Technical Field The present invention relates to an adjustable marine propulsion system and, more particularly, to a propulsion system including a plurality of structural frames and associated hydraulic rams capable of providing omni-directional horizontal thrust capabilities.

Background Art A common modern boat propulsion system attaches to the back of a boat (transom) and holds a propeller in a specific position in relationship to the water in which it operates. Common high speed boat propulsion systems hold this propeller approximately half in and half out of the water. In other words, at speed, the center of the propeller, or propeller hub, is close to the surface of the water. This type of operating system is known as a'surface drive', or a'surface piercing drive'. It is also acknowledged as delivering the greatest high-speed horsepower efficiency as compared to submerged propeller systems and waterjet propulsion systems.

In an effort to increase horsepower efficiency and boat speed even further, several inventors have sought to make their drives adjustable in one or more planes.

One such system is disclosed in U. S. Patent 4,964,823 issued to Newman et al The Newman et al system allows propeller elevation and trim adjustments, but is flawed in several significant areas: (1) The boat engine must be mounted in a transverse manner. Conventional type boat engines are normally greater in length than width.

Due to the width of the complete package, rigging a boat in this fashion would not allow the use of multiple engines and drives in most common applications. Multi- engine boats are more the rule than the exception when it comes to boats measuring 25-30 feet in length or more. There is no discussion in Newman et al. regarding a transmission or clutch of any kind, and the same is not found in the patent drawings.

The inclusion of such necessary equipment, if situated between the engine and drive, would exacerbate the problem even more; (2) The means of engine power transmission in Newman et al. from the drive sprocket to the driven sprocket is by way of a chain or belt drive. One problem which arises is that a belt or chain is constantly wearing. This necessitates a chain or belt adjustment; however in Newman et al. no provision is made for such an adjustment. A chain used in this fashion must be constantly lubricated and kept dry, this is especially true in a salt water environment. A belt drive must be kept dry as well.

When a chain is replaced a removable master-link is, as a rule, present to facilitate the process. However, when a belt needs replacing, due to the endless nature of belts, major disassembly of the unit will be required. In operation both chain and belt drives are horsepower inefficient and noisy.

The inboard end of the rigid lift arm of Newman et al. must be mounted concentrically to the engine crankshaft. This is the lowest (in relationship to the boat bottom) inboard mechanical attach point of the rigid lift arm. The distance between the propeller and the fin protruding from the lower gear case (these are the main load application points) and the rigid lift arm inboard attach point could be excessive.

Lateral load applications in particular place inboard rigid lift arm support in high stress. The apparently narrow mounting points of the rigid lift arm exaggerate the problem. To compound the issue further, the combination of hull deadrise and the width of the engine-drive package dictates higher than normal (in relationship to the boat bottom) engine-drive installations. All of above mentioned attach points and components could be built stronger than would normally be seen, however, there would be a penalty in weight, and cost.

U. S. Pat. 4,645,463 issued to H. M. Arneson discloses a simple surface piercing drive arrangement with apparent trim and elevation controls. The Arneson propeller can be raised and lowered to alter elevation; however, this adjustment simultaneously affects propeller trim. Inversely, any trim adjustments-even slight adjustments-will radically effect propeller elevation. Accurate propeller elevation settings, as well as precise trim settings, are vital to maximum horsepower efficiency.

Therefore, the chance of realizing optimum trim and elevation settings simultaneously with the Arneson arrangement is remote.

In steering, Arneson's engine power is transferred via a universal joint to the propeller shaft and this factor seriously limits maximum steering deflection angles.

Moreover, it also makes a conventional transmission-clutch assembly mandatory. The lower stabilizing fin of Arneson is situated in a position directly preceding the propeller. At high speed, the diverging sides of the fin create a low water pressure area immediately following the fin. During operation at high speed, air is drawn into this low pressure area, or the area remains a vacuum-void of both water and air.

The highest traction area of the propeller then runs into this never ending void. In turn, this void upsets propeller traction, and ultimately, horsepower efficiency is compromised.

Additionally, when the pilot is altering the direction of the vessel, this fin generates a considerable amount of water turbulence that detracts from maximum possible propeller thrust.

Summary of the Invention The present invention relates to an adjustable marine propulsion system with omni-directional horizontal thrust capabilities. The system is capable of independent- ly adjusting the elevation (propeller positioning vertically"up"and"down"), trim (propeller thrust line altered diagonally as viewed from a right angle to the boat's centerline), and directional control (steering toward port or starboard).

