Marine propulsion system

Claim 2

In a high speed power boat of the planing type, a tunnel in the aft underwater portion of the hull, said tunnel having a generally semi-circular configuration extending to the stern of the hull, a propeller shaft within the tunnel, a propeller on the shaft, means for rotatably supporting the shaft with the hub of the propeller in generally coaxial relation to the axis of the tunnel, there being a substantial portion of the tunnel ahead of the propeller, and flow control means associated with said tunnel portion ahead of the propeller, said means having passages to admit water to the tunnel ahead of the propeller at low hull speeds to fully immerse the propeller, said flow control means having flow separating surfaces to divert water from the tunnel when the hull is planing and thereby cause the propeller to operate partly submerged.

Claim 3

A high speed planing power boat according to claim 1 wherein only the blade portions of the propeller below the hub are submerged when the hull is planing.

Claim 4

A high speed planing power boat according to claim 1 wherein the propeller is of a supercavitating type.

Claim 5

A high speed planing power boat according to claim 1 wherein the flow means ahead of the propeller are spaced hydrofoil elements extending across the bottom of the tunnel.

Claim 6

A high speed planing power boat according to claim 4 wherein the hydrofoils have a configuration to induce aeration within the tunnel at a hull speed corresponding to the onset of planing.

Claim 7

A high speed planing power boat according to claim 1 wherein the propeller shaft adjacent the propeller is supported within a bearing and said bearing is mounted on a hydrofoil extending across the bottom of the tunnel.

Claim 8

A high speed planing boat according to claim 6 wherein said bearing has a strut extending upwardly to the roof of the tunnel.

Claim 9

A high speed planing power boat according to claim 1 wherein a hydrofoil extends across the bottom of the tunnel aft of the propeller.

Claim 10

A high speed planing boat according to claim 8 wherein a steering rudder is associated with said hydrofoil aft of the propeller, said rudder having a blade portion above said hydrofoil and another blade portion below said hydrofoil.

Claim 11

A high speed planing boat according to claim 9 wherein the lower rudder blade is connected to the upper rudder blade by a shaft passing through said hydrofoil.

Claim 12

A high speed planing boat according to claim 9 wherein the lower rudder blade is smaller in area than the upper blade.

Claim 13

A high speed planing boat according to claim 9 wherein the lower rudder blade has an asymmetric sectional configuration to counteract oblique thrust on the lower rudder blade from the water stream below the level of the propeller hub.

Claim 14

A high speed planing boat according to claim 9 wherein the blade portion of the rudder above the hydrofoil has a curved top edge to clear the top of the tunnel over the turning range of the rudder.

Claim 15

A high speed planing boat according to claim 1 wherein the tunnel portion aft of the propeller has a smaller semi-circular configuration than the portion in the region of the propeller.

Claim 16

A high speed planing power boat according to claim 1 wherein the underbody of the hull has a V-configuration in section extending to the stern and the tunnel is located on the centerline of the hull.

Claim 17

A high speed planing power boat according to claim 15 wherein the flow control means are hydrofoil elements extending across the bottom of the tunnel and are disposed in a V-configuration.

Claim 18

A high speed planing power boat according to claim 15 wherein each of the hydrofoil elements extending across the tunnel has a V-configuration corresponding to the V-configuration of the hull.

Claim 19

A high speed planing power boat according to claim 15 wherein the hydrofoil elements are coextensive with the underbody of the hull and merge in the vicinity of the centerline of said underbody.

Claim 20

A high speed planing power boat according to claim 15 having a plurality of hydrofoil elements disposed across the tunnel in spaced relation along the tunnel, said hydrofoil elements havng a V-configuration corresponding to the V-configuration of the hull, there being a hydrofoil element aft of the propeller, a steering rudder associated with the hydrofoil element aft of the rudder, the rudder having a rudder blade above the hydrofoil and within the tunnel and another rudder blade below the hydrofoil, means extending through said hydrofoil and connecting the lower rudder blade to the upper rudder blade, the top and bottom of the upper rudder blade being shaped to clear the top of the tunnel and hydrofoil below over the range of angular movement of the rudder.

