Anchor Swivel

[NormanS]

My bent link is very simple. It's a piece of 1/2" (12.5mm) round bar with a bend in it, and an eye at each end, and galvanised. One end is shackled directly to the anchor with a 1/2" shackle, and the other end to the 10mm chain, again with a 1/2" shackle. Obviously, the shackles are suitably moused. The link and shackles are considerably stronger than the chain. It works every time. What's not to like?

 

[J Neeves]

NormanS, sounds pretty good to me! I recall you made it yourself, or had it custom made, was there any difficulty in getting such a small item galvanised?

One thing I do not quite understand is that many people would not use a swivel, ever. They are fairly emphatic in their views, I'm one of them, as I think is Noelex. But many people have the opposite view and pay a lot, and I mean a lot of money, for their swivels. In fact some swivels seem to cost more than the equivalent decent anchor. Given that many simply do not bother to use a swivel and some of us think they are unnecessary what is/was the prompt for people to spend lots of money on an item that does not appear necessary and (given how they are commonly attached) are positively dangerous?

Did one of the yachting magazines extol their virtues, was their a huge debate on a forum?

Jonathan

 

[Delfin]

NormanS, sounds pretty good to me! I recall you made it yourself, or had it custom made, was there any difficulty in getting such a small item galvanised?

One thing I do not quite understand is that many people would not use a swivel, ever. They are fairly emphatic in their views, I'm one of them, as I think is Noelex. But many people have the opposite view and pay a lot, and I mean a lot of money, for their swivels. In fact some swivels seem to cost more than the equivalent decent anchor. Given that many simply do not bother to use a swivel and some of us think they are unnecessary what is/was the prompt for people to spend lots of money on an item that does not appear necessary and (given how they are commonly attached) are positively dangerous?

Did one of the yachting magazines extol their virtues, was their a huge debate on a forum?

Jonathan

So it will turn right side up for retrieval rather than twisting 176# with a boathook. Since the one I have is stronger than the chain, the positively dangerous designation is confusing.

 

[J Neeves]

Delfin,

Most people ignore the instructions (on the swivels I have seen) that underline there must be articulation between shank and swivel. I do see some swivels, expensive stainless steel devices with no instructions, sitting prominently in chandlers. Consequently most swivels I see on the bow rollers of yachts have the swivel fork connected directly to the anchor shank. The images of failed swivels all show bent forks - but despite this the practice continues (presumably it saves buying another shackle).

I actually see bent swivels still attached directly to the shank and also see the occasional bent shank (where the swivel attaches).

I'd prefer to see swivels designed such that it is very inconvenient, if not impossible, to connect them directly to the shank - and then the problem would disappear and I would no longer suggest them as dangerous. (Maybe an eye at each end rather than the fork and the eye? Or maybe a ring at the end to attach to the shank?)
Jonathan

 

[vyv_cox]

what is/was the prompt for people to spend lots of money on an item that does not appear necessary and (given how they are commonly attached) are positively dangerous?

Did one of the yachting magazines extol their virtues, was their a huge debate on a forum?

Jonathan

I bought mine simply because my windlass instructions recommend that one be used (Maxwell). I never had nor needed one before, but that was when I had a horizontal windlass. Having used one for over ten years now I know its performance and characteristics well, so this year I shall start the season without one and see how it goes.

 

[NormanS]

NormanS, sounds pretty good to me! I recall you made it yourself, or had it custom made, was there any difficulty in getting such a small item galvanised?

One thing I do not quite understand is that many people would not use a swivel, ever. They are fairly emphatic in their views, I'm one of them, as I think is Noelex. But many people have the opposite view and pay a lot, and I mean a lot of money, for their swivels. In fact some swivels seem to cost more than the equivalent decent anchor. Given that many simply do not bother to use a swivel and some of us think they are unnecessary what is/was the prompt for people to spend lots of money on an item that does not appear necessary and (given how they are commonly attached) are positively dangerous?

Did one of the yachting magazines extol their virtues, was their a huge debate on a forum?