In a preferred embodiment, the adjustable propulsion system comprises a plurality of generally tubular"A"frames pivotally attached between the transom of a boat and an upper gearcase. These frames allow the upper gearcase to be raised and lowered in an arc-type swing, thus altering the propeller elevation. The vertical movement is controlled generally by hydraulic rams disposed in a diagonal relationship with the"A"frames. The"A"frames also provide for trim control, as driven by a different hydraulic ram. A lower gearcase is rotationally fixed to the upper gearcase and is coupled to the rudder assembly. A hydraulically-controlled

steering motor is coupled to the lower gearcase and provides port and starboard steering capability.

These and further embodiments of the present invention will become apparent during the course of the following discussion and by reference to the accompanying drawings.

Brief Description of the Drawings Referring now to the drawings, where like numerals represent like parts in several views: Figure 1 contains a rear/right side/overhead perspective view example of the inventive marine propulsion system singularly mounted to the transom of a conventional fragmented'V'bottom vessel; Figure 2 is a sectional side elevation view of the system of Figure 1, taken along line 2-2; Figure 3 is an exploded rear/right side/overhead perspective view of the invention's main steering members exclusively-invention's propeller included to aid in view orientation; Figure 4 is a bottom plan view of example angles of the invention's propeller; Figure 5 is a fragmented view showing the invention's serpentine-like steering chain course from a bottom plan view having the lower gearcase; spray apron and chain case removed; Figure 6 shows the inventive drive in a raised position from a side elevation view; Figure 7 shows the invention drive in a lowered position from a side elevation view; Figure 8 shows the invention drive in a trimmed out position from a side elevation view; Figure 9 shows the invention drive in a trimmed in position from a side elevation view;

Figure 10 contains a rear/right side/overhead perspective view of a fragmented vessel hull including a multi engine-invention drive arrangement of the present invention-complete with installed hydrofoils; Figure 11 is an overhead plan view of two invention drives mounted in a close proximity propeller'V Drive installation-the vessel hull being fragmented; Figure 12 is an overhead plan view of two invention drives mounted in a splayed propeller'V Drive installation-the vessel hull being fragmented; Figure 13 shows a rear/right side/overhead perspective view of the invention's disengageable steering box coordination system in a partially free form sectional view -system is removed from its surrounding parts; Figure 14 shows a rear/right side/overhead perspective view of the invention's engaged steering tie bar-system is removed from its surrounding parts; Figure 15 shows a rear/right side/overhead perspective view of the invention's disengaged steering tie bar-system is removed from its surrounding parts; Figure 16 shows a primarily sectional rear view of the invention's disengage- able water transfer lock pin in the locked position-the plane of the section being indicated by line 16 in Fig. 14. and, system is removed from its surrounding parts; Figure 17 shows a primarily sectional rear view of the invention's disengage- able water transfer lock pin in the unlocked position-the plane of the section being indicated by line 16 in Fig. 14, and, system is removed from its surrounding parts; Figure 18 shows example angle top plan views-some fragmented-of the invention's disengageable tie bar coordination system range of motion while lock pins are engaged-system is removed from its surrounding parts; Figure 19 shows the invention's omni-directional dual drive control panel in a rear/left side/overhead perspective, partially free-form sectional, partially exploded view; Figure 20 shows the invention's omni-directional dual drive control panel in an overhead plan, partially phantom view; Figure 21 shows the hydraulic actuation systems for the rudder-hydrofoil in a primarily sectional, side elevation view-the plane of the section being indicated by line 2 in Fig. 1;

Figure 22 shows a rear/right side/overhead perspective view of the invention's rudder-hydroleron removed from its surrounding parts; Figure 23 shows a rear/right side/overhead perspective view of the invention's rudder-hydrofoil removed from its surrounding parts; Figure 24 shows a primarily sectional, side elevation view of a multiple lower vertical shaft and gear example version of the invention-the plane of the section being indicated by line 2 in Fig. 1; Figure 25 shows a lower/front/right side perspective, partial assembly view of the invention's propeller in the preferred embodiment tractor type position; and Figure 26 shows a primarily sectional, side elevation view of a multiple lower vertical shaft and gear example version of the invention-the plane of the section being indicated by line 2 in Fig. 1 Detailed Description of the Preferred Embodiment Figure 1, illustrates, in a perspective view, the main assemblies of the invention-an upper gearcase 82 and its assemblies, a lower gearcase 33 and its assemblies, a propeller 44, a spray apron 61, and a steering apparatus 62 are positioned and supported generally to the rear of a transom 69 of a boat or vessel 86.

