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tying light air dyneema sheets to a clew...


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Rigging a drifter for light air use and bought some 1/8" AS78  dyneema.

Plan to leave it on the freeflying sail as it's likely too bloody small to hold for anything more than a few knots of wind, and the Genoa has it's sheets attached with a soft shackle. 

Ordinarily I'd tie a simple girth hitch, and that would work, but I am thinking that with the Dyneema, I will need more friction. 

Multiple passes of the bight through the clew ring before passing the tails? 

How many ? 

Something more exotic? 

Cut it and put a pair of bowlines? 

 

 

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all sorts of things would work . . . . but I guess you want light and easy.

I would think a girth hitch with some lock stitching/whipping to stop slipping. Could also use a Brummel rather than the needlework but I guess that is fractions of grams heavier.

I guess same as you that girth hitch alone would slip.

BTW bowlines slip in bare dyneema -  water bowlines or figure 8 loops will not. 

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16 minutes ago, LionessRacing said:

Multiple passes of the bight through the clew ring before passing the tails? 

That ^ might work. But may upset, then jam pretty well too. I would take a bight and tie a figure-eight. Then hitch the loop. Equalizes the tension in the two hitch parts.

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Just use bowlines.

If it gets too heavy to hold, wrap it around a winch, or consider that you probably now have the wrong sail up.

You'll want that light sheet for attaching to your light kite, too.  Use long bowlines there so you can easily undo it without having to pull the clew right inboard.

No need for two sheets - you can walk it around the bow when you tack.

 

Real drifters don't have a traditional clew eye to tie to - just a short dyneema strop.

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2 hours ago, LionessRacing said:

Rigging a drifter for light air use and bought some 1/8" AS78  dyneema.

 Ordinarily I'd tie a simple girth hitch, and that would work, but I am thinking that with the Dyneema, I will need more friction. 

What's wrong with a spliced loop and a soft shackle? you worried about the weight of the splice?

Alternately, if you want one line with two legs, an alpine butterfly knot in the middle of the sheet attached to a soft shackle. It can slip in dyneema, but it will just tighten on the soft shackle. You could also just tie the alpine butterfly knot directly to the clew to cut weight further if you were going to leave it attached permanently.

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Leaving the sheets attached to the sail, as it's the only light air downwind sail, the asymmetric is a shy kite in 1.5 oz. 

This "real drifter" was made back in the '60's... Wire luff, nylon cross cut and a Hood Marblehead stamp at the tack.

I ended up buying two pieces of line due to a brain fart, so bowline's it is, it's 2X boat length per side... 

 (we were walking the sheet around previously while experimenting, as the tack is 5' ahead of the forestay that's a bit of a reach... )

Agree that if the wind's up to where it's not holdable with a few turns, it's too much sail. That's part of the thinking on the small diameter, to avoid damage through machismo..

Picked up a used dousing sock to try for the shorthanded race (Three Bridge Fiasco) on Saturday, 

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For our light air sheets, we use a locking brummel splice to luggage tag around a soft shackle. This solves a very important problem with the dyneema which is slipping and if needed, we can still remove them.

I more talented rigger  might be able to put an integrated soft shackle right into the end of the sheet!

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On 1/22/2020 at 3:04 PM, LionessRacing said:

Rigging a drifter for light air use and bought some 1/8" AS78  dyneema.

Cut it and put a pair of bowlines? 

 

On 1/22/2020 at 3:26 PM, estarzinger said:

BTW bowlines slip in bare dyneema -  water bowlines or figure 8 loops will not. 

 

On 1/22/2020 at 5:38 PM, duncan (the other one) said:

Just use bowlines.

Sure, bowlines in bare dyneema might slip under significant load, but I've successfully used them for the past couple of years for kite sheets in lighter conditions.

You say this is for a drifter so I think it would work fine...

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On my old boat, a Bristol 43.3, I have a dyneema outhaul tied to the crew of the main with a bowline. Never slipped a mm. It is oversized so not worried about loss of strength. It has survived 3 trips to Bermuda. 

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19 hours ago, gspot said:

Sure, bowlines in bare dyneema might slip under significant load, but I've successfully used them for the past couple of years for kite sheets in lighter conditions.

But why not use one of the knots which is proven will not slip?  They are easy to tie.  Figure 8 and standard water bowline are about the same strength, but a modified water bowline with tuck is significantly stronger.

Bowlines in bare dyneema will most definitely slip before they break. They are the common knot most prone to slipping.  Where they will slip depends (quite a bit) on the coating on the line, and its age (brand new amsteel is quite slippery), and its diameter. Determining/testing slipping load is further complicated by the fact it varies based on pulling rate (eg does the load come on suddenly or slowly). So there is not a clean answer, but if you waterboarded me and forced me to give an answer I would suggest slipping might start around 25-30% of breaking strength.  OFC many lines are oversized for easy grip so they will not see 25% loading . . . . but still why not use a non-slipping knot "just in case" - shit does occasionally happen and its better if your knots don't slip when it does.

