To swivel or not to swivel, that is the question!

[Fimacca]

Two swivel or not to swivel, that is the question!
I know, it is a real first world problem

Well, on receipt of my new anchor , and no I’m not going to talk about types of anchor here - do not worry!

I am pondering over a swivel. In my experience there have been quite a few insurance claims from failing swivels on swing Moorings.


However, many ofthe recommendations I read are to fit an anchor swivel.

So what do people think, should I just have the chain connected to the anchor with a shackle as per my current setup, or should I allow more movement from chain to anchor -
which may also make a weak point in the system?

 

[Plum]

Two swivel or not to swivel, that is the question!
I know, it is a real first world problem

Well, on receipt of my new anchor , and no I’m not going to talk about types of anchor here - do not worry!

I am pondering over a swivel. In my experience there have been quite a few insurance claims from failing swivels on swing Moorings.


However, many ofthe recommendations I read are to fit an anchor swivel.

So what do people think, should I just have the chain connected to the anchor with a shackle as per my current setup, or should I allow more movement from chain to anchor -
which may also make a weak point in the system?

I have never used a swivel for my anchor and have never seen a need for one.

Www.solocoastalsailing.co.uk

 

[Poey50]

It is easy to slip into a false dichotomy of no swivel versus poor quality swivel and/or poorly fitted swivel. If you are going to fit a swivel fit a good quality one and fit it properly. My Spade always came up the wrong way round so I fitted a good quality Kong swivel with three links between swivel and anchor as recommended by Vyv Cox. This made it easy to turn the anchor round for final retrieval. But then I discovered the boomerang that does the whole thing so the swivel is not needed.

 

[Chris_Robb]

Two swivel or not to swivel, that is the question!
I know, it is a real first world problem

Well, on receipt of my new anchor , and no I’m not going to talk about types of anchor here - do not worry!

I am pondering over a swivel. In my experience there have been quite a few insurance claims from failing swivels on swing Moorings.


However, many ofthe recommendations I read are to fit an anchor swivel.

So what do people think, should I just have the chain connected to the anchor with a shackle as per my current setup, or should I allow more movement from chain to anchor -
which may also make a weak point in the system?

If you have a horizontal windlass, then you wont need a swivel - it seems that vertical access swivels cause a twist - I canmt work out why - but everyone with one complains of twist and the need to fit a swivel. So start with jut a narrow wichard alen keyed shackle, which will make coming over the bow roller much smoother than a classic D shackle. Many stainless ones are of unknown breaking strain - hence Wichard - then you will sleep soundly!

If a Vertical access one than do as above and look at Vyv Cox's site, and for Gods sake dont connect it directly to the anchor - it will break how ever good the swivel is.

 

[[2574]]

I was in the “not needed” camp until we changed boat. We now have a through-stem anchor arrangement and if the anchor comes up the wrong way around it is just about impossible to turn it to the correct orientation. So I fitted a swivel which has solved the problem. We had to buy an Ultra swivel in order that it easily passes through the stem opening. It’s horribly expensive but does seem to be well engineered.

 

[dunedin]

We had a swivel but that meant the anchor often was the wrong way round and needed turning before being brought on board. Removed the swivel and removed most of the problem - as well as removing a potential weak link in the system.
(NB Anchoring > 100 times per annum)

 

[thinwater]

IME, the leading cause of anchors coming up backwards is motoring slowly forward while raising the anchor through the water. It is the natural thing to do. But most modern anchors will align with the flow of water, bringing them up backwards every time. Stop or back while raising.

Once I figured that out, I lived very happily with no swivel. In fact, it never came up the wrong way if I backed.

 

[NormanS]

I have never seen the point of a swivel, but the water that I sail in is so watery that if the anchor wants to turn while being retrieved, the water isn't going to stop it.
I do have a "bent link", three chain links away from the anchor, which absolutely guarantees that as soon as the link reaches the bow roller, it automatically rotates the anchor in to the correct orientation. The "bent link" is simply a piece of round bar, somewhat larger than the wire size of the chain. It has an eye at each end, and is bent about 40° off the straight. "Neeves" of this parish has copied the idea, but makes his out of a shaped piece of fancy steel plate.

 

[Poey50]

IME, the leading cause of anchors coming up backwards is motoring slowly forward while raising the anchor through the water. It is the natural thing to do. But most modern anchors will align with the flow of water, bringing them up backwards every time. Stop or back while raising.

Once I figured that out, I lived very happily with no swivel. In fact, it never came up the wrong way if I backed.

This was exactly the problem with our Spade and, although the swivel enabled it to be turned fairly easily on retrieval, the swivel facilitated the rearwards orientation when motoring forwards so it was both partial cause of - and solution to - the problem. I do like to get moving as soon as the anchor is free so the boomerang, rather than reversing is our preferred solution.

 

[Fimacca]

Thanks all.

NormanS, do you have a pic of what you suggest ?

 

[Daverw]

If you do look at Neeves banana link I have one spare for 8mm chain as I had two laser cut from 316 stainless earlier this year or can send you the 3D CAD file and any laser cutting company will cut one complete with slots etc

 

[dunedin]

This is the cost no object solution - Osculati self aligning swivel- Osculati Anchor Straightener Stainless Steel Swivel 6-8mm Chain

But we took ours off as unnecessary complexity

 

[NormanS]

Thanks all.

NormanS, do you have a pic of what you suggest ?

Aboard just now with limited internet and no access to relevant photos. I'll send you one when I can.

 

[thinwater]

I have never seen the point of a swivel, but the water that I sail in is so watery that if the anchor wants to turn while being retrieved, the water isn't going to stop it....

LOL. I like that!

Let me further explain.