These assemblies are held in place by a series of arms or welded type frames. A drive shaft 9 is attached to the outside of transom 69 of boat 86 and protrudes aft as much as a few meters.

In accordance with the present invention, three fabricated framework arrangements are needed for each drive: an upper'A'frame 78; a lower'H'frame 31; and a vertical'A'frame 84. In a preferred embodiment, frames 78,31 and 84 comprise welded arrangements of stainless steel tubing. The splayed, or proximal ends, of upper'A'frame 78 and lower'H'frame 31 are pivotally attached to transom brackets 71 mounted generally to transom 69 of vessel 86. The'head', or distal end of upper'A'frame 78 is attached pivotally to the'head', or distal end, of vertical'A'frame 84. Vertical'A'frame 84 is usually substantially shorter in length and narrower in width than either upper'A'frame 78, or lower'H'frame 31. Upper 'A'frame 78 is usually approximately twice the strength of vertical'A'frame 84.

Lower'H'frame 31 is usually approximately twice the strength of upper'A'frame 78. All frames are generally of a fixed length and width construction.

By way of transom brackets 71, upper'A'frame 78 and lower'H'frame 31 are pivotally fastened horizontally to the outside of transom 69 in a generally rearward facing direction. Their spatial orientation is usually'flat'. i. e., they are generally laid down flat, or parallel, with the water.

Both vertical'A'frame 84 and lower'H'frame 31 pivotally attach to, and thus define the location of, upper gearcase 82. In a preferred embodiment, upper gearcase 82 comprises an aluminum casting. The splayed, or proximal ends of vertical'A'frame 84 attach pivotally to the generally front/upper area of upper gearcase 82. The pivot line of vertical'A'frame 84 will usually be at a right angle to the direction of vessel travel.

Upper'A'frame 78 is used to define the location of the'head', or distal end, of vertical'A'frame 84. That is, vertical'A'frame 84 and upper'A'frame 78 meet'head'to'head', and are connected in a pivotal manner. The position of vertical <BR> <BR> <BR> <BR> 'A'frame 84 and upper gearcase 82 is further controlled by a variable length hydraulic trim ram device 77. As shown in Figure 1, the proximal end of trim ram 77 is pivotally attached to a position generally to the upper/rear area of the upper gearcase 82. The distal end of trim ram 77 is pivotally attached to the'head', or distal end area of vertical'A'frame 84.

Associated with transom 69 are a pair of adjustable length hydraulic, or possibly air type, elevation rams 18. These elevation rams 18 will usually be paired, but a single elevation ram, or more than two elevation rams, could be used when necessary, and all such arrangements are considered to fall within the spirit and scope of the present invention. These elevation rams 18 are pivotally attached diagonally, as shown in Figure 1, from a point relatively high on transom 69, to a point as rearward as is practical on lower'H'frame 31.

A transom housing 73 (see Figure 2) is water resistant and is bolted or similarly fixed through an aperture in transom 69. Transom housing 73 is held in place at the distal end pivotally with an arm or arms (not shown) extending forward from upper gearcase 82. The proximal end of water resistant housing 73 is centered

within the transom housing and floats fore and aft on a low friction spherical shaped centering donut. Water is kept out of the water resistant housing 73 through the use of gimbaled ball and seal type arrangements (not shown), or an upper gearcase boot 80 and a transom housing boot 75. In a preferred embodiment, these generally pleated type boots may be fabricated from a rubber type compound.

Lower gearcase 33, referred to in Figure 1 and clearly depicted in Figure 2 may comprise, in a preferred embodiment, an aluminum casting. As shown, lower gearcase 33 functions to hold propeller 44 in position. In the illustrated arrangement, a spray apron 61 is positioned over propeller 44. The apron is an additional feature and does not necessarily need to be used when practicing the present invention.

Upper gearcase 82, as shown in Figure 1, functions to hold a steering box 62, in a preferred embodiment a hydraulic type motor, in position. A chain-case 6 (see FIGs. 2 and 3) is fastened to the lower side of upper gearcase 82.

