Abstract: Catamaran boat hulls are described having sponsons, an underside tunnel surface between sponsons, two longitudinal steps disposed across each sponson's keel, and two transverse steps disposed lengthwise on opposing sides of each sponson's keel. The longitudinal steps for a sponson have a profile with a curved longitudinal step portion on the opposing outer edges with an outer edge portion of that curved longitudinal step portion being further away from the sponson's aft section, and an inward step edge offset where each of the two longitudinal steps meets a hull side of the sponson. The transverse steps help define variable deadrise inner lifting pad running portion with a lower deadrise aft transitioning to a higher deadrise forward. Spray rails protruding off the aft end of an underside wave spitter and away from the boat hull's centerline help manage undesired spray and use of radiused chines enhances lift and landing performance.

Abstract: Catamaran boat hulls are described having sponsons, an underside tunnel surface between sponsons, two longitudinal steps disposed across each sponson's keel, and two transverse steps disposed lengthwise on opposing sides of each sponson's keel. The longitudinal steps for a sponson have a profile with a curved longitudinal step portion on the opposing outer edges with an outer edge portion of that curved longitudinal step portion being further away from the sponson's aft section, and an inward step edge offset where each of the two longitudinal steps meets a hull side of the sponson. The transverse steps help define variable deadrise inner lifting pad running portion with a lower deadrise aft transitioning to a higher deadrise forward. Spray rails protruding off the aft end of an underside wave splitter and away from the boat hull's centerline help manage undesired spray and use of radiused chines enhances lift and landing performance.