What causes anchor chain to turn ?

[OldBawley]

What causes anchor chain to turn ?
I know, will have to buy new chain but still want to know.
For the second time the chain starts to turn as a corkscrew. We anchor 365days a year, often two times a day on separate places. Only this winter, due to the internet I tend to stay some longer on one place. Last month the chain was OK, now it starts to turn. Wintering in the near of Methana Greece where iron on the seabed is said to go. This chain is 5 years in use, excellent German made quality. First chain lasted 7 years, then rusting, and turning so bad that sometimes it formed knots. Bought a new one, Turkish rubbish. It had an burr on each weld and acted as an chainsaw in the haws pipe. New haws pipe, big one this time, chain gipsy re welded and machined ( In Turkey cheaper as buying new ) and second-hand as good as new high quality chain.
When still in business I ordered 100 m of 10 mil chain for a client. Most respected Dutch retailer. Had to send it back, it turned from the first time it was winched into the yacht. Second delivery OK.
Why ?

 

[vyv_cox]

What causes anchor chain to turn ?

Well, here's a thought. This photo shows typical modern, machine made chain.

All the welds are in line, 90 degrees apart on adjacent links. If you load the chain into the gypsy so that the welds are in contact with it I guess that there might well be a twisting motion as it releases going down the hawse pipe. Maybe if it was loaded so that the welds were facing outwards it would not happen? Perhaps you could experiment and report back, it would be interesting to know.
Presumably your Turkish remade chain was done manually, so the welds were randomly orientated.

 

[OldBawley]

the Turkish chain was bad from the start. I first spend two days hammering and de-burring because it was galvanised so bad that many links ware fixed together. The burrs ware on the outside of the weld ( all on the same side ) Dangerous. It never went down good, sometimes two links ware crossed so the chain blocked in full speed in the hawse pipe when dropping the anchor. You can imagine the forces on the deck stopping a heavy anchor and lots of chain in full speed fall. Needed a hammer to unblock the links. Stored the lot in my secret cave after one months use.
The first chain was very used before it started turning. Near the anchor some links ware worn down to 6 mm. ( 8 mm chain ) Not rust, chafe ware the shackles touched.
Turning the chain so the much used anchor end was inside now did not help. The chain kept on turning, sometimes so bad it formed knots.
The “ new” chain was fine for 5 year, now it starts turning.
The bow roller was originally smooth cast iron, after 20 years of daily anchoring it has developed chain -nests itself, so it looks a bit like a gipsy.
Turning the chain dos not help, some welds always touch the gipsy ( they are on 90° ) and the turning makes the chain jump the gipsy when heavily loaded. That means the gipsy is worn again.
Last summer we had more than once caught a mooring in the anchor-chain so extreme loads ware on the chain. Had to lift an oil drum full of metal scrap and concrete some meters high to free the damn thing. Took me eight hours.

The " Turkish" chain was probably Chinese to.

 

[SHUG]

Wasn't there a theory that its the anchor that twists the chain as it "flies" through the water during its descent?
Lets not start a thread on which anchor flies the best!!!
It's interesting to know if "twisting" is an integral property of chain just as "knotting" is an integral property of rope.

 

[OldBawley]

Has nothing to do with the anchor. The anchor is the same, a new good chain dos not turn, once old and used it starts screwing.
If I hang the anchor down, say five to six meter, the used chain turns like a corkscrew and stays that way.

 

[sarabande]

Have you considered the Coriolis effect and the rotation of the Earth's magnetic poles ? Residual magentism in the iron from which the chain is made can inter-act with Earth's magnetic field (in the same way that rocks 'remember' the direction of North when they cooled).

Considering the direction which anchor chain hangs down, if the natural magnetism of the chain is at 90 degrees to the terrestrial lines of magnetic force, there will be a rotational effect, magnified by the magneto-hydrodynamic effect of the electrically conducting aspect of salt water, thus inducing a force on the chain. Since the chain is a moving component as it it is being laid, this rotation is also influenced by Faraday's law of induction, where the magnetic flux changes in an equal relationship with the ambient electromotive force.

