Side loading on Ultra Swivel (or swivels in general)

[s/v Jedi]

Originally Posted by Muaddib1116

I've always assumed that they don't have enough strength. A little bit of research sort of bears that out. From 1st-chainsupply, the swivels that will fit 3/8" chain and smaller have a lower WLL by a few hundred lbs, but once you go up past 3/8", the swivels strength starts to get outpaced.

I mean, use whatever you want, if it works for you. But not a lot about boating is sticking just to what you need.

The way this works is that the anchor chain is ordered with enlarged end links. The hardware in the picture is 3/4” diameter... my chain is half at 3/8”

[Muaddib1116]

Originally Posted by s/v Jedi

The way this works is that the anchor chain is ordered with enlarged end links. The hardware in the picture is 3/4” diameter... my chain is half at 3/8”

Ah, cool, didn't know that was an option.

[s/v Jedi]

Originally Posted by a64pilot

The problem I have with those swivels is as a mechanic I can tell you that you never put a bolt in tension if it’s at all avoidable, it’s much weaker than a bolt in shear.
The Mantus design as an example has the pin in shear, plus it’s an oblong pin that is stronger than a round one.
Obviously the swivels you show are strong enough, you have been using them for 17 years and they have been in use for much longer, but there are stronger designs.
Just so long as the swivel’s strength is greater than the chain, I don’t think it matters what swivel you use, but I want the swivel stronger than the chain, and I think if you use G40 series chain, that’s not easily accomplished?

But to go back to the original question, yes the swivel in question is susceptible to side loading, the next question is just how big a side load does an anchor swivel see? My guess would be that the side load will build until the anchor of course resets, relieving the side load, and unless the anchor is hung in rocks or something, then the side load should never really be an issue.
But having said that I have seen bent anchor shanks, so obviously an extreme side load does happen, even if rarely because what else could bend and anchor shank to the side?

These swivels have been used forever and I have never heard of a failure. They are rated. This swivel is a Chicago Hardware and has a SWL of 7,000 lbs and the shackle is a Crosby (best shackle in the world) at 9,500 lbs. My chain is 3/8” G70 at 6,600 lbs.

What I don’t like is a stainless swivel and/or shackle on a galvanized anchor and/or chain.

[s/v Jedi]

Originally Posted by Muaddib1116

Ah, cool, didn't know that was an option.

This is how it’s been done to get in spec. My chain was ordered like this from Acco Chain. They even x-ray and test the links and then hot dip galvanize together with the chain.

When you zoom in you can see the larger end link:

[Souzag818]

One mans ceiling is another mans floor. No swivel for me, like no anchor with a roll bar...

[ranger58sb]

Originally Posted by Muaddib1116

In general, the consensus seems to be that swivels are a good thing, if not strictly necessary.

I suspect it'd be more accurate to think consensus is that swivels are only "good" when they're needed to solve some specific problem... otherwise to be avoided.

Originally Posted by Jim Cate

Far from a consensus in truth. Many experienced cruisers, ourselves included, disagree that swivels are a "good thing". In a few instances they add a bit of convenience, but are always an added failure point to be considered.

We stopped using one some years ago when Nolex published a photo of one in the very act of failing.

Building on that...

And then general opinion also seems to be all over the map, because of the various qualities (or not) of swivels that have failed (or not)... with reporting all conflated into a more widespread feeling that "swivels aren't great."

Some of the failure pics I've noticed over the years were simply crap swivels in the first place; some may have interpreted some of that to "all swivels are crap." Some of the pics were of decent swivels that failed anyway; another potential source of "all swivels are bad."

-Chris

[s/v Jedi]

I agree that most do not need a swivel at all. It now became clear to me that many use it as a connector because a shackle does not fit their chain link. They do not have enlarged end links on their chain.

We tried to go without swivel, but being anchored for months at times, the chain does develop twists that interfere with smooth windlass operation, while there is no problem at all with swivel.

