Dyneema Control Lines

[Dockhead]

I am replacing a bunch of control lines on my boat this year, to wit:

1. Jib sheet angle control lines (twings).

2. Genoa track control lines.

3. Traveler control lines.

These are the last non-dyneema ropes on my deck. The twings are 10mm polyester double braid, the others are 8mm.

For sure the new ones will be dyneema, but should they be double braid all the way to the end?

My mainsail outhaul -- which carries quite large loads -- is made of 12mm racing dyneema double braid spliced core-to-core to a piece of I think 8mm single braid dyneema. I am pleased with this, as the bare single braid is slippery and runs better through blocks, is lighter, less wind resistance, cheaper.

Based on this experience, last year I replaced my vang with a piece of 12mm racing dyneema double braid. Instead of splicing it to single braid, I simply stripped back the cover. Again, very pleased with the results -- runs better over blocks, is lighter.

Now the control lines -- should I take the same approach? If I use 6mm single braid for the twings, and 4mm for the other control lines, spliced onto 10mm/8mm double braid, this will be lighter, cheaper, more compact, and run better around blocks, than just using full lengths of double braid.

Are there any drawbacks? Should I worry about UV, for example? Anyone else doing this?

[Rucksta]

For Genoa Car leads I went to 6mm covered from 6mm partially striped.
The exposed area was only 1.5 track lengths and became untidy quickly.

Didn't notice increased resistance and the cars still return with a 2:1 6mm bungy.
Sheaves are sized for 8mm poly double braid.

[Mal Reynolds]

DH,

I don't spec dyneema for the traveler lines. The non-stretch induces more shock loading on the cars/blocks/traveler in case of a poorly controlled gybe or slamming loads after a storm or squall passes with waves and no wind.

I prefer the stretch that 100% double braid polyester provides. Some folks even spec climbing ropes.

[Dockhead]

Originally Posted by Mal Reynolds

DH,

I don't spec dyneema for the traveler lines. The non-stretch induces more shock loading on the cars/blocks/traveler in case of a poorly controlled gybe or slamming loads after a storm or squall passes with waves and no wind.

I prefer the stretch that 100% double braid polyester provides. Some folks even spec climbing ropes.

I certainly understand this argument, but I think I will prefer total discipline in keeping both lines taught at all times (which is right anyway). I have dedicated winches for these lines, and they are instantly accessible at all times from behind the helm, so on my boat at least, there's no excuse for subjecting the control lines to any shock load.

I have come to really hate any stretch in any line of any type whatsoever on the boat (climbing of course is totally different). If I want the boom there, I want it THERE, and I don't want it to pant in heavy seas. Especially with laminate sails, the traveler is a very sensitive control, where very small changes have a big effect. I want all that control.

I have dedicated winches for these lines, and they are instantly accessible at all times from behind the helm, so on my boat at least, there's no excuse for subjecting the control lines to any shock load.

Climbing ropes sound horrible!! YMMV, of course.

[thinwater]

I'm not a fan of Dyneema on the traveler. I changed from polyester to Dyneema once, and it was like jibing against a brick. I changed back within a few days. Polyester is better IME. That is one place where a little stretch is your friend, even when jibing under good control.

I understand your response, above, but I've been there. Your boat, your choice. You will have closer control and more stress on the gear.

BTW, on a genoa, I don't think anyone calls the control lines twings. That is the outboard down haul for a chute. They are Barberhaulers (named for the Barber brothers) if inboard and outhaulers if outboard (though some call both types Barberhaulers). Dyneema is nice for those because it runs through LFRs, but I'm guessing you use ball bearing pulleys.

[Dockhead]

Originally Posted by thinwater

I'm not a fan of Dyneema on the traveler. I changed from polyester to Dyneema once, and it was like jibing against a brick. I changed back within a few days. Polyester is better IME. That is one place where a little stretch is your friend, even when jibing under good control.

I understand your response, above, but I've been there. Your boat, your choice. You will have closer control and more stress on the gear.

BTW, on a genoa, I don't think anyone calls the control lines twings. That is the outboard down haul for a chute. They are Barberhaulers (named for the Barber brothers) if inboard and outhaulers if outboard (though some call both types Barberhaulers). Dyneema is nice for those because it runs through LFRs, but I'm guessing you use ball bearing pulleys.

