propeller - 2 or 3 blade
Get a three-blade prop. Anyone asking that question is novice enough to appreciate a boat that backs down when docking, which is probably the single best reason for a three-blade. As far as prop drag and racing, the only time prop drag has a significant effect is when you don''t have enough wind to make hull speed. Of course, lightweights sacrifice a bit while planing as well, but then you enter an area where there is absolutely no comparative testing to estimate the effect of a three-blade versus two-blade prop while surfing on wave faces. Put it out of your mind and learn sail shape, rig trim, tactics, right-of-way, and a hundred details of sailing and racing, then replace the fatty with something that''ll help you beat someone you really need to.