Browsing through the One Design rules of the Ballad Handbook this morning, I found the official
J measurement:
Das Maß zwischen Vorstagsbefestigung am Rumpf und der Vorderseite
des Mastes (J-Maß) ist 3500+/- 25 mm. Doppelte Vorstagen sind nicht
erlaubt.
It has been some years since German language classes, but I read that as:
The distance between forestay fitting on the hull and the forward side of the mast (J-distance) is 3500 +/- 25mm. Double forestays are not permitted.
Which is at odds with the sailplan drawing in the Ballad Handbook by 240mm.
But fairly close to what I measured, if we allow for the rubber blocking. Okay, next question: Our upper black band is only 7" or so below the top of the mast. Official sailplan drawing locates it 18" (452mm) below top. That seems excessively low, but maybe it is needed so the headboard clears the backstay? Also, official mainsail luff length is 32'-0" (9750mm). There is no way a mainsail that tall fits on our mast under the official black band, unless the boom is about 30cm above deck. (Which is about where the previous owners had it, rendering the vang useless.)
If we move the boom gooseneck up to just below the wide mast slot (anyone know the correct
lower black band height?) and accept the drawing's 452mm upper black band location, that indicates a mainsail luff of 31' (9450mm -- not 9750), a full 1' shorter than the sailplan. The existing mainsail is indeed 31' unstretched. Can anyone verify that dimension is right? We like the higher boom anyhow, as it will permit a reasonable spray dodger and make vang/Boomkicker attachment easier. But I would like the headboard to go as high up the mast as possible, for light wind performance.
Danke!
If you use the 2m scale printed below the official drawing, you get J=3500mm+/-, which is rather closer to my measurement than to their published distance. 