Anchor Swivel
- Thread starter thetone
- Start date
Why do you want an anchor swivel? Are you leaving your boat anchored for long time periods? Are you in some kind of tidal zone such that when you are at anchor your boat is being spun around in the same direction a lot? For the vast majority of sailors, a swivel is not needed.
The best swivel I've used is the mantus swivel.
dj
Agree. A swivel is not needed in most cases.
However, if you have an all-chain anchor rode, I find that a swivel is beneficial to help unwind the turns in the chain. The Mantus swivel is the best I have found because it's design will not enable it to generate a side load.
And Crosby brand shackles are the way to go. Forged in the USA. Not cast, or from China.
However, if you have an all-chain anchor rode, I find that a swivel is beneficial to help unwind the turns in the chain. The Mantus swivel is the best I have found because it's design will not enable it to generate a side load.
And Crosby brand shackles are the way to go. Forged in the USA. Not cast, or from China.
I’m another non-swiveler. For the type of anchoring I do I don’t want the extra point of failure.
Our 35,000 pound boat with a 40 pound Danforth anchor needed a new swivel and shackle. Settled on only USA made hot dipped galvanized products purchased from Defender. Both were 5/16", Crosby shackle and Chicago swivel.
Shackle: https://defender.com/en_us/crosby-g-209-series-anchor-shackle
Swivel: https://defender.com/en_us/chicago-hardware-jaw-to-eye-swivel
I had a swivel on my PDQ. Then I found a crack in it, when changing anchors. Never had one after that, never wanted one.
Tip. Anchors naturally align with the water flow, normally right way when the boat is moving backwards. If you tow the anchor in the water, very slowly, which way does it naturally align? Check your anchor. With most anchors, if you let the boat drift astern when raising anchor, it will come up right-way 95% of the time. If you raise the anchor while proceeding forward (most people do) it will come up backwards 95% of the time. Just let the boat drift backwards while lifting the anchor the last 10 feet. Easy peasy, no swivel needed. Kinda obvious, once you look.
Tip. Anchors naturally align with the water flow, normally right way when the boat is moving backwards. If you tow the anchor in the water, very slowly, which way does it naturally align? Check your anchor. With most anchors, if you let the boat drift astern when raising anchor, it will come up right-way 95% of the time. If you raise the anchor while proceeding forward (most people do) it will come up backwards 95% of the time. Just let the boat drift backwards while lifting the anchor the last 10 feet. Easy peasy, no swivel needed. Kinda obvious, once you look.
Since the question was "what size", not "do I need" ...
I do not subscribe to the idea that it is an extra point of failure. In a chain, every link is a point of failure. I am least concerned about the swivel, in that chain of vulnerabilities. Even if it was the weakest link (which I doubt), it also is the easiest and most-frequently inspected of all the links. (Of course, if the providence of the swivel's metal and manufacturing is uncertain, so is its security. But, that is true of every part of the system. Still, heed Rich's warning on this.)
Still, if the swivel is indeed the weak link (lowest WLL) in the rig, then the swivel is undersized. Mine has a WLL of 10,000 lbs. I don't know the true WLL of the chain, but I expect it is well short of 10,000 lbs - like in the neighborhood of about half that.
Yet, even though I have a swivel, I frequently wonder why. Since I have always had it, I guess I don't really know how much of a problem the twisting is.
What I am hearing is that folks who have removed them don't miss them. I am wondering if they just anchor in tamer conditions or if it really doesn't matter for a day or two on the hook. Maybe I'll post something in the PNW forum about that. Conditions up here are quite different from most areas. But, in my case, since the swivel well outperforms the chain, in terms of strength, I have no motivation to remove it. Not sure I would buy another one when this one EOLs, until I found I needed/wanted it.
