US3763817A

US3763817A - Tow-craft for swimmer

Info

Publication number: US3763817A
Application number: US00282923A
Authority: US
Inventors: A Francis
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-08-26
Filing date: 1972-08-23
Publication date: 1973-10-09
Anticipated expiration: 1990-10-09
Also published as: GB1385200A

Abstract

A tow-craft for towing a swimmer through the water which includes a buoyant housing and a drive assembly carried by the housing including a gasoline engine mounted in the housing and drivingly connected to an impeller assembly mounted on the lower aft end of the housing. The impeller assembly is connected to the engine by means of a shaft and includes a three-bladed axial propeller-type impeller mounted on one end of the shaft and surrounded by a substantially cylindrically shaped tube. A plurality of inlet vanes are mounted in the tube just forward of the propeller and a plurality of outlet vanes are mounted within the tube just aft of the propeller. The tube includes an inwardly converging throat portion just aft of the propeller. In one form the buoyant housing is in the form of a molded hollow hull with a handlebar disposed across the aft end portion thereof with a throttle control mounted thereon. Another form of the buoyant housing includes a rigid hollow central portion surrounded by an inflatable floatation chamber such as a conventional inner tube. The tow-craft includes a self-bailing device and means for cooling and muffling the exhaust gases from the engine and disposing of such gases beneath the surface of the water.

Description

Francis 1451 Oct. 9, 1973 TOW-CRAFT FOR SWIMMER [76] Inventor: Alphons Francis, 1121 NW. 82nd St., Oklahoma City, Okla. 73116 [22] Filed: Aug. 23, 1972 [21] Appl. No.: 282,923

Foreign Application Priority Data v@ 111261271 r t ita 40 9 ,4/ 521 US. Cl ..115/6.1,115/11, 114/183 [51 1111. C1. B63b 21/56 [58] Field 61 Search 115/6.1, 6, 11, 14,

[56 References Cited UNITED STATES PATENTS 2,708,759 5/1955 Strawn ll5/6.1 3,623,447 ll/l97l Jacobson 115/70 3,369,518 2/1968 Jacobson 115/70 3,426,724 2/1969 Jacobson 115/70 3,324,822 6/1967 Carter 115/70 3,112,610 12/1963 Jerger 115/16 3,613,630 10/1971 Jacuui 114/184 1,470,191 10/1923 Reidm; 114/183 R 2,733,679 2/1956 Winkelman et al.. 1'14/183 R 2,343,313 3/1944 Maynes 9/1 Primary Examiner-Milton Buchler Assistant Examiner- E. R. Kazenske Attorney-Jerry J. Dunlap etal.

ABSTRACT A tow-craft for towing a swimmer through the water which includes a buoyant housing and a drive assembly carried by the housing including a gasoline engine mounted in the housing and drivingly connected to an impeller assembly mounted on the lower aft end of the housing. The impeller assembly is connected to the engine by means of a shaft and includes a three-bladed axial propeller-type impeller mounted on one end of the shaft and surrounded by a substantially cylindrically shaped tube. A plurality of inlet vanes are mounted in the tube just forward of the propeller and a plurality of outlet vanes are mounted within the tube just aft of the propeller. The tube includes an inwardly converging throat portion just aft of the propeller. In one form the buoyant housing is in the form of a molded hollow hull with a handlebar disposed across the aft end portion thereof with a throttle control mounted thereon. Another form of the buoyant housing includes a rigid hollow central portion surrounded by an inflatable floatation chamber such as a conventional inner tube. The tow-craft includes a self-bailing device and means for cooling and muffling the exhaust gases from the engine and disposing of such gases beneath the surface of the water.

10 Claims, 14 Drawing Figures PATENTEUUCT ems v 3,763,817

' sum 1m 3 PAIENIE-D 3,763,817

SHEFT 20% 3 1 rowcnxrr FOR SWIMMER BACKGROUND OF THE INVENTION not by way of limitaton, to drive units for aquatic towcraft of the type suitable for towing a swimmer through the water.

2. Description of the Prior Art The prior art contains many teachings of aquatic towcraft for towing swimmers through the water. The prior art tow-craft have generally displayed relatively poor performance due to the difficulty of providing sufficient thrust fortowing a swimmer. The size and weight limitations of such tow-craft requires the use of lightweight engines having relatively small exterior dimensions. Such engines provide limited power for propelling'tow-craft.