Thanks; you made me think again about the traveler.


For my 120% yankee (it's a cutter, so no actual genoa), I have Lewmar Ocean 3 tracks.


The twings are for the blade jib which is use most of the time as the principle headsail in lieu of the genoa, which I use only for light conditions and mostly only when racing.


I think they are thus called -- I adjust the sheeting angle with a control line which lowers and raises the sheet inflection point (thus changing sheeting angle) through a triple purchase organised with LFR's.


For inboard-outboard control, which I need when hard on the wind, I use the staysail sheet as an inhauler to tweak the sheet inboard.


I copied all this from a minitransat or some other small hot racing boat. It works brilliantly, giving fantastic control over headsail shape and angle of attack, but the high friction with very high loads was not good.


The owner of the minitransat called the system "twings" so that's what I've always called them. Possibly there is more correct terminology, but I'm not aware of it. Also called twings here: https://l-36.com/twing.php. That is almost exactly the same as my system, except that I have triple purchase because of the higher loads of the bigger boat.





The blocks to replace the large LFR was carefully chosen because of the very high loads involved -- a Lewmar 90mm Sync Block with 2000kgf WLL. I believe it's a plain bearing block, not ball.

[thinwater]

Originally Posted by Dockhead

Thanks; you made me think again about the traveler.


For my 120% yankee (it's a cutter, so no actual genoa), I have Lewmar Ocean 3 tracks.


The twings are for the blade jib which is use most of the time as the principle headsail in lieu of the genoa, which I use only for light conditions and mostly only when racing.


I think they are thus called -- I adjust the sheeting angle with a control line which lowers and raises the sheet inflection point (thus changing sheeting angle) through a triple purchase organised with LFR's.


For inboard-outboard control, which I need when hard on the wind, I use the staysail sheet as an inhauler to tweak the sheet inboard.


I copied all this from a minitransat or some other small hot racing boat. It works brilliantly, giving fantastic control over headsail shape and angle of attack, but the high friction with very high loads was not good.


The owner of the minitransat called the system "twings" so that's what I've always called them. Possibly there is more correct terminology, but I'm not aware of it. Also called twings here: https://l-36.com/twing.php. That is almost exactly the same as my system, except that I have triple purchase because of the higher loads of the bigger boat.





The blocks to replace the large LFR was carefully chosen because of the very high loads involved -- a Lewmar 90mm Sync Block with 2000kgf WLL. I believe it's a plain bearing block, not ball.

It's just words.


I'm a big fan of 3D leads, whatever you call them and whatever the details. Simple to rig and you can twist and flatten the sail to any shape you need. And this is an application where you want zero stretch.

[s/v Jedi]

Why genoa car control lines? I found a position that works for everything in combination with the twings to adjust sheeting angle.

For UV: the core must have a good coating. Samson Warpspeed II (Amsteel Blue core) and MLX-3 (Blended core) both have the right coating for stripping the cover.

[Dockhead]

Originally Posted by s/v Jedi

Why genoa car control lines? I found a position that works for everything in combination with the twings to adjust sheeting angle.

This is for two different sails.


The boat was delivered with a 120% yankee and staysail. The staysail is self-tacking, and the yankee is controlled by a Lewmar Ocean track system, with remote controlled cars. That system is great and I use it whenever I'm using the yankee. The twings can't be used with the yankee -- they are too far forward.



The twings are for the 95% blade, which is an alternative to the yankee. When I ordered by blade I had to decide -- install a new set of tracks that much further forward? Or something else? The twings seemed better and easier, and I have been very happy with that decision.

Originally Posted by s/v Jedi

For UV: the core must have a good coating. Samson Warpspeed II (Amsteel Blue core) and MLX-3 (Blended core) both have the right coating for stripping the cover.

Thanks; hot tip!

[Dockhead]

Originally Posted by thinwater

It's just words.

I'm a big fan of 3D leads, whatever you call them and whatever the details. Simple to rig and you can twist and flatten the sail to any shape you need. And this is an application where you want zero stretch.

Yes, the control is fantastic.

