sourcing countersunk pin galvanised D-shackle

skyflyer

skyflyer

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Getting nowhere with a Google search for these, and wondered if they even exist and if so where can I buy some.

Basically it is to join 8mm galvanised chain - no gypsy involved so calibration not important - without loss of strength.
 
strange - just googled it again and up came a few - but anything galvanised seems to be "non-rated". So still needing to find a source of a rated galvanised countersunk shackle! (or remind me why i shouldn't worry about using s/steel with galvanised steel - it's a non-no isn't it?)
 
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ballyabroad said:
or have a look at one of these if you don't need to separate the chain again.

http://www.tecni-lift.co.uk/Crosby-8mm-G335-Chain-Missing-Link-890-kgs-WLL-221-013-138
Click to expand...

Used these before. They will not easily fit through the links of 8mm chain and certainly will not flex once they have been fitted, unless - as per Vyv Cox's recommendation - you compress the end link of the chain in a vice yo open up the aperture in the link. The decent ones are also hard work to peen over the rivets and the cheap ones have the tensile strength of cast iron it seems.

It was to avoid these issues that i wanted to go with shackles as the chain doesn't have to run over a gypsy, but i also don't want a sharp pin sticking out the side to catch on - amongst other things - my hands!
 
Why not buy a normal rated 'D' gal shackle and cut the end of the clevis pin off, it will then no longer protrude. If you need to be able to tighten or untwist - cut a slot in the cut end for a big flat screwdriver. The cut end will corrode only marginally more quickly than where the chain rubs the gal of the pin anyway and if you are worried, paint it. If you want to secure the pin, use Loctite.

The best European shackles appear to be Green Pin from Van Beest in Holland a 3/8th or 8mm will have a WLL of 1t. You can get Crosby G209 - A from Tecni Lift in the UK, a 3/8th" will have a WLL of 2t with a 4.5:1 safety factor. If you have access Peerless Grade B shackles under their Peerlift range offer a WLL of 2t with a 6:1 safety factor for their 3/8th". If you need smaller than 3/8th or 8mm and want the better WLL I think only Peerless offer, down to 3/16" (with an appropriate smaller WLL). CMP, best known for Rocna have a Yellow Pin shackle in their Titan range, 3/8th" with a WLL of 1t. They have a Black Pin range, supposedly with a WLL of 2t - ignore them, I've tested 2 neither was any different to the Yellow pin range

Jonathan

Edit - if you cut the end off, leave the shoulder (and as much of the protrusion as you can). Many shackles fail because the pin pulls out of the eye of the body of the shackle. Rated shackles I have tested fail because the pin shears at the thread (logical as the thread reduces the diameter of the pin). Because rated shackles are hard they are unlikely to pull through the eye. Rated shackles have a shoulder on the pin at the other end from the thread - presumably to stop the pin pulling though the eye. I confess not to have tested a shackle with the end chopped off :( close edit.
 
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interesting idea - especially as I could fit all my connectors BEFORE the chain is regalvanised and that would seal over the cut end and probably help stop the thread coming loose too. Would the heat of the galvanising significantly reduce the strength though?
 
Neeves said:
I confess not to have tested a shackle with the end chopped off :( close edit.
Click to expand...

I have - inadvertently :)

When we got our new Spade anchor, I originally attached it to the 8mm chain with a 10mm stainless Wichard long-D shackle I'd originally bought for Kindred Spirit's rigging (her shrouds were shackled to a spider band at the hounds). Can't remember the SWL, but it was fairly substantial as you'd want for a use like that. Because Ariam's bow roller is very narrow, I used loctite on the thread of the pin and then sawed off the protruding lug on the other end. These shackles don't have a flange before the lug.

I then went to test the new setup, and on the second lift of the anchor at our alongside berth, the shackle caught on the bow roller. The 1kw windlass was powerful enough to bend the legs of the 10mm shackle apart, freeing the non-threaded end of the pin and letting the chain out. The shackle remained dramatically bent, it didn't spring back. This all happened more or less instantaneously, of course I stopped pressing the button the moment I realised something was wrong, but it was too late.

I did manage to retrieve the anchor from the bottom of the river, after phoning Force 4 who kindly stayed open for an extra ten minutes so I could race over there and buy a SeaSearcher magnet. It took quite a lot of increasingly worried "fishing" with the magnet before I found and was able to lift the very expensive anchor - it wasn't directly under the stemhead, so it seems an unattached Spade will "glide" to some extent on the way down. But I got it in the end, and the SeaSearcher is now stowed right in the bow away from the compasses, ready for some future salvage job. I now use an 8mm stainless shackle with a countersunk hex head, with a 6 tonne break load.

The conclusion? If a shackle pin has a flange then it's probably fine to cut the lug off. But otherwise, do not trim the pin unless it will only be used for very light loads!

Pete
 
Lifting gear safety factor is usually 4:1 except for shackles, sometimes 6:1, sometimes as low as 4.5:1. All lifting suppliers point out shackle strength will be reduced by 50% if loaded at right angles (possible with an anchor shackle but unlikely with a shackle in the middle of a chain). Rigging shackles, for yachts, can have safety factors as low as 2:1.

I have tested a number of stainless shackles, all of them failed as a result of the pin pulling through the eye. Either the pin pulled through the thread and one countersunk shackle ratet at 4.7t failed at less and pulled the alan key head through the eye. I would not touch stainless shackles, too soft - both the eye and the clevis pin end deforms, and size for size Grade B shackles can be twice as strong.

