Ships – Steering mechanism – Fluid pressure
Reexamination Certificate
2000-03-31
2001-08-28
Sotelo, Jesus D. (Department: 3617)
Ships
Steering mechanism
Fluid pressure
C440S038000
Reexamination Certificate
active
06279499
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to electric propulsion units for recreational watercraft. More specifically, the present invention relates to propulsion units that mount in a forward area of the watercraft.
2. Description of the Related Art
Recreational watercraft are typically used for various activities such as fishing, cruising, water skiing, knee-boarding, tubing and like sports. To move the watercraft across the water, an adequate amount of thrust is necessary depending on the particular activity. The thrust may be provided by various types of propulsion systems, both engine-driven and electric-motor driven. Electrical and mechanical propulsion systems generally include outboard and inboard engine driven propeller systems.
Internal combustion engine drives are generally disposed at the rear of a watercraft at a transom, either outboard or inboard. Outboard motors are typically secured to the transom of a boat, while inboard motors have a propeller extending through the transom from an internal combustion engine disposed within a housing of the hull. Both outboard and inboard motors are particularly useful for high-speed and highly responsive navigation of the watercraft. Drawbacks of such drives, however, include their noise levels, exhaust emissions, relative complexity, size and weight.
Electric propulsion systems for pleasure craft are typically referred to as trolling motors or electric outboards. These systems include an electric motor that can be rotated at various speeds to drive a prop. The prop produces a thrust, which is directed by proper orientation of the propulsion unit. In conventional trolling motors, for example, a control head may be manually oriented to navigate the boat in a desired direction, or a remote control assembly may be provided for rotating a support tube which holds the propulsion unit submerged during use. While certain relatively minor differences may exist, the term electric outboard is typically employed for the conventional trolling motor design, but with a horsepower range elevated with respect to the conventional trolling motor, such as in excess of 1 horsepower.
While the conventional trolling motor provides quiet and reliable navigation, extremely useful for certain activities such as fishing, there is considerable room for improvement. For example, conventional trolling motors are typically after-market, add-on units designed for mounting on the deck of a watercraft. Such units are typically supported by a mounting structure, a wide range of which may be obtained commercially. These structures allow for relatively straightforward deployment of the motor to position the propulsion unit below the waterline alongside the watercraft, and retraction of the unit for stowage on the deck. The entire motor and mount, however, generally remain securely fixed to the deck, both during use and when stowed. The resulting structure is somewhat cumbersome and occupies useful space on the deck, limiting access to the water in the area of the motor mount. Moreover, while much energy and creativity have been invested in boat designs, the aesthetics and aerodynamics of the hull may be somewhat impaired by the trolling motor and mount positioned on the deck, typically adjacent to the bow. Furthermore, conventional trolling motors only provide thrust at a point around the perimeter of a watercraft, thereby allowing external forces such as wind to force the watercraft out of alignment with the desired direction of movement across the water.
SUMMARY OF THE INVENTION
The present invention provides a propulsion system for a watercraft designed to address these drawbacks. The propulsion system may be an integral part of a watercraft or may be retrofitted to a particular watercraft. In a preferred embodiment, the propulsion system is fixedly mounted to the hull in a central area, rather than along the perimeter of the watercraft. This frees up deck space, and avoids the problems associated with a trolling motor mounted to the deck. The propulsion system may be used to provide a primary thrust, an alternative thrust, a correctional steering thrust, or it may be used for a variety of other applications.
The propulsion system preferably includes a jet coupled to a jet-drive assembly, an angular drive assembly for rotating the jet to a desired angle of thrust, and a control system coupled to the jet-drive assembly and the angular drive assembly. The propulsion system may also include a recessional housing for streamlining the propulsion assembly into the hull of the watercraft. The recessional housing may be an integral part of the watercraft, or it may be retrofitted to a particular watercraft.
In operation, the propulsion system may be used with or without a rear motor, such as an inboard or outboard motor. If a rear motor is present, the angular drive assembly may rotate the jet to an angle of thrust necessary to account for external forces such as wind or water currents, or it may be used to dock the watercraft. If the propulsion assembly is used as a primary propulsion device, then the central location may be very advantageous in improving the steering and control of the watercraft.
REFERENCES:
patent: 3468276 (1969-09-01), Pollard et al.
patent: 3802376 (1974-04-01), Smith
patent: 4034696 (1977-07-01), Kureth
Griffith, Sr. Thomas E.
Wikel Harold L.
Bombardier Motor Corporation of America
Fletcher Yoder & Van Someren
Sotelo Jesus D.
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