anchor connectors

mmm, glad I read this thread.

I am going to use a Kong fixed chain connector to attach my chain to a new Delta anchor. one of these:

Anchor_connector_fixed.jpg


I thought about a swivel, but considered that the chain would twist enough to make this unnecessary. It does replace the original setup that attached a CQR.
 
I see your point (I am also connecting my Delta with a Kong but am going for a swivel) but side forces are an issue. If you have a swivel then the side forces should be a little bit less as the chain will always present parallel to the force. Not a huge difference, I imagine, but maybe enough to mitigate the slight reduction in strength due to the swivel. Last season I had a connector without a swivel and we did get the chain badly twisted at times, a bit of a pain, though at times we were in one place for a week or more.
 
There are two basic designs (at least). The less strong versions are made in two parts, riveted together to form the swivel. A bolt forms the chain/anchor connection. It may be a simple bolt with a countersunk screw or Allen head, or is sometimes internally threaded in its shank end so that a smaller screw can be driven into its end to lock it in place. Amusingly, this is called a 'sex nut'. This is a weak arrangement, an example shown here. The failed part in this photo is a 'sex nut' with the larger countersunk end still attached in the swivel body.
_P3P7779.jpg


The better type is made in four parts, with a much stronger swivel arrangement and here the chain/anchor attachment forms part of the forging on one side, locking into the other side with a half-round fixing. The connecting screw merely holds the two halves together. This is a far stronger arrangement as no tensile force comes onto the screw.
_P3P7806.jpg
 
See my other posting above. Your photo shows the weaker type.

Something I notice with my Delta now that we are in clear water is that it rotates quite significantly when being raised. No idea whether this is different from other patent designs but it doesn't happen with the Fortress. My chain twists in the locker even with the swivel but I feel sure it would be far worse without.
 
The photo is for illustrative purposes. I checked the packaging on the connector and it was (will double check) around 5000kg.
 
The only advantage of the uni-swivel is that it reduces the length of the lever arm - the load still comes on the jaws of the swivel at right angles. I have a shackle between the swivel and the anchor. Even then, the shackle has to be selected very carefully because it can wedge itself between anchor and swivel. A short length of a size of chain one larger than the rode seems like a good idea but increases complexity.

I advise anyone using this type of kit to check articulation fully before relying on it.
 
also, it is better to check if the Kong type can actually be assembled with the anchor, especially those having a thicker fluke: when I tried mine, the anchor thickness almost prevented the two halves free rotation; the space between the two halves (once closed) was enough, but when rotating the two halves the outer edge of the swivel clashed against the anchor, and had to be somewhat forced in place... at least on my anchor, it was a question of a few 10th of millimeter, but just a bit more and I could not have used it
 
I really wonder what all this talk of calibration is about. What possible real gain comes from using these devices? Why introduce even a small element of risk or potential weakness into the anchor rode when conventional connecting gear works just fine? Have Ellen M. or Mike Golding recommended them? Quite.

In my opinion these rode connectors are toys, in the same category as fender clips, and should remain there!

PWG
 
<< What possible real gain comes from using these devices? Why introduce even a small element of risk or potential weakness into the anchor rode when conventional connecting gear works just fine? >>

I mentioned the gain in a previous post. Some anchors swivel quite markedly when being raised with a windlass. Without a swivel the chain in the locker would become a near-solid mass in a very short time. Most windlass manufacturers recommend the use of a swivel.

So far as the potential weakness is concerned, several of the ones tested were stronger than the chain they were intended for. The chain exceeded its rated strength.

What is 'conventional connecting gear?' If you mean shackles, most were weaker than swivels unless a size larger than the chain was used. Some were disturbingly weaker. Several of these were intended for lifting gear, with marked SWLs, so presumably made to a reasonable standard.
 
vyv_cox

Checked now my chain connector, still in its package, it is joined like the swivel ones shown in the photo, with an allen bolt through the centre.

On the back it says it is rated for 5000 kg pull and 1250 lateral, same as the swivel connector.

I would welcome your view as to the use of this, should I change to a swivel connector, if so why? The anchor is a Delta.
 
No problem at all with the strength.

The only question is whether to go for a swivel or not. As in my earlier posts, my Delta spins quite considerably as it is hoisted by the windlass. Some of the twists go through the gypsy and the chain in the locker gradually becomes more and more twisted, necessitating tedious unwinding every couple of weeks. Without the swivel I assume this would be much worse, plus there is a risk of damaging or jamming the gypsy. I have never tried a fixed connector in conjunction with a windlass, so I really don't know what might happen.

If you don't have a windlass, or have a manual one, then you are perfectly OK with the connector that you have
 
[ QUOTE ]
I really wonder what all this talk of calibration is about. What possible real gain comes from using these devices? Why introduce even a small element of risk or potential weakness into the anchor rode when conventional connecting gear works just fine? Have Ellen M. or Mike Golding recommended them? Quite.

In my opinion these rode connectors are toys, in the same category as fender clips, and should remain there!

