Mantus Anchor Swivel Break

[Spade Anchor]

Originally Posted by uncle stinkybob

I use all mantus ground tackle including the swivel, no issues what so ever.
I thought perhaps this thread titled " Mantus Anchor swivel breaks would have more user date about "Mantus" as usual, anything "anchor" has turned into a Spade advertisement.

Sorry you feel that way. I was asked questions directly on a forum that is an open discussion forum. Kinda felt the need to respond.

[CarlF]

I looked into this a few years ago and went with a Ultra swivel. Here's why:

The "new age" swivels do not share the design or engineering weaknesses of the ones that having been breaking for decades. Swivels have gotten better.

Conversely, galvanized shackles have gotten WORSE in the era of cheap asian imports. I've had several West Marine shackles break for no good reason and now only buy US made Crosby shackles to have some confidence. A 7/16" Crosby 209 has a 1 ton rating with a 1:6 safety ratio (12,000lbs). The harder to find 209A "High Test" is 2.6 ton (31,000lb) 7/16" is the "up one size" from the chain size that many recommend for 3/8" chain. The Ultra 13 swivel that I use with 3/8" chain is rated at 38,000 lb breaking strength.

The modern swivels (Mantus, Wasi, Ultra) are all designed to deal with sideways pull. This is not a difficult engineering problem if you make it part of your design. None of them rely on a simple bolt to hold the thing together. They don't loosen.

And finally - they don't rust like shackles.

I just wish they cost a bit less.

[Dockhead]

Originally Posted by Spade Anchor

Based on the Wasi Swivel is rated at least 2000 lbs higher (breaking/tensile strength) than any chain you can attach to it. I am not aware of any shackle on the market that can do that.

I just don't know about that. According to your website, the biggest Powerball which would fit my setup with 12mm chain, the 10/13mm model, has SWL of 1600 kg and BL of 6400 kg, far less than G40 chain (about 2000 and 8000), much less high test G70. And far less than the Wichard HR 12mm shackle, at 3600kg SWL and 10 000 kg BL.

But in any case, the straight line strength is not the issue -- it's SIDE LOADS which have broken Kongs and which are of concern with swivels. You have quite a lever arm there, which will magnify the loads in a side loading situation, the PowerBall much more than other swivels.

Kong publishes ratings for their swivels in side loading conditions -- typically 1/3 of the straight pull rating. The 12mm model (the one I used to have and use with my old Rocna) is rated at 3000 kg SWL and 9500 BL in a straight pull, and 3000 kg BL in a side pull.


On the basis of the data I was able to google up just now, it's really hard for me to see a case for using a swivel for the sake of strength. If you need the swiveling, of course, then that's a different matter.

[Smokeys Kitchen]

Originally Posted by a64pilot

I don't think I could break my Mantus swivel, reason is the way its constructed, you just about can't get a side load on the thing.
The next weak link is the pin, which on the Mantus is oblong to give the most possible area.
If it has a downside, It may be that it may not fit through some rollers, its not a small thing.

On edit, who was it that said, give me a long enough lever and a fulcrum and I'll move the world?

Archimedes

We have a fairly new Mantus swivel on our Vulcan. We have used it several times in the Puget Sound area, and we are now starting our trip up the Inside Passage to SE Alaska, so we should get a feel shortly how its working and holding up. So far, no issues what so ever. If any are interested, I'll chime in again when in cell/wifi range with an update.

[thinwater]

As A64 pointed out, so long as you are not motoring forward (VERY common mistake), any modern anchor will come up right-way. Ballasting has nothing to do with which way it twists. Proper alignment between the anchor and the windlass is everything.

I haven't had a swivel for years and don't have the need. The anchor comes up right 98% of the time, and I'm pretty sure the swivel would reduce that figure substantially. If it does come up backwards, all I do is lower it while backing, and it spins right-way. So easy.

[grantmc]

There have been quite a number of cases where the swivel fails. It's caused by fitting the swivel directly to the anchor (wrong) and when side load is applied voila, broken swivel.

There should always be a few (3-4) links of chain BETWEEN the anchor and swivel, to ensure it can't get side loading when the boat swings around the anchor.

[GRIT]

For those wanting to use a shackle: High Strength Shackles | Titan Marine Products .

