Anchor problems - a warning!

[craigsmith]

Ok. "Utra" isn't an NZ company, but there is an Australian distributor/importer that dba that name. (Website). The Ultra anchor, for what it's worth, is a Spade copy, manufactured by a Turkish outfit called Boyut Marine. (Website). Similarly their swivel is a ball-and-socket design, essentially a copy of the WASI PowerBall (again Google to see for yourself). If you look at the 1st (Australian) site, they claim the products are "made in Europe" - bit of a stretch to lump Turkey in there but I guess Australians don't care about the sensibilities of political conservatives in the EU

I don't like the fact that the manufacturer is an imitator - for an anchor I wouldn't go near their Spade copy, as opposed to a genuine Spade. However I don't have any reason to impugn their swivel, but I haven't seen any independent proof testing of it either. Where is the certification for the 12,000 kgf break figure you quote. Remember this is a Turkish outfit, not NZ/Australian or EU / US. Has the chandlery tested it themselves? Nb. I am not trying to say it is untrue, but I have seen a lot of stamped numbers on bits of steel of dubious origin that don't mean much when it comes to the crunch. You must trust the manufacturer.

This is the Ultra swivel:

This is the original WASI PowerBall:

They (Ultra) refer to the swivel as a "flip" swivel, which I can say categorically is nonsense. It will not do what the Osculati Twist does, which is their implication. The anchor will (or won't) right itself once on the roller, the swivel only allows this to happen a bit more easily without twisting chain (whereas the Osculati itself turns the anchor before it gets to the roller).

More fundamentally I don't like the ball-and-socket configuration, i.e. the WASI idea. It is still designed to attach directly to the anchor, meaning the forks can and will be laterally loaded, trying to open them up. See the photo above for why attaching to the anchor is a bad idea. The 12,000 kgf breaking strength quoted for the Ultra is an in-line pull only... load it up sideways with severe shock loads, 1:1 scope, trying to break out a fouled anchor in surge, that is how you bust such swivels. The articulating swivel joint does not help this issue... and 30 degrees is not enough to remove for sure the possibility of laterally loading the swivel joint itself (you can't make a 90 degree ball-and-socket for obvious reasons). You can of course just put a shackle between it and the anchor, but then what is the point of the ball-and-socket.

I would look at the Osculati if that righting action is what you want, otherwise more simple in-line designs. The Kong is one example of a high quality (Italian) product from a reputable manufacturer (should still use a shackle between it and the anchor).

No affiliation with any of these companies or brands.

 

[craigsmith]

Re the lateral loading of swivels again. A poster above nicked this picture off John Harries' website. Here is the recent blog post with the pic:
http://www.morganscloud.com/2010/09/12/anchor-swivels/

I think it's worth referencing. I don't agree with John's summary rejection of swivels or stainless components per se, and I see this failure as an example of both poor quality product and the use of it installed directly on the anchor.

 

[AndieMac]

Thanks again for the heads-up and also the quick response Craig, I'll see about changing the ultra swivel for something more appropriate.
I prefer to go through the local chandlery because they offer full support should any products fail.
I did hear that Turkey was the place to get SS products very cheaply, especially custom gear.

 

[Deleted User YDKXO]

Really? I have not heard or seen that with Kongs. Do you have pics?

I know you're the world's expert on anchors but I can assure you that the ends of the Kong swivel that I had on my previous boat were beginning to splay out, not by much but the effect was visible. And yes, I regularly checked the bolts. Btw you haven't commented on this thing http://www.chandlerysupplies.co.uk/html/the_twist.html. Any view on the efficacy of this swivel?

 

[craigsmith]

I trust your eyes but not your identification of the brand, since you incorrectly referred to the above pictured swivel as a "Kong"... I was just trying to work out whether you are in fact talking about a Kong in your case. I think you'd be best posting a photo so there's no possibility of confusion. If it is a Kong then it'd be very interesting as it would be the first I've seen mechanically fail (or start to) during normal use.

I have mentioned the Osculati Twist a few times in the above posts. I don't like how the swivel joint is off-axis from the line of pull but in Vyv Cox's destruction test it did well nonetheless. Its righting action works very well if you don't mind the long length (consider distance between anchor and windlass). If you're talking about the jammed shackle shown above, maybe try a bow shackle instead of a D.

 

[Deleted User YDKXO]

I trust your eyes but not your identification of the brand, since you incorrectly referred to the above pictured swivel as a "Kong"... I was just trying to work out whether you are in fact talking about a Kong in your case. I think you'd be best posting a photo so there's no possibility of confusion. If it is a Kong then it'd be very interesting as it would be the first I've seen mechanically fail (or start to) during normal use.

I have mentioned the Osculati Twist a few times in the above posts. I don't like how the swivel joint is off-axis from the line of pull but in Vyv Cox's destruction test it did well nonetheless. Its righting action works very well if you don't mind the long length (consider distance between anchor and windlass). If you're talking about the jammed shackle shown above, maybe try a bow shackle instead of a D.

