Mantus swivel? Design flaws? Or no swivel at all?

[GordMay]

You mouse your shackle pin, so why not your swivel? The tie wire (or cotter pin) doesn't see any significant load, so presents no hazard.

[ranger58sb]

Originally Posted by sy_gilana

We never use a swivel. That would allow the anchor to come up bass ackwards or sideways. Our anchor comes up correctly for stowage every time, thanks to a grooved roller.

We use a swivel BECAUSE our anchor returns backwards about half of the time. At least the swivel makes it easier to manually orient our anchor prior to the final lift.

We have a grooved roller, too, but we also use a mixed chain/rope rode...

-Chris

[kas_1611]

Originally Posted by sy_gilana

We never use a swivel. That would allow the anchor to come up bass ackwards or sideways. Our anchor comes up correctly for stowage every time, thanks to a grooved roller.

My anchor used to come up bass akward all the time and jammed in the roller frequently due to the oversize link and double shackle I had to use until I fitted the Mantus Swivel. Got rid of the massive oversize link and the double shackles, anchor comes up right way around 98% of the time and never jams.

I'll use the swivel just for that alone.

Oh a 33kg Vulcan on 8mm G70 in case you are wondering.

[Mike Banks]

I have only ever used oversized galvanised swivels mounted using one heavy link and a bow shackle from the anchor shaft, shackle threads set in resin and moused. They have to be set back from the anchor shaft itself. I used an oversized roller and a wider than usual hawse--and never experienced any problems, because I always used heavy nylon snubbers enclosed in sacrificial hose at bearing surfaces and never let the hawse outlet and roller take any strain during surges. I also used a kellet in all but balmy weather.

I would NEVER secure a swivel to the anchor shaft as recommended by some specialist swivel makers. As soon as the anchor fouls a rock or coral, that swivel will either come apart, or cease to function as a swivel. The only safe swivel is a BIG swivel, and one that can not be subjected to lateral strain.
.

[Quadrille in JB]

We usually anchor in shallow water with lots of chain out due to summer storms in the Bahamas. The boat does lots of 360s so both anchors get twisted around. After awhile the windlass has a hard time with the twisted chain. To correct this I have to let all of the chain out so the 3/4” nylon rode will let it untwist. Then it’s a pain to retrieve all the chain. We use a 22 kg Spade and a 22 kg Delta at our high current Bahama Anchorage’s.
We just ordered a Mantus swivel as we have been very satisfied with the Mantus chain snubber.

[sailon46]

In my last July stop in Charlotte Amalie I anchored by the cruise boat anchorage. The following morning the anchor wouldn’t budge. Anything I did wouldn’t budge it. Since I was in 14 ft of water I put on the scuba tank after loosening the torque on the chain and on the bottom I found that my Delta,s Point was perfectly imbedded in the link of a ancient looking chain. Freeing the anchor was very easy just a wiggle and it was off. My Quick swivel did very good under serious torque.
Ernie on the Mary Jane

[Marathon1150]

No swivel at all is better. We used to have a Kong but after reading Practical Sailor’s review that demonstrated zero effectiveness in eliminating chain twist, and anecdotal stories of people waking up with a chain and half a swivel, we took it off. Three years later we are happy without a swivel. Our Rocna always turns right side up when it hits the Kingston purpose designed anchor roller. So no need for a swivel.

[noelex 77]

Originally Posted by Marathon1150

No swivel at all is better. We used to have a Kong but after reading Practical Sailor’s review that demonstrated zero effectiveness in eliminating chain twist, and anecdotal stories of people waking up with a chain and half a swivel, we took it off. Three years later we are happy without a swivel. Our Rocna always turns right side up when it hits the Kingston purpose designed anchor roller. So no need for a swivel.

I have read the article and the suggestion in the article that a swivel would not rotate could only have been made by someone who has never experienced the problem. The torque that can be generated such as shown in post #11 is extremely impressive. Scary may be a better adjective. There is no need to be concerned that a swivel would not rotate in these circumstances.

However, it is a rare problem, especially with older generation anchors. The torque will often cause the anchor to flip out before the chain reaches the stage shown in the photo. Once the anchor has lost grip on the seabed it will spin around, removing the twist. Installing a swivel to remove a rare issue may not be justified. But if you do instal a swivel to help with anchor orientation at the bow roller, at least the device is removing two problems.

