costs stg400/500+, the rode stg1,000+ the yacht is worth Stg50,000 - at the extreme Stg500,000 - why would you save to buy something on which there is no specification, no manufacturers name or something that is admittedly pretty - but less strong.

Why?

Jonathan

 

[noelex]

which is why, as Noelex noticed, the galvanised shackle is stronger

I don’t think I did indicate that.

It is often suggested in this forum that stainless steel shackles are very weak, but if you buy a quality shackle (and I agree with the suggestion of using a quality shackle for attaching the anchor to the chain) it appears, looking at the figures, that they have very much the same strength, at least for practical purposes, if you match like with like.

 

[Neeves]

I'm obviously not concentrating!

Which Peteresen shackles, 'D' or bow of 10mm (equivalent to 3/8th") have a WLL of 2t (which is the specification for a 3/8th" Crosby G209A shackle)?

Jonathan

edit

My reading is the 10mm Bow has a WLL of 0.8t and at a 6:1 safety factor that gives a UTS of 4.8t. The 'D' has a 1t WLL and at 6:1 that gives a UTS of 6t (I assume its stronger because the clevis shank is shorter). The Crosby bow has a WLL of 2t and at a 4.5:1 safety factor has a MBS of 9t - to all practical purposes the Crosby one is stronger, by far and has a more modest safety factor.

Personally as these safety factors seem to be largely developed for lifting - I'd tend to look UTS (or MBS as GHA uses).

I have tested Crosby shackles they do meet their own UTS. As I've mentioned I don't know how they calculate safety factors - so I tend to look at UTS.

Different shackle manufacturers use different safety factors (the safety factors are determined by the supplier). Which is why Harken shackles have a 2:1 safety factor (I recall, I have not checked again), Crosby use 4.5:1, Petersen use 6:1 and Grade A shackles the lower grade gal shackles are commonly 6:1 etc etc. Best to compute MBS and use that.

close edit

 

[Neeves]

It is often suggested in this forum that stainless steel shackles are very weak, but if you buy a quality shackle

The reason not to buy a stainless shackle has been indicated previously - their yield is lower. Even quality stainless shackles, Petersen, Cromox or Witchard, the clevis pin may distort in use - and then the only way to disengage the anchor is to cut the shackle off - a bit expensive at the costs indicated.

Recall that at a 90 degree loading WLL should be reduced by 50% - which brings the WLL of a 10mm quality stainless shackle to as low as 400kg - I've measure 650kg on our rode.

The stainless shackle are Proof Tested - but to nowhere near the tension of a Crosby shackle.

Its not only about MBS, or UTS, but on whether the shackle will be usable before it reaches UTS.

The Petersen 'D' shackles are no better in terms of strength than most rated bow shackles (and Petersen bow shackles are not as strong). Most 'regular' galvanised bow shackles Crosby's 209 series have a 1t WLL and a 6:1 safety factor - and cost even less than peanuts. Green Pin shackles from Van Beest are similar to the 209 quality. CMPs Yellow Pin Titan shackle are again similar.

I am one of those who suggest stainless shackles are weak and I would not recommend their usage - I do not recommend them for technical reasons - galvanised shackles are stronger, have a better yield and are cheaper.

I've tested CMPs Yellow Pin shackle a decent product, meets their own specification - I don't recommend them - because for the extra money Crosby's are better and I think worth the effort to buy them (which is why I buy them from the UK shipped to me in Sydney).

Ass I said - I see no technical and certainly no financial reason to use even a quality stainless shackle in the rode. If I had a stainless rode I would use a stainless shackle - but I would be oversizing both chain and shackle.

Jonathan

 

[noelex]

I'm obviously not concentrating!

Which Peteresen shackles, 'D' or bow of 10mm (equivalent to 3/8th") have a WLL of 2t (which is the specification for a 3/8th" Crosby G209A shackle)?

Jonathan

The stainless steel Petersen 10mm D shackle has the same 2T WLL as the galvanised 3/8 inch Crosby G209A. Petersen use a more conservative safety factor of 6 times (verses 4.5 times for Crosby) so the ultimate strength of the stainless steel Peterson shackle is higher at 12T versus the galvanised Crosby 3/8" at 9T.

The 10mm stainless steel shackle is in this case stronger than the 3/8" galvanised shackle.

However, the 3/8" galvanised Crosby shackle is slightly thinner than the 10mm stainless steel Petersen. So while the 3/8" galvanised Crosby is weaker, it may fit in situations where the Petersen will not. The advantage in strength of the stainless steel Petersen shackle is also lost when going for a bow shackle, which is likely to be a better choice for most applications.