We used to have a 5/8” swivel and shackle of the type I posted pictures of. We used that when we went through hurricane Ivan, with 120 knots sustained winds. The shackle, which has a higher rating, was stretched and had to be cut off as the pin did not turn anymore. The swivel was just fine, without any evidence of the load it experienced.
That incident is why we went up in size to 3/4” hardware. Let’s hope we never see it tested

[Moontide]

I don't use a swivel now but have in the past. The big problem I have always seen is the side loading which could overpower the attachment to the anchor.



When I did use one I always had about 1 foot of chain between the anchor and the swivel. This insured that the load on the swivel would also be in tension and never side loaded.



I really don't understand, and am scared, by the pictures of the fork fo the swivel being attached on the end of the shank. Disaster waiting to happen in my opinion.


Bill

[Muaddib1116]

Yeah, that definitely seems like a concern, and that's true of a shackle with the pin through the anchor shank, which is required with the Ultra anchor. It can put a prying load on the swivel/shackle fork/bow that puts the shear pin securement in tension, which it isn't designed for. I think the connection at the anchor should always allow the bow of a shackle to be through the shank, and then any swivel or chain can be connected to the shackle with the pin.

[slug]

Originally Posted by Moontide

I don't use a swivel now but have in the past. The big problem I have always seen is the side loading which could overpower the attachment to the anchor.



When I did use one I always had about 1 foot of chain between the anchor and the swivel. This insured that the load on the swivel would also be in tension and never side loaded.



I really don't understand, and am scared, by the pictures of the fork fo the swivel being attached on the end of the shank. Disaster waiting to happen in my opinion.


Bill

Yah. That’s the best way to rig most swivels

The chain leader can be short ...only a couple links

[lhuff35204]

After reading this article and finding that our Mantus anchor always rights it self in the roller I removed the swivel from our ground tackle.

https://www.practical-sailor.com/sai...ution-required

[tarian]

Unless some one can give a proper scientific explanation of not using swivels and using the most common and excellent swivels on the market and showing proper failures , written up, them I will keep using my Kong swivel with 3 links of chain then attached to Anchor , this has been a proven upgrade , if you do not want to fine if you do fine, but keep the speculation to the virus

[slug]

Originally Posted by lhuff35204

After reading this article and finding that our Mantus anchor always rights it self in the roller I removed the swivel from our ground tackle.

https://www.practical-sailor.com/sai...ution-required

Be careful with what you read .....

“The cup swivel lets you see all the critical components. We tested two galvanized cup swivels, one from Peerless (Acco) and another from Campbell; both U.S.-based manufacturers anchor shackles did well in our recent test (see PS July 2015 only). The two swivels were surprisingly similar; both were 5/16-inch models, for a 5/16th inch chain, and both failed at 7,500 pounds. One of them failed in the body of the swivel, and the other failed at the clevis pin.

The ultimate tensile strength (UTS) for these swivels is consistent with the advertised working load limit (WLL) of 1,250 pounds (with a 3:1 safety factor). But this is well below that of a typical 5/16-inch G30 chain, which has a UTS of 9,000 pounds. If you insist on having a swivel for your 5/16-inch anchor chain, you should at least upgrade to a 3/8-inch swivel (WLL of 2,250 pounds), or even a half-inch swivel (WLL of 3,600 pounds), if it fits. If you use larger chain, you also will want to upsize the swivel to match the chains UTS. “




The engineering for ground tackle calls for the attachment of the anchor to chain to act like a fuse that protects the system

The failure mode for the system is ....

First the shackle , swivel fails
Second the chain fails
Third the winch bow roller assembly fails
Forth the deck fails

For example

[Quadrille in JB]

When anchored for more than several days in high current situations our chain becomes so twisted that it will jump off of the Lofrans windlass. Adding a Mantus swivel to our 22kg spade primary anchor has solved this problem completely. It also makes it a lot easier to deploy our chain snubber

[lhuff35204]

We've been anchoring in tidal rivers, but haven't noticed any issues with twisted chain. I'll keep you posted.