OUTBOARD BOAT PROPULSION INSTALLATION

Abstract: Two centrifugal pump and paddle boat propulsion devices (2) are mounted in astern outboard positions on two swingable vanes (3), respectively, projecting aft of a boat hull (1), spaced athawrtships of the hull (1) and swingable from positions inclined rearwardly and downwardly from the hull transom into upwardly and rearwardly inclined positions in which the propulsion devices (2) and rudders (21) behind them are retracted above the level of the bottom of the boat hull (1).

Description: Description Outboard Boat Propulsion Installation Technical Field The present invention relates to a boat propulsion installation and particularly to such an installation of the astern outboard type. Bac ground Art A boat propulsion device of the type used for the present invention is disclosed in applicant's U.S. Patent No. 4,171,675, issued October 23, 1979. The boat propulsion device of that patent is a combination centrifugal pump and paddle propulsion system. Two pump and paddle units are mounted in wells at opposite sides of the boat hull located amidships. The rotors of the units are driven by shafts extending transversely of the hull through the hull sides. The wells receiving the propulsion units are located immediately aft of sponsons projecting laterally from the forward portion of the hull so as to form a stepped bottom generally centrally of the hull fore and aft. Such hull must be specially designed to accommodate the pump and paddle propulsion devices in the manner described. Disclosure of the Invention In accordance with the present invention, twin centrifugal pump and paddle propulsion devices are mounted, respectively, on swingable vanes attached to the bottom of a hull transom so that the propulsion units can be adjusted elevationally by swinging of the vanes about a transverse axis and such vanes can even be swung upward far enough to retract the impeller vanes above the bottom of the boat. The devices can be driven by hydraulic motors supplied with fluid by hydraulic pumps located within the hull of the boat and powered by an engine also housed in the boat hull. Rudders can be mounted on the respective vanes located aft of the propulsion devices. The angle of the trimming vanes relative to the hull can be adjusted by hydraulic jacks connected between such vanes and the boat hull. Such a centrifugal pump and paddle boat propulsion installation can be applied to a conventional boat hull such as a runabout or cruiser having a hull of the planing V-bottom type. Because the propulsion device can be mounted on a conventional hull, it can replace a previous type of propulsion device. The power plant can be located in astern outboard fashion so that it can be mounted conveniently and be readily accessible for installation and servicing. Since, in the preferred embodiment, the centrifugal pump and paddle propulsion device is driven hydraulically, direct shaft connections are not required, thus eliminating problems of sealing around a shaft projecting through the hull. The centrifugal pump and paddle propulsion device can be m'oved elevationally to minimize drag while avoiding cavitation and can be raised to locate the propulsion device clear of the bottom of the boat so as to enable the boat to travel ' through shallow water or even to be beached without injuring the paddles of the propulsion device. When mounted in an astern outboard position, the device can be arranged to project a hydraulic jet having a substantially downward component to assist in trimming the boat with its bow down to facilitate planing even at low speeds. Control apparatus can be provided so as to enable the units of twin propulsion devices to be driven at relatively different speeds, or even in different directions, to provide dynamic steering. Directional control of the boat can be improved by locating conventional rudders in the slipstreams of two twin propulsion devices, respectively, so as to enhance the steering eff ctiveness of such rudders. Brief Description of the Drawings Figure 1 is a side elevation of a runabout boat having an astern outboard centrifugal pump and paddle propulsion device installation according to the present invention, parts being broken away, and Figure 2 is a plan of such boat with parts broken away; Figure 3 is an enlarged side elevation of the stern portion of a boat such as shown in Figures 1 and 2 on which a centrifugal pump and paddle propulsion device is mounted; and Figure 4 is a similar elevation showing parts in different positions; Figure 5 is a stern elevation of the boat showing the centrifugal pump end paddle propulsion devices mounted thereon, the right propulsion device being shown in vertical section; Figure 6 is a top plan of the aft portion of the boat hull with the centrifugal pump and paddle propulsion devices mounted thereon, the right propulsion device being. shown in horizontal section; ' Figure 7 is a top perspective of a fragment