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As to the question, there isn't an easy way to answer that. But, as suggested, the #1 consideration is to select a brand that can be trusted. Magnus and Ultra come to mind, but I have not personally verified these. They just have good reputations. There is no shortage of anecdotes of inexpensive swivel failures and other issues. After that, key factors to consider:
I do not subscribe to the idea that it is an extra point of failure. In a chain, every link is a point of failure. I am least concerned about the swivel, in that chain of vulnerabilities. Even if it was the weakest link (which I doubt), it also is the easiest and most-frequently inspected of all the links. (Of course, if the providence of the swivel's metal and manufacturing is uncertain, so is its security. But, that is true of every part of the system. Still, heed Rich's warning on this.)
Still, if the swivel is indeed the weak link (lowest WLL) in the rig, then the swivel is undersized. Mine has a WLL of 10,000 lbs. I don't know the true WLL of the chain, but I expect it is well short of 10,000 lbs - like in the neighborhood of about half that.
Yet, even though I have a swivel, I frequently wonder why. Since I have always had it, I guess I don't really know how much of a problem the twisting is.
What I am hearing is that folks who have removed them don't miss them. I am wondering if they just anchor in tamer conditions or if it really doesn't matter for a day or two on the hook. Maybe I'll post something in the PNW forum about that. Conditions up here are quite different from most areas. But, in my case, since the swivel well outperforms the chain, in terms of strength, I have no motivation to remove it. Not sure I would buy another one when this one EOLs, until I found I needed/wanted it.
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As to the question, there isn't an easy way to answer that. But, as suggested, the #1 consideration is to select a brand that can be trusted. Magnus and Ultra come to mind, but I have not personally verified these. They just have good reputations. There is no shortage of anecdotes of inexpensive swivel failures and other issues. After that, key factors to consider:
- Chain Size: The swivel must be appropriate for the diameter and link shape of your anchor chain (e.g., 1/4", 5/16", 3/8"). In other words, it must fit - no-brainer.
- WLL (working load limit, not breaking strength): Calculate the WLL of the weakest link of your ground tackle, as it is, whereby your chain probably has the lowest WLL. The swivel's WLL should exceed that (or at very least, match it). If a separate shackle is required, that has to be considered separately, and its WLL should match or exceed the rest of the rig.
- What is the size and WLL of your chain? (You might not know this.)
- What is the WLL of your anchor? (You probably don't have any way of knowing this.)
Just tonight I was being asked about anchoring systems and I pulled up H40 "Anchoring, Mooring, and Strong Points".
If you need a swivel, then you need to look at the required design loads for your boat - you state a 32 foot C&C.
So your design load would be 2700 pounds as you see in Table 1 from that standard. So you would look for a swivel that is rated for that loading or higher.
dj
If you need a swivel, then you need to look at the required design loads for your boat - you state a 32 foot C&C.
So your design load would be 2700 pounds as you see in Table 1 from that standard. So you would look for a swivel that is rated for that loading or higher.
dj
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We do not have a swivel, nor do I feel the need to get one. After 2 years of live aboard cruising and hundreds of days at anchor, there has only been one or two days that having a swivel would have been handy. On the rare occasions when the anchor does come up backwards, lowering back in the water and as @thinwater suggests motoring a short bit the anchor orients itself (and washes off the mud) coming up into the roller correctly oriented.
We have an all chain rode and a spade anchor. I'm wondering if people who are having difficulty with orientation are using a rope rode and the rope is causing the orientation issue.
Points worthy of discussion.
Extra point of failure. Regarding strength, if you match WLL there should be no issue. But there are two additional factors to throw in the mix.
- Inspection. You can look at a chain or shackle. The failure points of a swivel are most often hidden from view. The crack on mine I only saw when the shackle was disassembled, since it was obscured by parts of the shackle itself.
- Leverage. Many swivels are installed dirrectly to the anchor shank. Indeed, they are designed and advertised that way, even though it adds a terrible side load to the swivel and a side load to the anchor. Mine was designed this way. I think most of us would agree this is a serious mistake, but some of the readers of this thread may not have thought of this issue. There should be a few links of chain or a pair of shackles between the shank and swivel to eliminate this leverage.
