How Well Do Anchor Swivels Reduce Chain Twist?


We know the theory behind using an anchor swivel: The swivel releases any twists in the chain when an anchored boat swings through 360 degrees or more. Still, as I’ve addressed in previous blog posts, we question the logic of using one. Our skepticism is supported by our own experience, previous testing, and input from long-term cruisers, but we also wanted to devise a test to investigate chain twisting.

We took 30 feet of 5/16-inch chain and freely suspended it roughly horizontal between two secure points. We tensioned the chain to about 90 pounds of load. We had a swivel at both ends; the top swivel was a standard cheap swivel that allowed us to manually twist the chain. At the anchor end, we tried two different name-brand swivels, the Mantus swivel (for sizes 5/16-inch to 3/8-inch chain) and a 5/16-inch, galvanized Acco swivel.

Working from the top, we twisted the chain to find out how many twists in produced enough torque to allow the attached Mantus or Acco swivel to release the turns.

The results were surprising. The Acco galvanized swivel took eight complete twists in the chain before it started to turn, and the Mantus swivel took 6.5 turns. Given that typically skippers might be deploying three times the amount of chain we tested with, it is obvious that several more turns-possibly three times as many-would be required for the bottom swivel to make any difference.

In order to transmit torque onto the swivel, the chain will need to free of the seabed, requiring more load (about 160 pounds for 100 feet of 5/16-inch chain in 20 feet of water), and the torque required to release twists will be higher than in our simple test.

In our view, it is unlikely that the swivel will reduce anything but a large number of twists, and these twists could be removed more safely and easily by slowing down the retrieval once the anchor clears the bottom. A slower retrieval also prevents the hydrodynamic force on an unbalanced anchor that might cause it to spin. In fact, anchor spin upon retrieval with a high-speed windlass is probably the most likely cause of twist, and is often mistakenly attributed to the windlass itself. Ironically, if your anchor rotates in a beneficial direction as it comes up, the swivel might actually prevent the anchors rotations from untwisting the chain.

If your anchor chain is twisted to the point that it is forming hockles or causing it to jump from the windlass, you will want to deploy all the chain, untwist it manually, and load it back into the locker. You can do this ashore (and mark your chain lengths at the same time, if needed), but it is often easier in deep water.

Unless you are retrieving the anchor so fast that it spins like a whirl-a-gig, or the tide and wind is spinning you around like a barber pole, you should not have to untangle it again for months or more.


How Well Do Anchor Swivels Reduce Chain Twist?

Jonathan Neeves


Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 45 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. You can reach him by email at


  1. Maybe it’s not valid (I don’t have enough experience to know) but the argument I read for a swivel is that it prevents chain twist that could dislodge a previously set anchor. Your article did not address this concern directly, but are you suggesting that, given what you’ve explained, it’s extremely unlikely that chain twist could ever un-set an anchor? This would be an interesting proposition to set up a field test for.

  2. Many years ago(1969) I moored my 27′ sailboat to an old engine block with chain without a swivel. Over the course of the Winter, the chain twisted and shortened to a point that the vessel dragged the engine block ashore in a strong wind.

  3. In the Bahamas, there are anchorages where you spin around the anchor several times a day. If you stay there for 4 days, you’ve got maybe 12 twists. After weighing anchor, you maybe go to another anchorage where the same thing happens. Maybe it’s a couple of months before you visit a marina where you can untwist the chain on a dock. I don’t believe that everyone needs an anchor swivel, but I think that there are situations where they are a very good idea.

  4. Thanks for investigating this issue! We’re in the Caribbean now, anchoring almost every day. I’ve been wondering how the twists occur. One theory I have is that as the boat swings through an arc, the chain drags sideways, rolling on the bottom. Does our Mantus swivel actually make this worse, as there is less resistance to twist? Would be nice if this aspect were tested in a controlled fashion.

  5. I use a swivel. I find it helps prepare the anchor for stowage on my rollers by allowing me to turn the anchor with a boat hook if it comes up and is not facing the correct way to ride the rollers.

    As mentioned, my experience is that a slow retrieval of the anchor chain seems to be the best defense for reducing the chain twists.


  7. Anchoring and using a mooring chain are two different things. You always use a swivel in a mooring chain set-up exactly for the reasons you describe.

