Abstract: A boat hull having an upper hull section, a pair of spaced apart substantially parallel elongated outer sponsons extending from a forward portion to a stern portion of a bottom of the upper hull section, the outer sponsons and upper hull section defining a tunnel therebetween; and an elongated center sponson extending along the bottom of the upper hull and positioned in the tunnel between and substantially parallel to the pair of outer sponsons and having a forward section with an upwardly extending trailing step wall defining an upward step in the center sponson, and an aft section that is located aft of the forward section, the aft section having an upwardly curved leading edge intersecting the step wall of the forward section. The upper hull section can have planar bottom.