Halyards

[grommet]

Hi, I know it's an older thread but I've been asked to splice Dyneema to standard double braid and I need some instruction. Does anyone know where I can find the info on making that splice?

Thank you

Not worth the hassle IMHO splicing two different sized lines together would be an absolute nightmare and the result would not be particularly strong. If it was me i would go for 8mm cruising dyneema. Its no more difficult to splice than braid on braid once you get used to doing it. Surprised by the stretch reported by a previous poster, might have needed a bit longer to bed in properly. Kevlar cores have no advantages these days. dyneema will last a lot longer.

 

[gregcope]

Hi, I know it's an older thread but I've been asked to splice Dyneema to standard double braid and I need some instruction. Does anyone know where I can find the info on making that splice?

Thank you

Am after the same.

12 core dyneema to double braid.

 

[estarzinger]

^^ how strong does the splice need to be? If it is just as a "messenger or low load tail", say to hoist the sail but not to carry the sail loads, then the dead easy way is to pull some if the core out of the double braid and cut it off, then feed the dyneema into the double braid cover where the cure used to be and sew it. I do this with the tails on my 2:1 halyards.

There are higher strength methods but they are more involved, and which one to use will depend on the specific relative size of the two lines.

 

[gregcope]

^^ how strong does the splice need to be? If it is just as a "messenger or low load tail", say to hoist the sail but not to carry the sail loads, then the dead easy way is to pull some if the core out of the double braid and cut it off, then feed the dyneema into the double braid cover where the cure used to be and sew it. I do this with the tails on my 2:1 halyards.

There are higher strength methods but they are more involved, and which one to use will depend on the specific relative size of the two lines.

Basically that - to pull the sail up by hand, through any blocks, through a clutch to the cockpit.

Once it gets "hard" it would go on a winch, which would also co-incide with roughly the third reef position anyway (ie need to be strong/carry loads).

 

[gregcope]

There are higher strength methods but they are more involved, and which one to use will depend on the specific relative size of the two lines.

Any examples? I have found none!!!

 

[grommet]

Thank you, this answers my question. It is a halyard I was asked to do. It is for a Sonar. Really appreciate the help. By the way, would you point me to the information on the higher-strength methods you mentioned? I always want to know as much as I can and how I can use Dyneema.

 

[estarzinger]

Any examples? I have found none!!!

The real simple approach I mentioned above is near 50% of the double braid strength and 'should be' strong enough for most sail hoisting applications, but perhaps not if it is expected to hold a reefed sail.

One further option is to use the following except slightly modified - the left hand rope do exactly as shown (that's your double braid) and with the right hand rope (your 12 strand dyneema) just eliminate the cover from the instructions.

http://www.samsonrope.com/Documents/Splice Instructions/DblBrd_C2_End_for_End_WEB.pdf

Note: You can further modify this, by pulling out and chopping off the double braid core a fid length short before you start this splice. That allows the double braid cover to slide right over the cross over and over the initial part of the dyneema, and then this is near 100% of the DB strength.

If this is too 'thick' AND you need more than 50% of the db strength . . . then you have to do a taper of the double braid (both the core and cover) and 'tuck and bury' the dyneema into the double braid, replacing exactly (and only) the thickness you have tapered out of the double braid with the stronger dyneema. This is more involved.

All should be sewn, and relatively long tapers should be used, to stop the dyneema from potentially slipping.

 

[gregcope]

The real simple approach I mentioned above is near 50% of the double braid strength and 'should be' strong enough for most sail hoisting applications, but perhaps not if it is expected to hold a reefed sail.

Agreed.

I would want the 12 Strand Dyneema to be wrapped around the winch/through the clutch for any reefing loads.

Another aspect is that by going for a smaller line the Dyneema needs to be bolstered in size by either of (or combination) inserting a line/cover within, or covering so that it reaches the 10-12mm size of my winches.

This would mean that the 12C Dyneema needs to be quite long, so the saving (having done the logic below) is much reduced.