    In my own experience, even with tide changes, my boat does not always spin the same direction for both tides. So it spins the chain a couple times the. I spins other times. I’m sure there are exceptions though.

    My main concerns about swivels is they have been known to fail. I know sailors that have had them fail.
    Most sailors I know who insist on using a swivel do so because the shackle connecting the chain to the does not easily pass over the bow roller or they get frustrated trying to get the anchor oriented correctly to roll up over the roller properly oriented for stowage. I have always managed to work it out with a little patience and the use sometimes of a boat hook.

  8. From what I read, and my own experience over 60 years of anchoring, a swivel is not necessary m, at all. Perhaps on a chain mooring , but not on a cruising yacht that stays in anchors but a few days.

  9. From what I read, and my own experience over 60 years of anchoring, a swivel is not necessary m, at all. Perhaps on a chain mooring , but not on a cruising yacht that stays in anchors but a few days.

  10. I have an oversized Mantus swivel.

    Reading multiple opinions that swivels are bad, I tried going back to a simple shackle but found that the bloody thing will catch and bang on the bow rollers or foul on the bow roller cheeks. It is distinctly more violent in passing over the bow roller.

    The Mantus swivel by comparison flows over the bow rollers much more smoothly.

    With a breaking strength significantly greater than the 5/16” HT chain, I do not think it is the weak link so the Mantus swivel stays in place.

  11. Love gadgets and swivels seemed like a good idea based on faith as a weekend cruiser for many years. We’ve been cruising full time and living on the hook for 5 years now and I removed the swivel (Mantus) after the first year as it wasn’t doing anything, the chain usually came up with plenty of twists anyway.

    I learned to keep the chain correctly oriented in the windlass gypsy and bring it up slowly when the twists start appearing and the chain will come up all the way oriented correctly untwisted. Bringing it up slowly is more to prevent the chain from jumping the gypsy than spinning the anchor which will happen anyway. I have a zip tie marking where to stop the chain on the gypsy when the anchor is home that is oriented UP so I know the chain is oriented correctly or not and can manually adjust if it jumps. As long as I deploy and raise the anchor and the chain doesn’t jump the gypsy it stays oriented correctly as indicated by the zip tie.

    Early on, one of the biggest mistakes I’ve made was to dump all 500 feet of chain while tied up to a mooring bouy to untwist it and it created such a huge tangled ball it took me hours to fix!

  12. I have had 150 ft of 3/8 BBB backed up by 200 ft of 5/8 NER Megabraid, with a Maxwell reversing solenoid 3500 windlass!! In 7 years of sailing around the world, mostly at anchor and not in marinas, and 3 round trip Atlantic Crossing from Florida, I have never used an anchor swivel and have never needed one. The trick is to retrieve your anchor and anchor chain slowly, and let it spin itself out of turns in the chain as it rises to the surface from the sea bed. At least that’s always been a solution for our 39 foot sloop especially easy in deep water!!!

  13. For me, the benefit of using a swivel is at the end of anchor retrieval. It allows the anchor to align with the bow roller. I have not seen evidence of twist in the chain, but sometimes the anchor comes up facing the wrong way to be stowed.

    My swivel is rated for approximately the same load as the other components of the anchoring system (chain, rode, shackles). Perhaps I am lucky, but the swivel has not failed, nor have I heard of failure from any of my sailing friends.

    I suspect that any twist is generated by the anchor’s motion through the water during retrieval, rather than from the boat rotating around the anchor several times while actually anchored. It’s hard to know what actually happens without an underwater camera.

  14. We lived aboard a 89 Tartan. We had a 66# Spade on 200′ of 3/8 chain.
    This anchor always came over bow roller upside down until I replaced the swivel with a very expensive SS ball bearing swivel. It never happened again. I never understood why but the new swivel made our lives much better.

    Fran Cichowski

    • My 66# Spade ALWAYS comes up backward too, and I have a Mantus swivel. I’m thinking the shape of the spade must twist it that way on retrieval. I’m going to start retrieving more slowly this season as that is the only thing I can think of that causes this.

  15. I don’t use a swivel and don’t think they’re needed for general anchoring. Having said that I’m not sure the test method in the article is a good real world test. A swivel in real world use would be be lubricated by water, and it would have much more intermittent loading and movement than this static load. I suspect those factors would allow it to untwist at many less turns than this test suggests.

