String

[MattStiles]

Quick techie question, what size D12 am I after for the shrouds?  The bit of the cascade that's "closest to the wire" that is.  The stuff I have atm looks like it's about 4mm by ruler, but I hear the stuff comes up bigger than nominal.  Does that mean it's 3mm line really?

While I'm at it, is V12 the right stuff?  As far as I can tell from the specs D12 is a little bit less strechy and a bit less strong?

Cheers,
Matt

[Antony (Guest)]

Matt,
That is too techinical a question for most of us, and certainly for me.  At the point that you have arrived at i call 01604 592808 and ask for Tom.   He will tell you the answer before you promise to buy it from P&B and you can always hang up if you have a favourite local chandler!   I do have some of the pink stuff left somewhere, but i suspect that the new stuff is better.
Antony

[matt (Guest)]

for what its worth I use 4mm spectra/dynemma on the cascade for the shrouds. Seems to do the trick. I've also used 5mm dynemma where the shroud load is highest and that has shown no indication of wear or breakage.
Accidentally went sailing with 2mm spectra/dynemma attaching the jib halyard and that broke precipitating a dismasting. So don't use 2mm!

[knitting (Guest)]

You will obviously be using a proper locking splice, or putting a few stitches through the splice.  Otherwise you can join the long and distinguished list of those whose splices have let go at an inopportune moment.  You’ll be in the excellent company of the aforementioned sailmaker and a recent ex chairman, to mention just a couple.
I'd also replace it after no more than two years.

[johnk]

P @ B website gives the following breaking loads for D12
2.5 mm - 569 kg
3.0 mm - 995 kg
4.0 mm - 2056 kg

2.0 mm would therefore be about 300 kg. I am not surprised that a 2mm D12 jib halyard might break

Ormiston website gives the following for 1 x 19 ss wire
2.5 mm - 500 kg
3.0 mm - 730 kg
4.0 mm - 1300 kg

If you allow in each case a 20% reduction for a good splice, use the same diameter D12 as the shroud wire. The pulley system will give you a factor of two or three depending on your pulley arrangement.

[MattStiles]

Thanx all.  Tom says D12 is fine, V12 is the really sexy stuff, and that 4mm is easier to splice than 3mm.  Ordered!
Now I'll be reading those splicing instructions extra-carefully.

Cheers,
Matt

[Lukepiewalker]

Remember D12/V12 is proportionally stronger than a 'normal' sheathed rope with a Dyneema/Vectran core of the same nominal size as it is all Dyneema/Vectran.
Vectran's most interesting advantage from a Dinghy sailing point of view is reduced creep, this is non-recoverable stretch at a molecular level which isn't as much of an issue with adjustable controls it will necessitate checking the 'calibration' from time to time. This is more of an issue over longer lengths of rope such as a halyard, especially in great big boats.

[Lukepiewalker]

Oh yes, that and Dyneema is better at going round corners and has better UV resistance.
And cheaper.

Witness the difference in rated breaking strain between 5mm D12 (2395Kg) and 5mm Excel Racing (100% Dyneema Core, 989Kg) to illustrate my earlier point...

[knitting (Guest)]

As highlighted above these strings do ‘creep’, this means that they stretch permanently the first couple of times you use them.  This can be a pain if you don’t allow for it but can be easily dealt with.
 
What most people do is;
-Splice all your eyes with big loops, this means you can tighten them up and make the line shorter without dismantling the splices.
-Leave a couple of inches of the tail of the splice hanging out so you can easily pull your loops shorter without getting the fid out.
-Rig the boat up and leave it for the day, or at least a few hours, fully loaded up.  That should allow all the creep to happen in one go and not when you’re sailing.
-Come back and shorten all your loops, so the stretched lines are now the right length, probably about time for a refreshing cold beverage.
-Stitch your splices if you’ve not used locking splices, or even if you have and you’re conservative.
-Go sailing to check the lengths.
-Cut the tails off, if you’re unlucky and disturb the splices too much they can settle and stretch next time you sail.
 
Isn’t life brilliant now we don’t have to rely on a chandler to provide expensive bits of wire that are the wrong length?
PS  If you wet the line it splices easier.

[Mike S (Guest)]

Stupid question -  aside from not being neat, is there anything wrong with making a loop with a non slip knot like a bowline rather than using a splice?
Mike
N3491

[Jane Wade]

Yes - it is almost impossible to put a non-slip knot on these ropes, the rope has been designed such that the splice compresses and therefore does not slip under tension. 

[knitting (Guest)]

You can tie knots in it if you want, but they reduce the strength of the line more significantly that splices.  A good splice will only reduce the strength by a relatively small amount.  In essence the rope doesn’t like going around tight corners, knots do tight corners, splices don’t.  The big boats have even started using special gadgets for tying on sheets and the like, because knots in those lines were causing regular failures.  You probably have heaps of excess load capacity so it’s not such a big deal, I’d still splice high load lines.
 
Have a look at the rope manufacturers websites.  They explain it all and recommend different splices for different lines.