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Re: Winterizing Standing riggging?
Hopefully this will point you in the right direction .....
Sailboats typically have aluminum masts and stainless steel rigging.
Such metals expand and contract upon changing temperatures. Aluminum has a higher rate of expansion/contraction due to temperature changes than does stainless steel. In wintertime the Aluminum will contract faster than stainless steel .... the 'shrinking' aluminum mast will unload tension in the rigging.
Common (300 series) stainless steel has a fatigue endurance limit of approx 30,000± psi, it also 'can' have a yield strength (permanently changes dimensions) at approx the same 30,000 psi (equivalent to approx. 30% rig tension!!). This is for common stainless steels; 300 series stainless steel can have 'better' values based on 'heat treatment and other metal forming processes'
Fatigue in 300 series stainless 'starts' to become a serious problem when the fatigue endurance limit (~30,000 psi) is repetitively (cyclically) exceeded -- usually at greater than ~1 million load cycles at greater than the fatigue endurance limit (~30,000 psi), at which time there's a high probability that such a 'part' will simply fall apart/shatter from the accumulated fatigue.
So, with your wintertime mast shrinking faster than the stainless rigging, which unloads the rigging; the normal (summertime) ~15% tension in rigging becoming less as it and the mast gets colder; the rigging tension remaining well under the fatigue endurance limit of 30% of ultimate tensile .... there's damn little potential for fatigue in your rigging during wintertime .....
...... unless your boat is heeled over to greater than about 45++° during during a 'blow' in excess of ~Cat 5 and/or any 'gusts' causes extreme mast vibration that would add up to ~1 million load cycles that exceed that 30% tensile strength ....
... the 'real' answer is:
If the rig didn't have severe oscillations from the wind in summertime, it will probably have LESS potential for vibratory oscillations when the rig relaxes during the winter.
You dont need to do 'anything' with the rigging for wintertime, it automatically unloads itself.
Last edited by RichH; 12-05-2017 at 05:11 PM.