Split tail twist

[Alistair Edwards]

I have recently replaced my conventional mainsheet with a split tail version. I am pleased with the results when I start sailing but unfortunately over time the two tails progressively twist round each other. I do not understand why the twisting is happening and wonder whether anybody else has encountered this problem.

The only potential solution I have come up with so far is to install a small swivel just before the tails join the thicker portion of the mainsheet.
Does anybody have any thoughts on this?

[Phil Brown]

Typically, if you pull in a laid (rather than braided) rope under tension, it will tend to rotate over the block(s) and impart a twist into the rope, particularly if you have a rachet block in there with a grippy sheave, when you release it and there is less load on the rope. it will tend to run freely over the block and slide rather than grip which would reverse the twist put in when pulling in. Net result, a rope with twist in.
You possibly have a mainsheet that has some unnatural tension in the layup which is producing that sort of result or perhaps you regularly sail an irregular course that has more pulling on port, say, than on starboard!
You could try Rooster's Polylite that has less tendency to twist in the first place

[Martin]

I get the same problem with my split tail (standard one supplied by P&B) Every so often I remove the mainsheet from the boat and untwist it. 
If you are new to split tails I would recommend that when sailing always keep the mainsheet under tension.  I have had the misfortune to gybe on a couple of ocassions with slack in the mainsheet and the tail managed to pul through and jam in the bottom block of the mainsheet. 

[Alistair Edwards]

Martin - I am using the P&B mainsheet as well. Keeping tension on the sheet does seem to be imprtant. I too have managed to get the tails jammed in the lower block. My swivel solution would prevent this.

I untwist the mainsheet before every sail but the twists return fairly quickly. I think Phil is probably right about the block imparting the twist. I think I will try using a bigger (non ratchet) block before I start cutting the tails and installing a swivel.

[Lukepiewalker]

Have you tried tieing the other end to something. It sometimes helps if the other end of the mainsheet isn't free to rotate.

[Martin]

Have you tried tieing the other end to something. It sometimes helps if the other end of the mainsheet isn't free to rotate.

Do you mean the other end that is in your hand? I so not sure how tying that off will help? 

[Lukepiewalker]

It sometimes helps if the rope can't rotate (not necessarily, but worth a try) to stop it from winding itself up as much. Imagine a hose with kinks in it, you get them out rotating the free end of the hose. Take all the twist (kinks) out of your mainseet, fix both ends, it should be a lot less twist prone, and it also shouldn't be able to tie any particularly interesting knots in itself.

[Lukepiewalker]

I'm not saying it'll definitely work, but it's worth a shot.

[Alistair Edwards]

A progress update.

I changed the lower block to a large non ratchet block but the twisting continued.

Tonight I cut the split tails and fitted a small swivel on the tails close to where they join the thicker section of the mainsheet. I went out for a sail and am pleased to be able to report no more twisting.