    • I agree
      A static load in dry conditions is a poor model of what occurs in real conditions.
      PS has provided essentially a single data point and I would take the info as such.

      Not to mention how many redundant systems/contingencies/backup to the back ups sailors routinely employ.

    • Capt. Ron, was spot on identifying a basic flaw in this study’s design. Namely, an anchor rode is NOT suspended in dry air, but beneath water which acts as an important lubricant helping the links untwist while encouraged by the swivel. It further assists untwisting due to the waves/boat pulsing action being experienced at anchor and while weighing anchor.
      While readers’ anecdotal comments have interest, I much prefer such sage advice as 1.) the U. S. C. G. illustration and recommendation on page 59 of their “A BOATER’S GUIDE TO THE FEDERAL REQUIREMENTS FOR RECREATIONAL BOATS” which illustrates a rode’s swivel, and 2.) a leading windlass manufacturer, Maxwell, Installation’s “General Requirements” specifically stipulates a swivel’s placement on the chain “to prevent the line from twisting”. There are many junk swivels available, instead, spend a few extra bucks to install a rated, high-quality one, such as Mantus, Norestar, Maxwell, Lewmar or Ultra.

  16. In many years of cruising, I have found a swivel useful when moored to a mooring. I use a 1″ swivel on my 41′ Gulfstar Ketch.
    At anchor, the only way the swivel would reliably work is if the swivel will be in the lower catenary when a modest load is applied. If it is at the anchor, for it to release, the entire catenary needs to be off the bottom; this can occur, just BEFORE it pulls the anchor out, in which case “it works”
    The best place to test is Barra de Navidad, Jalisco, MX or Boca Chica Panama, both of which have a reliable 360deg turn every tide cycle. Boca Chica has a strong current which pulled the catenary off the bottom every slack, which released the twists. Someday was left at anchor 6 months after which there were a very modest number of twists; Barra on the other hand has a mid current, and our anchor chain hockled after less than 2 months, even with the 1″ swivel at the anchor. Water depth was 13’at low, about 65-70 feet out, sheltered lagoon. My theory is there was never enough current to lift the chain so it could spin.

    • One further comment, If you have a swivel at the anchor, to get the chain to unwind more quickly, back against the anchor without breaking it loose, until the chain is off the bottom, it will mostly unwind quite rapidly.

  17. Thank you for this research. It would have been helpful if those responding had given the make & model of their windlass or the retrieval rate. Mine is a Maxwell HWC1500 with 300′ of 5/16″ HT Acco/Peerless Galvanized chain, both installed 12.5 years ago and reversed once 6.5 years ago. It is a fast-retrieving windlass which I have been thankful for in the past but I have come to the same conclusion as your findings lately; retrieving slowly is better. However, anchoring in Northwest deep waters can take a lot of chain compared to other areas; I would say my average anchoring depth is 60′ and I have anchored in as much as 100′ on an ideal night. My rode is normally 150-200′ and 250′ on occasion.

    During the windlass install I had the roller at the far end of my anchor roller grooved to accept a chain link thinking it would help eliminate twist before the chain got to the gypsy. I believe that helped initially but not with advancing chain age. The chain reversal also helped initially but was lost again with chain age. The advantage of minimal friction (as in new chain) of the chain makes all the difference with twist correction.

    I once anchored in Blenkinsop Bay just off Johnstone Strait in Brithish Columbia and found the boat in a near constant rotation throughout the night. So, selecting an anchorage that minimizes current rotation would be best advised.

  18. I use a swivel on my now powerboat. I have tried various swivels, but the big problem is that there is too much friction on the swivels that I tried to allow it to turn/swivel freely. The solution that I found that works well is an ultra-swivel, expensive yes but works. One of my concerns was handling the anchor when it was entering the bow rollers. I did not want to have to flip a 120 rocna Vulan by hand. Too easy to lose some fingers. The ultra swivel is designed to flip anchor into the correct entry position and does a good job of flipping. Key is to proceed slowly and allow the swivel to work using a gradual engagement to the rollers. If you do it fast is can be quite violent, and potential could cause some damage.

