Most hulls you find follow one of two fundamental patterns:
Displacement hulls, seen from under water, are effectively eye-shaped. They are designed to cleave through the water, pushing water outward at the bow, then allowing that displaced water to converge as the stern passes. This hulls tend to be efficient, offering relatively low resistance, and are ideal for lower-powered applications like sailboats or paddle craft. They tend to produce far less wake than planing hulls because of their efficient passage through the water.
Planing hulls can take a variety of shapes, but they all share the characteristic of being intended for planing, where the hull rises and effectively skips, or planes, across the surface. Because the hull needs to be raised, quite a bit of constant thrust must be applied. As such this hull design is used almost exclusively by powered craft.