During a lifetime of sailing I had never before had control over the angle of attack of a headsail before (no experience with jib booms), other than with the odd barber hauler.

The inhauler is a revelation -- it's amazing how powerful this control is, how sensitive the sail is to very small inputs of the inhauler.

I guess it shouldn't surprise us -- after all, the traveler is a primary control of the mainsail. But it's really fantastic to have this.

On my boat, I don't have separate lines for this (that would REALLY be spaghetti on deck). My staysail is self-tacking, with a single sheet on a Lewmar semi-elliptic track. I just take this off the staysail and soft shackle it onto the twing, and control it from the cockpit, taken to an electric winch on the coachroof top.

Note to those trying this -- be careful about chafe on the jib sheets, when using an inhauler. Don't ask me how I know . Now I'm careful to re-reeve the sheets inside the shrouds when I'm doing real hard on the wind stuff. I really regret ruining that fine (i.e. £££) 14mm racing dyneema sheet like that. Well, I didn't actually lose it -- I cut off the chafed part and spliced a new eye on it and it was still just long enough. Learned my lesson though.

[Benz]

The easiest thing is to buy a complete length of polyester or polyester/technora-covered dyneema rope, and strip the cover back where you don't need it. That way you have a continuous non-stretchy core all the way back to the winch.
I'm doing some sailing on a Pogo 40 that has a twing system as you describe, and it's amazing how much difference an inch in or out makes. It's the cruising model, and it still has the best rope everywhere: the dyneema-cored reef lines have a poly/technora/dyneema blend cover.
All those details really show in the performance, and I think, if you have a boat such as that or yours, Dockhead, the better rope is worth the cost. I'd rather have nice rope than nice electronics.

[Dockhead]

Originally Posted by Benz

The easiest thing is to buy a complete length of polyester or polyester/technora-covered dyneema rope, and strip the cover back where you don't need it. That way you have a continuous non-stretchy core all the way back to the winch.
I'm doing some sailing on a Pogo 40 that has a twing system as you describe, and it's amazing how much difference an inch in or out makes. It's the cruising model, and it still has the best rope everywhere: the dyneema-cored reef lines have a poly/technora/dyneema blend cover.
All those details really show in the performance, and I think, if you have a boat such as that or yours, Dockhead, the better rope is worth the cost. I'd rather have nice rope than nice electronics.

Yeah, it was actually a Pogo which was the model and inspiration for my sheet lead system.

And yes -- I agree 1000% -- good rope is worth its weight in gold!! When everything is set up right, and assuming you have good sails, an inch in or out is night and day!! You can't control that inch if the line is stretching at all.

I like good electronics, but if I have to choose between good ropes and good electronics, I'm with you, Benz! Good sails and good ropes are fundamental to sailing! Everything else is extra.

No polyester lines on my boat, and no dacron sails, ever again! With the sole exception of the traveler control line, which I was persuaded in this thread to leave as polyester.

[s/v Jedi]

Originally Posted by Dockhead

Yeah, it was actually a Pogo which was the model and inspiration for my sheet lead system.

And yes -- I agree 1000% -- good rope is worth its weight in gold!! When everything is set up right, and assuming you have good sails, an inch in or out is night and day!! You can't control that inch if the line is stretching at all.

I like good electronics, but if I have to choose between good ropes and good electronics, I'm with you, Benz! Good sails and good ropes are fundamental to sailing! Everything else is extra.

No polyester lines on my boat, and no dacron sails, ever again! With the sole exception of the traveler control line, which I was persuaded in this thread to leave as polyester.

I just replaced my Harken traveler control lines and used 8mm xls-3 polyester double braid. Previous line was a 10mm double braid polyester. I have recalculated required strength for every line aboard, which can be as simple as picking an entry from a table to huge calculations like for main and mizzen sheets and reef lines. I find that almost every line was oversized to next size up plus one more size up. I now have 12mm as maximum line diameter, using stronger fibers when needed. For jib sheets I limited diameter to 10mm using a blended core to improve light weather performance.

My traveler has a high purchase rate (triple blocks each side) and even 8mm is oversized but the minimum the clutches will hold. It’s amazing how much lighter the traveler car operates with the reduced diameter line.