The performance of the known tow-craft is further limited by the means employed for converting the power output of the engine to thrust for propelling the towcraft. Various schemes such as conventional propellers and pumps have been employed with limited success. Conventional propellers have been found to be inefficient due to cavitation losses while the pumps have been less than satisfactory due to the great power loss in the pump mechanism. The relative inefficiency of these two propulsion means presents an extreme problem when dealing with the inherent low power output of the available engines suitable for driving such tow-craft. Another disadvantage of the use of conventional propellers is the inherent danger presented by such propellers to swimmers in the immediate area of the tow-craft.

The known tow-craft have generally been limited by the relatively large overall size required in order to provide sufficient flotation to support the craft if one or more swimmers might be using the craft. This limitation restricts the portability of such tow-craft and provides a distinct limitation on the potential uses for such tow-craft.

SUMMARY OF THE INVENTION The present invention, contemplates a tow-craft for towing a swimmer through the water which includes a buoyant housing having a forward end portion and an aft end portion, a drive assembly carried by the housing, handle means mounted on the aft end portion of the housing for receiving the grasp of a swimmer to be towed, and control means mounted on the handle. The drive assembly includes engine means disposed within the housing for providing driving power for the towcraft, rotary shaft means connected to the engine means and having one end portion thereof extending through the aft end portion of the housing for transmit ting driving power from the engine means, and impeller means carried on the lower aft exterior of the housing and drivingly connected to the shaft means for propelling the tow-craft. The impeller means includes an axial drive impeller rigidly secured to one end portion of the shaft means, a substantiallycylindrically shaped tube, having forward and aft end portions, disposed substantially coaxially with the axis of rotation of the axial drive impeller and encircling the axial drive impeller, a plurality of substantially longitudinally aligned circumferentially spaced vanes each extending radially inwardly from the inner periphery of the tube toward the shaft means intermediate the axial drive impeller and the forward end portion'of the tube. The impeller means further includes an inwardly converging throat portion substantially coaxially aligned with the axis of rotation of the axial drive impeller carried within the tube intermediate the axial drive impeller and the aft end portion of the tube, and a plurality of substantially longitudinally aligned and circumferentially spaced outlet vanes each extending radially inwardly from the periphery of the throat portion toward the axis of rotation of the axial drive impeller. The tow-craft also includes first conduit means interconnecting the engine means and the throat portion of the tube for conducting exhaust gases from the engine means to the interior of the throat portion wherein the exhaust gases are released through the aft end portion of the tube.

An object of the present invention is to provide a tow-craft for towing a swimmer having increased efficiency and performance.

Another object of the present invention is to provide a tow-craft having a drive unit of improved efficiency.

An additional object of the present invention is to provide a tow-craft having a drive unit adapted to emit exhaust gases therefrom below and beyond a swimmer.

A further object of this present invention is to provide a tow-crafthaving small physical size, light weight and improved portability.

A still further object of the present invention is to provide a tow-craft which is economical in construction and operation.

Other objects and advantages of the present invention will be evident from the following detailed description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the tow-craft of the present invention.

FIG. 2 is a cross-sectional view of the two-craft of the present invention taken along line 22 of FIG. 1.

FIG. 3 is a side elevation view of the two-craft of the present invention.

N along line 77 of FIG. 5 to more clearly illustrate the construction of the impeller assembly.

FIG. 8 is an enlarged plan view taken along line 8--8 of FIG. 5 to more clearly illustrate the construction of the impeller assembly.

FIG. 9 is a cross-sectional view taken along line 9-9 of FIG. 8 to more clearly illustrate the construction of the impeller assembly.

FIG. 10 is an elevation view taken along line 10-10 of FIG. 8 to more clearly illustrate the construction of the impeller assembly.

FIG. 11 is a plan view of another embodiment of the tow-craft of the presentinvention.

FIG. 12 is a side elevation of the tow-craft of the present invention as illustrated in FIG. 11.

FIG. 13 is a cross-sectional view of the tow-craft of H0. 11 taken along line 13--l3 of FIG. 12.

