Inboard propulsion system for a boat

Claim 2

In a water jet propulsion system comprising an impeller means for creating a discharge oF water under a head pressure from water taken from a water intake, conduit means connecting the discharge to a nozzle for discharge as a jet of water, the improvement comprising means sensing the pressure in the water intake and means for varying the effective size of a discharge opening of the nozzle to control the velocity of the water discharge through the nozzle for a range of different intake pressures sensed by the sensing means so that the effective size is decreased as the intake pressure increases.

Claim 3

In a water jet propulsion system according to claim 1, wherein the means for varying the effective size of the discharge opening comprises the interior of the nozzle converging to the size of the discharge opening, a valve member mounted for reciprocal movement in the nozzle between a position extending into the discharge opening to reduce the effective size of the opening and a position withdrawn therefrom, and means for moving the valve member in response to changes in the intake pressure.

Claim 4

In a water jet propulsion system according to claim 2, wherein the means for moving the valve member comprises an electrical drive means connected to the valve member, and means controlling said drive means, said control means including means sensing the head pressure and said means sensing the pressure at the water intake to obtain a pressure differential with the control means causing the drive means to retract the valve member toward the withdrawn position when the pressure differential is greater than a predetermined amount and causing the drive means to move the valve into the discharge opening when the pressure differential is less than a predetermined amount.

Claim 5

In a discharge nozzle according to claim 3, wherein the electrical drive means includes a rack and pinion drive unit with the rack member connected to the valve member.

Claim 6

An inboard water jet propulsion system for a boat comprising a pair of water jet nozzles disposed adjacent the stern of the boat at opposite sides thereof, impeller means discharging water at a head pressure into a bowl, a single water inlet for providing water to the impeller means, means for sensing the water pressure in said water inlet, means for varying the effective opening of each of said pair of nozzles in response to changes in the pressure sensed by said sensing means with the effective opening being decreased in size as the pressure at the inlet increases, conduit means extending from each of the nozzles to said bowl and coacting therewith for dividing the water discharge from the impeller means into equal portions so that each of the nozzles converts the head pressure into a high velocity stream which is discharged as a propulsion jet.

Claim 7

An inboard water jet propulsion system for a boat comprising a pair of water jet nozzles disposed adjacent the stern of the boat at opposite sides thereof, impeller means discharging water at a head pressure into a bowl, a single water inlet for providing water to the impeller means, means for sensing the water pressure in said water inlet, means for varying the effective opening of each of said pair of nozzles in response to changes in the pressure sensed by said sensing means with the effective opening being decreased in size as the pressure at the inlet increases, conduit means extending from each of the nozzles to said bowl and coacting therewith for dividing the water discharge from the impeller means into equal portions so that each of the nozzles converts the head pressure into a high velocity stream which is discharged as a propulsion jet.

Claim 8

An inboard water jet propulsion system according to claim 5, which further includes deflecting means associated with each of the nozzles to change the direction of the propulsion jet therefrom to provide a reversed thrust for each nozzle, each deflecting means being individually controlled to enable both a selective deflecting of the thrust of one nozzle to provide a steering function and the deflecting of the thrust of both nozzles to provide a backing thrust for the boat.

Claim 9

An inboard water jet propulsion system according to claim 6, wherein each deflecting means comprises a deflecting hood mounted on the stern of the boat adjacent its respective nozzle for pivotal movement into and out of the water jet of its respective nozzle.

Claim 10

An inboard water jet propulsion system according to claim 7, wherein the hood of the deflecting means is mounted to deflect the water jet downwardly and outwardly in a reversed direction.

Claim 11

An inboard water jet propulsion system according to claim 5, wherein the means varying the effective discharge opening of each of the nozzles includes a valve member mounted for relative movement with respect to the discharge opening to change the effective cross-section thereof, control means sensing a pressure differential between the sensed intake pressuRe and head pressure for the impeller means and means for moving the valve member in response to the sensed pressure differential.

Claim 12

An inboard water jet propulsion system for a boat comprising a pair of water jet nozzles disposed adjacent the stern of the boat with a nozzle adjacent each side thereof, an impeller means having a single water inlet and discharging water at a head pressure into a bowl having means forming two bowl segments each receiving an equal volume of the discharge from the impeller means, conduit means interconnecting each of the nozzles to a bowl segment to discharge the head pressure of the impeller means as a water jet from each of the nozzles, means for sensing the pressure in the water inlet, each of the nozzles having means to vary the effective discharge size of the nozzle in response to sensed changes in the inlet pressure of the impeller means with the effective discharge size being reduced as the sensed inlet pressure increases, and deflecting means associated with each of the discharge nozzles, said deflecting means being individually controlled to enable selective deflecting of the water jet of a nozzle to provide a steering function and to enable selective deflecting of the water jet of both nozzles to provide a backing function for the propulsion system.