I find the blended core lines a no brainer for sheets for any cruiser, while for racers you can go down one more size with a Dyneema core. For a racer I would even have genoa sheets another size down in Dyneema for light weather. For my jib I can use 8mm Warpspeed II sheets instead of the 10mm MLX3 I now have and for light weather use 6mm Warpspeed II which still has an 5,100lbs breaking strength. SK99 based lines are even crazier: a 4mm single braid sk99 does 6,500lbs !

[thinwater]

Originally Posted by Dockhead

... Note to those trying this -- be careful about chafe on the jib sheets, when using an inhauler. Don't ask me how I know . Now I'm careful to re-reeve the sheets inside the shrouds when I'm doing real hard on the wind stuff. I really regret ruining that fine (i.e. £££) 14mm racing dyneema sheet like that. Well, I didn't actually lose it -- I cut off the chafed part and spliced a new eye on it and it was still just long enough. Learned my lesson though.

I had to add a second inside track on my cat.


Re. Stripping line, and Warpspeed II using a Dyneema core. If most of the length is stripped and only a little is covered, it can be just as easy and considerably cheaper to use Amsteel and buy just a little Samson XLS or XL for the cover. You sew the core to the Amsteel and tow the cover over the Amsteel. Throw the XLS core away. Then do the standard cover buries at each end, as needed. I have several lines that are stripped on both ends and have a short covered section in the middle.

• 3D leads. On multihulls the outboard leg is really long, because we can haul WAY out. But it is low purchase. The in or forward haul line is higher purchase. By combining them into one line, the tail in the cockpit is reduced and they can't tangle (no end).
• Bobstay/up-haul for sprit. Same idea. Just one line with a cover where it is handled. The purchase and the trip to the bow is bare.

In both cases probably 70% of the line is bare. The cover is XLS.


I got in the habit because the local chandlery didn't stock Warpspeed and I had extra Amsteel on hand. Now I do it because it is easy and because it's easy to get the cover color you want (plain polyester lines come in all colors and are widely available).

[Dockhead]

Originally Posted by s/v Jedi

I just replaced my Harken traveler control lines and used 8mm xls-3 polyester double braid. Previous line was a 10mm double braid polyester. I have recalculated required strength for every line aboard, which can be as simple as picking an entry from a table to huge calculations like for main and mizzen sheets and reef lines. I find that almost every line was oversized to next size up plus one more size up. I now have 12mm as maximum line diameter, using stronger fibers when needed. For jib sheets I limited diameter to 10mm using a blended core to improve light weather performance.

My traveler has a high purchase rate (triple blocks each side) and even 8mm is oversized but the minimum the clutches will hold. It’s amazing how much lighter the traveler car operates with the reduced diameter line.

I find the blended core lines a no brainer for sheets for any cruiser, while for racers you can go down one more size with a Dyneema core. For a racer I would even have genoa sheets another size down in Dyneema for light weather. For my jib I can use 8mm Warpspeed II sheets instead of the 10mm MLX3 I now have and for light weather use 6mm Warpspeed II which still has an 5,100lbs breaking strength. SK99 based lines are even crazier: a 4mm single braid sk99 does 6,500lbs !

Yes, a huge benefit with a virtuous circle is downsizing lines when switching to dyneema. You get the same or greater strength with far less stretch and far, far less weight, and even the cost isn't dramatically greater, when you downsize.

Your lines sound small, however! I downsized my jib sheets to 14mm racing dyneema from 16mm poly, and my main sheet from 14mm poly to 12mm racing dyneema. My 12mm poly furling lines went to 10mm racing dyneema.

What a difference! The new lines are half or less the weight, run better over blocks, much easier to handle, more flexible. My main sheet is extremely long because of multiple purchase and the way it runs; I could hardly pick it up myself in the old version. Now it's a snap.

The only line I didn't downsize was my vang -- it was 12mm poly and I used 12mm racing dyneema with cover stripped.

My staysail sheet, running backstays, and outhaul were all Dyneema as the boat was originally built, and I left them that way (the running backs are actually still original). I lengthened my outhaul by splicing on single braid dyneema, and the bare dyneema is what runs in the clew block and boom car -- which is great.