FIG. 14 is a cross-sectional view of the tow-craft of HG. ll taken along line l4l4 of FlG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and to H68. 1 through in particular, the tow-craft of the present invention is generally designated by the reference character 10. The tow-craft 10 generally comprises a buoyant housing or hull l2 and a drive assembly 14 mounted thereon. I

The housing 12 includes a hollow lower portion 16 and a removable cover portion 18. The housing 12 may be suitably constructed of glass-reinforced epoxy or polyester resin. The cover portion 18 is positioned over an opening 20 formed in the deck 22 of housing 12. The cover portion 18 is secured to the deck 22 by means of a plurality of suitable clamps or fasteners 24 to close the opening 20. A suitable seal or gasket 26 is positioned between the cover portion 18 and the opening 20 in the deck 22 to prevent the entrance of water into the lower portion 16 of the housing 12.

A hand rail 28 is mounted on the deck 22 adjacent to the forward end portion 30 of the housing 12. The hand rail 28 affords a second swimmer a convenient hand-hold at the forward end of the tow-craft 10.

A handlebar 32 is formed on the aft end portion 34 of the housing 12. The handlebar 32 provides the primary point of grasp for the swimmer operating the towcraft l0. Hand-holds 36 are provided on the opposite sides of the housing 12 to provide a convenient point of grasp for carrying the tow-craft from place to place.

The drive assembly 14 includes a gasoline powered internal combustion engine 38 disposed within the lower portion 16 of the housing 12. The crank shaft of the engine 38 (not shown) is aligned substantially parallel to the longitudinal axis of the tow-craft 10. The engine 38 is preferably a one-cylinder air-cooled two stroke-cycle unit of conventional design capable of developing approximately 1.3 horsepower between 3,600 and 4,000 r.p.m., and having a cooling air fan (not shown) mounted in a housing 40 adjacent to the forward end portion 30 of the housing 12. Cooling air is drawn into the housing 40 by the aforementioned fan and circulated through the engine to exit from a second housing 42 at the opposite end of the engine 38. A gasoline tank 44 is mounted within the housing 12 and is connected to the carburetor 46 by a fuel line 48. The tank 44 is preferably mounted a sufficient distance above the level of the carburetor 46 to provide gravity fuel flow through the line 48 from the tank 44 to the carburetor 46.

The engine 38 is supported within the housing 12 by means of a cylindrically shaped tube 50 rigidly secured at one end thereof to the housing 42 and having a flange 52 mounted on the opposite end thereof. The flange 52 is rigidly secured to the housing 12 by means of a plurality of bolts 54 as will be described in greater detail hereafter.

A propeller shaft 56 is rigidly secured at one end thereof to the crankshaft of the engine 38 with the opposite end thereof extending aft within the cylindrically shaped tube 50 through an aperture 58 formed in the housing 12.

An impeller assembly 60 is mounted on the aft end portion 34 of the housing 12 in substantial coaxial alignment with the propeller shaft 56. The impeller assembly includes a cylindrically shaped tube 62 having a flange 64 rigidly secured to one end thereof. As best shown in FIG. 7, the flange 64 is fixedly secured to the housing 12 by means of the previously mentioned bolts 54, the bolts 54 passing through mating alinged apertures (not shown) formed in the

flanges

52 and 64 and the lower portion 16 of the housing 12. A water proof seal is provided at the aperture 58 between the

flanges

52 and 64 by means of

suitable gaskets

66 and 68.

A threebladed axial propeller-type impeller 66 is fixedly secured to the free end of the propeller shaft 56. The propeller shaft 56 is rotatably supported within the tube 62 adjacent to the impeller 66 by means of a conventional sealed bearing 68. The diameter of the hub portion of the impeller 66 is preferably equal to the outer diameter of the tube 62 to minimize flow losses through the impeller assembly 60. The attachment of the impeller 66 to the propeller shaft 56 is preferably accomplished by means of a shear pin or set screw or other suitable means.

The impeller 66 is enclosed by a substantially cylindrically shaped tubular housing or duct 70 having a forward end portion 72 and an aft end portion 74. The forward end portion 72 extends longitudinally between the flange 64 and the impeller 66. Four substantially longitudinally aligned and eircumferentially spaced inlet vanes 76 each extend radially inwardly from the inner periphery of the forward end portion 72 of the housing 70 toward the propeller shaft 56 and are fixedly secured to the outer periphery of the tube 62. The lowermost inlet vane 76 includes a forward extension 78 which extends to a point adjacent to the flange 64. The function of the vanes 76 is to assure regular axial flow of water to the impeller without the water being disturbed by the rotation of the impeller 66. An opening 80 is formed in the lower forward portion of the forward end portion 72 of the tubular housing 70 to provide a water inlet to the impeller assembly 60.