I suspect that if you take a Grade B shackle and re-galvanise it then you will degrade its strength, for safety work on 25%. but it might be around 15%. But I'd not worry about regalvanising. I'd simply cut the end off and use. The shackle will corrode any way, in the same way your anchor shackle corrodes. I'd think of it as a consumable, watch it and when it looks grotty - change it. But a little bit of corrosion on the end of the in is going to be only cosmetic for a long time, maybe after a number of years it might impact strength, I think you will find that the gal on the rest of the shackle will provide a degree of protection to the cut surface anyway and you can always pain, use tar - whatever. Loctite is fine. If you use the sort that requires heat to disassemble you will find it very difficult to release, unless you have a blow torch, its really impressive. I think Vyv has Loctite numbers on his website - if not I can look them up (simply cannot remember). Many of these Loctites will work wet and will set to full strength underwater - the are anerobic (I think that's the word).

Personally I would not use anything but Grade B shackles, like the Crosby G209 - A. They cost little more than Grade A shackles but are stronger and the money saved is not worth it. I'd try to get Peerlift, Grade B (take care they have identical shackles that are Peerlift Grade A!) but Crosby are fine and you can get from Tecni Lift, and probably others. (lifting supply distributors).

Jonathan
 
skyflyer said:
so what is the problem with using stainless shackles with galvanised hardware? Is it a huge galvanic corrosion or just minor?
Click to expand...

Aiui it causes the galvanised chain to corrode faster but how big the effect is I do not know.

Boo2
 
Boo2 said:
Aiui it causes the galvanised chain to corrode faster but how big the effect is I do not know.

Boo2
Click to expand...

It certainly does but when I posted about that a while ago my experience was disbelieved by one of the forum experts. However, after having my chain re-galvanised I replaced the s/s shackle with a galvanised one, seized with galvanised wire, and there is now no rust.
 
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Neeves said:
My question would be

Why would you use stainless shackles with galvanised hardware? Where are the benefits?

Jonathan
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When I carried out my tests we deliberately selected chandlery-bought shackles, both galvanised and stainless steel. The stainless ones outperformed the galvanised in the majority of cases, results on the website. Lifting shackles are generally stronger, although not by a huge margin when compared with the Wichard ones, which having countersunk pins are better for use with narrow bow rollers.

So far as galvanic corrosion is concerned I can only say that after using a stainless shackle and swivel with galvanised chain and anchor for four or five seasons the worst that has happened is that the zinc has been lost from the three links of 10 mm chain between the two. The final three or four links of my 8 mm chain have also suffered some loss of zinc but not enough that I need to cut them off yet.
 
Except that last time I looked and Witchard no longer appear to sell the high tensile countersunk shackles. I have yet to find Grade B galvanised shackles easily available outside America (there is no European standard afaik), except for Crosby G209 A and they are, I'd say 50% stronger than anything in stainless, 3/8th" shackle 7/16th" pin actual break 9t. And if you can get Grade B from America, Peerless they will, for the same size, have a break of 12t. I have never tested Witchards HT shackles and the best in stainless, of the same size 6t.

Now whether you need 12t - that's another issue.

An advantage of stainless shackles is that they deform long before they break - so you get a very good indication if you are stressing them. Not so HT alloy gal shackles - it takes a lot to get them to deform and they can break, at the pin, with little deformation in the bow. Shackle makers warn that shackles loaded at 90 degrees should be used with a 50% reduction in strength - I have never seen a similar warning of stainless shackles but as they deform more easily I'd say they are just, if not more so, as prone to strength reduction with a side load.

The Chinese are making Grade B shackles but I have not found a reliable source yet.

I find the last link(s) of chain between chain and anchor, so with a HT shackle in between, corrodes preferentially (with no stainless in the rode). I chop mine off, those 2 or 3 links, every 2 or 3 years. I assume its a combination of the dissimilar metals, HT steel of the shank and shackle and mild steel of the chain - but have no real idea - and increased wear stripping the gal off the chain.

Jonathan
 
macd said:
That's news to me, but I last tried (successfully) to buy one about four years ago.
However, there are these: http://www.hayn.com/marine/misc/shackles.html
Available in the UK from AllSpars, and perhaps others.
Click to expand...

I'd hardly call them 'strong' a 7/16th" shackle is around 6t. If they lock up at 90 degrees that reduces to 3t - it depends on whether you think that important (and its very debatable - just right for a forum? :(). But the best of an alloy Grade B with 7/16th" pin will be 12t in a straight line pull (Crosby 9t). Again is depends on whether you think it useful to have a 12t shackle on a 3t-4t chain - but the shackles are hardly expensive.

Jonathan
 
Cutting off the head of an anchor shackle is a worthwhile modification. On many bow rollers the protruding head of the pin is at some risk of catching. This is usually just an inconvenience, but the anchor winch can produce a lot of force so there is the potential to damage something if it jams.

It is quite easy to do even with a high tensile shackle. Only hand tools (hacksaw and file) are needed. If you leave a small part of the head of the pin protruding there is enough room to drill a small hole so the shackle can still be moused. It also can still be undone (if not rusted up) by gripping the head with an adjustable spanner or vise grips.

The other option is to cut the head completely flush and use Locktight (or peening) to secure the pin, but with the pictured modification the small amount of streamlined head is very unlikely to catch, but it can still be undone and conventionally moused.


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