Dee Shackle Confusion

[A_Sails_Pace]

Now I don't know if it's just me but I can't make sense of the shackle strength side of things. I am currently trying to find 2 (10mm) shackles - 1 for either end of my anchor chain. I realise this should probably be more simpler than I am finding it.

I bought a bag of 10 shackles (from Diall) for £8. I realise now they aren't galvanised but they each hold a weight of up to 500kg.

Realising I should probably get galvanised ones I go to a proper chandlery where I find 2 galvanised ones for the same price as my previous bag of shackles. Makes sense considering this is a chandlery purchase. Though these ones are only marked up as 300KG in strength. There doesn't appear to be any others of the same size that is as strong or stronger than my cheaper 500KG ones.

My confusion is that 500KG doesn't sound like not a lot of weight at all (obviously 300KG sounds like a lot less), and I don't know whether to use the galvanised one's at 300KG or not?

For ref it's for a 29ft sailboat. I can't tell what strength the previous ones were because they had corroded so much.

I know I know, a big explanation for what is a minor issue. Still, thoughts appreciated.

A.S.P

 

[V1701]

See Jimmy Green here...

 

[A_Sails_Pace]

See Jimmy Green here...

Ah, thanks. Now, those Working Load Limits are more like it. It's baffling how most chandleries I have been into (or looked at online) haven't had anywhere near those load limits with 10mm Pins. Strange considering what people are using them for.

Thanks again mate.

 

[ghostlymoron]

What size and grade is your chain. I'd pick a shackle to suit.

 

[A_Sails_Pace]

What size and grade is your chain. I'd pick a shackle to suit.

My chain is an 8mm chain. I wanted the strongest shackle possible at either end. The 10mm fits nicely.

 

[Stemar]

I get the need for a shackle at the anchor end, but why at the other end? For one thing, it should never be under significant strain, and also, I want the bitter end of my rode to be rope that I can cut if I need to. If you have plenty of chain, it doesn't need to be any longer than needed to come out of the hawse pipe far enough to allow you to cut it, but being able to lose the anchor and chain in a hurry is a useful safety feature, though, like most safety features, it's one you hope you'll never use.

 

[vyv_cox]

If you want the best security don't use anything bought at a chandlery, buy professional lifting shackles by Crosby, e.g. Crosby® 210 Carbon Screw Pin Chain Shackles - The Crosby Group

 

[jwilson]

Your Diall shackles will probably rust in days in salt water. I wouldn't let them anywhere near an anchor chain. A decent chandler wil sell tested shackles as well as the much cheaper ones. The tested ones are usually much better galvanised as well as having a known load rating.

 

[Minchsailor]

Not sure that all shakles sold by a chandlery are 'decent ones'. Go for 'green pin' with the rating casted into them.

 

[Sumara of Weymouth]

Now I don't know if it's just me but I can't make sense of the shackle strength side of things. I am currently trying to find 2 (10mm) shackles - 1 for either end of my anchor chain. I realise this should probably be more simpler than I am finding it.

I bought a bag of 10 shackles (from Diall) for £8. I realise now they aren't galvanised but they each hold a weight of up to 500kg.

Realising I should probably get galvanised ones I go to a proper chandlery where I find 2 galvanised ones for the same price as my previous bag of shackles. Makes sense considering this is a chandlery purchase. Though these ones are only marked up as 300KG in strength. There doesn't appear to be any others of the same size that is as strong or stronger than my cheaper 500KG ones.

My confusion is that 500KG doesn't sound like not a lot of weight at all (obviously 300KG sounds like a lot less), and I don't know whether to use the galvanised one's at 300KG or not?

For ref it's for a 29ft sailboat. I can't tell what strength the previous ones were because they had corroded so much.

I know I know, a big explanation for what is a minor issue. Still, thoughts appreciated.