One supposes that these forces will be greated at approximately 45degrees N or S of the equator, where the magnetic toroid is most deformable. Perhaps one of the Australian sailing forums could see whether their anchor chains 'twist' in the other direction ?

 

[pampas]

The one thing I have noticed is that since using a electric windlass that the last 2 meters in the locker get twisted and as mentioned are a mess, This never happened in the past (With hand operation),at least twice a season I now have to pay out all the chain,untangle, even turned the chain end for end still same result,

Could understand if the chains bitter end was bolted but its not, I thought the rope would twist or take up any rotational movement. Defies logic as Spock would say.

 

[oldvarnish]

Has nothing to do with the anchor. The anchor is the same, a new good chain dos not turn, once old and used it starts screwing.
If I hang the anchor down, say five to six meter, the used chain turns like a corkscrew and stays that way.

It could still be due to the anchor. If your boat has any forward motion, even slight, when the anchor is coming up, some anchors due to their shape have a tendency to "fly". This is why some kinds of anchor seem to always come up the wrong way.
If you have new chain, the friction between the links will be higher due to the new galvanising, and this might be sufficient to prevent the acnchor spinning. As you use the chain, the galvanising wears and becomes smooth making it easier for the anchor to twist the chain.

 

[oldvarnish]

The one thing I have noticed is that since using a electric windlass that the last 2 meters in the locker get twisted and as mentioned are a mess, This never happened in the past (With hand operation),at least twice a season I now have to pay out all the chain,untangle, even turned the chain end for end still same result,

Could understand if the chains bitter end was bolted but its not, I thought the rope would twist or take up any rotational movement. Defies logic as Spock would say.

I've just read your last line more carefully - that is indeed very odd.

 

[Cariadco]

Have you considered the Coriolis effect and the rotation of the Earth's magnetic poles ? Residual magentism in the iron from which the chain is made can inter-act with Earth's magnetic field (in the same way that rocks 'remember' the direction of North when they cooled).

Considering the direction which anchor chain hangs down, if the natural magnetism of the chain is at 90 degrees to the terrestrial lines of magnetic force, there will be a rotational effect, magnified by the magneto-hydrodynamic effect of the electrically conducting aspect of salt water, thus inducing a force on the chain. Since the chain is a moving component as it it is being laid, this rotation is also influenced by Faraday's law of induction, where the magnetic flux changes in an equal relationship with the ambient electromotive force.

One supposes that these forces will be greated at approximately 45degrees N or S of the equator, where the magnetic toroid is most deformable. Perhaps one of the Australian sailing forums could see whether their anchor chains 'twist' in the other direction ?

Oh, Brilliant...is it the 1st of April by any chance....??

 

[Rum_Pirate]

Anyone post a picture of a length of chain that has 'turned'.

I'd really like to know what you are talking about.

 

[vyv_cox]

Both my Delta and Rocna anchors rotate as they are hauled up. Rotation is clearly visible in the clear water of the Med. My windlass is noticeably faster than some others, which I have always assumed was the cause of the rotation. It is difficult to understand how the twist in the chain can be transported through the gypsy but it does appear to happen, as my chain sometimes acquires a good deal of twist inside the locker, requiring the whole lot to be lowered in deep water. I believe my swivel connector helps to take some of the twist out, but evidently not all of it.

 

[ccscott49]

This is indeed very strange, I have no swivel, an electric (quite fast) winch and have never experienced any anchor chain twisting, ever! with CQR, Danforth, FOB and Halls pattern anchors. Dunno what that proves but that's the way it is.

 

[BurnitBlue]

... It is difficult to understand how the twist in the chain can be transported through the gypsy but it does appear to happen, as my chain sometimes acquires a good deal of twist inside the locker, requiring the whole lot to be lowered in deep water.

A vertical gypsy is most often installed with less than 90 degrees contact with the chain. My horizontal gypsy takes chain from the bow, wraps around the gypsy and enters the hawse hole forward of the winch giving a good 270 degrees contact with the chain.