PWG

[/ QUOTE ] /forums/images/graemlins/laugh.gif I quite like the idea of my swivel being rated the same strength as my chain. Its better than the shackle it replaced! It also means I can bring the anchor on board without any problems with it facing the wrong way. It also means my windlass doesn't get mucked up with twisted chain.

Can't see the relevance of Dame Ellen in the discussion.

By the way, thanks to everyone who reassured me about my swivel.
 
During the last year there was a report of an anchor being lost because of a swivel failing. It seems that an unseen part of the fitting was either not stainless or was a low grade stainless. I checked one of these fittings in a swindlery and certainly it cause a deflection on a compass. It may be worth checking that what you have is 100% stainless.
 
IMO there is a lot of crap sold in the chanderies. The cheep stuff is out on display, cos it makes the place look 'good value'. If you want a quality product, Winchard or Kong for inst' you have to rumage, ask or order. Its worth getting the right product and that is why a thread like this, together with Vyv Coxs' article in Y~M is so valuable when making buying decisions.

I rarely buy 'cheap', its those purchases that disappoint or fail. However it is scarry that some boat are relying on 'budget' products. Wonder if the boat you refer to was doing so?

Just my opinion
 
john_morris_uk - Yes that is a Kong but one size down than the one shown in the bunch of swivels photo.

He he he.. the weak swivel argument again. I don't know about this particular posters one but find many who say that are happy with the shackles they have which has massively lower WLL's in most cases just as vyv_cox says. In some cases many everyday shackles will break before the WLL of a good swivel.

Those sex-nut (great name) swivels do have issues. A big retail marine chain here had to do a recall on a pile after 4 of the first 10 they sent out failed as shown.

We left it out of our swivels for that very reason. All we do it crank the pins up tight and dot the other side with a centre punch. Only one every questioned in over 4000 sold. The big beast have them but then we are talking 4mm keepers into the head of 18 and 22mm pins.

We mark our with the WLL of the smallest chain it is designed for i.e the 6-8mm one is marked SWL 650kg. We actually make them to match the biggest chain i.e the real WLL is 800kg which is the same as the 8mm DIN chain. So when using at the marked WLL you actually have a safety margin of 6:1 not the usual 4:1. Just trying to save some dumba*ses from themselves, we have a lot here /forums/images/graemlins/smile.gif

Sideload wise we have yet to see any issues at all, with ours anyway. You do see the odd Kong with bent cheeks but nothing that spooky. If the system is size matched right through you will find most anchors will veer before it's a big issue. The odd one will bend it shank. We have never seen any good swivel that has any major sideload problems. Ours are tested to WLL x 3 sideload, never had a problem.

We do like the way the Kongs are constructed but went the way we did so it swivels under load a lot better. The Kongs do struggle with a bit of load on them sometimes.

We see many people with swivels who don't actually need them as such. Yes some anchors do spin a lot, Delta being up near the top of the list. We recommend them for use on Auto Rope to Chain rodes when using 3 strand but that's about it really. The Octiplait (8 braid, Brait, squarebraid and etc) is a non-rotating rope so generally does not need one.

To chuck another devise into the mix. For those who have one of those damn anchors that comes up up-side down each time what about an Anchor Straightener. Swivels a bit and leaves the anchor no choice but to arrive on deck the right way up. I'll get a piccy for you.

Great thread all. All sorts of good stuff here.
 
[ QUOTE ]
During the last year there was a report of an anchor being lost because of a swivel failing. It seems that an unseen part of the fitting was either not stainless or was a low grade stainless. I checked one of these fittings in a swindlery and certainly it cause a deflection on a compass. It may be worth checking that what you have is 100% stainless.

[/ QUOTE ]I am not too worried about whether the thing is 316 stainless or not - only about its strength.

I actually wrote a lot more than this - but deleted it when I had cooled down.

Perhaps there should be a way of showing the posts that were nearly sent? On second thoughts, perhaps not...
 
The swivel that failed was mine, starting the process that resulted in the YM article. It was a type commonly sold in chandleries, with a sex-nut connection. I had used it for at least five years. We were at anchor in Ibiza, wind about force 3, when we heard a bump and started sliding backwards. On hauling in the chain I found that the swivel had fractured across the jaws on both sides.

Linkview.jpg


The swivel is non-magnetic, so austenitic. The fracture face has a typical brittle appearance and has clearly failed well below its intended UTS. I have not subjected it to a detailed analysis but would guess that it has suffered stress corrosion. This is unusual in a material of this type at seawater temperature, so I assume it to have undergone some sort of heat sensitisation durin manufacture.

I would be very reluctant to use a swivel of this type now. Apart from the metallurgy, the cross-sectional area of the jaws close to the bolt is very small and I doubt its strength in tension.
 
I don't claim to be a metallurgist but I have studied what one does in cross-disciplinary studies and while that shows classic brittle fracture, had it been as a result of a corrosion crack I would have expected to see brittle fracture on one side, then evidence of bending before failure on the other. I rather suspect that the whole casting has been incorrectly tempered, leaving it too brittle. A reputable manufacturer should have picked that up. Do you know who made it?
 
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