I've got a 1979 swing keel that is rigged with 5/32" standing rigging.
I've been reading the C22NSA Tech Manual, the North Sails Tuning Guide, and the Loose Tension Gauge instructions to understand rigging strategies. I note that these references are based on 1/8" inch rigging.
Question 1:
What's the proper tension for the 5/32" rigging on a C22?
The Loose Tension Gauge Instructions referenced a desired shroud tension of 10%-12% of breaking strength and forestay tension of 15% of breaking strength. For 1/8* rigging this equates to 230 lbs of tension on the shrouds and 315 lbs on the forestay. For 5/32 rigging that's 360 lbs for the shrouds and 495 lbs for the forestay due to the roughly 50% increase in breaking strength .
The Tuning guide articles in the 2006 Tech Manual list between 100 lbs and 240 lbs for the lower shrouds and 400 lbs. for the uppers.
Do I tension my 5/32 rigging for the same lbs of tension as the 1/8* rigging or should I increase by roughly 50% due to the increased breaking strength of the larger rigging? Can the rest of the boat (deck, chain plates, compression post, etc.) tolerate the added tension?
Question 2:
Also, what's the current consensus regarding mast rake vs. pre-bend? I see articles suggesting 6-7" of rake and/or 2-3" of pre-bend.
I've been reading the C22NSA Tech Manual, the North Sails Tuning Guide, and the Loose Tension Gauge instructions to understand rigging strategies. I note that these references are based on 1/8" inch rigging.
Question 1:
What's the proper tension for the 5/32" rigging on a C22?
The Loose Tension Gauge Instructions referenced a desired shroud tension of 10%-12% of breaking strength and forestay tension of 15% of breaking strength. For 1/8* rigging this equates to 230 lbs of tension on the shrouds and 315 lbs on the forestay. For 5/32 rigging that's 360 lbs for the shrouds and 495 lbs for the forestay due to the roughly 50% increase in breaking strength .
The Tuning guide articles in the 2006 Tech Manual list between 100 lbs and 240 lbs for the lower shrouds and 400 lbs. for the uppers.
Do I tension my 5/32 rigging for the same lbs of tension as the 1/8* rigging or should I increase by roughly 50% due to the increased breaking strength of the larger rigging? Can the rest of the boat (deck, chain plates, compression post, etc.) tolerate the added tension?
Question 2:
Also, what's the current consensus regarding mast rake vs. pre-bend? I see articles suggesting 6-7" of rake and/or 2-3" of pre-bend.