How safe are anchor swivels

SeaSpray":2mzfvpln said:
I will probably go back to a regular shackle for peace of mind.
Click to expand...

From listening to experienced cruisers debate this issue, I have come to the same conclusion -- a swivel, no matter how well built, introduces a weak point into the ground tackle equation, and is rarely necessary. Even ultra expensive swivels like the Ultra Swivel require periodic attention to the locking nut.

Warren
 
I was concerned enough with mine that I dipped the pin in moderate strength locktite prior to assembly.

Now I'm sure someone will post that it is a known fact that "dried locktite turns into a slick lubricant and releasing agent when introduced to water". :sad

If the thread end wasn't still in there, I doubt it broke.

In my case, I'd probably be more concerned if that pin were to fall out on the highway.

Chris
 
I used HD Loctite (the red one), as it's all I had in the toolbox. :wink: Don't know about the water, but my thoughts are if it can handle oil, engine temps and engine torque etc, H2O shouldn't be an issue.
 
Depending on how the unit is made, you can either "stake" the threads so nothing backs out, or you can use stainless safety wire to lock things in place. Both work well.

Rick
 
I was told emphatically that you MUST add a standard shackle between the swivel and the anchor shaft. This is to prevent side-loading of the swivel when the boat moves from directly in-line with the anchor shaft, the swivel (that I have from WM at least) was not designed for side-loading.

I have yet to add mine, but I believe it will be soon because I need to renew my anchor line to chain splice, I'll do it at the same time.
 
Adding a shackle between the anchor and the swivel sounds like a good idea.

Before I added the swivel I did have twisting of the chain. Being thrifty I did not buy the most expensive swivel. I did buy one that had a specified load rating. I don't remember what that rating is but it is probably less than the chain, but seemed sufficient at the time.

I definitely do not want to wake up when my boats hits some rocks or another boat because of a swivel failure. With this information I am more inclined to go back to the trusty shackle and see if I can live with the twist.

Steve
 
Most of the less-expensive swivels are made in China, where the concept of quality control is not as advanced as in the US or Europe. Chinese swivels, etc. will be a couple of percent more likely to have weaknesses (voids, etc.) in the castings. I don't know about you, but I would not take that kind of chance with my boat.

Warren
 
Nigel Calder has a good treatment of this subject in his "Cruising Handbook" complete with pictures. (Yes, I know it's written for sailors, but there's still some good stuff in there.)

Paul Priest
J.C.Lately
Sequim
 
Steve...I would highly recommend a book by Earl R. Hinz...The complete Book of Anchoring and Mooring. Best book out there about anchors etc. He does not recommend swivels unless there is a need to anchor for extended periods. If a twisted rode is a problem when recovering your anchor...you are pulling it too fast and not allowing the twist to leave the rode.
The problem with swivels is that they are at best the weak link in the rode...at worst introduce huge loads that don't exist without a swivel. Swivels are rated for loads that don't account for the side loading...leverage introduced because of their design. This loads other compoments...maybe the anchor itself...sometimes causing failure. If you must use a swivel be sure to use shackles to attach them. Also be sure to mouse all pins or bolts.
 
OK, I have heard two new nautical terms here (in one thread) that I think I know what is meant, but I can not research anywhere?

"Stake" the threads and "Mouse" the threads.

I occasionally change out my anchor for where I'm going or at least change the connection point sometime to "breakaway" Columbia River type anti-snag position.

So, can you unstake or unmouse something? I'm starting to think a Shackle and stainless wire may be the way to go.

Chris
 
Let's look at loads in three possible directions. (I'm an engineer, I think like this.)

One would be an axial load, in line with the chain length. This would be the tensile load the swivel is rated for and if it's a quality swivel, sized correctly, it should be fine.

The second possible direction is a twisting load, and if the swivel actually swivels, this load is very small, resulting from friction only, and not a problem.

The third direction is where you can have a surprise problem. It's possible to get one end of the swivel jammed against part of the anchor (or something else) so that it can't pivot to stay in line with the pull of the chain. This isn't the "swivel" direction that allows for chain twist; this is a "sideways" direction that tries to bend the axle inside the swivel, instead of rotating around its axis. The swivel is probably weakest in this direction and can be made to fail easily.

