Side loading on Ultra Swivel (or swivels in general)

[Muaddib1116]

In general, the consensus seems to be that swivels are a good thing, if not strictly necessary. In the other Ultra anchor thread, Panope posted some photos showing that he had to put the shackle pin through the Ultra anchor shank, since it is not an oval hole. Ultra responded with the photos of their swivel, which look very nice.

I watched some videos on their swivel, and it seems like a big feature of it is the auto-flip feature that makes sure an anchor isn't coming up on the roller upside down. It's a clever feature that seems like it probably works well and is a big help depending on how your roller is setup. It does however look like it would not do very well with side loading.

Another really popular swivel, the Mantus swivel, for example, goes out of it's way to do two things, swivel and prevent any sort of binding. To do this, it requires a large shackle to go through the anchor shaft with the U part, and have the pin on the swivel. On their site, Mantus shows an example of this, where anchor rode pulled perpendicular to the anchor shaft, side loaded a swivel, and pried it open.

https://www.mantusmarine.com/mantus-...ebase/swivels/

It makes me curious about the Ultra swivel, because to accomplish their feature of flipping the anchor, it requires a rigid connection to the anchor shank, for the swivel tab to turn the anchor over. I wonder if it is vulnerable to side loads.

[s/v Jedi]

Why does it need to look sexy? I have been using commercial galvanized swivels and shackles with my galvanized 176lb anchor for 17 years and it’s all good

[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.

[Jim Cate]

n general, the consensus seems to be that swivels are a good thing,

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. We have noted zero issues with not having one in the thousands of anchorings since then.

Jim

[a64pilot]

Originally Posted by s/v Jedi

Why does it need to look sexy? I have been using commercial galvanized swivels and shackles with my galvanized 176lb anchor for 17 years and it’s all good

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?

[Muaddib1116]

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. We have noted zero issues with not having one in the thousands of anchorings since then.

Jim

Fair point. Do you put the pin of the shackle through the chain or through the anchor shank?

[darylat8750]

I used a swivel / shackle like S/V Jedi for several years. After having the chain get twisted anyway I was thinking about taking the swivel out of the system. Then I too saw Nolex's post and quit using the swivel.

[Muaddib1116]

Does anyone have a link to this post? I can't find it.

[slug]

Originally Posted by Muaddib1116

In general, the consensus seems to be that swivels are a good thing, if not strictly necessary. In the other Ultra anchor thread, Panope posted some photos showing that he had to put the shackle pin through the Ultra anchor shank, since it is not an oval hole. Ultra responded with the photos of their swivel, which look very nice.

I watched some videos on their swivel, and it seems like a big feature of it is the auto-flip feature that makes sure an anchor isn't coming up on the roller upside down. It's a clever feature that seems like it probably works well and is a big help depending on how your roller is setup. It does however look like it would not do very well with side loading.

Another really popular swivel, the Mantus swivel, for example, goes out of it's way to do two things, swivel and prevent any sort of binding. To do this, it requires a large shackle to go through the anchor shaft with the U part, and have the pin on the swivel. On their site, Mantus shows an example of this, where anchor rode pulled perpendicular to the anchor shaft, side loaded a swivel, and pried it open.

https://www.mantusmarine.com/mantus-...ebase/swivels/

It makes me curious about the Ultra swivel, because to accomplish their feature of flipping the anchor, it requires a rigid connection to the anchor shank, for the swivel tab to turn the anchor over. I wonder if it is vulnerable to side loads.

The mantus looks well engineered

That ultra looks like it will not tolerate side load

Many swivel suppliers give you both inline and side load ratings

It’s possible that the ultra is strong enough in side load conditions to satisfy requirements

[Dsanduril]

I think he’s actually posted a couple of such photos, but here’s the thread:

https://www.cruisersforum.com/forums...ng-127858.html

[Paul L]

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?

I've bent a swivel in exactly this case. Anchor wedged in rock/coral and you are working to free it by pulling in various directions. If you cruise long enough you will eventually get your anchor jammed at some time.

[CarlF]

I think you have to separate the "new gen" swivels from the old ones that have been breaking for decades.

Side loading a swivel is only a worry if it causes the swivel to fail before the anchor shank bends or below the listed breaking strength of the swivel. Most anchor shanks bend at a surprisingly low side loading.

Both the Ultra and Mantus are clearly engineered with side loading in mind. The Mantus will articulate 90 degrees. The Ultra about 30 degrees. The Ultra is also designed with a very beefy post/ball design that looks able to take a lot of side load.

In the end, it's all about good engineering. I've owned a Ultra swivel for close to 10 years and never worried.

[RaymondR]

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.

Couldn't let this one go by.

They are designed to be put in tension, it's why they have a nut and screw threads. Mostly they don't work properly unless put in tension as the nut will generally unscrew itself and fall of.

[RaymondR]

It would be better if they built the swivel into the anchor shank.

I use one because I anchor for longish periods in a lot of areas with tidal streams and varying wind directions. However in a situation where ground tackle integrity was critical I would probably take it out for the duration.

[Muaddib1116]

I took a look at that Noelex post and I'm not sure if it's really an indictment on modern purpose-built anchor swivels. Nor do I think it has much to do with side loading.

As far as the Ultra swivel, it does seem like the only way it would break or bend the anchor shank is if the anchor was stuck in rocks or something, and the boat shifted so there was a significant side load. I guess the thing is that it's maybe better to bend the anchor shank, than pry apart the swivel and detach from the anchor.