A day or two. A valid point. I've never anchored for more than 7 days (I had a cruising cat for 15 years). I moved on, and I think this is true of the vast, vast majority. If you live on the hook, will stay in one place for weeks, and the wind or tide will 360 the bot daily, yes, a swivel is needed just as it is on a mooring. I think most would agree with this. The anchor is a mooring.
But in 7 days, how many times will the boat turn a 360? Probably not twice every day, since some turns will be in the reverse direction. Some times it won't spin at all, because the wind is steady and the tidal current is negligible (not all tidal harbors have a measurable current). So at worst, the boat spins 10 times in 7 days. That's probably less than 1 turn in 10 feet and will not be an issue. It will spin out. But for most of us, a typical few-day anchor might mean 2-3 turns at most. So yes, it depends.
Life expectancy of stainless. Galvanized in re4gular use lasts 4-8 years, depending on use. Stainless looks good forever, but in saltwater its fatigue/corrosion/cracking life is about the same as the life expectancy of galvanized. If stainless components are replaced at the same frequency as their galvanized cousins, all would be well, but typically that shiny SS swivel might get reused. It should not. My cracked swivel was probably 15 years old, probably on its second chain.
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What actually fails? Failure of chain, unless in truly horrendous rusted and worn condition, is unheard of. Shackle failures nearly always involve unscrewing; tighten them, mouse them, and perhaps add Loctite. Quite avoidable. Swivel failures are not unheard of, but most are either old (more than one chain), cheap, or attached to the anchor shank. A rope rode can cut, but you don't often hear of it. The rope can chafe on the roller side plates; more likely, but completely avoidable. Mooring pendants chafe through with every major storm. Or the anchor drags. Obviously, 1000 times more likely, and the reason is seldom any type of gear failure.
As I said, I removed mine and never missed it. In fact, because the windlass and roller keep the chain aligned, I had fewer backwards anchor incidents after I tool the swivel off. With the swivel there was a 50/50 chance the anchor was reversed. Without the swivel the anchor would come up right-way 98% of the time, because I drifted backwards and because the chain wanted to come up twist free, aligned with the windlass. That is my expereince.
If I stayed in one place long enough that my anchor was a default mooring, I bet I would have a swivel.
I was referring more to the fact that, around here, you can spin around dozen of times in a single night. Even a well-protected anchorage can become practically an eddy, at times.
When I hear people who say they have never felt the need for a swivel, they tend to be in less swirly areas.
But, like I said, I don't have a basis for comparison. We used nylon rode for years, so didn't have a swivel, then. Since we got all-chain rode, we have always had a swivel. So, I can't really say it does/doesn't make a difference.
For us, personally, the WLL of the swivel is something like 5000 lbs (as I recall). Though I don't know the WLL of the chain, it isn't more than that.
But ...
I think that gets at the crux of any good weak-link argument.
Not what I thought you meant.
I once counted eight 360 spins just while we were eating dinner in about 40 minutes. It was like a high speed revolving diner. Nice view. Every time we've anchored there (sans swivel) we've don a good many spins. I didn't record it, but I recall some of the spins would come out when the tide reversed. Yup, we have twirly places. Something about how the tide goes around the river bend.
Every rule has exceptions. That place would be one if I stayed there.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,127
There are many thoughts about swivels.
With the tides changing direction twice a day and to take out the twists on retrieve, I bought the Mantus Swivel.
The swivels of yesteryear had their weakness's. A few anchors were left stuck tot he sea floor when the swivel broke.
If your looking take a look at Mantus, then you be the judge.
With the tides changing direction twice a day and to take out the twists on retrieve, I bought the Mantus Swivel.
The swivels of yesteryear had their weakness's. A few anchors were left stuck tot he sea floor when the swivel broke.
If your looking take a look at Mantus, then you be the judge.