Redundancy saved my bacon

[Jyoder]

Last time I re-made my old Diablo speed system I spliced a thin line of dyneema inside the pulley line as a fall back in case I didn’t notice wear in time and had a failure. Well, it worked! Glad I didn’t have a full failure last session as kite might have ended up in trees or worse.

[alpaia]

thanks for the tip that was good thinking to put that thin core , I guess it also makes the rope more round than single braid dyneema and slides better in the pulley.
it is a bit like rediscovery the benefits of a rope with a core and a cover in a way

[Herman]

Nice work Jyoder! Would be interested to know the following if yo don’t mind me asking:

How was the core held in place?

Any info on lie specs, would the constriction effect have held the redundant splice in place?

What was the ~ ratio of virgin line length to filled core line length? ( I normally allow for~ 25% reduction in length over a normal bury. )

[Jyoder]

Nice work Jyoder! Would be interested to know the following if yo don’t mind me asking:

How was the core held in place?

Any info on lie specs, would the constriction effect have held the redundant splice in place?

What was the ~ ratio of virgin line length to filled core line length? ( I normally allow for~ 25% reduction in length over a normal bury. )

That’s the issue, how do you splice a loop on the end of a line with a core in it? I decided not to splice the ends and just doubled them over and zigzag sewed them together like production kite lines. Very easy to get correct length this way too. Next time I will just buy sleeved/cored line instead of putting the core in myself, but this is what I had lying around at the time.

By placing my own core and sewing the ends, I may have created a situation where the core stretches less than the sheathe line, which may have accelerated wear, but I am not sure.

Regardless, then I had time to experiment, but now I need a quick easy fix so will buy cored line and sew ends like I’ve seen on newer foil kites. Only issue is this speed system has been remade so many times it’s probably out of spec to factory setting, but the 2016 Diablo v1 11m kite flies great after hundreds of hours so I keep making replacement to match what’s working and not reset to factory.

[Herman]

Thanks for the info, we seem to have reached similar conclusions regarding redundancy. I think a double braid of the same strength may not last as long as single braid if flown to first failure, but as long as the double braid is built so the outer fails first it should have a good chance of a safe failure mode. Stay safe having fun.

[nixmatters]

If anyone is interested, I've got some double braided 2,3mm Black Dyneema.
The sheath is 12-strand and the core is 4 strand, also braided. Can dig out more tech specs if really needed.