Anchor Chain Twist Nightmare

[robifz]

I have 80metres of 1/2inch anchor chain with a vertical anchor winch. The bow roller has a groove to hold the chain in place and I have vertical fall of about 3-5ft in the anchor locker. But when I pull up the chain I can see that it is ever so slowly putting a twist in the chain. The more times I anchor the more the twist is. After about every 20 times I anchor the twist is so much that I cannot drop the anchor anymore as the chain will jam in the chain pipe hole. If I am normally dropping 40m of chain the twist starts to develop around the 35m mark.

I can get around the problem by dropping the entire 80m of chain in about 20m of water and then slowly retrieving. If I already have a large twist I cannot do this and I need to pull out the chain by hand from the locker and untwist manually. Not easy with 1/2inch chain. Good for the muscles maybe but I am fed up with it.

I would like to solve this problem but I cannot figure out why this twist is being create. I would like to know what is the engineering thought behind how this all works.

My possible thoughts are:
- chain comes in to gypsy at 12oclock and exists gypsy at 8 oclock - that is goes 3/4 around before being stripped into the pipe. Maybe this is causing the twist and maybe it needs to go around the gypsy more?
- Vertical anchor winches always have this problem?
- Grooves in bow roller of gypsy are not correct pattern to hold chain in place?

Any advise would be much appreciated as I have been suffering from this problem for many years.

Rob

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[Hud3]

Welcome, Rob.

I have a vertical windlass and have never had a chain twist problem. The gypsy takes it around almost 3/4 the way, just as yours does. My anchor roller is smooth. Perhaps if you painted a link different colors, one on each side, and watched it carefully as it travels all the way to the chain locker you could see how it behaves.

Paolo has that problem, as well, and started a thread here http://www.cruisersforum.com/forums/f118/chain-twist-clogging-hawse-pipe-25665.html. Not a lot of solutions there, but perhaps some help for you.

[David M]

Do you have a swivel between your chain and anchor?

[Zephyr's Aura]

Just curious as to which windless both of you having problems have? Is there a problem in the design?

Tim

[robifz]

Originally Posted by David M

Do you have a swivel between your chain and anchor?

No but the twist is happenning 30 metres down the chain from the anchor.

I can imagine a swivel helping if you are swinging around an anchor all night but I am nearly always anchored against the prevailing trade winds and the boat never swings around.

[robifz]

Originally Posted by Zephyr's Aura

Just curious as to which windless both of you having problems have? Is there a problem in the design?

Tim

I have a custom built vertical winch that uses a DC-9 starter motor.

[robifz]

Originally Posted by Hud3

Welcome, Rob.

I have a vertical windlass and have never had a chain twist problem. The gypsy takes it around almost 3/4 the way, just as yours does. My anchor roller is smooth. Perhaps if you painted a link different colors, one on each side, and watched it carefully as it travels all the way to the chain locker you could see how it behaves.

Paolo has that problem, as well, and started a thread here http://www.cruisersforum.com/forums/f118/chain-twist-clogging-hawse-pipe-25665.html. Not a lot of solutions there, but perhaps some help for you.

I have read that thread and nothing new.

Yeh I will probably have to just sit down and watch the chain and try and figure out why it is twisting. I am almost tempted to increase the size of the anchor pipe and hole so that if any twists happen the chain can still come out of the locker and will de-twist in the water.

[Hud3]

Not sure why the link doesn't work. Try the Google search in the small pull-down "Search" menu up top. Type in "chain twist". There may be a couple of posts of interest in the thread.

[David M]

Originally Posted by robifz

No but the twist is happenning 30 metres down the chain from the anchor.

I can imagine a swivel helping if you are swinging around an anchor all night but I am nearly always anchored against the prevailing trade winds and the boat never swings around.

Your least expensive potential solution might be to add a swivel.

[TaoJones]

Originally Posted by Hud3

Not sure why the link doesn't work. Try the Google search in the small pull-down "Search" menu up top. Type in "chain twist". There may be a couple of posts of interest in the thread.

Try: http://www.cruisersforum.com/forums/...ipe-25665.html

TaoJones

[imagine2frolic]

David M,

That's a very complicated solution.. Although I have to admit it was my first question......i2f

[captjohn360]

SWIVEL....jt

[s/v Jedi]

We never had trouble and thus I took the swivel off and sure enough I got twists after a couple of times anchoring and even had to go down and fight chain for the first time. Put the swivel back, untwisted the chain and never had the trouble again.

My worry was that the swivel was the weakest link. I had a 5/8" swivel and shackle but after a hurricane the swivel was fine but the shackle was not... so the shackle was weaker. I now have a 3/4" shackle and swivel, a 176 pound Bruce and a 3/8" schedule 70 (G7) chain.

cheers,
Nick.

[David M]

I just got done doing some work where we deployed a 1200 pound weight that was attached to a submerged "fish" with 500 pounds of buoyancy.

What did we use as a swivel to keep the cable from twisting?

McMaster-Carr

There certainly are swivels out there that are strong enough.

[robifz]

Originally Posted by David M

Your least expensive potential solution might be to add a swivel.

But I do not understand how a swivel at the end of the chain can stop twists developing at the 30m mark. I never get any twists in the first 20 metres of the chain.

If a boat is not swinging around the anchor how can a swivel help?