With my vertical windlass the chain cannot rotate in the gypsy once captured. Period. If the rotation is correct it will stay correct unless something changes that. If the anchor hangs free, with no other forces, the rotations will spin out during the lift. It is possible that a turn will come past the roller, but that is easily cleared by lowering a few feet while twisting the chain with a Phillips screw driver through the links or similar. Then it comes up straight. But for my boat, at least, the anchor will come up right 90% of the time.

 

[Neeves]

As Norman suggests he did send me a picture of his anchor righting device, it had an uncanny similarity to the Oscalluti device that is linked to above. There are a number of similar devices, there was no need to copy Norman's. I made mine from BIS80 steel because I had a piece of steel plate that Biasalloy had given me for 'experimental' purposes. My device has no moving parts and needs no welding. The strength is in the design.

It was written in the now defunct Australian magazine, Cruising Helmsman, I have a photo copy of the printed article, no PDF, send me a PM if you would like a copy. I can also send you more pictures, I have plenty

Anchor Right, of Australia, lifted the design from Cruising Helmsman called it their own and call it a Flip Link. It may be available from Jimmy Green. Viking Anchors asked me if they could copy the design - I had no issues - it is nice they asked. I had published open source so people could make their own - I am happy to see the design being used. You can buy a Viking Boomerang mail order (a number of members have bought one). You can make your own, see posts above.

I made a number of different styles or designs, to the same concept - they all work.

This is a comparison of a Mantus swivel vs a Boomerang. When the Boomerang is installed properly it cuts the seabed like a knife and offers less resistance to burial than the chain. The drawings of the Boomerang are defined round 8mm chain and 3/8th" bow shackles and then scaled.



The original design allowed for 3/8th" shackles but I have used both hammerlocks and omega links to good effect



These are the Viking renditions - they are making from Duplex stainless and are engraving the device with their characteristic 'V'. They sent me one and this is it installed on our cat. its fine. However as I use 6mm chain and omega links as enlarged links at the ends of the chain I have made, yet another, boomerang to more comfortably accept the device.




The best option, if you have the time, is to take up Daverw's offer or make your own.

Thinwater had a copy of an earlier of my designs and you can access the detail on his blog.

Everything I make or do is backed up with test data. The 8mm Boomerang, featured in the article and made from Bis 80 steel, has been tested and failed at 9,000kgs. 8mm G30 chain has a min break strength of 3,000kg and historically has had an actual break strength of just short of 4,000kgs

As an aside:

When modern anchors set they do so with the toe and the shackle burying simultaneously. As the toe and then fluke bury the shackle and increasing lengths of chain are buried. The chain (and shackle) are obviously essential but they do detract from the performance of the anchor (a big shackle and a big chain, say 10mm instead of 8mm) will reduce the ability of the anchor to set. Using a big swivel just adds to the problems.

Good swivels do allow you to 'self right' the anchor at the bow roller - prod the anchor to lie correctly. A boomerang, bent link, banana link does it for you automatically.

But before you attempt to make a device, or buy one, check the arrangement of the chain. If the chain is twisted between gypsy and anchor the anchor will always arrive at the bow roller incorrectly.

Jonathan

 

[Neeves]

This is the article from Cruising Helmsman I don't know if it will be readable. YBW does not quite cater for this sort of image. As I said - send me a PM and I'll send a HiRes version, but sadly no PDF. The magazine closed (could not compete with the internet (and forum like this) and there is now no PDF access.

Jonathan

 

[Neeves]

This is the Oscalutti bent link which, questionably, has a swivel incorporated in the design. It is quite common the the Med but this one was on a Catana cat on a mooring near our cat. Norman's bent link is similar to this design except, sensibly, no swivel and Norman welded rings to his bent stainless rod. I will not endorse a welded device as I cannot confirm the quality of the welds - and welding needs to be unquestionably good. I am sure Norman's welding is exceptional - but welds made by others - don't know (and I'm not a welder but I see some awful welds). The Catana bow roller design is hidden under the trampoline and it is essential the anchor arrivers at the bow roller right way round as it is impossible to manually self right (no access)

Cutting from HT steel to a tested design allows me to endorse and sleep at night



I have tried a number of designs, on the central theme and this is the one we use regularly, when I'm not testing alternatives



SSAB make some really excellent very thin HT steels, much thinner than made by Bisalloy. The steels are used in the safety cages in high end automobiles (Volvo) and SSAB gave me some small samples to test.

I had the Boomerang cut to allow the device to be used without shackles, design should not sit still. Its a bit of a fiddle to assemble and the dimension need to be accurate but it works. Sadly strength was only 3,500kgs not high enough for me and it is a design in waiting. I need more of the thin, higher tensile, plate to try again.




Jonathan

 

[NormanS]

I knew that Jonathan would describe the device in great detail. I am a man of few words....
A feature that the "bent link" or "boomerang" or whatever you want to call it requires, is sufficient length between the bow roller and the windlass gypsy. Not all boats have this. Before splashing the cash, or even better, making your own, (this is supposed to be a thread for practical boat owners), check to see that you have sufficient space to accommodate the link.

 

[Fimacca]

brilliant, thanks all - plenty of info for me to decide upon.

Is it just me, or is this daft varanjes advert coming up on screen every 30 seconds! v annoying YBW !!

 

[Boathook]

I knew that Jonathan would describe the device in great detail. I am a man of few words....
A feature that the "bent link" or "boomerang" or whatever you want to call it requires, is sufficient length between the bow roller and the windlass gypsy. Not all boats have this. Before splashing the cash, or even better, making your own, (this is supposed to be a thread for practical boat owners), check to see that you have sufficient space to accommodate the link.

I tried a kong swivel but it didn't work as the shackle was on my windlass. This also stops me using a boomerang so I have a 50/50 chance of the anchor coming up the correct way.