A.S.P

Hi A.S.P.
I’m not surprised that you are rather confused. There is quite a lot to get your head around and plenty of opportunity to get things wrong. I suppose the most important thing is the strength of the product. Here we encounter BS (Breaking Strength), WLL (Working Load Limit) and SWL (Safe Working Load). Climbing equipment will give you the actual Breaking Strength normally in kN rather than kg (technically kgf). So beware of using climbing gear on a boat unless you are totally aware that if it says it will break at 1,000 kgf ( 9.8 kN) then it will BREAK at 1,000 kgf. Lifting gear is quite different and incorporates safety factors. For steel products the safety factor is generally 5 to 1 (although Crosby use 6 to 1). Therefore, if you purchase a lifting shackle (Crosby or Green Pin etc) if it says WLL 1 t (1,000 kg) then you can safely use it to lift something weighing 1,000 kg. The safety factor is built into the product. Manufacturers will only give a WLL (Working Load Limit) which is the maximum load that you can expose the shackle to designated by the manufacturers. SWL (Safe Working Load) is applied afterwards when the shackle is in use. For instance, if the shackle has a 1,000 kg WLL but your chain has a 800 kg WLL, then the assembly will have SWL of 800 kg.
A proper lifting shackle will be supplied with a Declaration of Conformity, it will have the WLL stamped on it and will also have a batch number. A reputable supplier will actually record every shackle sold so that users can be notified in case of the very rare possibility of a faulty batch.
I could go on but my boat needs varnishing…..

 

[A_Sails_Pace]

@Stemar - You make a good point actually. The one at the end opposite the anchor is just in place to prevent it from running out of the chain pipe. To be honest, having not long boat the boat this wasn't something I had overly thought about but you do make a fair point. I'll have a look at options for securing that end instead of a fixed shackle.

I also recognise what you guys have said about the rubbish Diall Shackles, and to be cautious when purchasing from a chandlery. Thanks for that advice as well.

@Sumara of Weymouth - thank you for that info. I think I understood most of it ) There's definitely a few things to consider. I suppose I was just trying to work out what actual shackle strength I needed with an 8mm galvanised chain. It's just once I started looking into it, it confused me a little (a lot). Appreciate the detail around WLL & SWL though. Thanks a lot.

Much appreciated for the advice in the comments above, thank you.

A.S.P

 

[Neeves]

There are three types of 10mm/3/8th" shackles.

Those bought from a hardware store that are cheap and excellent to restrain your dog.

There are Grade A shackles that for the size quoted will be stamped with a makers name, size and a WLL of 1t.

There are Grade B shackles that have the makers name and size stamped on them and have a WLL of 2t.

The only shackles meeting the Grade B specification in the UK are Crosby shackles in their G209a range.

Shackles if they lock up in the slot in the shank of your anchor will not then be tensioned in a straight lines and reputable shackles makers will advise if you side load at 90 degrees the shackle strength will fall by 50% - your shackle of a 1t WLL is now 500kg and 8mm chain if its G30 will have a WLL of 750kg. Ive tested most shackles available in Oz and the UK and I have tested side loading the shackles (and the 50% loss of strength is correct). You want the chain to be the weak link NOT the shackle.

Its a no brainer go and buy a Crosby shackles - as Vyv clearly said earlier. I'm in Sydney Australia and I buy my Crosby shackles from Techni in the UK.

Green Pin shackles are ,made to a Grade B specification but they are too big for 3/8th. Peerless and Campbell also make Grade B shackles but they are American Coys and they don't distribute afaik in Europe.

I'd buy 2 shackles and keep one as a spare, you. would be surprised at the people who drop a clevis pin in the sea having just imported said shackle - been there done that.

I know of shackle failures and loss of anchor, one was unmarked, no makers name, one was side loaded in both cases the anchor was lost. You might get lucky but I would not bank on it.

Its not rocket science.

Remember to mouse your shackle and for belt and braces - coat the thread with Loctite - blue - it will set under water.

CMP the people making Rocna anchors have a range of shackles yellow pin and black pin - the yellow pin are OK but are only a grade A. The Black pin I would not recommend - buy Crosby and sleep well at anchor. Sadly I have no connection to Crosby (nor Techni). Other distributors will sell Crosby shackles - I don't know - if anyone finds another UK source - please post and I can add to my posts on the topic.

Crosby now own Gunnebo the Scandinavian makers of all lifting kit, chain, etc etc - if you have someone nearby stocking Gunnebo kit - they might have Crosby shackles.