One further option is to use the following except slightly modified - the left hand rope do exactly as shown (that's your double braid) and with the right hand rope (your 12 strand dyneema) just eliminate the cover from the instructions.

http://www.samsonrope.com/Documents/Splice Instructions/DblBrd_C2_End_for_End_WEB.pdf

Note: You can further modify this, by pulling out and chopping off the double braid core a fid length short before you start this splice. That allows the double braid cover to slide right over the cross over and over the initial part of the dyneema, and then this is near 100% of the DB strength.

My present thinking is to take this allot further (exact measurements TBC);

0. Will need a piece of thicker Double Braid (DB) - assume 10mm in my model, around mast length. You will also need a length of thinner 12 Core Dyneema (12C) - assume 8mm in my model around 1/2mast+mast+coachroof and winds round winch (which probably adds upto 2xMast lengths). As measured from sail head with third reef set, for the 12C to go from the 3rd reef, up to the mast head, down inside the mast, back along the coach roof to the winch.
1. Take DB, and remove the core for approx half-mast length and milk back the cover
2. Cut the DB core off, but leave enough to splice - this should leave about half-mast length cover
3. Splice the thiner 12C to the DB core - splice TBC - this may need to be done with some tapering of the DB core and 12C so that the splice is not a bulge
4. Milk cover of DB back over the DB and 12C splice and then burry the cover into the 12C
5. Lock stitch and whip both the 12C and DB cover burry as well as where the 12C to DB core splice is

Costs - assume 10M mast - prices from Jimmy Green, Marlow Braid and D2 78 Racing;

- 10mm DB of mast length 13.2M £25.66
- 8mm 12C of 2x mast length 26.4M £146.36
- Total £171.02

Compared to;
- 10mm 12C of 2.5 x mast length (33M) £222.16

Saving £51.14 ...

Hum at this rate I think just tapering some 10mm D2 Race is less hassle!

If this is too 'thick' AND you need more than 50% of the db strength . . . then you have to do a taper of the double braid (both the core and cover) and 'tuck and bury' the dyneema into the double braid, replacing exactly (and only) the thickness you have tapered out of the double braid with the stronger dyneema. This is more involved.

All should be sewn, and relatively long tapers should be used, to stop the dyneema from potentially slipping.

Found this which it the nearest I have seen to DB to 12core splicing. Here they are splicing thiner 12 core to bigger DB - similar to what I am suggesting.

http://l-36.com/halyard_splice.php

 

[grommet]

Thanks so much for the help. It's been a puzzle since I was asked to do it, you really helped

The real simple approach I mentioned above is near 50% of the double braid strength and 'should be' strong enough for most sail hoisting applications, but perhaps not if it is expected to hold a reefed sail.

One further option is to use the following except slightly modified - the left hand rope do exactly as shown (that's your double braid) and with the right hand rope (your 12 strand dyneema) just eliminate the cover from the instructions.

http://www.samsonrope.com/Documents/Splice Instructions/DblBrd_C2_End_for_End_WEB.pdf

Note: You can further modify this, by pulling out and chopping off the double braid core a fid length short before you start this splice. That allows the double braid cover to slide right over the cross over and over the initial part of the dyneema, and then this is near 100% of the DB strength.

If this is too 'thick' AND you need more than 50% of the db strength . . . then you have to do a taper of the double braid (both the core and cover) and 'tuck and bury' the dyneema into the double braid, replacing exactly (and only) the thickness you have tapered out of the double braid with the stronger dyneema. This is more involved.

All should be sewn, and relatively long tapers should be used, to stop the dyneema from potentially slipping.

 

[grommet]

gregcope


gregcope I read your idea and it sounds like a strong splice but if I am doing the work I wouldn't add a whipping. The stitching has held on all my projects and when I've added a whipping I've made a high spot, a place for wear. I've been staying with stitching almost the whole length of the splice and though it takes time it's been making things pretty smooth.

 

[gregcope]

gregcope


gregcope I read your idea and it sounds like a strong splice but if I am doing the work I wouldn't add a whipping. The stitching has held on all my projects and when I've added a whipping I've made a high spot, a place for wear. I've been staying with stitching almost the whole length of the splice and though it takes time it's been making things pretty smooth.

Most splices I have read about in this space use a locking stitch - sometimes I cannot help myself splice... I have been known to splice bits on friends boats too.