To swivel or not to swivel
Adding a swivel to an anchor rode is a bit controversial. Many will advise against doing such a thing, fearing that the swivel becomes the weak link in the system. I tend to be in that camp.
When we upgraded our primary anchor on ZTC to a Rocna, I noted on their website that they specifically said not to add a swivel unless you found, after using the anchor for a while, that it was necessary. I followed that advise and found that it wasn’t needed.
When we took over One Love and upgraded her anchor to a Mantus, I left the swivel that was already on the rode in place. Why? I don’t know really. It just seemed like the path of least resistance when wrestling with that 85 lb. anchor.
The swivel which was living between our anchor and the chain.
As most of our readers know, we’ve spent much of our time since acquiring this boat on a dock. In the times that we have anchored, we’ve had two occurrences, one taking place yesterday, where the swivel has jammed, preventing the anchor from raising fully onto the bow roller. It took a fair bit of effort, and compulsory cursing, to get yesterday’s situation resolved. Not wanting it to happen again though, when we were at the dock picking up all of our stuff yesterday, I removed the swivel altogether, replacing it with a super strong rated bow shackle. How does it work? Well, the anchor deployed just fine, of course. The true test will be when we try to pick it up. Let’s hope it works.
Notes:
- I haven’t written too much about our Mantus but that’s only because of how much time we’ve been dock bound. I will say now that on the times that we have anchored, the Mantus has grabbed first time, every time. In fact, it grabs so hard that when it’s really blowing and the boat is moving back quickly, I actually use the engine(s) in forward idle a bit to soften the blow when the boat stops in place.
- The jamming issue is not totally the fault of the swivel but more so an interaction between it and the anchor. It seems to occur when the swivel slides down the slot at the end of the shank a bit and then does not return to the tip before the anchor begins to get raised, or perhaps gets loaded.
- Our new friends on Wandering Dolphin recommend the Wasi Powerball swivel. I don’t have any experience with it but will say that it does look pretty cool. If I had one, I’d try it, for sure.
We had the same swivel on Distant Shores II – at least it looks identical to me (but less pitted 😉
I had always worried about the center bolt that does the actual swivelling since that will be subjected to extremely high shearing-loads if the swivel ever jams as you describe. In that case the swivel is being held side-on to the chain and that center bolt was not designed for. We had that happen a couple of times with our Rocna, as you say it was due to the interaction of the Rocna’s short slot allowing the swivel to move forward then jam. Last year we took off the swivel and replaced with a hi-strength shackle and have not found any problems…
Hope it works for you too! It does feel better not worrying about it.
Paul
Hi Paul
Thanks for the comment. I’m glad I’m not the only one. Hope to see you again soon.
Hi guys
We had the exact same swivel on our Bruce aboard Nocturne. After only several uses, it’s showed damage to one of the side flukes near the through bolt. It was bent and didn’t look like it would support any more stress.
Crap!
Not good.
I like everything Wandering Dolphin had to say about anchoring, all good stuff, although, an extra full size anchor or two and plenty of chain with rode as deep in the bottom of the boat as you can store it, is what I call insurance. Maybe he pays some suits in a fancy building for his.
I took my fancy Italian swivel off and went with over size shackles, it’s what I’m confy with. I know it’s tough matching tested load of shackles to chain without going 3 sizes over. I haven’t talked to the local shrimpers here but I heard this G-Link shackle which goes by a few different names is the way to go to match size for strength.
http://www.gunnebojohnson.com/gunnebo-classic-alloy-chains-and-fittings/coupling-links/mechanical-connector-g-link/
That’s an interesting looking piece of kit.
Looks like electrolysis to me. I suspect you keep your chain in the windlass when anchored. You sometimes see this kind of breakdown in stainless chain that is used that way. I use a chain/rope combination and have seen no deterioration of the swivel or chain over 10 years. The thing about chain rope is that the chain is not connected to the boat when in salt water.
I see your point with respect to rode/chain vs. all chain. I see no signs of electrolysis on this swivel though. Perhaps the pic looks that way but I don’t see it. The jamming issue was 100% mechanical.
The best recommendation that I have seen, from those with experience of swivels jamming, is to have a few links of chain between the anchor and the swivel. The idea is that if you actually need a swivel because of the chain twisting up, then if it is attached directly to the anchor it can jam and be subjected to either side or shear loads that it is not designed for. A short length of chain allows the swivel to still be able to remove twist, but prevents the swivel being in a position to jam.
The Wasi Powerball is often recommended, and even then they say put a few links of chain between it and the anchor.
Mike
I could see how that could work but IMO it adds even more potential points of weakness.
Interesting, I have the wasi system, ss chain and swivel and have not noticed that kind of wear, though I will take another look…
SS chain? Fancy!
mike; i’ve read your whole blog over the last few weeks, congrats on the amazing adventure! my wife (liz) ans i live in calgary, and have chartered off the west coast as well as in the BVI. we are constantly debating weather we could retire in the BVI, live on a boat etc. i didnt notice when you made the decision to park ZTC and start the charter business, was that just a natural progression of your experiences, or did you just get bored and want to do something more ? either way, it looks like you’ll be a huge sucess, you’ve obviously done your homework and learned the carribean over the last few years, good luck! we are hoping to do another bareboat charter in 2015, we will keep an eye out for “one love” 🙂
Thanks for commenting. Definitely hail us on the VHF if you see us when you’re down here.
