Dux Pre tension
Hi Brian,
Your explanation about my Dux runners "seeming" to have a larger temperature induced expansion differential than the wire ones did, being partly because, unlike the rest of the rig, I had them snug, but with no pre tension, makes good sense.
The thing is... when my runners were wire, I had the exact same practice of having them rigged up "just" snug as a hand hold, and putting 4 or 5 turns on them for the rare occasions that I needed my staysail. (I have folding handle, "quick adjust" turnbuckles on the runners).
When I had the previous wire runners, and there was a difference between morning temps, to 35 degrees hotter that afternoon, the difference in wire tension was small enough that I couldn't tell without using a tension gauge. I never noticed it at all in fact. With the Dux, starting with the exact same tune, they hang completely loose in the morning, with some slack as well, and that afternoon, if it is 35 degrees hotter, they would be REALLY tight! (So much so, that to oppose my staysail stay, I might only put one more turn on them! The difference between the two materials behavior, at least in my admittedly limited observation, is pronounced!
It is of no consequence in my application, with such easily adjusted turnbuckles, and I think my runners is an ideal application for these lighter synthetics, but for the rest of the rig, I thought that this observation would be useful for others in deciding where they apply and where they don't... (like a short fat extrusion with all shrouds at similar pre load, VS a long skinny one with really tight uppers and fairly slack lowers. Just something to consider...
Mark
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