Claim 21

In a high speed power boat of the planing type in which the underbody of the hull has a V-configuration extending to the stern, a pair of tunnels in the aft underwater portion of the hull, there being a tunnel on each side of the centerline, each tunnel having a generally semi-circular configuration extending to the stern of the hull, a propeller shaft within each tunnel, a propeller on each shaft, means for rotatably supporting the shafts with the hubs of the propellers in generally coaxial relation to the axes of the tunnels, there being a substantial portion of each tunnel ahead of the propeller, and flow control means associated with each tunnel portion ahead of the propeller, said means having passages to admit water to the tunnels ahead of the propellers at low hull speeds to fully immerse the propellers, said flow control means having flow separating surfaces to divert water from the tunnels when the hull is planing and thereby cause the propellers to operate partly submerged.

Claim 22

In a high speed power boat of the planing type in which the underbody of the hull has a V-configuration extending to the stern, a pair of tunnels in the aft underwater portion of the hull, there being a tunnel on each side of the centerline, each tunnel having a generally semi-circular configuration extending to the stern of the hull, a propeller shaft within each tunnel, a propeller on each shaft, means for rotatably supporting the shafts with the hubs of the propellers in generally coaxial relation to the axes of the tunnels, there being a substantial portion of each tunnel ahead of the propeller, and flow control means associated with each tunnel portion ahead of the propeller, said means having passages to admit water to the tunnels ahead of the propellers at low hull speeds to fully immerse the propellers, said flow control means having flow separating surfaces to divert water from the tunnels when the hull is planing and thereby cause the propellers to operate partly submerged.

Claim 23

A high speed planing power boat according to claim 20 wherein the flow control means comprises hydrofoil elements extending across the tunnels ahead of the propellers, said elements being disposed adjacent the bottoms of the tunnels substantially at the angle of deadrise of the underbody of the hull adjacent said hydrofoil elements.

Claim 24

A high speed planing power boat according to claim 21 wherein other hydrofoil elements are located just ahead of the propeller and aft of the propeller, said elements also being disposed at the angle of deadrise of the underside of the hull adjacent said hydrofoil elements.

Claim 25

A high speed planing power boat according to claim 22 Wherein a steering rudder is located in each tunnel aft of the propeller, the axes of each rudder being substantially perpendicular to the hydrofoils of the tunnel within which the rudder is mounted.

Claim 26

A high speed planing power boat according to claim 20 wherein the propeller shafts and the tunnels are inclined at small angles to the centerline of the hull so as to diverge outwardly from the centerline toward the stern.

Claim 27

A propulsion system for high speed planing boats having a tunnel in the aft underwater portion of the hull extending to the stern, comprising a supercavitating propeller beneath the hull partially within the tunnel and partially projecting below the hull portions alongside the propeller, there being a substantial portion of the tunnel ahead of the propeller, and flow control means across the tunnel ahead of the propeller for causing the propeller to operate fully immersed at hull speeds corresponding to the displacement mode of operation and to operate semi-submerged at planing speeds.

Claim 28

A propulsion system for high speed planing boats having a tunnel in the aft underwater portion of the hull extending to the stern, comprising a supercavitating propeller beneath the hull partially within the tunnel and partially projecting below the hull portions alongside the propeller, there being a substantial portion of the tunnel ahead of the propeller, and flow control means across the tunnel ahead of the propeller for causing the propeller to operate fully immersed at hull speeds corresponding to the displacement mode of operation and to operate semi-submerged at planing speeds.

Claim 29

A propulsion system according to claim 25 wherein the flow control means comprises hydrofoil elements ahead of the propeller at approximately the level of the underside of the propeller hub.

Claim 30

A propulsion system according to claim 26 including other hydrofoil elements, at least one of which is mounted closely ahead of the propeller and another aft of the propeller.

Claim 31

A propulsion system according to claim 27 wherein the hydrofoil elements closely ahead of the propeller and aft of the propeller have surface areas greater than the surface areas of the hydrofoil elements of the other flow control means ahead of the propeller.

Claim 32

A propulsion system according to claim 25 wherein the tunnel has a generally semi-circular configuration in the region of the propeller, and a plurality of flow control elements extending across the bottom of the tunnel, said elements being disposed at spaced intervals along said tunnel, the propeller being located in one of the spaces between said flow control elements.

Claim 33

A propulsion system according to claim 29 wherein there are a plurality of flow control hydrofoil elements ahead of the propeller and at least one hydrofoil element aft of the propeller.