A properly faired water screw, or propeller 44, is fixed to the leading end of a propeller shaft 46. A replaceable rudder 53 can be conveniently attached to the trailing end of lower gearcase 33.

Figure 2 illustrates the aft end of the inventive drive in a generally sectional, side elevation view. As shown, the main drive parts of the invention-upper gearcase 82 and its assemblies, lower gearcase 33 and its assemblies, propeller 44, spray apron 61, and steering motor 64-are positioned and supported generally to the rear of transom 69 of boat 86. Upper'A'frame 78, lower'H'frame 31 and vertical'A' frame 84 are also shown in this view. As mentioned above, vertical'A'frame 84 is usually substantially shorter in length and narrower in width than either upper'A' frame 78 or lower'H'frame 31. Upper'A'frame 78 and lower'H'frame 31 attach to points that are generally equidistant from each other. Upper'A'frame 78 and lower'H'frame 31 are of generally equal length and, in operation, when viewed from a side elevation, constitute a parallelogram. On occasion, it may be advanta- geous to have unequal length arms, and therefore, a side elevation view of the arms in operation would not be that of a parallelogram.

As shown in Figure 2, upper gearcase 82 holds an upper gearcase input shaft 81, complete with related bearings and seals. Between transom housing input shaft

76 and upper gearcase input shaft 81 is a conventional style drive-shaft 9 complete with self centering constant velocity type universal joints, and a splined slip joint.

Drive-shaft assembly 9 is enclosed in a water resistant housing 10. Water resistant housing 10 is pivotally held in place at its distal end with an arm or arms (not shown) extending forward from upper gearcase 82. The proximate end of water resistant housing 10 is centered within transom housing 73 and floats fore and aft on a low friction spherical shaped centering donut. Water is kept out of upper gearcase input shaft 81 and water resistant housing 10 through the use of a gimbaled ball and seal type arrangement (not shown), or an upper gearcase boot 80. This generally pleated type boot is likely fabricated from a rubber type compound.

A lower gearcase spindle 34, which in a preferred embodiment comprises stainless steel machining, is used to hold the upper half of a vertical drive-shaft/gear 83 in position. Also held by lower gearcase spindle 34 is the upper vertical drive- shaft/gear's related bearings, and, if needed, oil or grease seals. The upper vertical drive-shaft and the upper vertical bevel gear are likely a one piece machining.

A spindle bushing 59 slips over lower gearcase spindle 34 with a close- however, not interference-machine fit and is held in place by a spindle lock ring 60.

In a preferred embodiment, spindle bushing 59 comprises a silicon-bronze type machining. Spindle bushing 59 functions to hold the necessary water sealing devices, preferably rubber type'O'rings or a like type seal 36. As shown, lower gearcase spindle 34, complete with related lower gearcase assembly, is bolted to the bottom of upper gearcase 82, where chain case 6 is also fastened to the lower side of upper gearcase 82.

All hydraulically controlled steering and trim control operations are powered by an engine driven pump or pumps (not shown). Hydraulic forces are transmitted through flexible hoses and rigid pipes (not shown).

Ideally, when the drive system of the present invention is adjusted to its highest mechanically stressed operating position, the diagonal compressive load path up through elevation rams 18 would begin generally from the center of the lower'H' frame/gearcase attach point. From there it would continue in a straight line up

through the elevation ram's lower attach point, and on to the elevation ram's transom attach point.

Referring to Figure 2, transom housing 73 is bolted or similarly fixed through an aperture in transom 69. In relation to the transom proper, transom housing 73 is fixed at a predetermined angle through the use of transom housing angle adapters 74.

Transom housing 73 holds transom housing input shaft 76 complete with related bearings and seals. Transom housing input shaft 76 may be connected directly to the engine crank shaft (not shown) without extraneous transmissions. The inclusion of a clutch or a like coupling/uncoupling type devise (not shown) and a spline type slip joint (not shown) would be advantageous, however not mandatory.

Figure 3 contains an exploded view of the parts involved in the steering operation of the inventive drive. As mentioned above, lower gearcase spindle 34 is likely a stainless steel machining and is bolted to the bottom side of upper gearcase 82 (not shown). Spindle bushing 59, likely a silicon-bronze type machining, slips over lower gearcase spindle 34 with a close-however not interference-machine fit and is held in place by spindle lock ring 60. Spindle bushing 59 holds the necessary water sealing devices-probably rubber type'O'rings or a like type seal 36.

