Abstract: An airboat and drive system for operating a pair of counter rotating air propellers that propel an airboat are described. An engine is mounted low in the hull of an airboat to lower the center of gravity and provide a more stable airboat. The drive system is connected to the engine through a drive shaft. The drive system includes a transmission, interconnecting frame, and counter rotating air propeller drive. The interconnecting frame mounts the counter rotating air propeller drive above the transmission providing proper clearance for the air propellers with the hull of the airboat. The transmission and counter rotating air propeller drive are connected through an interconnecting drive shaft. The amount of noise from a conventional belt drive is reduced. The modular design and simplified drive system is easier to assemble and align.

Abstract: An airboat and selectable drive system for an airboat are described. The airboat may be configured for mounting an engine either high or low in the hull of an airboat. The selectable drive system is connected to the engine. The selectable drive system includes a transmission interconnected to an air propeller drive. A clutch has three positions to include forward, neutral, and reverse. The air propeller drive rotates the air propeller in one of two directions based upon the selected position of the clutch. The drive system has the capability to rotate air propellers at different speeds. The reverse speed of rotation of the air propellers may be higher or lower than the forward speed of rotation. The modular design and simplified drive system is easier to assemble and align for both configurations.

Abstract: Boat hulls are prepared by positioning reinforcing material in a mold, applying vacuum to firmly hold the reinforcing material against the mold, positioning a fiberglass-resin mixture over the reinforcing material, placing a vacuum bag over the fiberglass mixture, and evacuating the vacuum bag to press the fiberglass mixture against the reinforcing material to bond the fiberglass mixture to the reinforcing material. Also discloses a boat hull construction.