Attaching Anchor to chain

[AntarcticPilot]

This thread (http://www.ybw.com/forums/showthread.php?366579-Chopping-bits-off-anchors) had me thinking; there's a peripheral point in that thread about using swivels to attach the anchor to the chain.

My anchor is attached to the chain by a large shackle. This appears to be amply strong enough and secure. However, the width of the shackle slightly exceeds the width of the bow roller, so when hoisting the anchor it is necessary to lift the end of the shank of the anchor onto the bow roller, and if I'm unlucky or a bit too enthusiatic, the shackle can jam in the bow roller. Obviously it would be better if the fastening between anchor and chain could easily pass over the bow roller.

I'd be worried about a smaller shackle, but a properly engineered swivel would seem to be a possible answer - not because of it's swivelling property, but because they are more stream-lined than a shackle.

Any thoughts or suggestions? I've looked at Vyv's pages (http://coxengineering.sharepoint.com/Pages/Connectors.aspx) but I'm afraid that when it come to mechanical engineering I'm a bear of very little brain. I can't readily sort out from that page what would be most suitable, though I'm sure all the information I need is there.

 

[Pasarell]

I've just gone through this exercise and, like you, spent a lot of time agonising about it. The bow roller on my Moody 33 is very narrow so even the smallest shackle that fits the anchor gets jammed. I wanted a connector that fits through but would also be the biggest I could use. My new 8mm chain from Bradney is now connected to the Delta anchor with a Kong 6-8mm swivel connector that just fits through the roller. I would have preferred the next size up but not an option without major surgery to the bow area.

 

[sailorman]

check-out Viv Cox`s web site for best practice

 

[prv]

I had exactly the same problem - on my main anchor rather than the kedge in that thread. The solution was to realise that not all shackles are created equal, and to go by SWL or break load rather than simply size.

I found a lifting shackle from S3i, with a 1-tonne SWL (more than my good-quality Bradney chain) and countersunk head and only 32mm wide. This compares pretty well with most of the streamlined "connectors" and swivels, and should fit nicely through my narrow bow roller.

Due to an uncharacteristic cockup with my order I haven't actually received it yet (promised tomorrow), but it will arrive with its own individual test paperwork proving its strength and that's more than you can say for most chandlery chain connectors.

Pete

 

[neil1967]

I have 10mm chain and use a 10mm stainless steel shackle with an allen-key bolt (so no protrusions) connecting 3 links of chain between the anchor and a kong swivel connector, which then connects to the rest of the chain. I believe that the shackle is as strong as the chain, and is only slightly larger, so it fits without any problems. I use locktite blue thread lock to reduce the risk of the shackle coming undone.

Neil

 

[prv]

A normal 10mm shackle wouldn't fit through my bow roller, though, even without the head on the pin.

Pete

 

[FWB]

I use this 2 way swivel from Force 4

http://www.force4.co.uk/1169/Force-...--Large--8-12mm-Chain--O-A-length--165mm.html

Boat is 9 tons long keeled with 10mm chain, had it for about 3 years in regular use and works well.

 

[winsbury]

I tried lots of different ways to solve this as our bow roller is narrow and conventional shackle jams easily. My wife is slightly disabled in one leg so finds standing on the foredeck and lifting the anchor very difficult indeed , particularly to haul in the last few inches or sort out any knotty problems if it doesn't retrieve cleanly.

The problems that needed to be addressed were :
a) fitting through the bow roller without jamming
b) ensuring the anchor comes over the bow roller the correct way up ( ie point down )
c) ensuring that the anchor cant swing into the bow during the last part of the retrieve
d) making sure sufficient pulling power is available to lift the anchor over the roller without having to lean over and do it manually
e) ensuring the chain doesnt foul the anchor when dropping
f) ensuring any twists are removed/prevented from chain/warp
g) ensuring the terminal equipment doesn't come undone

All solved in my case by using a countersunk 'blind' shackle to attach the chain to a double action swivel to anchor connector that bolts directly through the eye of the anchor combined with a small windlass to provide sufficient leverage for the last foot or so of the retrieve and secure the anchor to bow from a comfortable seated position on the foredeck. All bolts are countersunk hex type and secured with Loctite permanent thread lock so nothing sticks out wider than the chain.