  19. We have a Bruce 30-kg anchor attached to a Wasi Powerball swivel for the sole reason of being able to manipulate the anchor to the correct attitude for going over the anchor roller. We have done literally thousands of anchor deployments and retrievals. The swivel we have solves an important issue but has nothing to do with untwisting anchor chain.

    Fair winds and calm seas.

  20. I was sold on the idea of a swivel on the anchor chain and I bought an expensive one. I later found that it was the swivel that needed attention often to keep it working. I lived aboard for 3 years in the Caribbean and did away with the swivel.

  21. I have a Kong 316 stainless steel swivel anchor connector. It connects a 20′ length of 1/4″ diameter PC chain to my anchor. The anchor is a 22 pound Lewmar Delta. 200′ of 1/2″ nylon rode is spliced to the chain. We pull the anchor up manually, the boat does not have a windlass. We anchor in sand, clay, or mud. I have anchored about 40 times with my current boat, always less than 24 hours at a time. Normally we anchor with at least 10:1 scope, frequently more. The chain and rode has never had twists or hockles. The anchor has never dragged or released. The boat is a Beneteau 321 sailboat that weighs about 9,800 pounds.

  22. I have a lofrans anchor winch. The gypsie does not allow the chain to rotate. If you stay at anchor for a number of days it has been my experience that you will do a number of loopty loops winding the chain. As you bring in shortening scope chain tightens the twist which was quite noticeable without a swivel and would not unwind during the lifting from the bottom to the boat. If there is a lot of friction in the swivel the chain does not necessarily unwind. The galvanized swivels did not mitigate the twisting in the chain. As I noted in a previous post the ulta-swivel does remove most twist. So when you look at a swivel, put some load in tension on it and see if it turns if it does not maybe a no swivel would be a better solution IMO.

  23. It is worth mentioning that you shouldn’t use a swivel with 3-strand rode, because under high load it can untwist, unlay, and potential hockle if the load is released suddenly. As long as the rode is fixed against rotation at both ends (the anchor and where you cleated it off) the rope cannot twist and this is not a problem. This is not a problem with braided rope.

    When anchoring through many tidal swings it is good practice to uncleat and recleat every week taking in or letting out 10 feet of rode, both to limit the UV exposure of the length between the hawes pipe and the water, and to reduce algae growth on the rope. In the case of a permanent mooring pendant we recommend oversized braided line with a chafe cover.

    A single 3-strand snubber line will also do this, twisting the chain rode around it. The result can be severe chafe of the snubber in just a night or two. For this reason, braided snubbers are preferred. On the other hand, I have used 3-strand for bridle snubbers with a wide angle (catamaran); because it is a triangle, it is fixed against rotation and does not twist. A bridle with a narrow angle (monohull) my twist, although I have not seen that.

  24. As with most aspect of anchoring there is never one right answer. What works for you, or me, does not necessarily work for someone else. As an example…

    When an anchor is deployed and tension applied to the rode the anchor then addresses the seabed and – we hope – the anchor engages with the seabed and then sets. Simple stuff. But as the anchor engages, the toes starts to dig in then – with most modern anchors – the shackle end of the shank also digs in. The toe and the shackle bury, roughly, at the same rate. The anchor, again if it is a modern anchor, has been designed with a thin (strong) shank – because a beefy shank resists penetration and burial. If you add a swivel to your rode it will be the biggest component in the rode, bigger than the shackle and ‘fatter’ than the shank – and your swivel will detract from anchor performance.

    Adding a swivel needs to be considered in combination with the rest of the rode, the chain, anchor, shackle and windlass – not considered in isolation.

    The best way to remove twists in the chain is to retrieve the anchor until the anchor hangs vertically – torque will remove virtually all twists – but whether your chain is hanging in the air (and is dry) or in water the friction between the links will be sufficient to leave at least half a twist in the chain – this half twist may never ‘untwist’ and your anchor may arrive at the bow roller ‘upside’ down – now matter how good your swivel – the swivel also suffers from friction. Fortunately anchor design is such, for other reasons, that if it arrives upside down it will commonly self right – so why have a swivel……?

    Our Maxwell windlass retrieves quickly – so quickly that there is insufficient time for the anchor to self right, itself, and you either need a device that automatically self rights the anchor – or you stop the windlass before the anchor reaches the bow roller and you manually right the anchor.

    One redeeming feature to twists in the rode – they will not pass through the chain wheel/gypsy.