As shown in Figure 4, propeller 44 has the ability, in accordance with the drive system of the present invention, to rotate either clockwise or counterclockwise an unlimited number of times. Figure 4 shows, in phantom, graphic examples of propeller 44 in various rotational positions.

Figure 5 contains a bottom plan view of the drive system (with lower gearcase 33 removed) to illustrate the serpentine-like path of roller chain 51. Referring to Figure 5, a relatively small diameter drive gear (not shown) or sprocket 13 is attached to the lower end of the steering box 62 output shaft. A driven (large diameter) steering sprocket 12 is situated on the same horizontal plane as drive (small diameter) sprocket 13. Roller type chain 51 courses, as shown, around sprockets 12 and 13. This chain drive example may incorporate an additional idler sprocket 29 that would increase wrap on the driver sprocket 13 and help to maintain proper tension on roller chain 51.

Figure 6 contains a side view of the drive of the present invention in an elevated position. In this view, upper'A'frame 78 and lower'H'frame 31 comprise a parallelogram. Diagonally mounted hydraulic elevation ram 18 is shown in its retracted position so that the main drive unit is drawn up in a vertical arc.

In contrast, Figure 7 shows the drive of the present invention in an lowered position. In this view, upper'A'frame 78 and lower'H'frame 31 comprise a parallelogram angled in the opposite direction from that as shown in Figure 6. That is, in Figure 6, the parallelogram is angled upward, and in Figure 7, the parallelo- gram is angled downward. As shown in Figure 7, diagonally mounted hydraulic elevation ram 18 has been extended, and the main drive unit is pushed down in a swinging arc.

Figure 8 shows the drive in a trimmed out position, where diagonally mounted hydraulic trim ram 77 has been retracted as shown, and the main drive unit is drawn up and back in a vertical arc. In contrast, Figure 9 contains a view of the drive of the present invention with trim ram 77 in its extended position, with the main drive unit pushed down and inward (as is obvious from the position of propeller 44 in Figure 8 vis-a-vis the position in Figure 9).

An alternative embodiment of the present invention, utilizing a twin engine arrangement, is illustrated in Figure 10. The embodiment as shown utilizes the pivotal frames and hydraulic rams as discussed above. Figure 10 further illustrates the utilization of hydrofoils 54.

As shown in Figure 11, a twin engine arrangement of the present invention utilizes a pair of engines 21 positioned in a fairly wide manner. Inversely, the associated drive units) are situated fairly close to one another. This top view graphically shows the misalignment possible with the inventive drives as positioned over vessel bottom 85.

In the twin engine embodiment of Figure 12, the inventive drives are positioned in a fairly wide manner and, inversely, the associated engines 21 are situated fairly close together. This top view also graphically shows the misalignment possible with the inventive drives as positioned over vessel bottom 85.

Figure 13 illustrates steering boxes 64, drive-shaft with slip joint 11, and drive-shaft boots 65. The 90 degree angle gear type transmission 88 and drive-shaft engagement control device 63 are in a partially free form sectional view. Convention- al universal joints (non constant velocity, and not shown) are enclosed under the drive-shaft boots.

The 90 degree angle transmissions 88 are generally attached to the top end of the steering boxes 64. The generally vertical steering shaft would extend past the end of the steering box 64 housing, and into the housing of 90 degree transmission 88.

There, it would be fixed to a 90 degree bevel gear (not shown). Also within this housing would be a second 90 degree bevel gear attached to the end of the steering drive-shaft. These two 90 degree bevel gears would mesh together in order to transmit steering torque from the output shaft of steering box 64 to steering drive- shaft 62. Steering torque would then be rotationally transmitted down drive-shaft 62, through the drive-shaft engagement control device, and into the opposing 90 degree angle transmission 88' (x). The opposing 90 degree angle transmission is generally identical to the one previously described.

The drive-shaft engagement control device 63 is a device used to either transmit rotational loads from one end of the drive-shaft to the other, or to freewheel.

In the freewheel, or unlocked position, drive-shaft engagement control device 63 allows independent drive-shaft rotation from one end of drive-shaft 62 to the other.

When drive-shaft engagement control device 63 is in the locked, or engaged position, both drives will remain in perfect parallel alignment. In addition, the steering force from one steering box 64 will augment the other. When drive-shaft engagement control device 63 is in the disengaged position, each steering box 64 and hence, each drive-can rotate independently of the other.

