Anchor Connectors?

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cpedw

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The anchor is a Spade S80 on 50m of 8mm chain. Currently the two are joined by a galvanised bow shackle which is no longer the same shape that it started out. So it seems I need something heftier. A larger shackle won't fit the chain.

A quick browse of Jimmy Green's website reveals a lot of options:
Stainless or galvanised,
Kong or unbranded,
Fixed or swivel,
Articulated or not.

For most cases, JG advises fitting a bow shackle between the connector and anchor to reduced side loading.

Since the anchor currently self-stows fairly satisfactorily, I think I don't need a swivel or articulation. Is that a reasonable assumption? Any further points I should consider?

To complete the picture, the boat is a Nordship 35 DS.

Thanks,
Derek
 
Another option would be a stronger stainless shackle in the same size. I have a very narrow bow roller, so only an 8mm sized D-shackle will fit through it, but I was able to find one with a 6-tonne breaking strain which is more than sufficient!

I believe this is the one I bought, although I remember it as being a little cheaper:

https://www.s3i.co.uk/174socket.php?pid=2655

(the SWL is one tonne, but they use a 6:1 safety margin for certified lifting gear)

Pete
 
The only swivel that's come out as any good in tests is the Kong. We need a swivel because the anchor us on a windlass and often comes to the stem the wrong way round.

My understanding is that you don't need articulation for the stow, but in case the chain/shackle twists when the anchor is on the seabed.
 
cpedw said:
Bow on shank. The bow (or rather the bosses where the pin fits) won't fit through the chain link. What is the right way?
Click to expand...

That has always been my understanding. The holes are slotted for a reason. But even on anchor manufacture sites you see it done both ways. And though in principle it makes sense for the bow to be able to slide around, avoiding side loading, the chain does not stay centered on the pin either. The truth is that shackles are made for the lifting industry and what we do with them is non-standard. Also the problem with swivels attached direct to the anchor, which is common and look nice, but is certainly wrong (a few exceptions).
 
I'm afraid I think the use of a swivel has no effect on the anchor attitude on recovery.
Vyv Cox also found little difference.
The attitude of the anchor has to do with how it breaks out.
I used a swivel for about 2000 anchorings. I found it did nothing to minimise chain wind up.
Both Mantus and CQR, come up (if properly set) upside down as frequently as right way up.
All I found the swivel did was to unbalance the anchor in setting.
It now resides, in the chain locker, with the tripping line and other objects of doubtful value.

Of course there should be a short length of chain between swivel and anchor shank. But IMHO it's just another thing to go wrong.
 
Neeves usually comes in on these discussions, he has tested large numbers of shackles. Have not seen him around for a while so I will try to paraphrase him. Lifting and hoisting specialists can sell you far stronger shackles than you can buy in chandleries. Those made by Crosby seem to stand out, have a look at Tecni-lift, full link on my website, they stock a range of them and do mail order for small numbers. These shackles are hardened and tempered alloy steels, far stronger than the usual mild steel ones.

Alternatively the Wichard HR range are made from a heat treated stainless steel, 17/4PH but unfortunately they no longer seem to do the one with the countersunk pin in that grade. Mine are D shaped ones of that type, I have owned them for many years with no sign of shape change.

Edit: I see the ones linked to by prv are of this type, including countersunk pin, and apparently made in UK.
 
charles_reed said:
I'm afraid I think the use of a swivel has no effect on the anchor attitude on recovery.
Vyv Cox also found little difference.
The attitude of the anchor has to do with how it breaks out.
I used a swivel for about 2000 anchorings. I found it did nothing to minimise chain wind up.
Both Mantus and CQR, come up (if properly set) upside down as frequently as right way up.
All I found the swivel did was to unbalance the anchor in setting.
It now resides, in the chain locker, with the tripping line and other objects of doubtful value.

Of course there should be a short length of chain between swivel and anchor shank. But IMHO it's just another thing to go wrong.
Click to expand...

In the last ten years of anchoring with a Spade anchor and a Kong swivel I can only remember the anchor not setting first time on one occasion.

However the real advantage of the swivel for me is nothing to do with setting the thing. (I've never noticed it affecting its anchoring function) but the fact that I can lean down and turn the anchor round so it comes onto the stem head properly. I don't expect it to come up round the right way round and I'm never disappointed.

Just my experience...
 
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john_morris_uk said:
In the last ten years of anchoring with a Spade anchor and a Kong swivel I can only remember the anchor not setting first time on one occasion.

However the real advantage of the swivel for me is nothing to do with setting the thing. (I've never noticed it affecting its anchoring function) but the fact that I can lean down and turn the anchor round so it comes onto the stem head properly. I don't expect it to come up round the right way round and I'm never disappointed.

Just my experience...
Click to expand...

That is pretty much exactly my reason for using one. Jill does the foredeck work as she doesn't enjoy close-quarters helming. In the year that we went without a swivel (2014) the anchor still came up reversed on occasions, for reasons I have yet to understand, and she could not reverse it to its correct orientation. We then had to switch positions so that I could release some chain, turn it on the grooved bow roller and haul it home while she helmed. Having a swivel means that she can reverse the anchor herself.

