J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Headstay height

The class rules mast diagram showes the forstay fixing point height @ 10,414mm (34'-2"). The Basic Specifications chart says "I" dimension is 34'-0".

Shouldn't these two measurments be the same? Do the Class Rules need to be amended?

[This message has been edited by George Hero (edited 01-10-2001).]

I dont know the actual answer but, since the responses are few (none), I am willing to speculate. I = 34'0" is the designers number. You'd have to ask J/Boats what marks they used to define that distance. I = 34'2" is the Class rule. In order to define a dimension, the class had to determine how it would be measured. They apparently picked points that were easy to define. The extra 2" is probably just for convenience for the measurers.

Just speculation, remember.

Good question, but hard to answer without going up the mast of a few boats. "I" is defined as the height of the upper bearing surface of the headsail halyard sheave. I suspect the forestay attachment point is higher, though without measuring, I can't say it is two inches. For comparison, the spinnaker halyard is 35 feet above the sheer in the Class mast spec. That's ten inches above the forestay attachment. Seems excessive, but my eyes are looking at this from a bad angle, 30 feet away, standing on the foredeck.

My mast is down for the winter and if i get the chance in the next few days i will mesure the the distance between the shiv and the spin halyard and attachment et al. if you have specfic measurement points you would like me to take let me know
paul battin
frolic 472

I'd be interested in the measurment from the forestay attachment point down to the upper edge of the boom black band.
Depending on how you read the Class Rules Mast diagram, it should be either 7,654mm or 8,926mm

George - I get 8926mm (10414 + 1210 - 2698). That 3970mm distance is to the top of the spin pole track (the line extends through the line for the black band).