of a boat hull showing a centrifugal pump and paddle propulsion device mounted thereon, parts of the propulsion device being broken away. Best Modes of Carrying Out the Invention The boat propulsion installation of the present invention is particularly well adapted to boats such as open runabouts or cruisers having hulls of the. planing type such as V-bottom hulls. Such boats usually have a speed- in excess of 15 knots, typically 25 to 35 knots. When such-a boat is operating at low speeds, such as under 8 knots, its bow usually is elevated and its stern is depressed. When such a hull is planing it is substantially horizontal. At times, particularly if the boat is heavily • loaded and especially if such load is largely concentrated at the stern, it may be difficult to alter the attitude of the hull from a bow high—stern down attitude to a substantially horizontal attitude. Such transition from a stern low position to a substantially horizontal position can be facilitated by providing trimming vanes on the stern of the hull which usually are pivoted about their leading edges. Such vanes can be swung downward from a generally horizontal position into an upwardly and forwardly inclined position in which position movement of the vanes through the water will produce an upward thrust tending to pitch the bow downward. While a single such trimming vane can be utilized extending continuously athwartships of the hull stern, usually a pair of such trimming vanes is provided, the components of which are spaced transversely of the hull and which components can be angularly adjusted independently so as to compensate for nonuniform loading transversely of the hull. To propel the hull 1 two stern outboard propulsion units 2 are mounted respectively on trimming vanes 3 located adjacent to opposite sides of. the hull, as shown in Figures 2 and 5. The forward edges of such vanes are secured by pivots 4 to the lower portion of the hull transom. Each hull propulsion device 2 is preferably of the centrifugal pump and paddle type disclosed in Thompson U.S. Patent No. 4,171,675. Each device includes a housing 5 in which is rotatively mounted a rotor including radial vanes 6 spaced circumferentially and projecting outward from a hub 7. Such vanes extend between parallel shroud plates 8 and 9, the outer diameters of which may be sufficiently large so that their peripheries are substantially flush with-the outer edges of the blades 6. The rotor hub 7 supports the rotor composed of blades 6, hub 7 and shroud disks 8 and 9 on the shaft 10 of a hydraulic motor 11. Each trimming vane 3 has a central aperture in it of a size to receive therethrough the lower periphery of a propulsion device rotor. The hydraulic motor 11 is mounted on a vane alongside the aperture in such vane in a position to support the lower portion of the propulsion device rotor projecting downward through such vane aperture, as shown in Figure 5. Hydraulic liquid under pressure is supplied to each hydraulic motor 11 through flexible hoses 12 connected to a hydraulic liquid supply pump 13 mounted inboard of the hull 1 , as shown in Figure 1. Such pump is driven by an internal combustion engine 14, as also shown in Figure 1. The hoses 12 connecting the pump 13 and motor 11 pass through a control valve mechanism 15 for controlling the flow of liquid from the pump 13 to the motor 11 and, consequently, the speed of such motor and the propulsion impeller which it drives. Preferably, the propulsion devices are arranged with their hydraulic driving motors 11 on the outboard side of the housings 5, as shown in Figures 5 and 6. Water can be supplied from the exterior of the propulsion device through an elbow duct 16 having a downwardly facing aperture protected from intake 'of debris by a grill 17. The other end of the elbow duct opens through a central aperture in housing 5 arranged substantially coaxiaUy with the propulsion device rotor. Passage of water through the duct 16 can be controlled by a butterfly type of valve 18 located adjacent to the intake aperture of housing 5. Such valve can be turned on its axis between open and closed positions by a valve actuator 19. ' To provide very effective normal directional control for the boat, rudders 21 can be mounted on the rear portions of the trimming vanes 3 substantially in line fore-and-aft with the rotos of the propulsion devices so as to be located in the slipstream of water discharged by such devices. Such rudders can be mounted on the lower ends of rudder posts 22 mounted rotatively in the vanes. The rudder posts 22 can be turned to swing the rudders 21 by tiller arms 23 mounted on the upper ends of the rudder posts. Steering turning of the rudders can be coordinated by connecting the tiller arms by a tie rod 24. The tie rod 24 can be reciprocated, or one or the other of the tiller arms 23 can be swung, by mechanism not shown to turn the rudder posts 22 and swing the rudders 21 for steering purposes. In operation, the