Stretching 12 strand dyneema

[Roberto]

You may well be right, but 2 tons was the load specified by the OP.

Technical literature varies a lot in terms of applied % of breaking load etc, depending upon specific type of material (not generic UHMWPE), specific weaving, different temperatures etc etc, as I am not looking to replace my rigging but simply to have some replacement for broken pieces of rigging wire I just would like to make things simple: if I can remove some % of elongation beforehand, so much the better; if not, I'll tighten the lashing over and over again.

 

[Daydream believer]

10k daN
Seriously?
WTF is that in English?
I realise that you and maybe some others can probably read that sort of gobbledegook readily, and I too could figure it out could I be bothered, but is it really necessary to showcase your command of such ridiculously clever-clever esoteric flummel rather than telling us what the breaking strain actually is in terms understandable to normal people, ie Kg or tons (even in tonnes if you really are that pedantic).
After all, it's not as if this might need to be measured in space or on a planet with different gravity to ours...

Wasting your time
He could not answer it in #18 either so one assumes he copied it out of Google & does not know

 

[Chiara’s slave]

The less stretchy the rope, the less energy stored. (for the same tension).
Which is why hi-tech ropes are favoured by land rover nuts for winches etc.

Though some love a kinetic energy recovery rope. The ones who love to live dangerously.

 

[HenrikH]

If you are able to tighten the line between two sturdy trees, a weight hung in the middle will give pre-load. Dyneema quality DM20 have virually no creep

 

[Neeves]

For testing rope, say to measure its elasticity, I have always used trees, big ones, small diameter ropes, to keep the numbers small and a 4x4. Then extrapolate the small numbers for larger rope using weight of rope to size up. You need a hefty sling round the tree. The first time I tried it, unsuccessfully, I used nylon round the tree and on stretching the nylon the knots started to become hot and smoked. Not something I had expected - you live and learn.

This is of no use in this case unless you can do something as suggested in post 24.

Jonathan

 

[thinwater]

I suspect by the time the line is stored and handles and moved around for years, the construction stretch will return. I would just make sure you have enough room between the lashings to retension after some sailing. And you may have to re-splice or something to make it fit anyway.

Just sayin' that the goal may not be practical in the real world.