The aft end portion 74 of the tubular housing 70 comprises an inwardly converging throat portion 82 extending aft from the impeller 66. Six substantially longitudinally aligned and eircumferentially spaced outlet vanes 84 extend radially inwardly from the inner periphery of the thread portion 82 toward the axis of rotation of the propeller 66. A diverging portion or diffuser 85 is formed at the outlet end of the aft end portion 74 just aft of the converging throat portion 82 and the vanes 84. A tube 86 having a closed forward end portion 88 and an open aft end portion 90 is disposed within the throat portion 82 in substantial coaxial alignment with the axis of the rotation of the impeller 66 and is rigidly supported in this position by means of the six outlet guide vanes 84 which are each rigidly secured to the outer periphery of the tube 86. The primary function of the vanes 84 is to secure regular axial flow of the water passing through the throat portion 82 from the impeller 66 by substantially reducing the turbulence of the water.

The configuration of the aft end portion 74 is such that the velocity of the water driven therethrough by the rotary action of the impeller 66 increases as it passes through the converging throat portion 82 and along the outlet guide vanes 84. It has been found that the optimum included angle between opposite sides of the'converging throat portion lies between 12 and 17 with the preferable angle being approximately 16 degrees. The preferable angle of approximately 16 degrees has been found to provide maximum velocity of the water exiting from the impeller assembly 60 against the adverse pressure of the water immediatelyaft of the impeller assembly-60.

The'aft end portion 74' of the tubular housing 70 is conveniently secured to the forward end portion 72 by means of a plurality of threaded screws 92 disposed about the periphery of tubular housing 70.

Exhaust gases are directed from the engine 38 through a first exhaust conduit segment 94 which is connected atone end to the exhaust port of the engine 38 (not shown). The opposite end of the exhaust conduit segment '94 extends through an aperture 96 formed in the lower portion 16 of the housing 12 and communicates with one end portion of a muffler 98 disposed entirely outside the housing 12. A second exhaust conduit segment 100 communicates at one end thereof with the opposite end of the muffler 98 while the opposite end portion of the exhaust conduit segment '100 extends back into the lower portion 16 of housing 12 through an aperture 102 formed therein. Suitable water-tight seals are provided between the

exhaust conduit segments

94 and 100 and the respective apertures'96 and 102.

A'third-exhaust conduit segment 104 communicates at one end thereof with the opposite end of the second exhaust conduit segment 100 and extends upwardly within the housing 12 forming an inverted U-shaped "loop 106 disposed within the cover portion 18 of the housing 12. The exhaust conduit seg'm ent 104 is routed downwardly from the U-shaped loop 106 and is directed through the previously mentioned flanges 52 and64 of the drive assembly '14 and the aperture 58 formed in the housing 12. As best shown in FIG. 7, the

exhuast conduit segment 104 is routed from the aperture 58 along the cylindrically shaped tube 62 of the impeller assembly'60'and terminates at its opposite end in communication with the interior of tube 86 of the impeller assembly 60.

Joints

112 and 114 are formed in'the exhaust conduit segment 104 at the aperture 58 ,and at the point of connection between the forward and

aft end portions

72 and 74 of the tubular housing 70, respectively, to facilitate disassembly and the maintenance of the impeller assembly 60. Again referring to FIG. 7,-the exhaust conduit segment 104 preferably lies in the same plane with the uppermost inlet vane 76 and the uppermost outlet vane 84 thereby minimizing any obstruction to waterflow through the impeller assembly 60. The exhaust conduit segment 104 extends through an aperture 116 in the forward end portion 72ofthe tubular housing 70, and extends through an aperture 118 formed in the aft end portion 74 of the tubular housing 70.

The previously described routing of the

exhaust conduit segments

94, 100 and 104 together with the muffler 98 provides for the efficient emission of exhaust gases from the engine 38 in the propwash from the impeller assembly 60. This arrangement of the exhaust assembly also improves the fuel scavan'ging characteristics of the engine 38 by substantially lowering the back pressure of the exhaust gases passing through the previously mentioned exhaust conduit segments.

The disposition of the muffler 98 outside the housing 12 provides two desirable advantages of the present invention. The first advantage is that the disposition of the muffler 98 under the water minimizes the noise level within the housing 12 and provides for extremely quiet operation of the tow-craftlO. The second advantage is that the muffler 98, being in contact with the water, provides for efficient heat transfer of the heat contained in the hot exhaust gases to the water surrounding the muffler 98 thereby lowering the temperature of the exhaust gases that exit from the open aft end portion 90 of the tube 86 in the'impeller assembly 60. The latter advantage is of great importance when it is considered that a swimmer using the tow-craft 10 is positioned im mediately aft of the impeller assembly 60.