Drive-shaft engagement control device 63 is likely hydraulically operated. Its command is from either the pilot, or an on-board computer (not shown). By way of arc-shaped arrows, Figure 13 also shows exemplary angles attainable with drive-shaft 62.

Figure 14 contains a partial view of an assembly of the inventive drive. An upper end plate 79 vertically and pivotally locates a set of articulating arms 1.

Articulating arms 1 in turn pivotally locate an engagement pin hydraulic cylinder 19 and, therefore, the engagement pin itself. A radius plate 50 horizontally and radially locates the engagement pin's hydraulic cylinder 19, and therefore also, the engagement pin. Radius plate 50 encircles the centerline of lower gearcase 33 (not shown). Radius plate 50 is able to rotate independently of lower gearcase 33, concentrically with lower gearcase 33.

Referring to Figure 15, engagement pin receiver 20, located by spray apron 61, serves two functions: First, it serves as the target for the engagement pin and second, it serves as the upper end of the transfer tube spigot type boss. The lower end of the transfer tube spigot type boss is integral with the rudder 53. Transfer tube 7 is a short hose type transfer device. It is fixed between engagement pin receiver 20 and rudder 53. Also integral with rudder 53 is a high speed water inlet 24.

The engagement pin proper will usually serve as the low speed water inlet when the engagement pin is in the disengaged position. On occasion, it may be necessary to have an auxiliary slow speed water inlet (not shown). This auxiliary slow speed water inlet would indeed be fixed to a point on the vessel situated below the slow speed waterline of the vessel.

A tie bar 67 is permanently fixed to an area generally to the lower end of the engagement pin's hydraulic cylinder 19. Tie bar 67 is attached pivotally in both a vertical and a horizontal plane.

Engine cooling water (not shown) is carried to engine 21 via a separate flexible water transfer hose 23 (see FIGs. 16 and 17). The aft end of flexible water transfer hose 23 would generally be attached to the upper end of the engagement pin, and the forward end would generally be attached to a common sea strainer type device (not shown), or an engine cooling water intake device (not shown).

In particular, Figure 16 shows the engagement pin in a sectional view -in a lowered position. The engagement pin has entered engagement pin receiver 20.

In contrast, Figure 17 shows the engagement pin as displaced with respect to engagement pin receiver 20 (i. e., in the"disengaged"position).

Figure 18 is a top view of a tie bar 67 reaching from one drive across to another. A pair of spray aprons 61, radius plates 50, and upper end plates 79 are

also shown. The movement of end plates 79 so as to alter the position of tie bar 67 is evident from viewing FIGs. 18 (a)- (e).

Figure 19 is a partially exploded, partially sectional view of an omni- directional dual drive control panel or, electronic helm, 37 useful in controlling the drive of the present invention. A vessel shaped control handle 43 is a spring loaded semi-floating type arrangement. There are generally potentiometer drive pegs protruding from the back or bottom side of the vessel shaped control handle 43.

These potentiometer drive pegs correspond to holes located in the center of potentiometers 41. Potentiometers 41 are generally electronic units capable of sensing varying degrees of pressure. Electronic leads (see Figure 20) from potentiometers 41 carry the electronic impulses to an onboard control device-usually a computer (not shown). Control panel 37 includes a speed selection switch 42, where speed selection switch 42 is used as a means of engaging or disengaging the omni- directional dual drive control panel.

Figure 21 illustrates the workings of a rudder-hydrofoil port-work 54 and associated piston 28 in a primarily sectional view. Rudder-hydrofoil 54 is a single acting type hydraulic cylinder and as such, here is a single control port only. To keep from developing excessive pressure or vacuum, the dry side of the cylinder piston 28 must be vented to a safe atmospheric source by way of the cylinder breather 5.

Figure 22 shows an exemplary hydroleron 56, where hydroleron 56 is a simple <BR> <BR> <BR> 'L'shaped hydrofoil type device. In contrast, Figure 23 shows an exemplary hydrofoil 54, where hydrofoil 54 is a simple'T'shaped device.

Figure 24 shows a primarily sectional, side elevation view of a multiple lower vertical shaft and gear example version of the invention-the plane of the section being indicated by line 2 in Figure 1.