I would only hold Crosby shackles on a yacht - too easy to make a mistake in the dark - and there is no use for other shackles on a boat.

Take care, stay safe

Jonathan

And

I forgot - do not use a 'D' shackle for an anchor - use a bow shackles, bow through the shank slot, clevis through the chain. A bow shackle allows the shackle to articulate. A 'D' shackle simply extends the length of the shank and depending on the anchor - you might bent the shank

Finally - you will pay a bit more for a Crosby shackle - but in the grand scheme of things they are as cheap as chips - compared to the cost of you yacht. They do allow you and your crew to sleep safely and soundly. They are worth the money! Do what Vyv said! - link in Post 7

 

[Neeves]

I was a bit time short when I posted my previous post and as its early red wine time here in Oz I can fill in the gaps. I hope the thought of red wine with your cornflakes is not too upsetting.

I was giving a lecture in a Queensland yacht club and one of the attendees offered me this sample (of a failed shackle). It has nt embossing, no conformation of who made it, not even the size. But it is 3/8th". In my estimation - excellent to secure a dog.

However he has. largish, catamaran 45' and was rafted up with e friend in a smaller cat in Moreton Bay (overnight). They were secured by the rode of larger cat. The weather overnight was bouncy but not sufficient to spoil sleep (possibly enhanced by some excellent (not again) red wine). In the morning the 'rafted up friend' left. The owner of the cat then retrieved his anchor - it was initially a bit of a struggle - and then easy.

There is a spanking new Anchor Right Excel anchor somewhere in the mud of Moreton Bay.

Note that the shackle has not 'broken' the clevis pin has simply pulled out of the the thread, possibly side loaded. Mousing wire - intact. The attendee gave me the shackle.




A member here sent me the following photographs. I confess - its inexcusable but I forget who (too much red wine). If the member is still active - chastise me - in public

He was anchored in the waters of northern Scotland. He retrieved his Rocna anchor (no reflection here on Rocna anchors) and when the anchor (or maybe shackle 'hit' the bow roller there was a bang and the Rocna disappeared into he dank and chilly depths.








Amazingly the bits and pieces were found on or around the bow roller.


Invest in reputable shackles - take note - its not worth cutting corners.


Sorry to interrupt the cornflakes, sorry for another contribution devoted to anchoring - I'll get back to my red wine. You all have a good day - and maybe reflect on your anchor shackle.

Take care, stay safe

Jonathan

 

[vyv_cox]

Astonishingly, your second case history appears to be an example of brittle fracture, a first for me. If there is one characteristic in a shackle that is not required, it is brittleness! The ductile/brittle transition temperature of carbon steels is around ambient, so Scottish waters might be expected to be in the danger region but this is normally taken care of by composition. It seems the shackle may have unusually high carbon and low manganese contents, with presumably no alloying elements and maybe high sulfur.

Another good reason for buying from a known reputable supplier.

Not a shackle but a similar very poorly manufactured C-link, C-links.

 

[Neeves]

I've tested a few shackles, to destruction, primarily bow, galvanised, alloy shackles that we would use for an anchor. I don't tend to test shackles that have no manufacturers name on them as its a waste of time - I don't know where they come from and if they are good - I cannot buy any and if they are poor I cannot suggest steering clear.

Reputable bow shackles all fail, under test, the same way - the clevis pin shears. It shears where the pin is thread - and if you think about it the 'thinning' of the pin by threading is offers less steel - so a weak point.

Once the pin shears the bow then distorts. The difference in the distortion does not reflect on the shackles but it a function of how the tension developed once the clevis pin sheared.

The top picture is of a CMP Titan 3/8th" shackle, it met specification and has a WLL of 1t



The lower picture is of a Peerlift 3/8th" shackle. It has a WLL of 2t and met specification. Peerlift sell these shackles in their G80 range ( most of our anchor chains, Oz, UK are a G30 quality increasingly G40).



Good shackles, Crosby, Peerless, Campbell, (all American), Yoke (Taiwan) and CMP's Yellow Pin and a couple of mainland Chinese makers meet specification. Only Campbell, Peerless, Crosby and Yoke meet Grade B specifications - that is effectively a 3/8th" shackle has a 2t WLL. Only Crosby seem easy to source in the UK and none are easy to source, at all, in Australia. I have not tested Van Beests Green pin shackles - not easy to source in Australia.

