Hi PTP,

from my expierence with synthetic shrouds (sk75), I think initial creep is about 5%. I used them for half a year (mast up all the time), in the hope that the creep settles. However it found the shrouds to elastic in strong winds and got tired to retension the shrouds so often. In this time it doesn't settle.
I think that one part of the creep comes from the braid and will affect any braided line. But it should settle after first use. In addition to that some materials like dyneema creep.

Creep does not recoil, by definition.

Actually I don't know about AS-78 and technora, but vectran was designed to have "no" creep (rumors say as towing line for sonars). You need about three times the diameter as the wire to get the same stiffness, if I remember right.

Not sure how your sail is rigged. Is a screacher a flat cut genaker or suoer sized jib? Normally you have the luff line attached to the head and tack shackles of the sail. In this case, the creep of the line means that the luff of your sail has to carry more load (the luff keeps its original length, the line gets longer). Then, increasing the halyard tension stretches the luff more than the line, which might be mean to your sail... However on land you can shorten the length of the line from time to time.

I am a lazy guy and resetting some line in sails keeps me from sailing. I would take a "non creep" line. Like polyester or vectran if you want to save 100g or so for some $$$ more.

Actually I have a "hooter" or screacher or whatever (a flat genaker...) and I use polyester as luff line.

Hope that helps.

Cheers,

Klaus