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^^ and really, if you are going to make a regular use loop in bare Dyneema . . . you should splice it, not use a knot. Stronger, cleaner and dead easy . . . just proper.  Only use a knot if it is a one-time use or something that needed to be done quickly on the foredeck (which the estar knot was exactly invented for), or end-for ending is a big deal. (you can use a 5xbrummel splice or tuck splice if bury bulk (or length) jams a sheave and it gives you much better strength than a knot)

 

just a further fyi on all this . . . .OP is down at 3mm.  The 'standard' principles all still apply there, but he is near a 'physics' boundary . . . when you get below 2mm, down into fishing line territory, the test results and best solutions start to change.

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Not to mention what a bitch it is to try to splice 2mm line. I did a bunch of buried eyes in 3mm Dyneema for my lazy jacks and got pretty good at it but I wouldn't want to go smaller. I agree that a buried eye in 3mm Dyneema for permanently fastened lines are a no-brainer.

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12 minutes ago, IStream said:

Not to mention what a bitch it is to try to splice 2mm line. I did a bunch of buried eyes in 3mm Dyneema for my lazy jacks and got pretty good at it but I wouldn't want to go smaller. I agree that a buried eye in 3mm Dyneema for permanently fastened lines are a no-brainer.

I've made splices in 1/16" (I believe) Lash-it. I also did a bunch of button knot style soft shackles in it. It has been a while but, IIRC, it's wasn't all that hard.

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On ‎1‎/‎25‎/‎2020 at 6:51 PM, knobblyoldjimbo said:

Buntline hitch.  Apparently it retains a lot of the strength of the line.  I used it on a 5mm spectra halyard on my 18ft TY, I had to cut it off at the end of the season because it had bonded to itself!

I was just gonna say that.  It worked well for my lifelines.  Plus, who doesn't want to learn a new (ancient) knot

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On 1/29/2020 at 2:08 PM, Lex Teredo said:

Buntline . . . I was just gonna say that.  It worked well for my lifelines.  Plus, who doesn't want to learn a new (ancient) knot

If you like the buntline, and are using bare dyneema, it's worth looking at the EStar modification (scroll down here a bit below the video instruction and you will see a section with explains the estar modification).   This was the result of a challenge posed by Stan Honey - the Volvo boys were tieing buntlines in bare dyneema (uncovered core leaders on halyards and sheets) and they were slipping, so they were adding stopper knots to the tails.  This was not elegant, and could still slip.  So I developed the EStar modification,  tested to not slip in even the most slippery dyneema, and smoother/more compact that the stopper knot approach, and close enough to the buntline you don't need to learn a new knot - just a specific extra tuck.

This is really worth doing especially on a 'safety' application like life lines . . . . but again as commented above, a spliced (bury) loop would be better for that .. . .  and bury loops are just so simple dead easy in single braid, imho they should be as known and comfortable for sailors as a bowline.

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8 minutes ago, estarzinger said:

If you like the buntline, and are using bare dyneema, it's worth looking at the EStar modification (scroll down here a bit below the video instruction and you will see a section with explains the estar modification).   This was the result of a challenge posed by Stan Honey - the Volvo boys were tieing buntlines in bare dyneema (uncovered core leaders on halyards and sheets) and they were slipping, so they were adding stopper knots to the tails.  This was not elegant, and could still slip.  So I developed the EStar modification,  tested to not slip in even the most slippery dyneema, and smoother/more compact that the stopper knot approach, and close enough to the buntline you don't need to learn a new knot - just a specific extra tuck.

This is really worth doing especially on a 'safety' application like life lines . . . . but again as commented above, a spliced (bury) loop would be better for that .. . .  and bury loops are just so simple dead easy in single braid, imho they should be as known and comfortable for sailors as a bowline.

Thank you, sir.  Always appreciate you dropping the knowledge bombs on those of us who haven't spent untold hours bending, folding, spindling and mutilating knots and splices in lab conditions.    

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On ‎1‎/‎25‎/‎2020 at 2:42 PM, IStream said:

I'm 52 years old, fat-fingered, with failing eyesight. Let me bitch in peace, please.

This site really needs a couple new reaction emojis - howling in laughter / nodding in sympathy / my hands really fukken hurt I think it's going to rain today.

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  • 3 weeks later...

I love new knots but sometimes its a challenge to get crew that know how to reliably tie a bowline nevermind something new...

Lately I’ve been finishing my spectra lines by pulling the end back inside the rope. It makes a tidy end quicker than whipping, but it also makes a thick bit at the end... Evans, do you think that swelling in the end would act as a stopper to help with slipping in conventional knots?

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