Jonathan

Yes, I just made it myself. Re galvanising, it's a case of adding such a small item onto a bigger consignment.
Re the use of swivels, sadly, to many minds, bright shiny and expensive = essential item.

 

[J Neeves]

Yes, I just made it myself. Re galvanising, it's a case of adding such a small item onto a bigger consignment.
Re the use of swivels, sadly, to many minds, bright shiny and expensive = essential item.

Thanks for the input on galvanising.

I had noted Vyv was using a swivel and had not appreciated till he documented same that Maxwell actually recommended them. It will be interesting to hear how Vyv gets on denuded of swivel. But I had also thought, at the back of my mind, they were a recent innovation - so why did/do we need them now and not previously. I also recalled there were always 'cheap' looking swivels (that I never actually see being used) but these bright shiny ones seem to have sprouted ever so recently. Equally fascinating are the numbers of companies making them - much more than anchor or chain makers, much more than shackle makers (unless they all come from the 'Grand Swivel Factory' in China).

Maybe the new shiny ones stand out more than the older gal ones.

But I could agree with your deduction - if they are that expensive they must be essential.

Jonathan

 

[vyv_cox]

This was the original one that broke, triggering my investigations into the strength of various designs and types

It is fairly shiny but probably not as shiny as the Kong that replaced it, which is technically far superior. So maybe shiny = good? :encouragement:

 

[J Neeves]

This was the original one that broke, triggering my investigations into the strength of various designs and types

It is fairly shiny but probably not as shiny as the Kong that replaced it, which is technically far superior. So maybe shiny = good? :encouragement:

Great image, sends shivers down your back. I'd certainly only buy a really shiny one now

I'm guessing swivels are tested in tension - down their length. It never occurs to the manufacturers they will be used at the end of a very long lever (aka a shank).

Jonathan

 

[vyv_cox]

Great image, sends shivers down your back. I'd certainly only buy a really shiny one now

I'm guessing swivels are tested in tension - down their length. It never occurs to the manufacturers they will be used at the end of a very long lever (aka a shank).

Jonathan

The fracture face is typical of some sort of intergranular corrosion, quite a brittle appearance although the hardness is low and the general condition of the swivel is ductile. I suspect stress-corrosion with the stress coming either from the lever arm bending as you suggest but maybe also from the compression of the interscrew fixing. Whichever it is, using a Kong, that has a far superior fixing design, combined with fitting a couple of chain links between it and the anchor, should prevent a recurrence.

The failure occurred in San Antonio, Ibiza. the wind strength at the time was about the top end of a force 2, the water flat calm, no tide of course. We were sitting in the cockpit enjoying a beer when there was a loud bang, typical of SCC failures, and we began to slide backwards. The swivel was on the end of the chain. I had to obtain help from some divers on the following morning to recover the anchor, which was buried in weed but only a couple of metres down. Since then I have always had a marker float on my anchor.

 

[Roberto]

Quite a few people use swivels, or other types of not-rotating but very similar connectors, because the two metal cheeks of the bow roller are not large enough to allow a properly sized shackle to pass through: the anchor is not free to fall, or the shackle blocks under the davit when raised because its pin is too long and won't go over the roller. The connector is slimmer and easily passes through.
For example the "coloured" shackles (red, yellow piins) are quite wide, if one wants to reach a WLL similar to chain then often two big ones have to be fitted head-to-head as the shackle bow does not pass inside a chaink link, a lot of bow rollers are what? 50-70mm wide maybe, two opposing coloured ones would most probably be blocked.
I guess it is the same reason why a number of boats have ridicoulously small shackles.

There are shackles with "flush" pins, some are screwed by an hex allen key, though those commonly available are not WLL stamped in any way. Wichard makes some in HR steel, though they state "not suitable for permanent use underwater", some types of stainless steel are not suitable for "permanent moorings", but people are sufficiently impressed by the "not underwater" term to forget the "permanent" bit, and they do not use them.


Just a possible explanation, just repeating what I heard a number of times

 

[noelex]

I think this a common reason to use a swivel.

