Unveiling Bullseye Strops for low friction rings

[Seaworthy Lass]

Originally Posted by Dockhead

I wonder if it would make sense to use bare single braid Dyneema (or Acera) for the sheets, and just hook on double braid tails where the sheet is handled on winches. Slicker and lesser diameter, would dramatically improve running through blocks and LFR's. What do you think? In my case I could just strip the cover off the first 10 meters or so.

What you describe is commonly done racing, so it must work well, but I have no experience with this. The only drawback I can see is that dyneema core with an outer layer of braid is generally not coated, so it will deteriorate faster. Maybe not an issue in this application though. We did not alter the lines from standard double braid polyester when ordering the new boat, as this was a replaceable item and ordering anything non standard was disproportionately costly. These will in time be replaced with racing dyneema.

What I did do though is add a 2 m long single braid dyneema strop to the yankee clew and attach the sheets to this with soft shackles. The advantage is that it is very easy to reach when the sheets need to be moved outboard with greater sailing angles and there is less weight dragging the clew down in light air.

SWL

[Dockhead]

Originally Posted by Seaworthy Lass

What you describe is commonly done racing, so it must work well, but I have no experience with this. The only drawback I can see is that dyneema core with an outer layer of braid is generally not coated, so it will deteriorate faster. Maybe not an issue in this application though. We did not alter the lines from standard double braid polyester when ordering the new boat, as this was a replaceable item and ordering anything non standard was disproportionately costly. These will in time be replaced with racing dyneema.

What I did do though is add a 2 m long single braid dyneema strop to the yankee clew and attach the sheets to this with soft shackles. The advantage is that it is very easy to reach when the sheets need to be moved outboard with greater sailing angles and there is less weight dragging the clew down in light air.

SWL

If you are using polyester sheets, I would replace them sooner rather than later. It makes a big difference in sail trim and performance for a quite small cost (in the grand scheme). You have laminate sails, right? For sheets, the greater flexibility of UHMWPE also makes a really dramatic difference in how they handle.



If you go to double braid racing dyneema, you can go one size down. I went from 16mm poly to 14mm double braid racing dyneema. If you are using 14mm poly, then you can go to 12mm double braid or something even smaller in single for the leader.



I don't now about handling 12mm sheets, though, so maybe 14mm racing double braid with long leaders in single braid of whatever size the core is. That would be a massive increase in strength and stretch compared to 14mm poly.

[Seaworthy Lass]

Originally Posted by Dockhead

If you are using polyester sheets, I would replace them sooner rather than later. It makes a big difference in sail trim and performance for a quite small cost (in the grand scheme). You have laminate sails, right? For sheets, the greater flexibility of UHMWPE also makes a really dramatic difference in how they handle.

Our sails are radially cut Contender Fibercon Hybrid (woven, not laminated mix of dyneema and dacron).

Sheets are currently 14 mm double braid polyester.

What brand/trade name of sheets did you go with? I have done zero research regarding this. The only thing I know is that it is generally best avoiding cheaper double braid cruising dyneema.

Any advice here will save me heaps of time, as I know you would have looked into this carefully .

SWL

[Breaking Waves]

Originally Posted by Seaworthy Lass

Wind your dyneema snuggly (but not tightly) in the Bullseye pattern around your ring.

question: I was thinking of making several of these for possible breaking. Is there any more specific guidance on where exactly to place the bury's? The first one I made "loose", thinking that would be good from a stress perspective, but it ofc does then not actually capture the ring.

I need to make them as identical and repeatable as possible.

[Seaworthy Lass]

Originally Posted by Breaking Waves

question: I was thinking of making several of these for possible breaking. Is there any more specific guidance on where exactly to place the bury's? The first one I made "loose", thinking that would be good from a stress perspective, but it ofc does then not actually capture the ring.

I need to make them as identical and repeatable as possible.

To capture ring securely, I think the “artificial throat” (top of the junction closest to the ring) needs to sit close to the rim LF ring (as in my avatar).

I do agree that loose is better from a stress perspective, so if the ring is not in a position where it is subject to flogging, I make the junction a little lower.

One of the steps in the construction is to mark the bury points on the two tails then twirl the weave around as snuggly as needed avoiding twists, and mark the insertion points. Then untwirl the weave, measure the two distances marked, average them and remark the insertion points. Having the legs equal lengths makes load distribution better.