The dispensing of the exhaust gases from the engine 38 through the tube 86 also provides two distinct ad vantages. The first advantage is that engine exhaust noise is minimized by the emission of exhaust gases beneath the surface of the water. The second advantage is that the emission of the exhaust gases into the propwash from the impeller assembly causes the gases to be thoroughly mixed into the propwash and propelled far behind the swimmer thereby eliminating the possibility of objectionable exhaust gases being encountered by the swimmer being towed.

It has been found by experimentation that in a preferred embodiment the nominal length of the impeller assembly 60 from the flange 64 to the aft end portion 74 is approximately 7% inches. The preferred nominal diameter of the impeller assembly 60 has been found to be approximately 4 inches. The optimum diameter of the three-bladed impeller 66 has been found to be nominally 3% inches. The optimum nominal dimensions of the throat portion 82 have been found to be approximately 3 inches in length with a maximum nominal in side diameter of slightly more than 3% inches at a position adjacent to the impeller 66 with the throat portion 82 converging to a nominal mimimum inside diameter of approximately 2% inches at the aft end portion 74.

While it has been found that the optimum number of inlet and

outlet vanes

76 and 84 are as specifically called for hereinbefore, it will be readily apparent to those skilled in the art that other numbers and arrangements of vanes may be utilized in practicing the present invention.

its lowermost end portion 122 positioned in the lowermost portion of the lower portion 16 in the housing 12. The tube extends upwardly therefrom forming an inverted U-shaped portion 124 disposed within the cover portion 18 of the housing 12. The tube 120 is routed downwardly from the U-shaped portion 124 and out through the

flanges

52 and 64 of the drive assembly 14 and the aperture 58 formed in the housing 12 along the

tubes

50 and 62 to a point of termination at its opposite end portion just forward of the impeller 66 in the impeller assembly 60 as best shown in FIG. 7. A joint 128 is formed in the tube 120 between the

flanges

52 and 64 to facilitate the disassembly of the impeller assembly 60 from the remainder of the drive assembly 14 and the housing 12. The positioning of the opposite end portion 126 of the self-bailing tube 120 in the low pressure area just forward of the impeller 66 permits any water entrained in the lowermost portion of the lower portion 16 of the housing 12 to be drawn through the tube 120 by the action of the impeller 66 when the engine 38 is in operation.

The inverted U-shaped portion 124 of the tube 120 and the inverted U-shaped loop 106 of the exhaust conduit segment 104 are included to prevent the entrance of water through the exhaust and self-bailing tubes when the engine 38 is not operating, thereby preventing flooding of the lower portion' 16 of the housing 12 or the entrance of water into the exhaust port of the engine 38.

The tow-craft 10 also includes a hand-operated throttle control lever 130 mounted to the right side of the handlebar 32 and connected to the throttle of the carburetor 46 of engine 38 by means of a bowden cable 132 to provide the swimmer with means for controlling the speed of the tow-craft 10. The tow-craft 10 also includes an engine starting rope 134 with a handle 136 formed on one end thereof and the opposite end thereof connected to the engine 38. A conventional single pole double throw toggle switch 138 is mounted on the deck 22 of the housing 12 near the handlebar 32. The switch 138 is disposed in the primary circuit wiring of the magneto of the engine 38 thereby providing the swimmer with the facility for shutting off the engine 38 by closing the switch 138 and thereby shunting the primary circuit of the megneto to ground. When the switch 138 is in the open position the primary circuit is isolated from ground and the engine 38 is in condition to'be started and run.

The cover portion 18 of the housing 12 includes openings 140 formed in the upper portion thereof 142 to provide for circulation of cooling air to the engine 38 and to supply aspiration air to the carburetor 46. The openings 140 are preferably formed on the aft end portion of the upper portion 142 to prevent the entrance of water into the housing 12 which might inadvertently splash over the forward portion of the housing 12.

