I depends on where the break is..........generally if you broke it in the middle third the board it is not worth repairing unless you absolutely can't afford a replacement. Within a foot of the tail or nose and it can be repaired fairly easy and with little effect on the board's performance. If the board is broken in the middle even a good repair job is going to effect the performance, it will stiffen it.
Thats a good explanation (especially the drawing for truing up the rocker). EXCEPT it doesn't mention putting in wooden stringers across the snap. Unless the snap is within a few inches of the nose I think theres too much stress to rely on cloth alone. I'd resin in a couple of stringer to span the snap. I've tried it without and the board eventually breaks again. Never had trouble when i used a couple 12" stringers. agree w/ everything Charlie sed. Big hassle.