Once you have this distance, if you are using the same diameter line and same LF ring you can churn out identical ones.

Regarding ring selection, it needs to fit two lots of line around the ring without being overcrowded. Going larger is no problem. I used a ring with a specified hole size of 25/17 for 6 mm dyneema.

SWL

[Dockhead]

Originally Posted by Seaworthy Lass

Our sails are radially cut Contender Fibercon Hybrid (woven, not laminated mix of dyneema and dacron).

Sheets are currently 14 mm double braid polyester.

What brand/trade name of sheets did you go with? I have done zero research regarding this. The only thing I know is that it is generally best avoiding cheaper double braid cruising dyneema.

Any advice here will save me heaps of time, as I know you would have looked into this carefully .

SWL

My boat is now almost 100% dyneema; even the furling lines. She was originally built with a good bit of dyneema, and I gradually replaced the rest. I guess the main furler is the only polyester left on the boat.



Based on my experience -- "cruising" dyneema double braid is a waste of time; I prefer quality polyester. You have the drawback of non-structural cover without any dramatic increase in strength or non-stretchiness. For applications where you want double braid, use best quality "racing" cordage. Mine is mostly Marlow; but I have Liros which I also like, and there are other good ones. I like this cordage best when the cover fits relatively tightly; I have trouble with my expensive Marlow racing dyneema halyards because the cover is quite loose and clutches don't grip them perfectly.


Replacing mainsheet and jib sheets with one size down "racing" dyneema was one of the best things I ever did to the boat. The reduction of weight and increase in flexibility (which comes from both the reduction in size AND the more flexible material) is shocking. Such a pleasure to handle the sheets now. And the lack of stretching stops "panting" of the leech, and opening up in gusts, and allows you to finely adjust and then constantly hold the sail shape. This will be more noticeable with laminate sails, but should matter a lot with good woven ones, too. Also, the weight -- my jib sheets were almost too heavy for me to pick up with one hand, before. After -- one finger.



Even the furling lines noticed -- they were all 12mm poly, and I went to 10mm racing dyneema double braid. Et voila, an end to bunching up of furling line in the drum and other such nonsense, great reduction of weight and bulk, great increase in flexibility (which makes a noticeable different in smoothness of furling), in short a joy to handle.


I think one step beyond all this might be to use single braid for all of it, as leaders, with some kind of larger poly-covered line for the parts which will touch winches and hands. That will work even still much better; imagine how nicely the bare slippery and slimmer dyneema will run through blocks and LFR's. Such an approach would be good for halyards, too.


For halyards, my dream would be to have pieces of single braid with eyes on them which go onto some kind of track with hydraulic or some kind of large mechanical advantage screw thingie, and a TENSION GAUGE. To lower the sail, you release the tension from this gadget, and hook on a separate tail which would be handled with a normal winch and cam clutch. This will also facilitate UNtensioning the halyards when you're not sailing. I need to patent this. The normal way to tension halyards is ridiculous.

[Dockhead]

Originally Posted by Seaworthy Lass

. . . Regarding ring selection, it needs to fit two lots of line around the ring without being overcrowded. Going larger is no problem. I used a ring with a specified hole size of 25/17 for 6 mm dyneema.. . .

Just keep in mind that the bigger diameter the ring, relative to the size of the cordage, the less friction and the better it will work. Less important if there's no big loads and/or no big change of direction; otherwise more and more important. I would not use the specified rings except for really light load applications.

[Seaworthy Lass]

Originally Posted by Dockhead

For applications where you want double braid, use best quality "racing" cordage. Mine is mostly Marlow; but I have Liros which I also like, and there are other good ones. I like this cordage best when the cover fits relatively tightly; I have trouble with my expensive Marlow racing dyneema halyards because the cover is quite loose and clutches don't grip them perfectly.

Are these:
Marlow D2 GRAND PRIX 78 (24 plait cover)
(as opposed to D2 RACING 78?)

and Liros Racer (32 plait cover)?

Any benefit to the denser woven Liros cover?

I was a bit put off Marlow after having been sold Marlowbraid as double braid in one chandlery. That wasn’t Marlow’s fault, but I found the rope was a pain to splice and it didn’t handle well.