Maybe a twisted chain can get transmitted past a vertical gypsy, especially if the winch is mounted under a hatch where the contact would be less than 90 degrees due to it being below bow level.

Just a thought.

 

[vyv_cox]

Is your nomenclature of horizontal and vertical the same as mine? Vertical to me means with a vertical axis, like this Lewmar one. I don't think I have ever seen a vertical windlass that didn't have at least 270 degrees of contact. My Maxwell has at least that, perhaps more. Many horizontal windlasses have only about 90 degrees of contact, turning the chain around the gypsy and dropping it straight down the hawse pipe.

 

[BurnitBlue]

Is your nomenclature of horizontal and vertical the same as mine? Vertical to me means with a vertical axis, like this Lewmar one. I don't think I have ever seen a vertical windlass that didn't have at least 270 degrees of contact. My Maxwell has at least that, perhaps more. Many horizontal windlasses have only about 90 degrees of contact, turning the chain around the gypsy and dropping it straight down the hawse pipe.

I took my reference of vertical from the gypsy. I see that the correct way is to refer to the orientation of the shaft and not the gypsy.

My anchor winch looks like a sheet winch, is that you call a vertical winch?

Ooops, need to correct my log book.

 

[OldBawley]

Rum pirate asked for some pics, so while taking up the anchor this afternoon I took some pics.
Nr one is the anchor chain going into the water, the stainless steel chain on the left is the bob-stay.
Had been anchored four days, same wind direction. Swivel on the anchor.
Nr two is the same chain coming over the bow roler and from there onto the ( Very rusty) chain gipsy.
When cropping the pictures, I noticed that the chain going from bow roller into the water is turning anti clock, the same chain going from gipsy to bow roller is turning clockwise.
The bow roller is cast iron, used to be smooth, has now developed nests due to usage.
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[Malo37]

very queer

 

[RAI]

I wonder if the chain has worn such that it prefers to hang twisted.

 

[Rum_Pirate]

Rum pirate asked for some pics, so while taking up the anchor this afternoon I took some pics.
Nr one is the anchor chain going into the water, the stainless steel chain on the left is the bob-stay.
Had been anchored four days, same wind direction. Swivel on the anchor.
Nr two is the same chain coming over the bow roler and from there onto the ( Very rusty) chain gipsy.
When cropping the pictures, I noticed that the chain going from bow roller into the water is turning anti clock, the same chain going from gipsy to bow roller is turning clockwise.
The bow roller is cast iron, used to be smooth, has now developed nests due to usage.
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Thanks for the pics (worth a thousand words two thousand in this case ).

If you lower your anchor and chain 'straight' and then immediately retrieve, surely the chain does not 'twist'.

If you lower your anchor and chain 'straight' and leave the vessel for weeks/months the vessel will/may spin due to wind and tide and thereby become 'twisted' when retrieved.

If you lower your anchor and chain 'twisted' and then immediately retrieve, surely the chain will come back up 'twisted' .

If you lower your anchor and chain 'twisted' and leave the vessel for weeks/months the vessel will/may spin due to wind and tide and thereby become more 'twisted' when retrieved?

If you 'motor' up and let the chain hang vertically and retrieve slowly, even if 'twisted' the chain will 'untwist' as it goes over the roller and subsequently they gypsy. The chin will then untwist as the anchor is raised off the bottom.


Where have I gone wrong in the above ?

KATE (78'0" overall) is moored in about 25 -30'.
Moored to a massive block of concrete
Also anchored to a large CQR.
The wind changes hourly, or so it seems.

Last week I skin dived to try and 'untwist' the lines.
I was quite impressed at how long I could still hold my breath and how deep I could dive.
Managed to unwind about 20 turns, plus untangle a loose rope tail that was also wrapped in the lines.
Dived to the bottom and found that the mooring rope was twisted on itself with the chain section of the CQR wrapped around it.
The CQR had not set properly and had also entangled itself in the ropes, both its and the mooring rope.
Gave up at that point.
Needed somebody with scuba.