Spinakker pole bridle question
 

I'm making up a spinnaker pole for a friend and am not sure how long to make the bridles. Is there any rule of thumb here? Such as x amount of standoff (the ring relative to the pole) per x amount of length?

It depends. Small boats like the Wianno Sr have no bridle, attaching lift and downhaul at mid pole. The larger the boat, the more you want to get the lift and downhaul stresses away from the middle. For that reason, all bridles I've rigged went to the ends. If you by chance are rigging a boat that's jibed by the dipped pole method, only disconnecting from the guy and not both mast and guy, then of course you'd run the lift and downhaul without bridle either to the center of the pole if the boat's small or the end.

This is an end for end pole on a 33' boat (13'6" J measure) The bridles will go out to the ends, I'm mainly concerned about how long to make them so that they do their job well but don't have the rings too far above and below the pole.

rings should be 15% of pole length off pole ( 1.5' on 10' pole)

get leg lengths by using http://en.wikipedia.org/wiki/Pythagorean_theorem

this will give a safe bridle for an average pole.