The Kong swivels are good, but with this type of swivel a few links of chain between the swivel and anchor is needed to eliminate the side loading problem. See here for an excellent explanation by Vyv Cox who first came up with idea:

Swivel problems and solutions – Cox Engineering

This photo shows the correct attacment of this type of swivel:

[powsmias]

won this in a contest here https://www.spadeanchorusa.com/wasi-...all-swivel.php attached to a mantus 45 and wouldn't be there if i didn't win it. a bit pricey but happy to know one has never failed and happy for the generosity from spade anchors for the contest they ran here. no disrespect to mantus i have their 45 anchor, dinghy anchor, roller with the anchor mate and snubber with chain hook. nice stuff!!

[fxykty]

Originally Posted by powsmias

won this in a contest here https://www.spadeanchorusa.com/wasi-...all-swivel.php attached to a mantus 45 and wouldn't be there if i didn't win it. a bit pricey but happy to know one has never failed and happy for the generosity from spade anchors for the contest they ran here. no disrespect to mantus i have their 45 anchor, dinghy anchor, roller with the anchor mate and snubber with chain hook. nice stuff!!

Our boat came with one of those as well as a Spade S140 anchor. When we got the boat the swivel was connected directly to the anchor (which is how the Wasi manual recommends!?!),



and a slight bend in the end of the anchor shaft is visible. Hmmm, Spade, can I get a warranty replacement for this?



We added a few shackles and links between the anchor and the swivel to prevent side loading.



Thoughts?

[Shrew]

I been using a Mantus Swivel for 3 seasons. I believe Mantus recommends 4 wire ties on the swivel. I opposed the wire ties, so that two were twisted on one side and two on the other. No issues whatsoever. I did find a single wire tie snapped, but still in place last year. I removed them all, cleaned the swivel parts, lubed the interior portion that spins and put it back together and replaced all of the ties.

[NormanS]

I wouldn't have the potentially weak link of a swivel anywhere on my anchor rode. What I do have is a "Bent Link" shackled between the anchor and the chain. It is simply a piece of round steel bar with an eye at each end, and bent like a banana. As soon as the bent link hits the bow roller, it automatically rotates the anchor to the correct orientation. No need for poking about with boat hooks or screwdrivers.


You do need to have the bow roller sufficiently extended forward from the hull to prevent the anchor from damaging the boat, while rotating (sometimes quite vigorously). You also need to have sufficient length between the windlass gypsy and the anchor.

[a64pilot]

The Mantus swivel is stronger I believe then even g70 chain if it’s properly sized. It’s not the weak link, not even close.
It is however a big thing so be sure it will go over your roller etc. before you buy one.

[LongRange]

In these parts of the Med, Osculati swivels are rather popular. (Who actually makes them, I have no idea.)



To me, it seems an excellent design with no obvious defects. The body is a massively hefty chunk of stainless, far stronger than chain, and it adds a good 2 kg to the weight of the anchor, right behind the shank. The anchor is always rotated correctly in the roller, and chain twist is eliminated.

In the larger of the two sizes, the internal T-shaped lug that provides rotation is 14 mm in diameter. The pin that goes through the chain link, and the bolt that secures the end-cap, are both 12 mm, stronger than 10 mm chain.

Mine is attached to a 33 kg Rocna with a 12 mm Wichard bow shackle, which I think may be the weakest part of the system.

I have not used a Mantus swivel, but it seems like a cut-down version of the Osculati design without the hefty auto-alignment corkscrew. I cannot see any obvious advantages over the Osculati design. The comparative disadvantages look to be a lack of self-orientation in the roller, less added weight at the base of the shank, perhaps a propensity to catch that protruding hex nut on deck hardware, and a relatively thin-section sleeve with more invisible inner surface area.

I am also not sure that the oblong captive pin that goes through the foremost chain link is such a good idea. It presumably prevents free pin rotation, and thus potentially subjects that link to weird side-loading.

[Jimmyhenry]

Only ever had one swivel. It broke. Made me ask why I would ever bother having one. I asked many engineering friends to explain why. None could. The whole concept seems flawed. The only good reason was to swivel the anchor once it reached the bow roller. That suggests another problem is present. Adding a swivel just avoids fixing the real problem and adds another weak link.
We have a Rocna 33kg. Sits in the roller correctly 100%. Grooved roller is the answer.