An alternative is to rated galvanised lifting shackle drill a small hole in the pin then cut off the large head from the pin. This makes the ends of the shackle almost flush. It is not as narrow as a swivel, but the edges are smooth so there is nothing to catch on the bow roller. It can still be moused.

 

[vyv_cox]

I use Wichard 17/4PH countersunk shackles, 10 mm with 8 mm chain, for attachment to the anchor. These shackles are excellent, a good deal stronger than the chain and they pass through the bow roller easily. I have been using Loctite 242 for several years now with no sign at all of the screw pin loosening.

 

[noelex]

I have some larger shackles on board that are flush and can moused as well. (See photo). Unfortunately they are a little too large even for my oversized anchor.

Perhaps a manufacturer could consider making something similar in a 1/2 shackle preferably, tested in galvanised G7.

 

[NormanS]

Quite a few people use swivels, or other types of not-rotating but very similar connectors, because the two metal cheeks of the bow roller are not large enough to allow a properly sized shackle to pass through: the anchor is not free to fall, or the shackle blocks under the davit when raised because its pin is too long and won't go over the roller. The connector is slimmer and easily passes through.
For example the "coloured" shackles (red, yellow piins) are quite wide, if one wants to reach a WLL similar to chain then often two big ones have to be fitted head-to-head as the shackle bow does not pass inside a chaink link, a lot of bow rollers are what? 50-70mm wide maybe, two opposing coloured ones would most probably be blocked.
I guess it is the same reason why a number of boats have ridicoulously small shackles.

I'm sure you are correct. The cheeks for my bow roller(s) are 100mm apart.

 

[Roberto]

I use Wichard 17/4PH countersunk shackles, 10 mm with 8 mm chain, for attachment to the anchor. These shackles are excellent, a good deal stronger than the chain and they pass through the bow roller easily. I have been using Loctite 242 for several years now with no sign at all of the screw pin loosening.

Yes but Vyv I'd say 99.9% of sailing people have nothing near your knowledge of metals

What do they do ?
New anchor ? Buy a big, substantial shackle. I want to be safe.
Oh, it won't fit inside the chain link... bright idea: back to the chandler I'll buy a second one.
Back to the boat Damn, they do not pass through the roller.
Back to the shop: on the shelves they find a smaller shackle, the Wichard HR steel flush-pin shackle, the swivel..

I am based in France so am mainly talking about what happens here, when people think good quality stainless steel they think Wichard. They are very widely distributed, along with their technical literature, etc. Until a few years ago Wichard stated "do not use HR steel underwater", specifically referring to their High Resistance Martensitic steel, though people were reluctant to use *any* type of stainless steel underwater "because wichard say so", or so they understood.

This is what of the disclaimer is left today, page 34 from
http://www.wichard.com/documents/stainlessSteel.pdf
All Wichard products are passivated. Corrosion attacks stainless steel and is always visible in the form of black coloured roughness. Although this is dangerous, it is rarely seen in current use, except in cases where martensitic (HR) steel is in total, prolonged immersion. What many people erroneously call corrosion, is really rust, or oxidation. This is due to outside causes. In the marine environment, stainless steel is subject to considerable aggressive forces and is not totally corrosion free.

After reading this, as an end-user I would understand: do not use these HR steel shackles for a permanent underwater mooring (for example chain to a concrete block on the bottom), they are absolutely acceptable for temporary immersion -which is what happens with common anchoring practice. Say maybe use a passivating compound from time to time.


Still, as there is no agressive "chain connector marketing" so far, I guess these habits will last some more years, anchoring techniques have shown to be rather stable in absence of violent external forces


regards
r

 

[vyv_cox]

It is generally accepted that it is unwise to use stainless steel shackles on moorings because the carbon steel chain it joins will be less noble than the shackle and will corrode preferentially. There are other reasons to do with corrosive wear, I think, although I am less clear about them. For anchoring purposes I don't believe that corrosion is ever going to be an issue. All that has happened to my mixed metals arrangement over many years is that the galvanising has gone on the last three or four links of the chain.

17/4PH is not HR by the way, it is far superior in corrosion and almost as good in strength. Really good stuff but not cheap as it goes through a complex heat-treatment process.

