Attaching Dyneema Sheets to Headsail Clew

[CAELESTIS]

Originally Posted by Pete7

Hijacking Dockhead's thread slightly, will a soft shackle reduce the tendency of the sheets to catch on a baby stay? which is something I am suffering from at the moment. Particularly noticeable when sailing single handed and you don't have a crew to watch or time the head sail cross the boat.

Peter

That was my primary motivation for switching to soft shackles. They work perfectly on tacking.

[Sun and Moon]

Originally Posted by hoehn000

soft shackle really is the way to go. I use this method to splice them:

Better Soft Shackle

I also make a couple wraps of velcro around the middle just in case...but I don't think it's necessary at all. if you use the same diameter dyneema as the core of your sheets the sheets will fail far before the soft shackle.



The shackle is going to be stronger than your loop, and with the forces applied untying the cow hitch is going to be very difficult.

I've heard countless sailors extolling their virtues, but I've never actually seen a soft shackle. Do you push the stopper knot through the eye to open and close it? If so, why doesn't it pull out on its own?

[CAELESTIS]

https://www.youtube.com/watch?v=wHc6J4VPYtw

[Pete7]

Originally Posted by Seaworthy Lass

Yes, if you have tied two sheets on (as opposed to one line and cow hitch).

Splicing the ends of the sheets and using a soft shackle reduces windage too . SWL

Oh dear sounds like a trip back to knot school is needed especially using knitting needles to do splices.

Pete

[Dockhead]

Originally Posted by UNCIVILIZED

BTW, why did you get Dyneema sheets, now? As not long ago, well, to put it politely, you were vehemently in the "anti" camp, on them.

I've never been "anti-Dyneema" -- I love the stuff.

My original sheets (original build) were fat 16mm polyester double braid with just the most wonderful hand -- when I bought new sails, I wanted to reproduce that feel. I didn't think Dyneema was strictly necessary and also I didn't have money for it after having blown my entire budget on sails. I was quoted over $1000 for a pair of cruising Dyneema sheets from Spencers.

Well, the new sheets were a big disappointment, being much less nice than the old ones. Besides that I chafed one of them badly due to a mistake (ahem) with a split pin.

So this year, I decided to go one size down and to Dyneema, and my rope guy found me an absolutely fantastic deal which did not break the bank.

We'll see how good in use they are. Obviously being thinner they will be harder to handle, but the texture of the cover is really wonderful and might actually make up for the loss of diameter. We'll see.

[Dockhead]

Originally Posted by estarzinger

^^

either the 8 or 9 mm is probably 'strong enough' with a straightforward soft shackle but you can do two easy things to make them much stronger.

(1) is to double them thru the eye/clew (eg make the soft shackle longer and wrap them twice around before closing).

(2) use the "stronger" design - which has buried tails and the button knot (rather than the diamond knot and cut tails). This is both stronger (220-250%) and eliminates one common failure mode (tails slipping into diamond knot)


I have a whole bunch of 12mm heat set dyneema single braid left over from a break test I recently did of splices (of throat angle and bend ratios) - I could make some REALLY strong soft shackles with it if anyone wanted them . . . . but I personally would prefer for most applications to use 8mm and either or both of the two tactics above, because the stopper knot gets bulky with bigger diameter line.

OK, thanks for the tips!

I have a pair of soft shackles made for me by a certain kind mermaid on here, but they are otherwise occupied. They have beautiful Turk's Head knots -- just lovely ropework -- I considered framing them rather than using them

I don't think my skill is adequate for that, so I think I'll try the method on your website; thanks again!

[Dockhead]

Originally Posted by Seaworthy Lass

By the way, I have come up with a cross between the High Strength and Better soft shackles, incorporating the best features of both.

This is how the new BB soft shackle looks:



Instructions for the BB soft shackle can be found here:
http://www.cruisersforum.com/forums/...le-155714.html

Anyone with testing equipment? I am confident enough of the design that we have been using it to attach snubber to chain.

SWL

Ah, yet another one! OK, maybe I'll try that one.

[StuM]

Originally Posted by Dockhead

Ah, yet another one! OK, maybe I'll try that one.

I highly recommend them. I got several lengths of 6mm at a very good price from the manufacturer (about 8-10 m each which were left overs from production jobs) when I was down in Aus a few months ago and made up a batch of them using SL's instructions. They are providing sterling service.


(Thanks SL).

[hoppy]

How about a Liros soft shackle?

The end with the loop passes through the line before going over the knot. It looks to me that it should better hold than some dynema shackles when there is no load and the sail is flogging. The webbing makes it easy to open the hole to pass the loop through.

[SVNeko]

Originally Posted by Dockhead

I have new Dyneema headsail sheets, hurra! They are lovely things of Marlow Racing 78 D2. The racing Dyneema (I’ll never use the cruising crap again) is a totally different deal, with the cover fitting tightly with the core, with an excellent “hand”. My rope pusher in Portsmouth made beautiful soft eyes in the ends of them.

So now I need to figure out how to hook them up. I had originally thought to use Dyneema soft shackles, but I’m slightly nervous about the security of them. I guess I shouldn’t be, but I can’t help it. Considering the tons of force they will have to carry.

