I put a spinnaker on my 89 Hobie 18. Pole is 12 - 12.5 feet, end of pole snuffer. Spinnaker dim were taken out of a old Murrys Catalog. I picked up a all alum mast for $170 and use that for the spinnaker rig. Keep the tang 1/3 to 1/2 between the shroud tang and top of mast. With the pole that long and the standard size spinnaker I need to sheet to the front crossbar. Still playing with the spinnaker to make it faster.