 

[Andrew G]

Vyv,
I’m particularly interested in your use of the “Wichard 17/4PH countersunk shackle”, with Loctight because normal shackles are too tight in my bow roller cheeks. (I’m looking to see if I can get two Wichards in Australia).
I have two questions:
1) Looking at your website I found a picture of the 8mm chain/swivel/3 links of 10mm chain/10mm shackle with the pin through the anchor stock. What are the pros and cons of having the shackle pin pass through the chain link rather than the anchor stock (I would normally pass the pin through the link but I’m always happy to learn)?
2) I have recently retired my Plastimo anchor swivel because it had an Allen key/tapered head on the pins which I couldn’t mouse (similar to the Wichard shackle) – I used to use lots of Loctight and indexed the head with lots of centre pop punching – am I being too conservative by removing it? (I would prefer a swivel because my anchor comes up the wrong way (at least or more than) 50% of the time and it is really hard to turn otherwise). I would adopt your practice if I could trust the swivel, particularly the pins. (all care absolutely no responsibility!).
Cheers Andrew

 

[J Neeves]

Vyv,
I’m particularly interested in your use of the “Wichard 17/4PH countersunk shackle”, with Loctight because normal shackles are too tight in my bow roller cheeks. (I’m looking to see if I can get two Wichards in Australia).
I have two questions:
1) Looking at your website I found a picture of the 8mm chain/swivel/3 links of 10mm chain/10mm shackle with the pin through the anchor stock. What are the pros and cons of having the shackle pin pass through the chain link rather than the anchor stock (I would normally pass the pin through the link but I’m always happy to learn)?
2) I have recently retired my Plastimo anchor swivel because it had an Allen key/tapered head on the pins which I couldn’t mouse (similar to the Wichard shackle) – I used to use lots of Loctight and indexed the head with lots of centre pop punching – am I being too conservative by removing it? (I would prefer a swivel because my anchor comes up the wrong way (at least or more than) 50% of the time and it is really hard to turn otherwise). I would adopt your practice if I could trust the swivel, particularly the pins. (all care absolutely no responsibility!).
Cheers Andrew

If you are only using a swivel because your anchor meets the bow roller 'upside down' then maybe you could consider NormanS' solution of the bent lead, which automatically ensures the anchor addresses the bow roller in the correct orientation (see his earlier posts on this thread). If you follow this route, the 'bent lead' - you will still need Vyv's 3 links - so shank, attached to shackle, 3 links of chain, shackle, bent lead, shackle, chain. (You need 3, 5 or any odd number of links - otherwise the anchor will be upside down again).

If possible I would not put the shackle pin through the shank - it increases the load on the shank (and on the pin), better to allow the shackle to articulate by putting the bow through the shank hole. If you cannot get the bow through the shank hole, you need a different shackle. Shackles seem to be nominally similarly and standard sized - but each type is slightly different, different pin diam, different opening size, shop around. (We are a bit starved of choice, certainly for gal shackles in Oz - and I suspect Europe).

But I am pre-empting Vyv's comments

Jonathan

 

[vyv_cox]

1. I don't believe it makes any difference which side the pin is on but I try to obtain the best fit. The anchor stock is thicker than the chain wire, so it fits best that way around. However, if I was attaching 8 mm chain directly to the anchor I would do it the other way because the end of the shackle D will not go through a link of the chain. Some people like to have a larger ring on the end of the chain to enable this but such rings are often too wide to pass through the roller.
2. Before adopting Loctite I carried out several tests, torqueing the pin into the shackle, leaving it underwater for a month or so and then disassembling while using the torque wrench again. At the time there had been some discussion here in which some posters claimed that Loctite-type thread sealants would deteriorate under water. I could not detect any change in the torque values. Since then several years have passed, during which all my anchor connections have been Loctited. I don't measure the torques but I try to assess with the Allen key when undoing them. I'm pretty convinced that there is no loosening.
I suggest you use the Kong type of swivel in which the screw only holds the two sides together, not ones with interscrews.