Abstract:
A water jet propelled boat that includes a source of pressurized air that by a single action control may be delivered to bow and stern portion positioned resilient bags to inflate the same to vary the contour of the wetted portion of the boat to a desired configuration. The boat includes a number of laterally spaced sponsons that have forward bottom surfaces that taper downwardly to merge into substantially straight rearward bottom surfaces on which the boat rides when traveling at high speed. Pressurized air is discharged from the source to flow rearwardly under the boat and impart a lift to the latter. The desired configuration of the bags is one which in combination with the action of the sponsons and the rearwardly flowing bubbles results in the boat moving through the water in a fuel efficient manner.

Description:
DESCRIPTION OF THE PRIOR ART 
     In the past, both hydro lift and pressurized air lift have been utilized in reducing the drag of marine vessels in moving through water. The present invention employs both principals in a novel combination to reduce hull drag and high speed hull slamming, while improving the stability of the vessel, and appreciably reducing the horse power requirements and fuel consumption in moving the vessel through a body of water. 
     A major object of the present invention is to supply a substantially rectangular hull that has a pair of side keels extending the longitudinal length thereof, with a first inflatable bag being situated between the keels and overlying the bow, and a pair of second pliable bags that may be inflated are situated adjacent the stern of the vessel, and the bags when inflated varying the contour of the surface portion of the vessel to one that is particularly adapted for the speed at which the vessel is operated, with these bags in combination with a number of laterally spaced, longitudinally extending sponsons that extend downwardly from the bottom of the boat, and the injection of pressurized air downwardly through the center forward portion of the hull to flow rearwardly therebelow, all cooperating to provide a vessel that moves through the water at high speed with a minimum of frictional resistance and in a fuel effecient manner. 
     SUMMARY OF THE INVENTION 
     A power driven marine vessel, preferably in the form of a jet propelled boat, that may have the contour thereof selectively varied to lessen the hydrodynamic drag thereon as the speed of the boat is increased relative to the body of water on which the vessel floats. 
     The boat includes a substantially rectangular hull that includes a deck, a downwardly and rearwardly curving bow that develops into a flat bottom, a pair of laterally spaced side walls that extend downwardly from the deck below the bottom to define a pair of longitudinally extending side keels. A pair of outwardly disposed sponsons extend downwardly from the bottom and are situated adjacent the side keels, and a pair of inwardly disposed sponsons are situated between the outer pair of sponsons. All of the sponsons are disposed rearwardly from the bow of the vessel and have lower surfaces that taper downwardly and rearwardly to develop into flat portions that are substantially parallel to the water when the vessel operates at high speed. The inner pair of sponsons define a central channel therebetween, and the inner and outer sponsons cooperate to define a pair of side channels that are situated on opposite sides of the central channel. 
     A first inflatable bag of a pliable sheet material extends downwardly and rearwardly over the bow of the boat, while a pair of second inflatable bags are situated in the rear portion of a pair of side channels. A pair of engines on the hull drive a pair of propellers to generate jets of water that force the hull forwardly. By varying the velocities of the jets relative to one another, and diverting direction of flow the boat may be steered. One or more power driven blowers are employed for producing pressurized air that is used ih selectively inflating the first and second bags, as well as injecting air downwardly through openings in the bottom of the hull to flow rearwardly thereunder. 