You're right, it isn't a Kong but I have used a Kong swivel on my boats since 2003 when I first saw it at the Genoa boat show, until recently when I have gone over to a Twist. I can definitely say that the Kong swivel did splay out at the ends after a few years on my boat and I thought it prudent to replace it after that became visible.
You recommend a bow shackle to stop the problem of a jammed shackle but bow shackles generally have lower breaking loads than D shackles. Is that an issue or are the breaking loads of shackles so much higher than the load that can be exerted on an anchor that it doesn't matter?
Or put it another way. I have a 53ft motor boat with a 30kg Bruce and 70m of 10mm chain. What is the minimum breaking load that the shackle connecting the swivel to the anchor should achieve?

 

[craigsmith]

I can definitely say that the Kong swivel did splay out at the ends after a few years on my boat and I thought it prudent to replace it after that became visible.

Fair enough and certainly prudent. If the steel has been bent past yield, the swivel joint is going to part sooner or later with continued use.

I would guess that it has happened because you had the swivel mounted on the anchor shank - correct?

Would love to see a pic or two.

You recommend a bow shackle to stop the problem of a jammed shackle but bow shackles generally have lower breaking loads than D shackles. Is that an issue or are the breaking loads of shackles so much higher than the load that can be exerted on an anchor that it doesn't matter?

No the shackles should be as strong as possible, beyond the chain's strength if possible. Of course like anything you may get away with it, but why introduce a weak point.

Why do you say bow shackles are weaker than Ds? Shackles tend to break at their heads, in which case the body shape is a moot point. A cursory look over some catalogs here shows no differences in the breaking loads. You may have a counter example but I wouldn't read much into it. Bows are fine and generally to be recommended.

Or put it another way. I have a 53ft motor boat with a 30kg Bruce and 70m of 10mm chain. What is the minimum breaking load that the shackle connecting the swivel to the anchor should achieve?

I thought you had a Delta. Maybe confusing with someone else.

The answer to your question depends on the chain grade.

10 mm chain. If G40 / high test, SWL is 1250 kgf, break is just over 5,000 kgf. 11 or 12 mm pin will fit through the end link. 11 mm Green Pin standard bow shackle has SWL of 1,000 kgf but with a more conservative safety margin, comparing like-for-like we find break load is 6,000 kgf so quite a lot stronger than the chain. Find a 12 mm pin version and the picture only gets better.

The Green Pin shackle I refer to is pictured here, 3rd one down (with the safety bolt arrangement):
www.rocna.com/kb/Shackles
I consider that something approaching the ideal shackle type. Other brands are fine if reputable.

The thing to watch with bow shackles is their throat width and whether you can get it through the anchor attachment point okay.

 

[Deleted User YDKXO]

I would guess that it has happened because you had the swivel mounted on the anchor shank - correct?

Correct. Is that wrong?

Why do you say bow shackles are weaker than Ds? Shackles tend to break at their heads, in which case the body shape is a moot point. A cursory look over some catalogs here shows no differences in the breaking loads. You may have a counter example but I wouldn't read much into it. Bows are fine and generally to be recommended

See breaking loads quoted by this company for like for like bow and D shackles
http://www.s3i.co.uk/shackles.php I have checked with this manufacturer and they say that bow shackles always have a lower breaking load than D shackles due to the shape of the shackle and looking at the relative shapes, this is understandable

I thought you had a Delta. Maybe confusing with someone else

Yup, you're right. I did change the 15kg Bruce anchor on my last boat (Ferretti 46) for a 25kg Delta. You may not remember but I had an exchange of e-mails with you on the Rocna (around 2005?). I wanted to buy a Rocna but the Rocna had a deeper shank than the Delta and would have required the bow roller to be modified, whereas the Delta slotted in fine. As it is, the Delta performed very well in the sand/stones/weed conditions found in the Balearics. I have bought another boat this year (Ferretti 53) which came with a 30kg Bruce. This boat was located in the Adriatic/Croatia area and I am going to keep her there for a couple of seasons at least. I thought I'd see how the Bruce performed there first before changing. So far the jury is out on the Bruce. It has held well in most places but in some places I've found it difficult to get a set. The sea bed conditions are somewhat different to the Balearics; no sand but stones/rocks and in some places, sticky mud. Btw I have seen quite a few Rocnas in this area

10 mm chain. If G40 / high test, SWL is 1250 kgf, break is just over 5,000 kgf. 11 or 12 mm pin will fit through the end link. 11 mm Green Pin standard bow shackle has SWL of 1,000 kgf but with a more conservative safety margin, comparing like-for-like we find break load is 6,000 kgf so quite a lot stronger than the chain. Find a 12 mm pin version and the picture only gets better

Yup, a 12mm shackle will fit through the chain but I actually have an 8mm D shackle fitted on the boat. I already have occasional problems with the shackle not sliding easily through the bow roller assembly due to the protruding collar pin so a larger shackle will probably give even more probs although I could go for a shackle with a socket head pin that doesn't protrude.
You can see from my link that the quoted breaking load for the 8mm D shackle is 3000kg and for the 8mm bow shackle only 2400kg. The company says that they normally quote a safe working load at a factor 6:1 so the SWL of the 8mm shackle is only 500kg and 400kg respectively, which is 50% or less than the SWL of the chain. Looks like I need to change my shackle for at least a 10mm. All things being equal, which type of shackle would slide better thru a bow roller assembly, bow or D?