A small boat has left and right sponsons extending in a longitudinal direction and respectively attached to left and right side walls forming a boat body. The sponsons are provided with an attachment section contacting a left side wall, a gliding section extending substantially horizontally from a lower edge of the attachment section, an inclined section connecting to a side edge of the gliding section, an upper edge of the attachment section, and projecting sections extending from an upper edge to a lower edge of the inclined section. Water flowing along the inclined section is guided by the projection sections and removed or separated from the inclined section. Accordingly, a small boat that turns through a small arc turning locus is provided, e.g., a small boat that is capable of relatively tight turning.

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.

Adjustable angle sponsons and personal watercraft having adjustable angle sponsons. The present invention provides sponsons having at least two adjustable angular settings downward of horizontal for the sponson. Sponsons include a fin or blade having an outward edge for penetrating beneath the surface of the water. The angle of the fin preferably can be set to a vertically straight down position, as well as other, more benign, outwardly extending angular positions. The vertically downward position provides for a responsive, aggressive handling boat, while the more outward positions provide a less aggressive, gentler riding personal watercraft. One adjustable angle sponson includes a fin secured to a longitudinal shaft having a key extending along the shaft length. A sponson housing can include a cavity for receiving the shaft longitudinally as well as at least two longitudinal keyways for receiving the key in different angular positions. The adjustable angle sponsons provide driver adjustable sponsons, adaptable to the skill and changing desires of the driver, and adaptable to varying passenger loads and water conditions.

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. The present invention further includes methods for adjusting the handling characteristics of a personal watercraft by adding and removing thicknesses of material from under the sponson.

The invention relates to a fin stabilization system adapted to minimize roll about the longitudinal axis of the boat during sharp cornering at very high speeds. In one form, equipment such as a machine gun is mounted to the bow of the boat and targets are adapted to be engaged in high-speed maneuvers when cornering and the deck of the boat is not excessively rolled whereby blocking visibility in a turn.