hydraulic motors 11 will be driven to rotate the rotors of the propulsion devices. If the water flow control valves 18 are open and the intake ends of the elbow ducts 16 are at or below water level, the centrifugal pumping action of the impeller vanes 6 will draw water through the elbow ducts into the housings 5 and eject such water through the open bottoms of the housings to produce an upward force on the vanes 3. Such force will tend to elevate the stern of the boat and depress its bow to facilitate planing of the boat hull. As the stern of the hull rises, the intake ends of the elbows 16 would tend to be lifted out of the water, after which change little or no water would be pumped by the propulsion device impelle'rs into the housings 5. Instead, the propulsion of the boat would be'effected entirely by the paddle action on the water in which the boat floats of the outer ends of impeller vanes 6 traveling through the water beneath the vanes 3, as shown in Figure 4. At that time, the control 19 may be actuated to turn the butterfly valve 18 into closed position so as to block further supply of water to the propulsion unit through the central housing aperture. In order to make sure that the propulsion devices are sufficiently low in the water so that the tips of impeller vanes 6 engage the water positively without the occurrence of cavitation, hydraulic jacks 20 may be actuated to extend thei lengths so as- to swing the vanes 3 supporting the propulsion devices downward such as to the position shown in full lines in Figure 4. With the trimming vanes in such positions, the lower portion of the rotor periphery and the rudder 21 will project a substantial distance below the bottom of the boat. In such positions, the bottoms of the rotor peripheries and the rudders would be vulnerable to strike obstructions over which the hull 1 might skim. Consequently, it is desirable for the vanes 3 to be in as high a position as possible commensurate with efficiency of propulsion by the propulsion units and proper trimming of the boat hull. If the boat is traveling in very shallow water or the boat hull should ride onto an obstruction or is beached, the hydraulic jacks 20 can be shortened to swing the vanes 3 into the upwardly inclined broken line positions shown in Figure 4 in which the lower ' portions of the peripheries of the impellers and the bottoms of the rudders 21 are raised above the bottom of the hull 1. A typical range of possible adjustment of the vanes relative to the transom of the boat hull 1 is 40 degrees. If the transom is substantially vertical when the boat is cruising, the angle between the transom and the vanes 3 ' could be approximately 90 degrees. In order to avoid or minimize cavitation before the boat i's up to planing speed, the trimming vanes may be swung dov/nward about their axes 4 to positions as much as an angle of 110 degrees to the transom. Alternatively, in the most upward-retracted position, the vanes 3 may be raised to angles of approximately 70 degrees to the hull transom. Such angles of trimming vane adjustment are particularly applicable when the trimming vane pivot axis 4 is substantially at the bottom of the transom. In such instance, during planing of the hull the bottoms of the vanes 3 v/ould extend aft substantially in aligned continuation of the bottom of the hull. The size of the propulsion units-would be matched to the size and speed of the boat. For a boat 25 feet in length, for example, the diameter of the impeller rotor would be approximately 20 inches (50.8 cm) and the diameter of the passage through the elbow 16 would be about 10 inches (25.4 cm). The speed of the rotor at cruising speed would probably be within the range of 2,000 to 3,000 " rpm, and the speed of the hydraulic pump 13 would probably be in the range of 700 to 800 rpm. By utilizing a hydraulic pump 13 to supply power to the hydraulic motors 11 of boat propulsion units, the direction of rotation of such pump could be reversed to reverse the hydraulic motors and the direction of rotation of the propulsion device impellers for reversing the travel of the boat. By manipulating the controls 15 for the hydraulic liquid supplied to one or both of the hydraulic motors 11 , the impellers of the propulsion devices could be driven at different speeds to effect dynamic steering of the hull. Actually, one of the motors 11 could be stopped and the other driven forward or reverse to effect maximum dynamic steering control. While, as discussed above, the installation of the propulsion units according to the present invention is particularly well adapted to propel boats having planing hulls, such installations can be used effectively for driving boats having displacement hulls. For such installations, it may be desirable for the trimming jacks 20 to set the vanes 3 on which the propulsion devices are mounted, inclined somewhat downward and rearward at cruising speed rather than being substantially horizontal.