90% of the time it retrieves fine, every now and again the CQR anchor will come up the bow roller inverted, simply drop it and let it rotate and try again.

edit : while typing the photo in the previous post was added - this is virtually identical to our arrangement.

 

[vyv_cox]

It doesn't have to be a swivel: there are many fixed connectors that combine being torpedo shaped with good strength, Kong do one http://www.marinesuperstore.com/item/AC/kong-fixed-anchor-connector. Unfortunately I suspect that it may suffer the same potential bending problem as its swivelling cousin. I like the Wichard countersunk shackles but to add one of these plus three links of chain to a fixed connector would be nonsensical. Otherwise, it's take a chance that any bending force would not exceed the SWL, not shown in my link but 850 kg for the swivel, which is the lateral one, not the axial.

 

[vyv_cox]

I use this 2 way swivel from Force 4

Boat is 9 tons long keeled with 10mm chain, had it for about 3 years in regular use and works well.

Unfortunately that design could suffer in the same way that the Kong does. If you were to pull the chain towards the camera with the connection to the anchor where it is now I think it would hang up, putting a big bending force onto the hinged joint. This happened to me several times, on hauling the anchor the swivel was wedged in this position. It had very probably been like that on the seabed. See the swivel connect page of my website, under anchoring, for illustrations.

 

[alahol2]

I've been using one of these for the last 10 -15 years... http://www.s3i.co.uk/8mm-Maillon-Rapide-Large-Mouth.html

 

[AntarcticPilot]

It doesn't have to be a swivel: there are many fixed connectors that combine being torpedo shaped with good strength, Kong do one http://www.marinesuperstore.com/item/AC/kong-fixed-anchor-connector. Unfortunately I suspect that it may suffer the same potential bending problem as its swivelling cousin. I like the Wichard countersunk shackles but to add one of these plus three links of chain to a fixed connector would be nonsensical. Otherwise, it's take a chance that any bending force would not exceed the SWL, not shown in my link but 850 kg for the swivel, which is the lateral one, not the axial.

Thanks, Vyv. I see that the one you link to is stainless; both my anchor and my chain are galvanized. Is that likely to give problems?

 

[winsbury]

I just took a look at your website, the issue that your three links solves is indeed potentially a problem but is there any real evidence that by not having the three links is dangerous or substantially weakened. A Simpler solution ( especially useful for the other similar thread on this topic ) is to have a round hole rather than an elongated one in the shaft of the anchor.

 

[vyv_cox]

Thanks, Vyv. I see that the one you link to is stainless; both my anchor and my chain are galvanized. Is that likely to give problems?

Very few people anchor for long enough for galvanic corrosion to occur. I anchor probably far more than the average, spending up to six months of the year almost entirely at anchor. The worst that happens is that the zinc galvanising on the two or three links nearest to the connector will be lost. My testing found that in general stainless shackles and connectors were stronger than their galvanised equivalents.

 

[winsbury]

Thanks, Vyv. I see that the one you link to is stainless; both my anchor and my chain are galvanized. Is that likely to give problems?

This has been covered in other threads but basically because its not submerged for very long periods the usual problems associated with the mix are not for practical purposes relevant. Its a different story for permanently submerged installations such as mooring buoys where dissimilar metals are to be avoided.

 

[vyv_cox]

I just took a look at your website, the issue that your three links solves is indeed potentially a problem but is there any real evidence that by not having the three links is dangerous or substantially weakened. A Simpler solution ( especially useful for the other similar thread on this topic ) is to have a round hole rather than an elongated one in the shaft of the anchor.