     The flow of air to the first and second bags from the blower is controlled by valve means. When the vessel is operated at high speed the first and second bags are inflated to vary the configuration of the hull portion exposed to the water, with this new configuration being one that imparts a lift to the hull that tends to minimize the hydrodynamic drag on the vessel as it moves forwardly through the water. Additional lift is imparted to the vessel as it moves forwardly through the water at a relatively rapid speed due to the tapered configuration of the lower surfaces of the sponsons, and the additional lift imparted to the vessel by pressurized air being directed thereunder and flowing rearwardly through a central longitudinal channel under the hull to discharge at a desired rate from the stern portion of the vessel. This desired rate is achieved by varying the position of a pivotally supported elevator located at the rearward extremity of the central channel through which the pressurized air discharges rearwardly. The desired role will be one in which a minimum of the lower surface portion of the vessel is exposed to hydrodynamic drag. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of the hull of the vessel; 
     FIG. 2 is a bottom plan view of the vessel; 
     FIG. 3 is a longitudinal cross sectional view of the vessel taken on the line 3--3 of FIG. 2; 
     FIG. 4 is a longitudinal cross sectional view of one of the duct systems and valves used in controlling the flow of pressurized air to the first and second inflatable bags; 
     FIG. 5 is a longitudinal cross sectional view of the hull taken on the same line as FIG. 3, but with the first and second bags shown in non-inflated positions and situated in abutting contact with the bottom portion of the hull structure; 
     FIG. 6 is a diagrammatic view of the single handle control system for varying the inflation of the resilient bags; 
     FIG. 7 is a longitudinal cross sectional view of the hull structure taken on the line 7--7 of FIG. 2, with the pivotally supported elevator situated on the rear of the hull being indicated in a downwardly depending position; 
     FIG. 8 is the same view as shown in FIG. 7 but with the first forwardly disposed bag non-inflated, and the elevator raised to an abutting position with the rearward portion of the hull; 
     FIG. 9 is a combined side elevational and longitudinal cross sectional view of the hull structure taken on the line 9--9 of FIG. 2; 
     FIG. 10 is a rear elevational view of the hull structure; 
     FIG. 11 is a forward side elevational view of the hull structure; and 
     FIG. 12 is a diagrammatic view of the engine, duct structures and water jet producing assemblies. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The vessel A of the present invention as best seen in FIGS. 1, 2 and 3 includes a generally rectangular hull B. The hull B includes a downwardly and rearwardly curving bow 10 that develops into a flat bottom 12. The hull B has a deck 14 from which a pair of laterally spaced side walls 16 extend downwardly, and below the bottom 12 to define a pair of side keels 18. The hull B has a transom 20. 
     A pair of outer sponsons 22 are situated rearwardly of the bow 10 and project downwardly from the bottom 12. An inner pair of sponsons 24 also project downwardly from the bottom 12. The inner pair of sponsons 24 define a central longitudinally extending channel 26 therebetween. The pair of inner sponsons 24 and the pair of outer sponsons 22 define a pair of outer channels 28 therebetween. 
     Each of the sponsons 22 and 24 has a flat rear bottom surface 30 that is substantially parallel with the surface of the body of water over which the vessel A travels when the vessel is propelled at high speed. The forward bottom surfaces 30a of all of the sponsons 22 and 24 taper upwardly and forwardly to merge into the bottom 12. 
     A first inflatable bag C of a pliable sheet material extends downwardly and rearwardly over the bow 10 and is in abutting contact therewith when the first bag is not inflated. A pair of second inflatable bags D are located in the rear portions of the pair of outer channels 28. 
     The first inflatable bag C includes side walls 32 that develop into lips 34 that are adhered to the hull B as best seen in FIG. 7. 
     The vessel A is illustrated in FIG. 12 as including a pair of engines 38, each of which has a drive shaft 40 extending rearwardly therefrom. Each of the drive shafts has a propeller 42 secured to the rearward extremity thereof. 
     Two laterally spaced inverted L-shaped tubular housings 44 are located in the rearward portion of the hull B. Each of the housings 44 has a water intake poriton 44a that projects downwardly below bottom 12 through an opening in the latter. Each of the housings 44 has one of the propellers 42 therein with the propeller axially aligned with a rearwardly and inwardly tapering tubular discharge portion 44b of the housing, which portion extends rearwardly through the transom 20 as shown in FIGS. 10 and 12. 
     A motor 46 is illustrated in FIG. 12 that by dual drive shafts 48 operates a pair of blowers 50, each of which has the discharge thereof flowing into a valve box E from which first, second and third pressurized air conducting ducts 52, 54 and 56 extend. 
     The first bag C is inflated by pressurized air flowing thereto through two first ducts 52, one of which is shown in FIG. 9. Each of the second bags D may be inflated by pressurized air flowing thereto through one of the second ducts 54. A third duct 56 supplies pressurized air to the forward portion of the central channel 26 through an opening 58 in the bottom 12 of hull B. 
     Each valve box E has the rearward inlets 52a, 54a and 56a of the first, second and third pressurized air ducts 52, 54 and 56 in communication with the interior thereof, with pressurized air being discharged into the interior at a substantially constant rate by blower 50. Each valve box E includes a pair of laterally spaced side walls 59 that pivotally support first and second shafts 61 and 63 therebetween. The first and second shafts 61 and 63 have first and second dampers 60 and 62 secured thereto, which dampers may be pivoted towards or away from the second and third pressurized air inlets 54a and 56a as shown in FIG. 4. 