I buy my Crosby shackles mail order from the UK.

As Vyv says

good reason for buying from a known reputable supplier.

Jonathan

 

[Pasarell]

I had a similar question a few weeks ago. I'd been unable to find rated shackles in Greece so spoke to Geoff Crowley (of this parish) at Knox Anchors who supplied my anchor a couple of years ago. I'd bought new 10mm chain at the same time all connected with a Kong swivel but wanted to get rid of the swivel. He stocks Crosby shackles and I bought 2 (as Jonathan recommends above!). The bow of the shackle will fit through my 27kg anchor shank and the pin fits through Lalizas 10mm chain. Shackles are a work of art compared with those from most chandlers, clearly stamped with Crosby and WLL 2t.
Definitely a little more expensive than basic shackles but a tiny amount compared with cost of chain and anchor.
No connection except as a customer but Geoff can be contacted at www.info@knoxanchors.com

 

[A_Sails_Pace]

@Neeves & @vyv_cox

Thanks gents. Much appreciated. I'm looking at the Crosby bow shacks as we speak. actually.

I guess the other night I was just wondering what WLL would be required for my 29ft boat and 8mm chain, but I suppose the answer is just to get the strongest one possible that fits (the 10mm pins fit through both my shank and my chain. Anything more and it's a squeeze).

The Crosby chain links look decent as well. The one I already have just looks and feels a little poxy.

Thanks again, all.

A.S.P

 

[Minchsailor]

I was a bit time short when I posted my previous post and as its early red wine time here in Oz I can fill in the gaps. I hope the thought of red wine with your cornflakes is not too upsetting.

I was giving a lecture in a Queensland yacht club and one of the attendees offered me this sample (of a failed shackle). It has nt embossing, no conformation of who made it, not even the size. But it is 3/8th". In my estimation - excellent to secure a dog.

However he has. largish, catamaran 45' and was rafted up with e friend in a smaller cat in Moreton Bay (overnight). They were secured by the rode of larger cat. The weather overnight was bouncy but not sufficient to spoil sleep (possibly enhanced by some excellent (not again) red wine). In the morning the 'rafted up friend' left. The owner of the cat then retrieved his anchor - it was initially a bit of a struggle - and then easy.

There is a spanking new Anchor Right Excel anchor somewhere in the mud of Moreton Bay.

Note that the shackle has not 'broken' the clevis pin has simply pulled out of the the thread, possibly side loaded. Mousing wire - intact. The attendee gave me the shackle.

View attachment 133817


A member here sent me the following photographs. I confess - its inexcusable but I forget who (too much red wine). If the member is still active - chastise me - in public

He was anchored in the waters of northern Scotland. He retrieved his Rocna anchor (no reflection here on Rocna anchors) and when the anchor (or maybe shackle 'hit' the bow roller there was a bang and the Rocna disappeared into he dank and chilly depths.


View attachment 133818

View attachment 133819

View attachment 133820

Amazingly the bits and pieces were found on or around the bow roller.


Invest in reputable shackles - take note - its not worth cutting corners.


Sorry to interrupt the cornflakes, sorry for another contribution devoted to anchoring - I'll get back to my red wine. You all have a good day - and maybe reflect on your anchor shackle.

Take care, stay safe

Jonathan

That was me!

 

[Neeves]

Apologies Minch Sailor - and thanks for the images - as you see - useful.

Jonathan

 

[Neeves]

@Neeves & @vyv_cox

Thanks gents. Much appreciated. I'm looking at the Crosby bow shacks as we speak. actually.

I guess the other night I was just wondering what WLL would be required for my 29ft boat and 8mm chain, but I suppose the answer is just to get the strongest one possible that fits (the 10mm pins fit through both my shank and my chain. Anything more and it's a squeeze).

The Crosby chain links look decent as well. The one I already have just looks and feels a little poxy.

Thanks again, all.

A.S.P

Make sure you buy the shackles that includes the 3/8th" shackle with a 2t WLL. They offer and almost identical 3/8" shackle with a WLL of 1t.

Jonathan