Vectran forestays

The luff of my jib is a stiff wire that forms the forestay once it's tensioned.  But every time we roll up the jib to store it, the wire twists crumpling up the foot of the sail and the mylar is sufferring.

On the basis that the jib halyard (and hence forestay tensioning system) is all Vectran, I tried a length of 4mm marlow excell V12 as a forestay when sailing without the jib once, and it seemed OK (but I used it doubled and kept the lazy stay attached - just in case) .  Overcautious surely as this stuff has a 1.6 tonne breaking load!

Has anyone tried a vectran forestay instead of a wire one? Is it safe?  If so, why are we still using wire?

It's becoming common in some high performance development classes such as International 14's and 12ft Skiffs.

The advantages are that it's lighter, and sometimes stronger. It's also cheaper by the metre, and you save money have terminals or eyes fitted. And it's easier to cut if you get trapped.

The disadvantages are that for equal breaking load the string will have a bigger diameter, and therefore greater windage. The string is not UV resistant, so needs to be replaced every 6months if you leave your mast up outside. The string is not wear resistant, and often wears out where the string passes through spreaders. The latter two problems can be overcome to a certain extent with an "outer" but this again increases windage.

Edited by Strawberry

Nick

I  think   I had 5 or 6mm  vectran   put on the 14.  This  approx 4 years ago so  ropes have developed  but the reason for  this was  2 fold,   it not just breaking strain but  the   elongation under load  that counts   and you  need to go up to  6mm to get the same  as dyform for your forestay.  The other advanatage at least  it gives you some leeway  if the forestay is left out in the sun.

 

 

Dyneema, in common with most ropes, suffers from creep - that is, it will stretch not merely when initially subjected to a load but also over time, whereas Vectran is much more creep resistant.

So for things that are (or should be) frequently adjusted, Dyneema is fine, but for standing rigging which needs to maintain its length throughout a race, use Vectran.

I'd have thought that Vectran would be great inside a jib luff, so long as the diameter was well-chosen, but it is probably harder to tell when it has been damaged (we replace wire if there are any loose strands, after all), so catastrophic failure could be more of an issue (it's easier to cut than wire too, after all).

Yes, their stretch characteristics are similar, but creep is different.