Therefore, I am thinking about using a simple spliced loop of 8mm D12 Dyneema, cow hitched to the clew, and then cow hitched again through the soft eye in the sheet. The splice is roughly as strong as the base material, and the base material is doubled, so this should be mega strong, no? And totally secure? To take it off, I will have to thread the entire sheet back through the loop (since it’s cow hitched), but the new sheets are so light and easy and pleasant to handle, that I just can’t see this as being a big problem.

Any reason not to do it this way?

Or any better way I haven't thought of yet?

How would you cow hitch a loop to both of them? I can't picture it. If you like fiddling with rope, soft shackles are dead simple to make and the exact right solution for this.

[Dockhead]

Originally Posted by SVNeko

How would you cow hitch a loop to both of them? I can't picture it. If you like fiddling with rope, soft shackles are dead simple to make and the exact right solution for this.

Double cow hitch now abandoned, but for the record --

1. Cow hitch the loop to the clew.

2. Insert the other end of the loop through the soft eye in the sheet.

3. Thread the entire sheet through the exposed end of the loop, starting with the other end of it.


Et voila! Double cow hitch!

[Bor the Wolf]

First of, I would never use Dyneema for a sheet. It lacks the elastic dampening needed to cope with a header and also to offload my hands and arms. It is great stuff for a halyard, the sail once trimmed won't move. As an International OD racer I have yet to see a Dyneema sheet in the fleet.

The easiest way to attach a sheet to the Genoa: a bowline.
I also used a modified fishermans bend (through the clew). Modified by using a figure eight instead of a half hitch. (A figure eight knot unties easier after the race).

[estarzinger]

Originally Posted by Dockhead

Double cow hitch . . . . .

I seem to remember we talked about this before and you said you wanted the sheets to be 'relatively easily removable' . . . but a straightforward lashing (between the clew and eyes) is very simple and easy and clean and strong. But not fast to undo if you want to move the sheets. The soft shackles advantage is it is fast and easy to undo - but is a bit bulkier than a lashing (and a bit more complex to make up).

We used a lashing on Hawk's RFing jib. We rarely changed it - instead flew several other jibs off a code zero furling system. But I seem to remember that you have two jibs you like to swap off the RFer.

The lashing can be untied - takes perhaps 10 minutes? (never timed it)

As an aside, we also had lashings built into our RFing jibs right where they entered the foil groove. We used those so there was no point loading where the sail entered the groove - lashed around the foil. Without the lashing we found a common first failure mode was the bolt rope stitching tearing at that point. This was originally suggested to us by North NZ loft.

[Dockhead]

Originally Posted by Bor the Wolf

First of, I would never use Dyneema for a sheet. It lacks the elastic dampening needed to cope with a header and also to offload my hands and arms. It is great stuff for a halyard, the sail once trimmed won't move. As an International OD racer I have yet to see a Dyneema sheet in the fleet.

The easiest way to attach a sheet to the Genoa: a bowline.
I also used a modified fishermans bend (through the clew). Modified by using a figure eight instead of a half hitch. (A figure eight knot unties easier after the race).

Well, that "elastic dampening" is spilling wind from your sail while "panting", and is dissipating energy. Stretch is not desirable either in sheets, halyards, or indeed in sails. I don't know what "International OD" racing is, but I spend half the year in Cowes every year, and I haven't seen a polyester sheet on a racing boat in years, maybe decades. The racers here like to strip the cover off the non-handled part of their Dyneema sheets, to reduce windage. For cruisers of course this is not such a big deal, and I was using polyester sheets even with carbon laminate sails until now. But no question Dyneema is better.


Concerning attachment -- I agree about bowlines, when you're talking about polyester sheets. Works great, simple, doesn't snag, secure, reasonably strong. I've always done this on all of my boats.

The problem here is that Dyneema can't be safely or securely knotted. Otherwise I would continue using bowlines.

[Dockhead]

Originally Posted by estarzinger

I seem to remember we talked about this before and you said you wanted the sheets to be 'relatively easily removable' . . . but a straightforward lashing (between the clew and eyes) is very simple and easy and clean and strong. But not fast to undo if you want to move the sheets. The soft shackles advantage is it is fast and easy to undo - but is a bit bulkier than a lashing (and a bit more complex to make up).

We used a lashing on Hawk's RFing jib. We rarely changed it - instead flew several other jibs off a code zero furling system. But I seem to remember that you have two jibs you like to swap off the RFer.

The lashing can be untied - takes perhaps 10 minutes? (never timed it)

As an aside, we also had lashings built into our RFing jibs right where they entered the foil groove. We used those so there was no point loading where the sail entered the groove. Without the lashing we found a common first failure mode was the bolt rope stitching tearing at that point. This was originally suggested to us by North NZ loft.

Thanks; I do remember and it's good to have some more alternatives.

I think I'm pretty well sold on the soft shackles, however, and in fact I want to start splicing them up this evening.


I have two different principle headsails -- a 120% yankee for lighter conditions (up to 20 true upwind, roughly) and a 95% blade for stronger conditions. It's laborious to change the sails due to the massive size so I can't just change back and forth every time the wind changes, like on a dinghy, and I've never tried it at sea, but I like to be able to change with as little hassle as possible, so I think I'll pass on the lashings for this sail. Soft shackles seems pretty clearly good solution.