Okay, this is maybe an odd question, but I just wondered…
Do you still respond to “ZTC”, “Zero to Cruising”, or “Zebra Tango Charlie” when hailed, even though you’re on “One Love” now? Or maybe it’s never happened…
Dave W.
On the radio? It hasn’t happened and would be unlikely to do so. We would still answer if we heard it as there certainly are no other boats around with that name.
I bought a Wasi swivel that I bought “unused” from another cruiser for $40 in the SXM boot fair. It works very well and we often see the anchor “twist out” as it comes up to the roller. The ball connection also allows for sideways twist between chain and anchor as the boat swings, preventing sideways “pull” on the anchor. Jon on s/y Imagine Of Falmouth.
$40.00 is a great deal for that.
Regarding swivels – it’s not IF they’ll fail, it’s WHEN they’ll fail. Because they eventually will. Often suddenly and without warning, and of course, at the worst possible time.
What are you basing that statement on, Robert? Do you have first hand knowledge? Second hand?
I base it on the fact that stress intensification occurs at tightly radiused corners of objects subjected to load, especially cyclic load. The center of that swivel carries a great deal of load across a small area, the head of which is milled with basically no radius. Regardless of the rating of the swivel or its design margin, on a micro level the inside corner of the underside of that center pin sees much higher loads. There’s no way to make that center pin stong enough without making the swivel the size of your thigh. It’s just a fundamentally flawed design. If its only purpose was to act as a swivel, it would be fine, but it also has to carry the load of the rode through various angles. I’d never use one on our boat. I wouldn’t be able to sleep at night. But it’s just my opinion, your results may vary. 🙂
Thanks. My question was really to know if you had personal experience with them failing, or were basing your opinion more on hearsay or theory.
We actually had one come apart. Supposedly that never happens. But a $900 A120 Spade anchor is on the bottom of the Chesapeake none-the-less.
So there’s a first hand report! Sorry, Eric.
Was it the same type that I posted a pic of?
One of the differences between ZTC and One Love is not only the weight, but the windage. I am sure I am preaching to the choir here, but in addition to lessening the shock as you have described, it is important to engage the chain brake before you set the anchor. It is even better if you can get the bridle on, but this can take a bit of coordination.
The windlass is not designed to take those shock loads, nor should it be used to pull the boat forward when raising the chain.
Yes, you are preaching to the choir. We live here. :p
But keep on preaching, I don’t know everything and am open to learning, as are many of our readers.
In my opinion the answer is to use a load rated ‘eye to jaw galvanized swivel’ like this:
http://www.jamestowndistributors.com/userportal/show_product.do?pid=247&familyName=Jaw+and+Eye+Galvanized+Steel+Swivel+Shackle
Attach it to the chain with a load rated galvanized shackle. The sizing for both items should be determined by having the breaking strength equal to or better than the breaking strength of the chain.
This is straightforward old fashioned, time tested technology which I prefer in cases such as this where the safety of the entire vessel is literally hanging by one point. I wouldn’t trust any of these newly designed swivels for lots of reasons – but mainly why take a chance?
Or don’t use one at all perhaps.
FWIW, we had a fancy stainless swivel that came with the boat. It was nearly impossible to get substantive information about WLL or even breaking strength, but, near as I can tell, it was just about 20% of what the chain was rated for. We removed it (it’s for sale, if anyone wants it). Unfortunately, a regular SPA shackle won’t fit through our bow roller, so I had to resort to a hammer-lock connector. I can’t find one in galvanized, so it looks like I will be replacing it periodically.
Hammer lock connector?
A hammer lock connector is a split length wise chain link that has rivet-like protrusions that fit into the other half. You then beat the pins with a hammer to fuse the two halves together, it is commonly used to splice 2 lengths of chain together and has, surprisingly, close to the same strength as the chain itself.
Nice thing is that they are low profile and will commonly thread through a gypsy just as well as the chain does.
Bad thing is, (and I have no facts to back this up) that it would be more prone to wear and breakage than a normal link would be. Just seems like a “weak link” to me.
Roger. Yeah, for whatever reason, I am adverse to using those to connect lengths of chain.
Please remind me of the weight of your new One Love…….wondering in relation to your 85lb anchor……thanks!
24.38 tons.
a. When I upgraded from the factory Delta to a Manson Supreme I noticed that the swivel had developed a crack on the inside, where it could not be seen until taken off the anchor. Ditched that and did not replace it.
b. Sometimes the chain can wrap or jam as you have described; it never did on the Delta, but the slot is a little different on this and it jams about 1 time in 20, if the tide has taken us in a circle. I keep a 15-foot rope with a hook (not a chain hook, just an open 1 1/2″ hook) handy in the bow locker for numerous retrieval jobs. I lower it down, snag the roll bar, and lift the anchor backwards. Most of the time the tangle falls off. If not, I lift a little higher and clear the mess. With a 35-pound anchor it’s simple, with an 85-pound anchor I might use the spinnaker halyard. No strain.
Another good idea from Drew. Unfortunately, snagging our anchor would be more tricky as it deploys from behind the tramp, not the bow.
Hmmmm…. we just got a stainless steel swivel to go with our new Rocna and new chain rode. I did this as our old CQR and chain rode often came up twisted and then jammed in the gypsy. I was hoping this would, solve the problem, but will now be keeping a good eye on the swivel. Thanx for the heads up!
Cheers!
Wayne & Dana.
I am not convinced it would solve the problem. Let me know how that works.
Mike,
We took our swivel off in Grenada last year.
We have not missed it.
Eric
Aren’t you always on a dock? Just kidding.