Dyneema jib halyard replace wire

[tawhiri]

I am thinking of replacing my jib halyard which is 10mm braid on braid rope spiced to 4mm wire with 8mm dyneema.
I found this on ebay which is less than half the price of normal dyneema:
http://www.ebay.de/itm/8mm-Dyneema-...063?pt=Bootsteile_Zubehör&hash=item565ea0b1e7

Is there a catch? Is the core only 6mm therefore it is cheaper.
Do I really need to have a coat, and are there different grades of dyneema?

Thanks A

 

[Iliade]

Looks like a bargain to me... Yes there are different grades, yes having a sheath of terylene makes it nicer to handle and possibly easier to winch/cleat, but a halyard doesn't usually get a lot of handling by most of us in truth.

EDIT: I used a translator - it is terylene sheathed so take back most of that!

 

[charles_reed]

There are many different combinations of HDPE (dyneema or spectra) - pure HDPE-cored rope is stiff and quite unpleasant to handle and usually has a gold-fleck in the polyester outer casing. So-called "cruising" dyneema has variable proportions of polypropylene mixed with the HDPE in the core to make it far more pleasant to handle. From the knot and the quoted load (assuming it to be breaking load) I think you will be buying some very expensive polypropylene braid.
I'd suggest buying a Max-braid HDPE of 6mm which will be quite strong enough, but difficult to tail. Be aware of creep in HDPE which occurs over long periods @ loads in excess of 50% of SWL and is enhanced by time under load and temperature.
Purchase from Leros, Marlow or English Braids - others tend to be a trifle undisciplined in their mixes.

It's such a minefield (HDPE-enhanced ropes) that some highly reputable merchants (ie Boatropes) refuse to deal in it.
I have bought, very cheap HDPE on e-Bay, but as the sellers usually don't know much about what they're selling you need to cross-examine them about its appearance, not its labelling.

 

[tawhiri]

Well I did buy 25 m of this rope, and it is not very flexable. It has two coats over 6mm SK75 dyneema. I get the impression it will do the job.
However it is near impossble to splice. Even after removing the intermediate coat the core will not fit throght the splice.
Does anybody have ideas.

 

[simonfraser]

Dyneema is a pain to splice, find a professional.
You could have ordered it with an eye spliced on .......

 

[knuterikt]

Well I did buy 25 m of this rope, and it is not very flexable. It has two coats over 6mm SK75 dyneema. I get the impression it will do the job.
However it is near impossble to splice. Even after removing the intermediate coat the core will not fit throght the splice.
Does anybody have ideas.

How are you doing the splice?
pictures?
You must do a core to core splice.
Here is a good instruction http://www.samsonrope.com/Documents/Splice Instructions/DblBrd_C2_Eye Splice_AUG2012_WEB.pdf

Remove the intermediate cover for the complete length of the splice.
the intermediate cover is there only to increase the diameter of the rope.
It's only the core that is load bearing.

More instructions

I pull the outer cover back the total length of the splice and secure the intermediate cover with a tight sewn whipping before I remove the rest of the intermediate cover.
I then complete the splice as in the above instructions.

On some triple/double braid Dyneema ropes you might be able to bury the cover inside the cover on other ropes you must secure it on the outside.
When you remove the intermediate cover from the rope you make more room inside the cover

On this rope there is not enough room for the double core + cover inside the cover

http://i372.photobucket.com/albums/oo167/knuterikt/Splicing/SpliceAdmiralCovered_c.jpg

More instructions http://www.pbo.co.uk/gallery/34456/1/dyneema-eye-splice

 

[tawhiri]

Yes it was an eye to eye splice according to the instructions here:
http://www.gleistein.com/assets/download_pdfs_images/Kataloge/Splicebookenglweb.pdf
Eye Splice, Method 1

The istructions from:
http://www.samsonrope.com/Documents/Splice Instructions/DblBrd_C2_Eye Splice_AUG2012_WEB.pdf
seem to more detailed, and have answered a question I had about tapering.

My spice is nearly complete, but the last 10mm of core do not fit into the cover, see picture.
I will probably manage better the next time



Thanks

 

[knuterikt]

Yes it was an eye to eye splice according to the instructions here:
http://www.gleistein.com/assets/download_pdfs_images/Kataloge/Splicebookenglweb.pdf
Eye Splice, Method 1

The istructions from:
http://www.samsonrope.com/Documents/Splice%20Instructions/DblBrd_C2_Eye%20Splice_AUG2012_WEB.pdf
seem to more detailed, and have answered a question I had about tapering.

My spice is nearly complete, but the last 10mm of core do not fit into the cover, see picture.
I will probably manage better the next time

View attachment 43264

Thanks

You are close
Check that the opening is not passing through a yarn.
try to milk more cover towards the opening in the cover.
with instructions I use the "inner" eye in the dyneema is little bit larger than the outer eye formed by the cover, this give a little bit more slack to work the crossover.
If you are unable to complete the splice find out why
-To little cover
move your insert point away from the eye keeping same size. This give more cover to work with.
-the inner eye to tight
make the inner eye a little bit large