Drive and control system for watercraft

Abstract

A surfboard-based powered water craft is propelled by gas or electric power plant. A water jet pump supplies water under pressure, which is exhausted through a steering nozzle. A steering shaft, carried by the surfboard-based body, pivots in response to movement of a steering arm. The steering arm pivots about a vertical axis and a horizontal axis. The weight of the power plant is carried forward the center, whereby a rider on top of the surfboard based body tends to balance the weight of the power plant.

Description

[0001] Not Applicable.BACKGROUND--FIELD OF INVENTION[0002] This invention relates to powered personal watercraft, specifically to an improved drive and control system typically for surfboard-based watercraft.BACKGROUND--DESCRIPTION OF PRIOR ART[0003] Surfboard-based powered personal watercraft have been developed and refined for over three decades. Today these watercraft are of increasing use, but an ideal drive and control system for same has not yet been provided. U.S. Pat. No. 4,274,347 to Dawson (1981) discloses a power operated surfboard with a gasoline engine and drive system mounted to the rear of the craft. A watercraft based on Dawson's design, tradename Surrlet, has been commercially produced and available for many years. The Surflet craft is considered a benchmark craft in the field and realized many inherent advantages to the surfboard-based powered watercraft. A refined Surftet craft is still commercially available, but it's design and function have kept it obscure rela...

AI Technical Summary

Problems solved by technology

Today these watercraft are of increasing use, but an ideal drive and control system for same has not yet been provided.

A refined Surftet craft is still commercially available, but it's design and function have kept it obscure relative to the personal watercraft market.

Montgomery's design still fails to realize many of the handling and overall performance advantages inherent to the surfboard-based hull it utilizes.

This results in a watercraft with an unladen center of gravity that is also behind the hull longitudinal center.

Relative to intended and true craft use, these rearward center of gravity designs are inherently unstable and performance limited and also interfere with rider / craft / water interface.

This weight rear design also harms the the overall effciency and planing ability, or rising partially out of and gliding across the water ability, of these craft when ridden.

The inherent instability of both the SurfJet and the PowerSki Jetboard is best demonstrated as these watercraft become airborne off a jump or wave on the surface of the water.

However due to their rearward weight bias, when the SurfJet and the PowerSki Jetboard are typically launched off a jump of more than a few feet, the rear of the craft will fall away and separate from the rider.

These prior art craft cannot provide for rider controlled landings of the higher jumps of which they are capable.

This arrangement does not provide for a rear deck as relatively flat as possible, nor a craft cross- section at the rear as relatively thin as possible, both critical to optimal rider / craft / water interface.

The SurfJet and the Powerski Jetboard are sensitive to rider weight distribution due to their relative small size and water displacement.

This preponderance of weight to the rear tends to tip these craft up in the front and push the rear down when they are floating in water.

This tendancy away from the optimal flat and parellel hull to water surface relation introduces drag and decreases overall efficiency.

The SurfJet and PowerSki Jetboard do not provide optimal weight distribution across their hulls for craft planing, overall efficiency, or overall effectiveness.

The SurfJet and PowerSki Jetboard designs do not provide a mechanical means to steer the craft and are designed to turn via rider weight change only, as in surfing and windsurfing.

This is impracticable in a powered personal watercraft due to the weight and size of a craft necessary to carry a typical rider.

The high directional stability of these designs when underway in the water, combined with the extra weight necessary to power the craft equals a craft that cannot be effectively maneuvered or ridden in a way that emulates surfing or even Jet Skiing.

The limited performance generally, and the unusually high rider effort required for high craft performance specifically, have kept these watercraft from widespread use.

These two prior art surfboard-based watercraft cannot provide an optimal surfboard-like ride or handling.

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