Date: 10/31/2008
Name: Mark Weinheimer
email: innerbanks@embarqmail.com
subject:mast step placement and headstay length
According to Bill McClure, former Chief Measurer, the original design placement for the mast step allowed the mast to rest on the sliding hatch when it was lowered into the standard mast prop and they received complaints about broken hatches. The decision was made to move the step forward so this didn't happen. The bylaws state the after edge of the mast should be approximately 98 1/2" from the forestay hole on 1973 or later boats or if repair is necessary, where it was from original manufacture. I suspect that the variation you get from the 100 to the 99.5 etc is simply due to the fact that the one design standard was only loosely applied during the building of our little boats. Moving the step forward is also probably the root of the lee helm so many people have experienced over the years before raking the mast aft. My rig tune numbers are from a very late model Mk3 - #2577 - which has the shorter J measurement. The object of the exercise is to keep the middle of the mast from going forward when loading the backstay and have enough rake to get a bit of weatherhelm. This is easier on boats with the lower chainplates aft of the centerline of the mast. On my friend's #255, the maststep is at 100 1/2" aft, the chainplates have been moved from the original position to aft of the step and the rig tune numbers work - the boat is very fast, especially in light to moderate air. The only difference is that the headstay is harder to get attached than on 2577.
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