As shown in FIGS. 8 and 9, it may be desirable to form the aft end portion 74 of the tubular housing 70 such that the longitudinal axis thereofis offset from the axis of rotation of the impeller 66 at an angle 144 as shown in FIG. 8. The angle 144 may vary between and 20 and is intended to provide an inherent tendency' of the tow-craft 20 to circle in the immediate area of a swimmer who might lose his grip on the handlebar 32 of the tow-craft 10. The angle 144 of the aft end portion 74 is preferably in the direction of the muffler 98. This allows the inherent drag of the muffler 98 to supplement the angled thrust of the impeller assembly 60 to achieve the aforementioned circling tendency of the tow-craft l0.

OPERATION OF THE PREFERRED EMBODIMENT In operation a swimmer places the tow-craft in the water with the impeller assembly 60 submerged beneath the surface thereof. The swimmer then grasps the handle 136 of the starting rope 134 and pulls the rope 134 to start the engine 38. The swimmer then grasps the handlebar 32 with both hands with his right hand on the throttle control lever 130. By squeezing the throttle control lever 130 downwardly against the handlebar 32 the throttle on the carburetor 46 is opened and the engine 38 achieves operating speed.

Water is drawn into the impeller assembly 60 through the opening formed in the forward end portion 72 of the tubular housing 70 by the rotating three-bladed impeller 66. Water drawn into the impeller assembly 60 is forced by the impeller 66 through the throat portion 82 formed in the aft end portion 74 of the tubular housing 70 thereby providing forward thrust to the tow-craft 10 sufficient to tow the swimmer along through the water.

In the event the tow-craft 10 is to be used for lifesaving purposes, the swimmer being rescued can grasp the handrail 28 or either of the hand holds 36 and be towed along by the tow-craft 10 along with the rescuing swimmer. When utilizing the handrail 28, the swimmer being rescued should grasp the handrail 28 with both hands while facing the forward end portion 30 of the housing 12. As the tow-craft 10 is propelled forward the rescued swimmer should trail his legs under the housing 12 toward the rescuing swimmer and will be conveyed through the water back first.

DESCRIPTION AND EMBODIMENT OF FIGS. 11, 12, 13 AND 14 FIGS. 11 through 14 illustrate an alternate embodiment of the tow-craft of the present invention which is generally designated by the reference character 150. The tow-craft includes numerous elements previously described for the tow-craft 10, which elements will be accorded the same reference characters usd hereinbefore.

The tow-craft 150 generally comprises a buoyant housing or hull 152 and the drive assembly 14, previously described in detail above. The housing 152 includes a relatively rigid inner portion 154 of hollow construction and a relatively flexible air-inflatable flotation chamber 156 disposed around the periphery of the inner portion 154. The inner portion 154 of the housing 152 includes a hollow lower portion 158 and a removable cover portion 160. The inner portion 154 1 may be suitably constructed of glass-reinforced epoxy or polyester resin. The cover portion 160 is positioned over an opening 162 formed in the upper portion 164 of the hollow lower portion 158. The cover portion 160 is secured to the upper portion 164 of the lower portion 158 by means of a plurality of suitable clamps or fasteners 166 to close the opening 162. A suitable seal or gasket 168 is positioned between the cover portion 160 and the opening 162 to prevent the entrance of water into the rigid inner portion 154 of the buoyant housing 152.

A handlebar 170 is formed on the aft end portion 172 of the hollow lower portion 158 of the housing 152. The handlebar 170 provides the primary point of grasp for the swimmer operating the tow-craft 150. The handlebar 170 is adapted to pivot about its point of connection with the rigid inner portion 154 along a substantially horizontal axis to a folded stowed position as shown by the dashed lines in FIGS. 11 and 12.

v The inflatable flotation chamber 156 is disposed about and received in a circumferential recess 174 formed in the outer periphery of the inner portion 154 of the buoyant housing 152. The flotation chamber 156 is conveniently equipped with a conventional valve stem and core (not shown) to facilitate the inflation of the chamber 156 by conventional air pump means. The flotation chamber 156 may advantageously be in the form of a conventional automobile or truck tire inner tube or specially fabricated of suitable flexible airtight material such as polyurethane or rubber coated nylon cloth or the like.

As will be readily apparent, when the flotation chamber 156 is properly positioned in the recess 174 and fully inflated, the flotation chamber 156 will be rigidly secured to the rigid inner portion 154 of the buoyant housing 152. The installation of the flotation chamber 156 on the rigid inner portion 154 is quite similar to the mounting of an automobile inner tube to the rim of an automobile wheel.

The mounting of the drive assembly 14 in the buoyant housing 152 is identical to that previously described for the mounting thereof in the housing 12 of the towcraft l and, therefore, need not be described in detail again.

