Twists induced in running rigging

[ggray]

Yes, it is interesting. I wasn't really thinking about loss of strength, only possible fouling.

But it does take a lot of twists, a lot more than I've ever experienced.

To suffer 10% loss of strength, it would take more than 2 full twists in a meter span. That's a lot of twist, and the lines we are talking about are probably oversized, sized for handling, stretch, and clutch holding more than ultimate strength.

[Cynara]

I started sailing on my own boat in 1972 and then bought our cruising boat in 1977, which got more use. Never had an issue with halyards twisting. All our lines were double braid. Mayb they are being made out of different material or process today. When I coiled the line I let it coil it wanted to

[Karanga]

Originally Posted by Seaworthy Lass

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.

Hi SWL
"halyard twist is primarily caused by turns being flung off carelessly"
You have made this comment several times now. I don't understand it, and wonder if you can explain more.
Is there a 'different' way of taking coils off the winch, than simply casting them off? How does one be careful?
More importantly, obviously when wrapping the coils (3 or 4 or) around the winch, twists are going to be introduced unless the tails are relatively short. If the tails are long (normally so?) then the introduced twists should revert back to untwisted as soon as the coils are removed, since neither the head nor tail has rotated relative to each other. No?

[Seaworthy Lass]

Originally Posted by Karanga

Hi SWL
"halyard twist is primarily caused by turns being flung off carelessly"
You have made this comment several times now. I don't understand it, and wonder if you can explain more.
Is there a 'different' way of taking coils off the winch, than simply casting them off? How does one be careful?
More importantly, obviously when wrapping the coils (3 or 4 or) around the winch, twists are going to be introduced unless the tails are relatively short. If the tails are long (normally so?) then the introduced twists should revert back to untwisted as soon as the coils are removed, since neither the head nor tail has rotated relative to each other. No?

Hi Karanga
When starting this thread I included poor coiling of line as well. I added the latter in brackets as I couldn’t imagine this being done by CF members . I have since learned incorrect winch placement can add to the problem, as the loaded line can roll on the flange if the winch is too high. There is possibly also a whole host of other issues if significant twist can be incurred the very first time a line is winched, as Benz reported.

To address your last question first:
The reverse twists induced in the line not under load occur when the turns are first made on the winch. The situation will vary with boat size and what can be handled manually, but if the turns on the winch are made early they will end up well separated from the reverse twists once winching is completed.

It then depends on what is done with the loose line. Any tidying will tend to work the bunch of reverse twists out, or if not completely out, they at least have a tendency to move closer to the end. Line not under load is not stable when twisted.

Even if the newly winched line is not tidied (and if several lines are left untidied I have found the lines can tangle awfully, particularly if the reverse twists end up twisting around adjacent line) then depending on winch position and how long the line is left lying/moving around, the twists tend to work their way down a bit on their own. Even a small shift towards the tail will mean they won’t be able cancel out the turns on the winch if the winch was used from the start.

So from my experience it is very unlikely the naturally induced reverse twists have much hope of cancelling the twists induced by the turns on the winch.


Regarding “careless casting off”, this depends on whether the line is secured by a clutch etc. If it can be secured, then after casting off there is an opportunity to carefully pass the line through your hands and remove all the twists before neatening the line via figure 8 turns. Usually the same number of turns don’t need to be put on the winch when removing the load (and if this is done just before release, the reverse twists in the loose line are right next to the winch) so the problem is minimised.

SWL