However, we originally bought a swivel when we bought our first Maxwell windlass simply because they recommended one. In the year that we went without one we thought that the windlass was less 'happy', making more noise than with one. My experiment with an Osculati was an unhappy one and we have been back to the Kong with three links of 10 mm chain for a year now. The three links were replaced this year as the galvanising on the old ones had finally gone after about six years.
 
john_morris_uk said:
In the last ten years of anchoring with a Spade anchor and a Kong swivel I can only remember the anchor not setting first time on one occasion.

However the real advantage of the swivel for me is nothing to do with setting the thing. (I've never noticed it affecting its anchoring function) but the fact that I can lean down and turn the anchor round so it comes onto the stem head properly. I don't expect it to come up round the right way round and I'm never disappointed.

Just my experience...
Click to expand...

I have found that fitting a "bent link" between the anchor and the start of the chain, guarantees that the anchor rotates to the correct orientation as soon as the bent link hits the bow roller. The bent link is simply a short length of round bar, with an eye at each end, and bent off the straight by about 40° or so. My wife assures me that it works every time. No swivels are involved, merely one additional shackle.
 
A tip to get the anchor the right way up - go astern slowly with the anchor just submerged. It works with Delta and Spade anchors. I don't know about others.
 
cpedw said:
A tip to get the anchor the right way up - go astern slowly with the anchor just submerged. It works with Delta and Spade anchors. I don't know about others.
Click to expand...

Oddly I've found the same if you let it dangle when going forward too. Moving from Croatia to Greece meant encountering mud or sticky sand quite a lot so we have recently got into the habit of leaving the anchor submerged until clear enough of other boats to put on a burst of speed and watch the mud wash off. And the anchor just seems to orient itself right too.
 
the last posts open up the question of hydrodynamic stability of different anchors. It's the same as flying a kite: a single point of attachment, and air/water flow over the shank and flukes. Some anchors will 'fly' upside down with the shank below the 'wings'; other anchors will still try to plough their way down to the sea bed again. It's the dihedral angle and CofG that determines whether an anchor comes to the bow in a convenient attitude or inverted.

It's Noelex who has lots of videos of anchors; there may be one of anchors being retrieved in different attitudes.

I do not like the idea of a swivel directly to the attachment slot on the shank; the potential for leverage normal to (at roughly 90 degrees) the strongest designed direction of pull (the swivel's longitudinal axis) is considerable and VC's pics clearly show what happens if pull is at an angle across the swivel.

The shape of chain link is not optimised to create a straight (untwisted) pull at the attachment point. For that you need a ring at the top of the anchor so that it conforms to the chain bar at all directions of pull. Perhaps anchors should have a ring in the attachment slot, on to which one can then put the three or four links needed to ensure that the swivel is pulling in a straight line. All the old-style fisherman's anchors seem to have one !
 
NormanS said:
I have found that fitting a "bent link" between the anchor and the start of the chain, guarantees that the anchor rotates to the correct orientation as soon as the bent link hits the bow roller. The bent link is simply a short length of round bar, with an eye at each end, and bent off the straight by about 40° or so. My wife assures me that it works every time. No swivels are involved, merely one additional shackle.
Click to expand...

That sounds like a terrifically cunning and simple solution. If you could post a picture or roughly dimensioned sketch of it some time that would be much appreciated.
 
Many modern anchors adopt a setting position where the the end of the shank (where it is connected to the chain) needs to bury under the substrate simultaneously with the fluke. The concern here is that any unnecessary bulk in the anchor chain connection will inhibit the burying ability and therefore the holding power of the anchor.

Modern anchors should hopefully have lots of reserve holding capacity so added bulk in the form of anchor straighteners and associated shackles should not be ruled out. It is very convenient especially for powerboats to be able to retrieve the anchor from the helm with the reassurance that the anchor will rotate the correct way. However, be aware if you are adding bulk you are likely to also be sacrificing some anchor holding ability. It would be nice to quantify the reduction. My guess is that it is significant but only mild. Whatever anchor chain connection system you use keep the bulk and resistance down if possible.

This photo illustrates what I mean. It shows a typical modern anchor, a Delta. It is only in the very early stages of setting with just the toe digging in. Already the the shank at anchor/chain connection is well buried. If you inhibit the end of shank burying with a lot of bulk in the anchor/ chain connection, the fluke will have a reduced amount of bury . The fluke is also forced at a shallower angle by the elevation of the end of the shank.

image_zps2ly5hmy7.jpeg
 
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MikeBz said:
That sounds like a terrifically cunning and simple solution. If you could post a picture or roughly dimensioned sketch of it some time that would be much appreciated.
Click to expand...

So a quick Google search and I see that "Anchor straighteners" are commercially available, except that they all seem to incoporate a swivel which I don't want.
 
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