Abstract: A personal watercraft having improved bottom hull shapes in general, and improved center keel shapes in particular. The center keel can have a substantial section over which the keel angle becomes sharper progressing from front to rear, and the concavities on either side of the center keel become deeper progressing from front to rear. The center keel can have a point of maximum downward slope on either side of the keel centerline, with the maximum vertically downward slope becoming greater with greater rearward distance over a section of the personal water craft bottom hull. The bottom hull can have keel troughs on either side of the keel centerline that become deeper over a section of the personal watercraft bottom hull, traveling from front to rear over that selected section of personal watercraft bottom hull. The center keel shape can provide a smoother ride and improved handling in rough water.

Abstract: Ventilated sponsons, personal watercraft having ventilated sponsons, and methods for adjusting the handling characteristics of personal watercraft by ventilating the sponsons. The present invention provides ventilated sponsons, sponsons, having holes formed through the sponsons to allow high pressure water trapped under the sponson to escape. The holes formed through the sponson thus allow for fine tuning and adjusting the performance characteristics and handling characteristics of the personal watercraft long after the point of manufacture. Ventilating the sponsons can increase straight line stability while maintaining tight cornering characteristics.

Abstract: Tunable sponsons for personal watercraft and personal watercraft having the tunable sponsons. The present invention provides personal watercraft having sponsons with an adjustable height relative to the water surface and the hull. One adjustable sponson has a horizontally, outwardly extending portion from the personal watercraft hull followed by a downwardly extending portion including a fin for penetrating below the water surface. The effective height of the sponson outwardly extending portion above the water can be reduced or lowered by adding a thickness of slab of material along the length under the sponson outwardly extending portion. One tunable sponson includes apertures mounted along the sponson underside for securing additional material. The effective height of the sponson horizontally extending portion above the water can be increased by removing a removable sponson extension previously secured to the sponson.