temporary fixing of dyneema

[meirriba]

You wrote that you are going to have turnbuckles on both ends of the shroud so need to be precise.
I may be totally out, but what I would do is to have a turnbuckle only at the upper end.
On the deck end , I would take the line to required tension and wrap it several times around the deck eye of the chainplate and secure the end.
If after a time, you will find that the line was stretched and tension lost, just unwrap the line, re-tension to required measure and sail away.

[markxengineerin]

Hi Mark, I do only have a turnbuckle on one end (deck level) and the upper end is similar to Colligo Marine's "cheeky tangs".

I would take the line to required tension and wrap it several times around the deck eye of the chainplate and secure the end.

The difficult part about that is how do you get it to not slip, be removable, and also not damage the line in any way? I think it would be easier with regular line, but dyneema is so slippery, I think this is why people usually use splices.
If there was a "system" developed with a custom deck eye to enable what you suggest, I think it would be a nice solution. The "deck eyes" in my case are 1" diameter discs, no room for additional wrapping.

[Jdege]

Is dyneema sufficiently stretched on the spool?

That is, if you measured length with un-messed-about-with line, straight off the spool, did your splices, then stretched the line back to it's on-the-spool length, would you be close enough?

[earthbm]

Fwiw, in my experience (not with DUX, just regular SK78, but even with dux I think) it would be very hard to hit these precise stretch tolerances. Mine stretched 3-5%. Just do the lashings.

[fxykty]

Originally Posted by earthbm

Fwiw, in my experience (not with DUX, just regular SK78, but even with dux I think) it would be very hard to hit these precise stretch tolerances. Mine stretched 3-5%. Just do the lashings.

With DUX (and DM20 and other heat set lines) it is possible to be repeatable with splicing and pre-stretching (to remove constructional stretch) to within 0.1% of length. However, if your pre-stretching is not up to the static load you are tensioning the rig to then you will have a bit more stretch as it sits after tensioning. All done within a week and well within the adjustment range of a turnbuckle. In two years we’ve had to re-tension once, 4 turns each side.

Note, non heat set lines such as SK78 are not suitable for standing rigging as they continue to creep.

[wsmurdoch]

Could you make one rigging end adjustable by making a long bury eye splice through a gusseted tubular thimble with an oversize eye which you would reduce in size as the rope stretched/creeped. That type of thimble should be resistant to crushing and should be stable when installed in an oversize eye. Google "gusset tubular thimble" for examples.