They're rated higher than G4 chain, which is what most of us use. G4 or G43. The 10mm has a working load of 2 tonne, and a breaking load of 10 tonne. The 8mm: 1250kg and 6500kg. The pin on the 8mm has a 10mm diameter, and the pin on the 10mm has an 11mm diameter. (For our friends in the USA (8mm=5/16, 10mm=3/8, 10 tonne=22,000lbs)

I prefer swivels, or at least I always have. But we're going to try the shackle mentioned above, on the new boat for a while, and see how it goes. If we go for a swivel, we'll go with the ultra swivel, uas13. Rated at 17500kg (38000 lbs) breaking strength (fits 10-12mm chain) it ought to do the job. Ultra Anchors

The Ultra swivel turns the anchor at the roller, so it always comes up right side up.

Horses for courses gentlemen.

Cheers.
Paul.

[zboss]

Originally Posted by a64pilot

I don't think I could break my Mantus swivel, reason is the way its constructed, you just about can't get a side load on the thing.
The next weak link is the pin, which on the Mantus is oblong to give the most possible area.
If it has a downside, It may be that it may not fit through some rollers, its not a small thing.

On edit, who was it that said, give me a long enough lever and a fulcrum and I'll move the world?

I don't like the stainless construction (why can't they make it out of galvanized steel?) but I can live with that. What bothers me most is the stainless shackle, which has a lower working load than the best galvanized shackles of the same size.

Originally Posted by Spade Anchor

Usually with the Spade Anchor a swivel is not needed.

I love our spade anchor but when there is any current, or when we are moving forward my Spade anchor wants to turn the wrong way and face with the pointy end toward the current, usually 180 degrees from where I need it to be.

Originally Posted by grantmc

There have been quite a number of cases where the swivel fails. It's caused by fitting the swivel directly to the anchor (wrong) and when side load is applied voila, broken swivel.

There should always be a few (3-4) links of chain BETWEEN the anchor and swivel, to ensure it can't get side loading when the boat swings around the anchor.

This thread is supposed to be specifically about mantus swivels. These cases you mention are well documented poor swivel designs.

[a64pilot]

I feel pretty sure my Rocna spins so that it presents the least drag in the water, which is of course pointy end into the flow.
When I got the Mantus swivel I didn't use the supplied safety wire, I have a roll of aircraft .041 safety wire that I felt better about. I have had no problem with the wire yet, but if I remember right, you can't take the thing apart without first removing the shackle, so even if the wire broke allowing the barrel to unscrew it won't come apart?
I'm away from the boat now and can't look.

[UNCIVILIZED]

If you guys are really that concerned about strength, or corrosion resistance, just go to a titanium shackle. Then you'll have to find something else to worry about. Period.

[zboss]

Originally Posted by a64pilot

I feel pretty sure my Rocna spins so that it presents the least drag in the water, which is of course pointy end into the flow.
When I got the Mantus swivel I didn't use the supplied safety wire, I have a roll of aircraft .041 safety wire that I felt better about. I have had no problem with the wire yet, but if I remember right, you can't take the thing apart without first removing the shackle, so even if the wire broke allowing the barrel to unscrew it won't come apart?
I'm away from the boat now and can't look.

If the barrel unscrews, the swivel will come apart. When we were at the boat show, they recommended wrapping the threads with pipe tape before screwing it on. I suppose using loctite tape would work as well.

http://na.henkel-adhesives.com/indus...=8797952147457

[SVNeko]

Originally Posted by Dockhead

Even Kongs, considered by many to be the best, have been reported to break.

The swivel is likely to be the weak link in your ground tackle. I like the looks of the Mantus one though.

That's why I added "recent".

[gjorgensen]

Originally Posted by UNCIVILIZED

Anyone besides me ever use Spectra to mouse a shackle shut, along with wire? And any multi-strand wire users out there?

I have. I'll do a wire and some spectra as a safety in case the wire fails. The spectra is stronger and doesn't corrode. The knot is the untrustworthy part, but I use it as a backup anyway. My splicing skills are nowhere near good enough to turn it into a tiny soft shackle, which is really what it wants to be.

[pdxsailordiver]

I'm thinking of getting the Mantus swivel to go with my new rocna anchor.
Instead of safety wire would a long cotter pin be better?

[powsmias]

Originally Posted by Spade Anchor

ANy pictures available? Just curious.

Sorry, not one pic.. came up with windlass and i had to get some slack in chain before it got to the roller end or wouldn't clear.. imagine part my fault after dropping anchor maybe let out too much too fast. if i can get it in that position again i get you a photo.. thanx