Watercraft makes waves

Will motorbike-like racing on water be the next great motorsport? It will, if Jetbike inventor Gerald Wiegert, CEO of Aquajet Corp., gets his way. The inventor envisions motorcycle-like watercraft races, extreme sports, stunt shows, and military applications. But before Wiegert could get the concept off of the drawing board and into the water, his team had to crack balance, stability, and packaging challenges.

For a personal watercraft (PWC) to handle and feel like a motorcycle, Wiegert explains, it has to be narrow, and steer like a motorcycle. It must ride high on the water at high speeds, maintain stability at lower speeds, and not tip over while stationary. As a result, the narrow (25.5-inch wide) Jetbike differs from other PWC designs not only with its dual front and rear steering, but in what Wiegert calls its high draft design.

"Other personal watercraft have a low draft area," Wiegert explains, "meaning they are generally submerged only a few inches below the waterline." Aquajet's patented high draft design uses vented ballast chambers that allow the Jetbike to be submerged approximately 24 inches below the waterline at rest, and at speeds less than 7 mph.

By taking on water and displacing air from vented ballast chambers in the sides and rear of the craft, the Jetbike settles in the water, partially submerged. When powered, it rises up out of the water onto plane. Wiegert notes two key advantages to this system: easier boarding when it's low in the water; and faster deceleration.

Wiegert claims the Jetbike is the first and only PWC with both front and rear steering mechanisms. "Other personal watercraft steer with the side-to-side thrust nozzle action at the rear of the hull," he explains. "As a result, the machines are uncontrollable in an off-throttle (power-off) situation." In contrast, Jetbike riders move handlebars to control a "twin fin" front ski that is linked to the rear steering nozzle. The patented system is said to provide off-throttle maneuverability and better handling and responsiveness because the rider can maneuver with the front ski even when the throttle is off.