As shown, Figure 25 has a propeller 44 fixed in a tractor, or leading, type fashion. In this example lower gearcase 33 follows propeller 44. Spray apron 61 is bolted (or similarly fixed) to an annular boss at the top of lower gearcase 33. A rudder 53 or rudder-hydrofoil 54 is fixed to the trailing end of lower gearcase 33.

Figure 26 illustrates an alternative pusher propeller 47, in this arrangement with propeller 47 located behind its lower gearcase 48.

In operation, the present invention is a propulsion system designed for all boats. It is designed primarily for high performance, competition, or high speed military applications. However, due to its high degree of adjustability, it is compatible with generally any common type powerboat hull afloat, including powered sailboats.

The drive of the present invention is primarily applicable to in-board engine planing hull type boats.

As shown in Figure 1, the drive system of the present invention is attached to the outside of transom 69 of a boat and protrudes aft as much as a few meters.

Transom housing input shaft 76 may be connected directly to the engine crank shaft (not shown) without extraneous transmissions. The inclusion of a clutch or a like coupling/uncoupling type devise (not shown) and a spline type slip joint (not shown) would be advantageous, but not mandatory. Transom housing input shaft 76 transmits torque received from the vessel's engine 21 or transmission 68 through the transom housing 73 to drive-shaft 76, and on to upper gearcase input shaft 81. From there, upper gear case input shaft gear 81 transfers engine torque to the upper vertical shaft/gear 83. Torque is then transferred to the lower vertical shaft/gear 85 through a splined type slip joint. Propeller shaft gear 46 then receives the engine generated torque from lower vertical shaft/gear 83 and, thusly, propeller 44 is rotated.

In operation, upper'A'frame 78 and lower'H'frame 31 in effect comprise a parallelogram-when viewed from a side elevation. All upper'A'frame 78 and lower'H'frame 31 attach points are pivotal, hence, upper gearcase 82 (likely an aluminum casting), lower gearcase 33 (also likely an aluminum casting), and all related parts can move in an arc type vertical manner. This vertical movement is what lends to the inventive drive its propeller elevation control. This range of travel is best viewed in Figs. 6 and 7.

The motive power for this vertical motion is realized from the use of hydraulic cylinders or rams 18. Rams 18 are mounted in a diagonal fashion with the proximal, or cylinder end of the ram 18 pivotally fixed to a position relatively high on the

vessel transom 69, and the distal, or rod end, mounted conveniently close to the upper gearcase (x)/lower'H'frame pivotal union point.

When rams 18 are extended, propeller 44 is shifted to a lower elevation or depth within the water. Inversely, when rams 18 are retracted in length, propeller 44 is raised up to a higher elevation, or a reduction in water depth is realized.

Hydraulic trim ram or rams 77 controls trim settings. The proximal or cylinder end of the trim ram 77 is attached to the distal end of vertical'A'frame 84.

The distal or rod end of trim ram 77 is attached to the generally top aft area of upper gearcase 82. This attachment creates three more triangulated, short-arm load paths.

When trim ram 77 is extended, the drive is trimmed for bow-down operation. When trim ram 77 is retracted, the drive is trimmed for a bow-high attitude. All trim adjustments are possible at any time there is hydraulic operating pressure available -including while operating at part or full throttle. Hydraulic operating pressure is generally derived from an engine driven pump or pumps.

A second option for altering vessel trim or pith control is through the use of a rudder-hydrofoil 54 (see Figure 23) or a hydroleron 56 (see Figure 22). In effect, the hydrofoil section of the rudder-hydrofoil 54 is a vertical thrust vectoring, sub- surface wing. Rudder-hydrofoil 54 is generally pivotally attached to the trailing end of lower gearcase 33 by way of a rudder-hydrofoil clevis mount 55. Control for rudder-hydrofoil 54 is through the use of a series of tunnels and channels that travel through upper gearcase 82, lower gearcase spindle 34, spindle bushing 59, lower gearcase 33, and finally to rudder-hydrofoil cylinder 54.

Lower gearcase 33 contains the lower end of vertical drive-shaft/gear 83, complete with its bearings. Lower gearcase 33 also holds propeller shaft 46, complete with its bearings, seals, and gear, in position as well. Lower vertical shaft/gear 35 and propeller shaft gear 46 mesh together in order to transmit engine generated torque from one to the other.