Claims: Claims 1. In a boat having a hull and a trimming vane mounted on the hull transom for swinging about a generally horizontal axis, the improvement comprising a stern outboard propulsion device mounted on and carried by the trimming vane, and means connected between the trimming vane and the boat hull for swinging the trimming vane for adjusting said propulsion device elevationally relative to the boat hull by swinging of the trimming vane. 2. In the boat defined in claim 1 , a second trimming vane mounted on the hull transom for swinging about a generally horizontal axis and spaced athwartships of the boat relative to the first trimming vane, and a second propulsion device mounted on and carried by said second trimming vane, and means connected between the second trimming vane and the boat hull for swinging the second trimming vane for adjusting said second propulsion device elevationally relative to the boat hull by swinging of said second trimming vane. 3. In the boat defined in claim 1, the propulsion device including an impeller and a hydraulic motor mounted on the trimming vane and drivingly connected to said impeller, hydraulic pump means mounted inboard of the boat hull and connected to said hydraulic motor for supplying liquid thereto, and flexible conduit means connecting said hydraulic pump means and said hydraulic motor for supplying liquid thereto in various positions of the trimming vane swung relative to the boat hull. 4. In the boat defined in claim 1, the propulsion device including a housing, an impeller received in said housing,' said housing having an opening in a side thereof axially of said impeller, and an elbow having one end connected to said housing opening and its other end facing downward for supplying water to said housing. 5. In the boat defined in claim 4, valve means in the elbow operable to constrict the passage of water through the elbow to the housing opening. 6. In the boat defined in claim 1, the propulsion device being operable to produce a current of water rearwardly from it, and a rudder mounted on the trimming vane behind such propulsion device in a position for engagement by the current of water produced by the propulsion device irrespective of the position of the trimming vane swung relative to the boat hull. 7. A boat comprising a hull, a trimming vane mounted on the hull transom for swinging about a generally horizontal axis, a stern outboard- propulsion device mounted on and carried by said trimming vane at a location aft of the hull transom, a hydraulic motor supported from said trimming vane and connected to said propulsion device for driving it, hydraulic pump means located inboard of said hull, power means located inboard of said hull and connected to said hydraulic pump means for driving it, and flexible conduit means connecting said hydraulic pump means and said hydraulic motor for supplying liquid thereto in various positions of said trimming vane swung relative to the boat hull. 8. The boat defined in claim 7 , including a second trimming vane mounted on the hull transom for swinging about a generally horizontal axis and spaced athwartships of the boat relative to the first trimming vane, and a second stern outboard propulsion device mounted on and carried by said second trimming vane, a second hydraulic motor supported from said second vane and connected to said " second propulsion device for driving it, and control means for the hydraulic pump means for supplying different amounts of hydraulic liquid to the two hydraulic motors of the respective propulsion devices for producing different degrees of propulsion by the two propulsion devices, respectively. 9. The boat defined in claim 8, including two rudders mounted on the trimming vanes behind the two propulsion devices, respectively, in positions for engagement by the currents of water produced by the propulsion devices irrespective of the positions of the trimming vanes swung relative to the boat hull. 10. A boat propulsion device comprising a housing, an impeller received in said housing and rotatable about a generally horizontal athwartships axis, said housing having an opening in one side thereof axially of said impeller, an elbow having one end connected to. said housing opening and its other end facing downward for supplying water to said housing, said impeller having a recess opposite said elbow connection of an axial depth approximately one-half of- the axial width of said impeller, a drive shaft mounting said impeller, and bearing means for said drive shaft extending into said recess approximately to the axis center of said rotor. 11. A boat propulsion device comprising a housing, an impeller received in said housing and rotatable about a generally horizontal athwartships axis, said housing having an opening in one side thereof- axially of said impeller, an elbow having one end connected to said housing opening and its other end facing downward for supplying water to said housing, and valve means in said elbow operable to constrict the passage of water through said elbow to said housing opening.

Inventors: THOMPSON MERALL L, THOMPSON, MERALL, L.
Applicants: THOMPSON MARINE PROPULSION SYS, THOMPSON MARINE PROPULSION SYSTEMS, INC.
Application year: 1986
Main classification: B63H5
IPC codes: B63B39, B63H5