While it is difficult to directly compare metric with imperial shackles, I don’t see any evidence in the above type of examples to suggest a quality galvanised shackle is any stronger (at least to any practical degree) than a quality stainless steel shackle.

I think the often suggested advice presented on this forum that all stainless steel shackles are weak, should be corrected.

 

[noelex]

The stainless shackle are Proof Tested - but to nowhere near the tension of a Crosby shackle.

The 10mm stainless steel D Petersen shackle and the 3/8 inch galvanised Crosby 209A that you suggested should be compared, are proof tested to exactly the same load (4T) according to the manufacturers.

The 10mm stainless steel bow Petersen shackle is proof tested to 3T.

Looking this time at proof load testing I can once again see no evidence to support the continually presented view that quality stainless steel shackles are vastly weaker than quality galvanised shackles.

 

[GHA]

The 10mm stainless steel D Petersen shackle and the 3/8 inch galvanised Crosby 209A that you suggested should be compared, are proof tested to exactly the same load (4T) according to the manufacturers.

The 10mm stainless steel bow Petersen shackle is proof tested to 3T.

Looking this time at proof load testing I can once again see no evidence to support the continually presented view that quality stainless steel shackles are vastly weaker than quality galvanised shackles.

Site says petersen are individually load tested to 2 X WLL, from memory individual load testing is an extra from Crosby, no idea how much . But narrows the cost difference if comparing like for like.

 

[Neeves]

We must be looking at different websites??

Jonathan

Please define the WLL of 10mm Petersen 'D's shackles so that I might compare with the data I see on the Petersen website I pull up.

Many thanks

J

 

[Neeves]

I've checked and re-checked.

Shackles are define 2 ways, by their clevis pin and by their strength.

The website I pull up, kindly provided by GHA, defines the Petersen Hi Tensile 'D' shackle with a 10mm pin as having a WLL of 1t (the body of the shackle is 12mm, from the website). The Crosby G209A, from the Crosby website I pull up, has a WLL of 2t (I did not check the size of the body) but it has a 3/8th" pin (approx 10mm).

This information might be totally erroneous - a clarification from Noelex of the information he sees on the relevant websites might clarify.

I'm simply quoting from website - except in the case of Crosby I have also measured the pin and tested it and can confirm it has UTS in excess of 9t.

 

[noelex]

The Crosby G209A, from the Crosby website I pull up, has a WLL of 2t (I did not check the size of the body) but it has a 3/8th" pin (approx 10mm).

This information might be totally erroneous - a clarification from Noelex of the information he sees on the relevant websites might clarify.

Jonathan, I am very surprised you would think and write the above.

The 3/8 inch Crosby shackle does not have a 3/8 inch pin. Like most high strength shackle manufacturers, Crosby use the body diameter as the nominal size (or in simple terms the diameter of wire that the shackle is made from).

3/8 inch is 0.375 of an inch.

The Crosby 3/8 inch shackle does not have a 0.375 inch pin. It has a BODY diameter listed as 0.38 of an inch (ie 3/8 inch rounded to 2 decimal places). This is as you should expect. The pin diameter is larger at 0.44 inch. See the Crosby website for the sizes. They are all listed.

Just so no one is confused. The nominal size of a shackle is the body diameter. This applies to metric and imperial shackles.

You can see this with the entire range of Crosby (and other manufacturers) shackles. For example The Crosby 1 inch shackle has a body diamter of 1.00 inches. The pin diameter is larger (1.13 inches). This is important to realise when you ordering shackles. Most high strength shackles have a larger pin size than their nominal size.

If you order a 10mm Petersen shackle from Jimmy Green (or anyone else) you will get a shackle with a body diameter of 10mm and as with the Crosby, the pin diameter will be larger than the nominal size. See the link posted by GHA in post #23. This is a 10mm shackle.

 

[Neeves]

Noelex,

You are quite correct the designation of shackle is defined by the body of the shackle - not the pin. I got carried away with idea stainless could be the equal of alloy galvanised - but that is no excuse.

I don't have a Crosby shackle here, they are on our cat, but I have checked a Peerless Blue Pin G80 shackle (which I do not recommend) with a 3/8th" embossing and can confirm as you state, that the 3/8th is the dimension of the body and the pin is larger around 7/16th" or 10.9mm. The similar Crosby shackle would have similar dimensions, they are nominal.