The assembly consisting of lower gearcase spindle 34, upper vertical shaft/gear 83 and bearings, and spindle bushing 59 and lock ring 60 is lowered into lower gearcase 33. In doing so, upper vertical shaft/gear 83 and lower vertical shaft/gear 35 slide together by way of a splined type slip joint. Spindle bushing 59

is screwed tightly into place within lower gearcase 33. For security's sake, a chemical bonding agent or an extra fastening device (not shown) can be employed in order to insure that spindle bushing 59 does not work loose.

Lower gearcase spindle 34, complete with related lower gearcase assembly, is bolted to the bottom of upper gearcase 82. When lower gearcase spindle 34 is fastened to upper gearcase 82, the upper vertical shaft's driven gear meshes with the upper gearcase input shaft's drive gear. Lower gearcase 33, complete with related assemblies and parts-now supported by upper gearcase 82-can rotate an unlimited number of times in a clockwise and/or counterclockwise direction. Lower gearcase 33 of the inventive drive is rotated clockwise or counter-clockwise by the use or ether a series of sprockets 12,13 and chain 51, or by the use of a gear drive arrangement (not shown).

A properly faired propeller 44 is fixed to the leading end of propeller shaft 46 which is housed in lower gearcase 33. Rudder 53 can be conveniently attached to the trailing end of lower gearcase 33. As a result, when underway and lower gearcase 33 is rotated, both propeller 44 and rudder 53 thrust is vectored to port or to starboard.

Vessel steering forces are realized by alterations in the direction of rudder 53, and by changes in the thrust directions of propeller 44. This, in turn, effectively steers the boat. Directional changes of rudder 53 and propeller 44 occur simultaneous- ly.

The steering motor's output shaft, and hence the driver gear (not shown) or driver sprocket, are able to rotate clockwise and/or counter-clockwise an unlimited number of times. As a result, the entire lower gearcase assembly 33 is able to rotate around lower gearcase spindle 34 clockwise and/or counter-clockwise an unlimited number of times as well. Therefore, when reversal of thrust is needed, lower gearcase assembly 33 is simply mechanically rotated in a generally 180 degree fashion.

As previously stated, the entire lower gearcase assembly 33 is able to rotate an unlimited number of times both clockwise, and/or counter-clockwise. At any time, thrust generated by the invention drive may be directed in any horizontal direction.

This in turn moves the vessel in the opposite direction of the directed thrust. Due to the fact that thrust can be directed in absolutely any horizontal direction, the subject vessel can be moved in any horizontal direction, as well.

In a preferred embodiment, the invention's propeller 44 is in front of lower gearcase 33. As such, propeller 44 is free to intercept the oncoming flow of water without the water first passing over turbulence inducing obstructions, i. e., bevel gearcases; stabilizing fins; rudders; struts; prop shafts; or other. This clean propeller entry is not the case with a conventional drive. Most conventional drives use a fin that precedes the propeller. At high speeds, this fin sends an area void of water straight into the highest traction zone of the propeller. When the drive is turned, as when the pilot is changing the direction of the boat, the width of the void is increased, and the fin creates a considerable amount of turbulence that travels directly into this high traction zone.

With this invention's arrangement, the higher the velocity of the vessel, the cleaner the entry of water into propeller 44. At speed, from the moment the drive is introduced to a specific location in a body of water, until propeller 44 is past that specific location, there is a divergent angle of incidence between the water and propeller hub and blades. This actually feeds the propeller if not pressurized water, at least water that does not contain air bubbles, turbulence from obstructions, the void caused from a fin, and water on the verge of cavitation.

At high speed-once propeller 44 is past the above specific location-the diverging inertial forces within the water in contact with the propeller hub, centrifugal force within the water accelerated by the propeller 44, and the reduced volume of water aft of propeller 44 considerably lowers water pressure surrounding lower gearcase 33. This encourages cavitation around lower gearcase 33, and therefore, lower gearcase hydro-dynamic drag is reduced. Water volume reduction is a product of the formation of a'rooster tail'. A replaceable'rooster tail'deflector device will evenly guide the'rooster tail'water around the vertical portion of the lower gearcase.

These features make it virtually impossible to cavitate the invention's propeller at speed. Additionally, the rear mounted rudder receives accelerated or'energized' water. This further enhances the responsiveness of the rudder.

This invention has been described by reference to precise embodiments but it will be appreciated by those skilled in the art that this invention is subject to modification and to the extent that these would be obvious to one of ordinary skill they are considered as being within the scope of the appended claims.