Dyneema rig goes slack in the cold??? Not for me!!

[Jeff on Aurora]

Well, my investigation into Dyneema rigging as an alternative to stainless steel didn't last very long. This video of a cruising boat in 30 degree temperatures shows how their rigging went so slack that the boat can't be sailed until the temperatures warm up. Whiskey tango foxtrot!

https://www.youtube.com/watch?v=-Uye1oWpZOw

Apparently, Dyneema actually EXPANDS when cold, unlike just about any other material I've ever encountered.

Has anyone with synthetic shrouds come up with a work-around for this?

I'm heavily inclined to stay with trusty SS.


Thanks!

[rslifkin]

I doubt the rigging is expanding. The mast will shrink in the cold and if the rigging doesn't also shrink enough, then it'll become slack.

[Jeff on Aurora]

Originally Posted by rslifkin

I doubt the rigging is expanding. The mast will shrink in the cold and if the rigging doesn't also shrink enough, then it'll become slack.

From what I'm reading, it actually IS the Dyneema expanding, weird, huh? From another post by the "Rigging Doctor"

"Dyneema experiences a negative linear thermal expansion coefficient in the direction of the fiber. What this means is that it stretches as it cools. Minor differences in temperature will not create an appreciable difference in length, leading to loss of tension, but more drastic differences will.
What this means is that your rigging will go slack during the winter which is of little consequence since the sailing season ends before it gets cold enough to notice the difference. I tensioned my rigging when it was between 60F and 80F. Now that the temperature has dropped down to below 20F, we are seeing an appreciable slackness in the standing rigging. "

Check out the linked video from my first post - you won't believe how much slack and wobble there is in the rig. Start watching at 6:00 into the vid. Completely unusable for sailing.

J.

[Benz]

I tune my synthetic rig when it's cold out, then in the summer it gets a tiny bit tighter. As has been mentioned, it may be the aluminum mast shrinking with cold.
Either way, unless you're cruising in places with huge-HUGE-temperature fluctuations, it's hardly the end of the world to give a quick tune when the weather gets cold, if you're hardy enough to sail in sub-freezing temps.
Which I'm not.