Twists induced in running rigging

[tenchiki]

Envision the wraps on a winch as a clockwise coil of N turns (include the self-tailer or cleat). That puts some twist in the line. Rather than leaving the tail in a jumble in the cocpit, I take the tail and do a counter-clockwise (ie "reverse") coil of N to N+1 turns, followed by figure-8 for the remains of the tail, to minimize any other twist. Then when I pull the sheet off, the clockwise and counter-clockwise coils cancel each other out, and no twist in the tail. I'm not totally sure why I need N+1 CCW turns to cancel out N CW turns. Probably has to do with under strain vs not under strain.

Doing a zillion short tacks up the Alameda Estuary to the central SF Bay sure lets you figure out what makes sheets twist and not twist...

[Seaworthy Lass]

Originally Posted by tenchiki

Envision the wraps on a winch as a clockwise coil of N turns (include the self-tailer or cleat). That puts some twist in the line. Rather than leaving the tail in a jumble in the cocpit, I take the tail and do a counter-clockwise (ie "reverse") coil of N to N+1 turns, followed by figure-8 for the remains of the tail, to minimize any other twist. Then when I pull the sheet off, the clockwise and counter-clockwise coils cancel each other out, and no twist in the tail. I'm not totally sure why I need N+1 CCW turns to cancel out N CW turns. Probably has to do with under strain vs not under strain.

Doing a zillion short tacks up the Alameda Estuary to the central SF Bay sure lets you figure out what makes sheets twist and not twist...

That is what I envisioned after your initial description .
I imagine it would work well. I will try that on our headsail sheets (our mainsheet is on a continuous line, if that is the right term, so it isn’t required).

Regarding the main halyard that is held by a clutch, I’ll continue doing what I have been lately: when the sail is up, I cast off the turns & untwist the entire line and use figure 8 turns to coil it. When the main needs to be dropped, I put on just one turn and don’t cast this off until the sail is down. Before using figure 8s to store the line, I untwist the final turn. For me this has made a dramatic difference to how much the main halyard now twists.

SWL

PS For anyone thinking this is not occurring for them, go to the clew of your headsail (the easiest line to follow from its origin) and follow the weave on one of the sheets, rotating it to keep the line of pics constantly straight. I bet you will eventually be swearing at the hockles and that the tail will be spinning like mad when you get to the end.

[Seaworthy Lass]

Originally Posted by Benz

It only seems to take one hoist--all winch--for the halyard to have a twisting problem on the second hoist. So I can only conclude that the first hoist induced the twist.
Think about it, though: even coming off the spool, the line has a certain way it wants to turn, according to how it was spooled at the factory (this is why the little measuring table that spools the line as they measure it off the roll at West Marine has to rotate the proper way or it all goes kinky). Now you put it around a few bends, especially a sharp one at the mast-base turning block and around and around a winch, and then crank it with serious tension. No wonder it gets giddy!
……

This is just a thought, but if compression of one side of the line when it goes around the spool, winch and blocks is contributing to the twisting problem, then it may help to have the winch on the starboard side so that blocks turn the line left rather than right. The compression induced by the winch would then be partially compensated by that induced by the blocks.

If the rope already has a “memory” due to how it was wound on the spool, and winching exacerbated the twisting problem (always clockwise turns on the winch), it may make a difference which end of the line is used when rigging.

Just tossing around ideas. There must be some way of minimising this problem.

SWL

[Letterkenny]

Going to try this method going forward. Will be going down to the boat tomorrow to remove my 2 to 1 and get it straightened out. Would go 1 to 1 but seems like that might be a bad call from what I heard from other owners that inquired about this to Selden.

[Benz]

Originally Posted by Seaworthy Lass

This is just a thought, but if compression of one side of the line when it goes around the spool, winch and blocks is contributing to the twisting problem, then it may help to have the winch on the starboard side so that blocks turn the line left rather than right. The compression induced by the winch would then be partially compensated by that induced by the blocks.

If the rope already has a “memory” due to how it was wound on the spool, and winching exacerbated the twisting problem (always clockwise turns on the winch), it may make a difference which end of the line is used when rigging.

Just tossing around ideas. There must be some way of minimising this problem.

SWL

It sounds like you're doing everything possible to minimize the problem with the resources at hand.
My solution would be to design boats that don't need halyard winches. It would require a shift in the design fads of the last few decades, but maybe it's time for yacht design to modernize and start using gaff rigs. Problem solved.

[Seaworthy Lass]

Originally Posted by Letterkenny

Going to try this method going forward. Will be going down to the boat tomorrow to remove my 2 to 1 and get it straightened out. Would go 1 to 1 but seems like that might be a bad call from what I heard from other owners that inquired about this to Selden.

In case it has retained memory of any of the twisting, it would help to reverse the ends.
Edited to add: No it wouldn’t. Skip that.

Note:
Any swivel at the peak of a 2:1 system will allow a twisted line to twirl on itself, exacerbating the problem. To demonstrate this, just grab a bit of thin line and while it is straight twist it between your fingers. Get someone to hold the mid point (or use your teeth) and bring the 2 ends together. Nothing happens until the mid point is released and left free to swivel, then the line will twist madly on itself.

A swivel on a 1:1 system will allow the twists to work their way out.

[ggray]

Well, I watch the halyard twist as I'm winching, perhaps 60 feet of the 2 part halyard. (Used to be able to hoist 3/4 way or more by hand, but that was 20 years ago.)

As I ease the halyard to lower the sail, I feed some twist (untwist?) with my fingers.

I then have no problem with halyard twist. Never had one with jib sheets. Not that much winching.