Claim 13

An inboard water jet propulsion system for a boat comprising a pair of water jet nozzles disposed adjacent the stern of the boat with a nozzle adjacent each side thereof, an impeller means having a single water inlet and discharging water at a head pressure into a bowl having means forming two bowl segments each receiving an equal volume of the discharge from the impeller means, conduit means interconnecting each of the nozzles to a bowl segment to discharge the head pressure of the impeller means as a water jet from each of the nozzles, means for sensing the pressure in the water inlet, each of the nozzles having means to vary the effective discharge size of the nozzle in response to sensed changes in the inlet pressure of the impeller means with the effective discharge size being reduced as the sensed inlet pressure increases, and deflecting means associated with each of the discharge nozzles, said deflecting means being individually controlled to enable selective deflecting of the water jet of a nozzle to provide a steering function and to enable selective deflecting of the water jet of both nozzles to provide a backing function for the propulsion system.

Claim 14

An inboard water jet propulsion system according to claim 10, wherein the means for varying the effective opening of each of the nozzles comprises a valve member mounted on an actuating rod for reciprocal movement from a position withdrawn from the opening of the nozzle to a position inserted therein, an actuating means for the valve member, a control means for the actuating means including said means sensing the inlet pressure and means for sensing the head pressure in the bowl segment, said control means causing the actuator means to move the valve member into the nozzle opening to restrict flow therethrough as the pressure differential between the inlet and the head pressure of the bowl segment drops below a predetermined value and causing the actuator to withdraw the valve member when the pressure differential exceeds a predetermined value.

Claim 15

An inboard water jet propulsion system for a boat comprising a pair of water jet nozzles disposed adjacent the stern of the boat with a nozzle adjacent each side thereof, an impeller means having a single water inlet and discharging water at a head pressure into a bowl having means forming two bowl segments each receiving an equal volume of the discharge from the impeller means, conduit means interconnecting each of the nozzles to a bowl segment to discharge the head pressure of the impeller means as a water jet from each of the nozzles, deflecting means associated with each of the discharge nozzles, said deflecting means being individually controlled to enable selective deflecting of the water jet of a nozzle to provide a steering function and to enable selective deflecting of the water jet of both nozzles to provide a backing function for the propulsion system, and means for varying the effective opening of each of the nozzles comprising a valve member mounted on an actuating rod for reciprocal movement from a position withdrawn from the opening of the nozzle to a position inserted therein, an actuating means including a rack and pinion drive unit for the valve member, and control means for the actuating means including means sensing both the inlet pressure and the head pressure in the bowl segment, said control means causing the actuator means to move the valve member into the nozzle opening to restrict flow therethrough as the pressure differential between the inlet and the head pressure of the bowl segment drops below a predetermined value and causing the actuator to withdraw the valve member when the pressure differential exceeds a predetermined value.

Claim 16

An inboard water jet propulsion system for a boat comprising a pair of water jet nozzles disposed adjacent the stern of the boat with a nozzle adjacent each side thereof, an impeller means having a single water inlet and discharging water at a head pressure into a bowl having means forming two bowl segments each receiving an equal volume of the discharge from the impeller means, conduit means interconnecting each of the nozzles to a bowl segment to discharge the head pressure of the impeller means as a water jet from each of the nozzles, deflecting means associated with each of the discharge nozzles, said deflecting means being individually controlled to enable selective deflecting of the water jet of a nozzle to provide a steering function and to enable selective deflecting of the water jet of both nozzles to provide a backing function for the propulsion system, and means for varying the effective opening of each of the nozzles comprising a valve member mounted on an actuating rod for reciprocal movement from a position withdrawn from the opening of the nozzle to a position inserted therein, an actuating means including a rack and pinion drive unit for the valve member, and control means for the actuating means including means sensing both the inlet pressure and the head pressure in the bowl segment, said control means causing the actuator means to move the valve member into the nozzle opening to restrict flow therethrough as the pressure differential between the inlet and the head pressure of the bowl segment drops below a predetermined value and causing the actuator to withdraw the valve member when the pressure differential exceeds a predetermined value.