     In FIG. 6 it will be seen that an arm 65 extends outwardly from one end of the first shaft 61 and by a pin 67 is pivotally connected to a piston rod 69 that is slidably movable in a hydraulic cylinder 71 that is pivotally supported. The pivotal support for the cylinder 71 is illustrated in FIG. 6 as an apertured lug 73 that extends outwardly from an end 75 of the cylinder and by a pin 77 is connected to a fixed mounting 79 that is a part of the boat A. First and second sprockets 81 and 83 are mounted on the first shafts 61 and 63 and connected by an endless chain belt 81a. 
     A pump 85 is driven by a motor 87, which pump has a suction line 89 extending to a reservoir 91. The discharge from pump 85 is in communication with a multiport valve 93 that may be positioned by a handle 95 to discharge hydraulic fluid to either of two conduits 97 and 99 that are connected to opposite ends of the hydraulic cylinder 71. When hydraulic fluid is discharged into cylinder 71 through one of the conducts 97 or 99 hydraulic fluid flows back to the valve 93 through the other thereof to be delivered back to the reservoir through a conduit 101. 
     From the above description it will be seen that by manually manipulating the single handle 95, pressurized hydraulic fluid may be so discharged to cylinder 71 to move first and second dampers 60 and 62 concurrently either towards or away from the second and third air inlets 54a and 56a. 
     When the first damper 60 is moved towards the second pressurized air inlet 54a the rate of pressurized air flow to the second conduit 54 is decreased as is that to the second bags D. Pressurized air can escape through both the first bag C and second bags D through resilient valves 80 in communication with the interior thereof, with the rate of flow of pressurized air and water that may enter the bags being at a rate less than that at which pressurized air is discharged thereinto. Pressurized air at all times flows from the confined space of valve box E to the third conduit 56, as the first and second dampers will never be moved to positions to completely obstruct the second and third air inlets 54a and 56a. 
     As the rate of flow of pressurized air from the confined space in valve box E is decreased by movement of the first damper 60, the pressure of air in the confined space 57 as does the rate of flow of pressurized air through first inlet 52a and first conduit 52 to first bag C. This increased rate of pressurized air flow to first bag C increases the pressure therein and bag C expands as a result thereof. 
     Thus, it will be seen that a single manual control, namely, the valve handle 95, permits the air pressure in the first and second bags C and D to be concurrently varied to provide an inflated configuration of the bags that is particularly adapted for the surface condition of the body of water over which the boat travels. When the first damper 60 is pivoted away from the second air inlet 54a, the pressure within the first bag C is lessened and the pressure in the second bags D increased. 
     It will be particularly noted that the pressure in the first bag C is varied without the first pressurized air inlet 52a being obstructed in any manner. 
     An elevator 64 is pivotally supported from the hull B in the rearward portion of the central channel 26, and has a rod 66 pivotally connected that extends to a hydraulic cylinder 68. The hydraulic cylinder 68 is pivotally supported from the transom 20. By pivoting the elevator downwardly rearward flow of pressurized air through the central channel 26 is impeded and additional lift is imparted to the hull B. 
     Each of the bags C and D has a valve 80 on the rearward portion that discharges water entering the interior of the bag together with pressurized air into the body of water on which the vessel A floats. East valve 80 is commercially available and formed from a resilient tubular body. The valve 80 is known in the trade as a &#34;duck bill&#34; valve, and tends to remain in a closed position until the pressure to which it is exposed exceeds a predetermined valve. 
     There are three different modes of operating the vessel A. In the first mode when the vessel A is moving at a slow speed, the first and second bags C and D will be deflated, and the vessel will handle in a conventional manner. 
     At an intermediate speed such as when the vessel A is moving through a rough sea the vessel will be operated at a second mode. The forward bag C will be subjected to air at substantial pressure to provide shock absorption from waves to which the hull B would otherwise be subjected. Air pressure to the second bags D is decreased to increase the draft on vessel A and add stability to its movement. 
     In the third mode at which the vessel A is operated at high speed air discharge to the central channel is terminated, with air pressure in the second bags D being gradually increased, and the air pressure the first bag C thereafter increased. In the third mode the effective contour of the hull B has been changed due to inflation of the bags C and D to the extent that the vessel A moves forwardly through the water with a minimum of surface contact therewith and with a minimum of hydrodynamic drag. The above described movement is augmented by the discharge of pressurized air to the central channel 26 to impart lift to the hull B. 
     The use and operation of the invention has been described previously in detail and need not be repeated.