Originally Posted by Dockhead

Replacing mainsheet and jib sheets with one size down "racing" dyneema was one of the best things I ever did to the boat. The reduction of weight and increase in flexibility (which comes from both the reduction in size AND the more flexible material) is shocking. Such a pleasure to handle the sheets now. And the lack of stretching stops "panting" of the leech, and opening up in gusts, and allows you to finely adjust and then constantly hold the sail shape. This will be more noticeable with laminate sails, but should matter a lot with good woven ones, too. Also, the weight -- my jib sheets were almost too heavy for me to pick up with one hand, before. After -- one finger.

Even the furling lines noticed -- they were all 12mm poly, and I went to 10mm racing dyneema double braid. Et voila, an end to bunching up of furling line in the drum and other such nonsense, great reduction of weight and bulk, great increase in flexibility (which makes a noticeable different in smoothness of furling), in short a joy to handle.

I will have something to look forward to then .
This is something I will organise next season.
Stripping the cover should be easy. I will consider doing that. It also has the advantage that eye splices are dead easy compared to ones in double braid. Worth stripping for that alone .

SWL

[Seaworthy Lass]

By the way, regarding ease of use of line, one thing I noticed is that after several months, significant twisting of both furling lines and sheets occurs. This twisting is induced each time the line is thrown off after being wound around a winch several times. I find these lines function much better if now and again I go to the trouble of untwisting them.

Is this just so well known that it isn’t discussed?

[fxykty]

What do you guys think of these LFR strop solutions as provided by a local rigging supply shop?



I’m thinking of redoing them with the elegant strops demonstrated in this thread.

[poiu]

Originally Posted by estarzinger

Yes, a perfect Brummel reduces strength by 5-10%, a less than perfect one more than that.

Pretty much no-one in applications where strength and safety and reliability are critical uses brummels.

I appreciate if you don’t do it right the strength will be a little reduced. In what way are they unsafe or unreliable?

[Breaking Waves]

So, I got initial 'engineering' thoughts from the test lab in Hunston about the 3 methods for LFR strops. Am having a continuing discussion with them so I understand better, but I realized that some of this audience will perhaps not be entirely satisfied. So, I am going to arrange to make and have them break 3 samples of each technique (tight whipping, tight spliced loops and bullseye). Will probably take a couple of weeks.

I'm using an antal factory made sample as a baseline model (which uses 6mm dyneema for the strop), and to copy for the three whippings I will make. Just for anyone interested, here is a pic of their whipping - 10 loops of 1mm diameter dyneema, each half hitched together, and then the entire whipping tied together (with strands pulled internally) from top and bottom.



It's interesting. I would have guessed these are machine made. But it's pretty obvious on close inspection they are handmade. There are a couple of Sharpe marks on the strops. I guess this market is pretty small.

[Breaking Waves]

also, as a further fyi, applies to both the splice and whipping solution



'in theory', Load on line in 'loop' = (1/cos(1/2 throat angle))*(application load/2) - there are some practical considerations which may modify this.

[Breaking Waves]

and further, just for interest - commercial use of similarly shaped 'thimbles' (the Samson "composite thimble" here) used to attach high modulus rope to a pin, rather than as yachting uses it as a rope deflector. But the strop attachment questions are similar.

[fxykty]

Originally Posted by Seaworthy Lass

No need . Our yankee sheet has been put through it and we have just had a day's sailing.
I am much happier personally giving it a trial in case it all goes belly up rather than have someone else use it and have problems.
So far so good .

It was is a bad location for a low friction ring, but I wanted to apply a decent load on the Diamond strop. The yankee sheet had an appalling deflection angle, so at high loads with old poly line the friction was not good. It as still workable though. I will move it forward of the winch next time we sail, which will fix that. I will also try and remember to look at alu temps next time with an IR thermometer.

The strop itself handled itself superbly, even with shock loads. It looked "happy". No nasty cow hitch needed either. I think this Diamond strop is a little gem!

I have a zillion more ideas. My mind is buzzing with all the possibilities. I will post photos from today and my other ideas when we get a better internet connection. The signal is absolutely pathetic at this anchorage.

SWL

I have big clew blocks on my first and second reef clews (Sea Sure Reefing Blocks), but only a clew ring for the third reef. I’m thinking this short soft shackle with captured LFR is the solution for smoother running of that third reef line. Will this work, or too much risk of the LFR twisting or flogging out?