It might be, although I suggest it would still be worth experimenting to find whether the connector would hang up. Also, a round hole would not overcome the sideways loading issue. However, in practice, most modern anchors with plate stocks have an elongated hole that allows the eyes of a shackle to pass through without weakening the stock any more than necessary.

 

[FWB]

Unfortunately that design could suffer in the same way that the Kong does. If you were to pull the chain towards the camera with the connection to the anchor where it is now I think it would hang up, putting a big bending force onto the hinged joint. This happened to me several times, on hauling the anchor the swivel was wedged in this position. It had very probably been like that on the seabed. See the swivel connect page of my website, under anchoring, for illustrations.

Yes a valid point. My choice of double swivel was to reduce any twist in the chain when the anchor is set.
The anchor is not launched through the bow roller.
Perhaps a better set up for me would be a short length of chain from the anchor to the swivel, the more I think about that the more I like the idea

 

[winsbury]

It might be, although I suggest it would still be worth experimenting to find whether the connector would hang up. Also, a round hole would not overcome the sideways loading issue. However, in practice, most modern anchors with plate stocks have an elongated hole that allows the eyes of a shackle to pass through without weakening the stock any more than necessary.

yes you're right, the lozenge hole is somewhat of a necessity, I hadn't thought that through fully.

I notice someone else suggested using a mallion, as I sell climbing gear professionally I would be delighted if everyone started using these for my bank balance but in reality the strength of these connectors when cross loaded is relatively very low and there is a distinct possibility of that occurring at the anchor to chain interface with nasty consequences, I would therefore be very dubious of using a mallion anywhere that cross loading might occur. The other problem with mallions is adequately locking the thread is difficult and the large area of the hex nut lends itself to getting knocked on rocks or other obstructions that could conceivable undo it. Mallions are intended for uses where longditudinal loading is assured but its necessary to be able to remove them on occasions.

There's and interesting article in PBO this month about the rise of popularity of carabiners for quick mooring and the potential pitfalls of this, carabiners are also not designed for cross loading and will twist and pop open remarkably easily if loaded in certain directions - climbers are usually taught this early on but those that don't know may not live to tell the tale.

Bottom line here is dont be tempted to use carabiners or mallions for anchor connections.

 

[alahol2]

...

I notice someone else suggested using a mallion, as I sell climbing gear professionally I would be delighted if everyone started using these for my bank balance but in reality the strength of these connectors when cross loaded is relatively very low and there is a distinct possibility of that occurring at the anchor to chain interface with nasty consequences, I would therefore be very dubious of using a mallion anywhere that cross loading might occur. The other problem with mallions is adequately locking the thread is difficult and the large area of the hex nut lends itself to getting knocked on rocks or other obstructions that could conceivable undo it. Mallions are intended for uses where longditudinal loading is assured but its necessary to be able to remove them on occasions.

...
Bottom line here is dont be tempted to use carabiners or mallions for anchor connections.

We'll have to agree to disagree. The possibility of cross loading on a maillon used as an anchor/chain joint is virtually nil, the physical layout doesn't allow it. It's actually far more likely with a shackle. I've never yet pulled up the anchor with the maillon anything other than inline. If the nut is tightened with a spanner it will not come undone, use Loctite if there's a doubt. If, by applying some incredible force, you did manage to strip the thread on the nut, the maillon is, to an extent, 'failing safe' which a shackle will not do.
Carabiners, I agree, are for climbing not mooring.

 

[NormanS]

I guess I'm lucky, in that my bow roller(s) are both broad enough and big enough to cope with oversise shackles for my 10mm chain. I have never seen the point of having a swivel, but what I do have is a bent link of 12.5mm round bar, with an eye on each end, shackled between the chain and the anchor. This ensures that as soon as the bent link comes onto the roller, the anchor is automatically rotated, if necessary, and always stows first time.