[Letterkenny]

I might have been too far gone but I tried to compensate by untwisting more as I let down the halyard but still didn’t get rid of the twist. Unfortunately wasn’t able to make it to the boat today so will go on Monday to do this project of running up the mast to fix it.

My dealer said that this is prone to newer lines (mine being a year old). Can anyone confirm this?

[Benz]

Originally Posted by Letterkenny

I might have been too far gone but I tried to compensate by untwisting more as I let down the halyard but still didn’t get rid of the twist. Unfortunately wasn’t able to make it to the boat today so will go on Monday to do this project of running up the mast to fix it.

My dealer said that this is prone to newer lines (mine being a year old). Can anyone confirm this?

Only if the new line was unspooled carelessly, like with the WM measuring/coiling table set up the wrong way. Or if the person who put the halyard together was careless and coiled it up wrong: there's a lot of ways to bungle a new piece of rope. Production boat companies are notorious among riggers for supplying poorly spliced and carelessly handled rope with their boats.

[Seaworthy Lass]

Originally Posted by ggray

……
I'm not sure it's the wraps (turns) on the winch that induces twist. When I'm winching a long halyard (and my first step of twist prevention, is hoisting by hand as far as possible) it looks like the line is rotating. Perhaps the bottom flange of the drum is make in the line roll.

Your comments about noticing a twist occurring when winching and thinking the line may be rolling over the bottom flange of the drum, combined with Benz’s comments that a significant twist can be induced in a halyard following the very first hoist (even when the rope is correctly spooled initially), made me look at our winched lines very carefully during yesterday’s sail.

I think the height of the winch relative to how the line leads to it may be contributing to the problem.

We specified the amount our winches needed to be raised (63 mm) to give a perfect lead of the line onto the winch from a bank of three clutches on each side. There is no noticeable roll of the line forward of these winches. So in our case any halyard twist is primarily caused by turns being flung off carelessly.

On the other hand, our inboard yankee sheets enter the winch at an angle of around 20°, actually rubbing slightly on part of the flange. It does not take much winding on the winch to start inducing a twist between the winch and the block.

It is hard when winches are used for lines entering from assorted directions depending what tack you are on, but it is an additional thing to consider in yacht design. If the winches are too low, riding turns will easily occur. If they are too high, it seems the line may twist forward of the winch.

[ggray]

Seaworthy, that's probably it.

My halyard enters the winch making first contact with the bottom flange of the winch. Whether this alone makes it rotate I can't be sure, and since I wouldn't be making a change to the mounting, it doesn't matter. That's the way it is! I can deal with the twist easily enough.

But this makes me think a little more about it. Lines to winches, IIRC are supposed to lead from something like 10 degrees below the face of the drum. Is there any margin between this angle (what ever it is), and the angle which makes the line contact the flange? I guess that could be considered the sweet spot. But I'd rather deal with a little twist than have over-rides from the line coming in too high!

Getting to be too much theory!

[Seaworthy Lass]

Originally Posted by ggray

Seaworthy, that's probably it.

My halyard enters the winch making first contact with the bottom flange of the winch. Whether this alone makes it rotate I can't be sure, and since I wouldn't be making a change to the mounting, it doesn't matter. That's the way it is! I can deal with the twist easily enough.

But this makes me think a little more about it. Lines to winches, IIRC are supposed to lead from something like 10 degrees below the face of the drum. Is there any margin between this angle (what ever it is), and the angle which makes the line contact the flange? I guess that could be considered the sweet spot. But I'd rather deal with a little twist than have over-rides from the line coming in too high!

Getting to be too much theory!

We have Anderson winches and they specify the ideal entry angle of line to the drum is merely 3-8° from below the drum. We had our 2 winches that lead off the 2 banks of clutches raised when they were initially fitted so the entry angle is 3° to give the best exit from the clutches. No twisting of the line occurs forward of the winch and no riding turns occur for these 2 winches if they are used for the lines coming off the clutches.

The two winches to the rear of this are just fitted on the combing. All the rest of the lines lead up to these at angles greater than 3-8°. Not much we could do about this. Most of the twisting comes from throwing off the turns and it is also not hard routinely untwisting these lines though so it is not a big deal (I do the headsail sheets after each sail).

To maintain maximum line strength I think it is important to eliminate these twists. I have photographed some twisted single braid to show how just half the strands are loaded fully when twists are present in braided line. It is not just ease of passing over blocks and sheaves that suffers.

[requiem]

To echo what tenchiki and others mentioned, wrapping lines around a winch is the same as coiling braided line in circles as if it were laid line: twist-inducing. My own habit is to regularly flake the lines, particularly when they may need to run freely.

Climbing rope often included specific instructions on how to uncoil it for the first time to avoid being left with a twisted rope. Essentially it was "unspool in reverse" rather than taking the end off at an angle, as one would to taking a line off a winch.

Here's some background reading: https://www.blackdiamondequipment.co...-twisty-ropes/

For similar reasons, audio techs and others will get very unhappy if you coil their cabling improperly. A related problem arises when the core is twisted within the sheath. You can sometimes see this on older extension cords that have often been coiled in circles: eventually the twists in the internals becomes visible through the sheath, and it remains particularly hard to coil.

[sails4fun]

Note that twist induced in use can affect the strength of ropes. While this paper addresses twist in larger mooring ropes - it should be used as a solution when twist has been introduced to lines on board.


https://www.samsonrope.com/docs/defa...rsn=10649876_2

[Seaworthy Lass]

Originally Posted by sails4fun

Note that twist induced in use can affect the strength of ropes. While this paper addresses twist in larger mooring ropes - it should be used as a solution when twist has been introduced to lines on board.


https://www.samsonrope.com/docs/defa...rsn=10649876_2

Another interesting link .