But Petersen do not make an equivalent and the smaller shackle they supply with a 10mm pin has a WLL of 1t and the next larger with a 12mm body (with a WLL of 2t) may be too large a pin for an 8mm chain. It is therefore difficult to equate the 2 shackles as the stainless one of 2t has a larger pin diameter and if it does not fit the chain - its strength is academic in trying to compare. Unfortunately as I'm not willing to pay the price - I cannot confirm if the Petersen 2t shackle might fit an 8mm chain (though Jimmy Green would, or should know)

But I can confirm that Crosby' 3/8th" shackle does fit an 8mm chain and you can therefore chose the option of a 2t WLL with some confidence.

Again I apologise for the confusion.

Jonathan

 

[robertj]

I’m really pleased that I’m reading this lying to anchor. I have a 8mm chain to Kong swivel connected to 12mm chain to a wichard 12mm stainless steel blind D shackle connected to the 20kg rocna. I won’t sleep now.

 

[vyv_cox]

I’m really pleased that I’m reading this lying to anchor. I have a 8mm chain to Kong swivel connected to 12mm chain to a wichard 12mm stainless steel blind D shackle connected to the 20kg rocna. I won’t sleep now.

Very similar to me then. I have been sleeping on mine for many years now, no problems at all. The Wichard HT shackle is a very superior oroduct.

 

[Neeves]

I believe the Witchard HT shackle to be, as Vyv says, a superior product - on par with Petersen and Cromox. The need for having such high strength shackles is in case your shackle locks up in the anchor slot and is side loaded. I was given a galvanised shackle that failed under side loading, the pin pulled out of the thread. The new Excel anchor was lost. So it does happen. Shackles are cheap - even expensive Duplex, HT shackles are cheaper than anchors. I've also been given chapter and verse on a non rated gal shackle that failed and the Rocna anchor lost - it does happen. If I know of these 2 cases - there must be many others.

If you are using an unrated shackle, maybe you should lose some sleep. If you are using an unnmarked, unnamed stainless shackle, maybe you should lose some sleep.

If you are convinced of the benefit of stainless - maybe you should consider investing in a HT Duplex shackle - it will last a lifetime. If you prefer a galvanised shackle and are not using a Crosby G209A or equivalent maybe you would reconsider, the shackle will last for years (before you decide corrosion has compromised its strength).

I appreciate the conjunction of events to cause a shackle to lock up and the anchor to be deeply embedded such that it is snatch loaded might be slim - but you carry, or not, a liferaft you have never used in anger, you carry an EPIRB you have never used in anger, you carry flares and a full set of lifejackets etc, etc shackles cost peanuts. I don't know anyone, personally, who has used an EPIRB, LIferaft or Lifejacket in anger - but I know of 2 shackle failures - neither were likely to have occurred if they had spent Stg20. How many fire extiinguisher do have on board - I know of a number of yacht fires, mostly MOBOs and one yacht - in not one instance were the fire extinguisher used, or of any use - the vessels burnt to the waterline and sank. I also know of 2 swivel failures, which is why I would only commend Kong or Ultra (there may be other - I don't know them).

I'm not saying do not carry these safety devices (we have them all) - just get the risks into proportion and context.

A 12mm HT Witchard shackle on an 8mm chain and 20 kg Rocna seems to meet my ideas soundly. I assume you have used Loctite. I cannot understand - other then my significant 'cock up' that only served to confuse and having read the thread why you would lose even a millisecond of sleep. I'm not keen on HT stainless (call me parsimonious) but you have exceeded any suggestions I might make - a 12mm HT shackle on a 8mm chain, perfect, Kong swivel, ideal - if you must use a swivel. I assume you use the 12mm chain because that's' the only thing that 'pair' with the shackle and swivel (otherwise it a bit OTT - but nothing much wrong with OTT.)

sleep soundly


As a complete aside - ever wondered how anchor makers stay in business. They, anchors, are almost indestructible. I wonder how many sales of anchors are for anchors that are lost - but embarassment ensures we never know the reasons why. I see lots of anchors attached with grossly undersized shackles when I prowl marinas.

Jonathan

 

[noelex]

Using the correct method for sizing shackles, I hope we are now in agreement that quality stainless steel shackles and quality galvanised shackles, if matched, are roughly similar in strength, at least from any practical perspective.

As the Petersen stainless shackles are metric and a slightly different dimension from the imperial Crosby shackles, there will be anchor chain combinations where one material will just fit and will therefore be the better choice (from a purely strength perspective), but on average there will be little or no strength difference between a quality stainless steel and a quality galvanised shackle. There are other manufacturers of quality galvanised and stainless steel shackles and some of these come in alternative sizes.

Hopefully in the future will will see forum threads on anchor shackles without the misleading message that all stainless steel shackles are weak.