The tow-craft 150 also includes a system of exhaust conduits and muffler as well as a self-bailing device. The arrangement of the exhaust conduits and muffler and self-bailing device of the tow-craft 150 is also identical to the arrangement described previously for the tow-craft 10 and therefore need not be described in detail again.

The tow-craft 150 includes a hand-operated throttle control lever 176 mounted on the right side of the handle-bar 170 and connected to the throttle of the carburetor 46 of the engine 38 by means of a bowden cable 178 to provide the swimmer with means for controlling the speed of the tow-craft 150. The tow-craft 150 also includes an engine starting rope 180 with a handle 182 formed on one end thereof and the opposite end thereof connected to the engine 38. A conventional single pole-double throw toggle switch 184 is mounted on the rigid inner portion 154 of the housing 152 near the handle bar 170 by provide the swimmer with means for shutting off the engine 38. The installation and function of the switch 184 is identical to that previously described in detail above for the switch 138 and, therefore, will not be described in detail again.

The cover portion 160 of the housing 152 includes openings 186 formed in the upper portion thereof 188 to provide for circulation of cooling air to the engine 38 and to supply aspiration air to the carburetor 46. The housing 152 is also equipped with a duct 190 communicating between the air fan (not shown) mounted in the housing 40 of the engine 38 and one of the openings 186 to provide cooling air directly from the respective opening 186 to the engine 38.

As noted above, the handlebar 170 may be pivoted about a horizontal axis relative to the housing 152. This capability permits the handlebar 170 to be folded into .a stowed position indicated by the dashed lines in FIGS.

1 1 and 12 when the flotation chamber 156 has been deflated and removed from the inner portion 154 of the housing 152. Sufficient storage space 192 is provided within the inner portion 154 of the housing 152 to stow the deflated flotation chamber 156 during transportation and storage of the tow-craft 150.

OPERATION OF THE EMBODIMENT OF FIGS. ll, l2, 13 AND 14 ventional air pump. When the flotation chamber 156 is fully inflated, the tow-craft is then placed in the water and is operated as previously described in detail for the tow-craft 10.

The tow-craft 150 may be placed in condition for storage or transportation by deflating the flotation chamber 156 and placing the flotation chamber 156 in the storage space 192 within the housing 152 and folding the handlebar back to its stowed position as indicated by the dashed lines in FIGS. 11 and 12.

It is believed apparent that the various embodiments of the present invention attain the objectives set forth herein. Changes may be made in the arrangement or combination of parts or elements shown in the drawings and described in the specification without departing from the spirit and scope of the invention as defined in the following claims.

What is claimed is:

1. A tow-craft for towing a swimmer through the water, comprising:

a buoyant housing having a forward end portion and an aft end portion;

a drive assembly carried by said housing and includ-- ing: engine means disposed within said housing for providing driving power for said tow-craft; rotary shaft means connected to said engine means and having one end portion thereof extending therefrom through the aft end portion of said housing for transmitting driving power from said engine means; impeller means carried on the lower aft exterior of said housing and drivingly connected to said shaft means for propelling said tow-craft, said impeller means including:

an axial drive impeller rigidly secured to the one end portion of said shaft means;

a substantially cylindrically shaped tube disposed substantially coaxially with the axis of rotation of said axial drive impeller and encircling said axial drive impeller, said tube having a forward end portion and an aft end portion;

a plurality of substantially longitudinally aligned and circumferentially spaced inlet vanes each extending radially inwardly from the inner periphery of said tube toward said shaft means intermediate said axial drive impeller and the forward end portion of said tube;

an inwardly converging throat portion substantially coaxially aligned with the axis of rotation of said axial drive impeller carried within said tube intermediate said axial drive impeller and the aft end portion of said tube;

a plurality of substantially longitudinally aligned and circumferentially spaced outlet vanes each extending radially inwardly from the inner periphery of said throat portion toward the axis of rotation of said axial drive impeller;

handle means mounted on the aft end portion of said housing for receiving the grasp of the swimmer to be towed;

control means mounted on said handle means and operatively connected to said engine means for controlling the speed of said tow-craft; and

first conduit means interconnecting said engine means and said throat portion for conducting exhaust gases from said engine means to the interior of said throat portion wherein the exhaust gases are released through the aft end portion of said tube.

2. A tow-craft as defined in claim 1 characterized further to include:

second conduit means interconnecting the lowermost portion of the interior of said buoyant housing and said impeller means for removing therethrough water which may become entrained in the lowermost portion of said housing.

