J/30 Class Association Forums J/30 Forum One Design Class Rules setting the head stay length

The following are the measurements from the sheaves to the pin at the top of the headstay
upper sheave to pin 4 3/4"
lower sheave to pin 2 7/8

So to set headstay length first measure your spin halyard shackle and ball length which will vary from boat to boat

If the length is 3" and you are using the upper sheave distance from the pin to front of shackle is 1 3/4" add that to max head stay length of 35'10 1/2" for a tape measurement of 36' 1/4" inch

Don't for get to put a light line on the spin halyard so you can pull it down (tapes break)