If the swivel is installed in between chain links somewhere it should be impossible to jam it in this problem position. The potential problem shows up when you have the swivel mounted directly to the anchor's shank and the mounting allows for the possibility of the chain being able to pull sideways against the swivel while the swivel gets "stuck" in the mount so it can't swing around to stay in line with the chain. If you have this kind of an installation, you've got a time bomb waiting to go off some time. Snap.

If your installation assures that the swivel can't be side loaded and you've bought a quality swivel and locked the pin so it can't come loose then all should be safe.

The problem I found on my 22 is that there's very little room between the windlass and the hoisted anchor. I don't think I can mount a swivel in there in a fashion that would guarantee no possibility of side loading, so I'm not using a swivel. If I put it farther along the chain, it wouldn't go through the windlass.

Regarding general swivel design, if the ends of the swivel were big loops, like chain links, this bending issue probably couldn't come up. (You'd have a challenge to attach the chain or anchor, though.) When the ends of the swivel are parallel arms with a pin going through, then the flat side of the parallel arms can be made to jam against the flat sides of the anchor shank and you can have the bending problem.

Diagrams would help a lot, but I think I've covered it all in text here. There are other possible complications, too, like a compound bending and tensile load resulting from trying to load the swivel sidways and having part of the swivel act as a lever to add a tensile load to the bending load on the axle.

I think the main concern, though, is making sure you can't have the side loading condition (third direction discussed above) as a result of your installation geometry. Then you should be safe.

Jeff
 
The point that I think everyone is overlooking is that, according to what I read in the trawler community discussions, a swivel is not necessary.

Warren
 
I recall Bob (Thataway) saying that swivels, even the most expensive ones, just don't work under heavy loads when you need them the most, and that they were not necessary, and therefore an unjustified complication. KISS... (again)!

Joe. :teeth :thup
 
Hi Folks,

Some of the windless operate at one speed and therefor the anchor comes up pretty fast. I have a swivel attached to the anchor and the rode so it will not twist.

I have read all the comments about swivels breaking and I feel that the forces of a 22' C-Dory are not the forces one would get with a larger and heavier boat.

I will keep the swivel but will inspect it more to make sure I do not have a problem.

If it was a real serious problem, West Marine would not carry them.

What I am going to is mark the anchor chain so when it starts to come out of the water, I can control it better by stop and starting the windless.

My two cents worth.

Fred
 
**** BRINGING BACK AN OLD (2009) THREAD *****

Two questions.
1. Are folks using swivels now, or is it still a split group? And if so, what kind and what results, OR IF NOT, how is that going? Is there much issue with twisting?

2. The last post mentions marking the chain. I have 70 feet of chain and I am looking for good ideas on marking it. Paint, I'm OK with, anyone have a particular type that stays and shows up easily?

Harvey
SleepyC :moon

IMGP2460.thumb.jpg
 
I've never used one and would not. I've never seen the need or even the benefit. How can the boat spin around on the rode enough to bind up the chain? Under what circumstances does an anchor spin around when on the bottom? I just don't see the need. If there ever was a problem, drop and retrieve the anchor in 500' of water and you're good for another year.

Second reason is my experience with failures on other swivels. Camera equipment and saxophones. Those are little swivels, but the same principal. They have some kind of a socket that can't be inspected. A wear point. Swivel failures are usually catastrophic, meaning that one minute it looks okay and the next it has parted. With the anchor swivel, you can add sand as an abrasive.

Given that the only benefit is that they look cool, I'll pass.

Mark
 
cemiii":2yebn8fc said:
OK, I have heard two new nautical terms here (in one thread) that I think I know what is meant, but I can not research anywhere?

"Stake" the threads and "Mouse" the threads.
Click to expand...

Don't know if cemiii is still visiting the Cbrats or not - but for the sake of leaving no question unanswered - better late than never.

To mouse a thread is similar to the use of a cotter pin except that wire is used - threaded through a hole in the bolt or pin.

To stake a thread involves flattening the threads protruding from the nut after tightening the bolt. For an anchor shackle it could be laid on an anvil and the other side hit with a hammer(only need to do this on 1 side). It can be undone with force but is considered permanent because the threads are destroyed once undone - on both the male and female fastener.

Regards, Rob
 
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