Shroud Tension

[dclark]

What about temperature changes? I keep mine slipped year round with the mast up. I set my tension on typically warm afternoon. Will the steel wire contract and increase tension during the colder winter months?

Actually, other things being equal, the opposite. Yes, the steel will contract as it gets cold, but the aluminum in the mast has a higher thermal expansion coefficient, about 1 1/2 times that of steel. Since the mast is providing the stiffness in compression to conteract the shroud tension, in cold weather it will contract more than the shrouds, thus, the tension will be less in the winter. This would seem to be beneficial.

Of course, other things are not equal. The confounding factor is the boat itself. It is essentially polyester (plastic) with a thermal expansion coefficient about twice that of aluminum. On top of that, it's not a simple mechanical system like a wire in tension or the mast in compression, it's a complex composite structure with a bunch of different shapes, stiffening bulkheads, thick and thin sections, etcetera.

How the entire system of mast, standing rigging and the boat they're both attached to might behave in extreme temperatures is anybody's guess.

Also, quite seroiously, give the rest of us a break. In Orange County, CA, you're asking about winter to summer temperature extremes? There aren't any.

Thanks for the info, I hadn't thought of the other factors. And hey it was pushing 95 degrees when I tensioned them. In they winter there will be times it drops to under 50 at night and a lot of nights under 60. Burrr.

[Frank C]

... And hey it was pushing 95 degrees when I tensioned them. In they winter there will be times it drops to under 50 at night and a lot of nights under 60. Burrr.

I do love Southern Calif, but I live in Northern Calif.

We've had record temps this past week over 100-F, with nights at 70. On the same day it's 100 here, it can be 65/55 in San Francisco (just twenty miles from SF Bay). Mark Twain said (to effect) ... the coldest winter he ever spent was a summer in San Francisco.

Come January, we'll have days at 55 max, nights frequently dropping 35, occasionally below freezing. I do love the sailing in Northern California, but the climate in Southern Calif is truly amazing. Go on, Dave, rub it in!