Does the shape of the sailboat affect its sail?

Answer 1

There is a constantly ongoing interrelationship between hull shape, angle of heel, immersed hull area and shape, windage and wind resistance of the uppers of a hull, angle and speed of the wind, sea state, and the sail. So yes -- clearly there is. If you're asking, "does a given hull design place a requirement on the size and type of sails?" -- yes it also does. A hull designed for a fore-and-aft rig typically will not perform well with a squaresail rig. Likewise, putting up a 180% Genoa headsail on a sabot just... won't.... do. Typically, the designer allows for the rig(s) in the overall boat design.