3. A tow-craft as defined in claim 1 wherein said first conduit means is characterized further to include:

a first segment having a first end thereof in communication with the exhaust port of said engine means and having the second end thereof extending outwardly through the lower portion of said buoyant housing;

muffler means having an inlet and an outlet and disposed without said buoyant housing beneath the surface of the water for muffling and cooling exhaust gases from the engine means with the inlet thereof in communication with the second end of said first segment;

a second segment having a first end thereof in communication with the outlet of said muffler means and having the second end thereof extending inwardly through the lower portion of said buoyant housing; and

a third segment having a first end thereof in communication with the second end of said second segment and forming an inverted U-shaped loop within said housing and having a second end thereof in communication with said throat portion of said impeller means.

4. A tow-craft as defined in claim 1 wherein the longitudinal axis of said inwardly converging throat portion is inclined at an angle slightly to one side with respect to the axis of rotation of said axial drive impeller, and wherein said outlet vanes are substantially longitudinally aligned with the longitudinal axis of said throat portion.

5. A tow-craft as defined in claim 1 wherein said buoyant housing is characterized further to include:

a rigid inner portion of hollow construction;

an air-inflatable flotation chamber disposed around the periphery of said inner portion; and

means carried by said inner portion for securing said flotation chamber to the periphery of said inner portion.

6. A tow-craft as defined in claim 5 wherein said flotation chamber is toroidal in shape and is received in a circumferential groove formed in the periphery of said inner portion of said buoyant housing.

7. A tow-craft as defined in claim 6 wherein said flotation chamber is a conventional rubber pneumatic tire innertube.

8. A tow-craft as defined in claim 6 characterized further to include:

second conduit means interconnecting the lowermost portion of the interior of the inner portion of said buoyant housing and said impeller means for removing therethrough water which may become entrained in the lowermost portion of the inner portion of said housing.

9. A tow-craft as defined in claim 8 wherein said first conduit means is characterized further to include:

a first segment having a first end thereof in communication with the exhaust port of said engine means and having the second end thereof extending outwardly through the lower portion of the inner portion of said buoyant housing;

muffler means having an inlet and an outlet and disposed without said inner portion of said buoyant housing beneath the surface of the water for muffling and cooling exhaust gases from the engine means with the inlet thereof in communication with the second end of said first segment;

a second segment having a first end thereof in communication with the outlet of said muffler means and having the second end thereof extending inwardly through the lower portion of said inner portion of said buoyant housing; and

a third segment having a first end thereof in communication therewith the second end of said second segment and forming an inverted U-shaped loop within said inner portion of said housing and having a second end thereof in communication with said throat portion of said impeller means.

10. A tow-craft as defined in claim 9 wherein the longitudinal axis of said inwardly converging throat portion is inclined at an angle slightly to one side with respect to the axis of rotation of said axial drive impeller, wherein said outlet vanes are substantially longitudinally aligned with the longitudinal axis of said throat portion.

mg UNITE STATES PATENT OFFlCE CERTll lQAE @F CQRECHON P en 37638l7 Dated October 9. 1973 .Inv n fl A lnhons Francis It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

F In the printed specification, column 4-, line 47 .7

after "the" and before "portion" the word "thread" should be --throat-. ,In column 4, line .54, after "of" and before "rotation" delete -the. In column 5, line 38, before "conduit" the word "exhuast" should be -exhaust--. In column 7, line 48, after "tow-craft" the reference character "20" should be -l0--. In column 8, line 29, after "characters" change "usd" to -used---.

Signed and sealed this 12th day of February 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,LIR. Attestin CQ'MARSHALL DANN g lcer Commissioner of Patents

Claims

2. A tow-craft as defined in claim 1 characterized further to include: second conduit means interconnecting the lowermost portion of the interior of said buoyant housing and said impeller means for removing therethrough water which may become entrained in the lowermost portion of said housing.
3. A tow-craft as defined in claim 1 wherein said first conduit means is characterized further to include: a first segment having a first end thereof in communication with the exhaust port of said engine means and having the second End thereof extending outwardly through the lower portion of said buoyant housing; muffler means having an inlet and an outlet and disposed without said buoyant housing beneath the surface of the water for muffling and cooling exhaust gases from the engine means with the inlet thereof in communication with the second end of said first segment; a second segment having a first end thereof in communication with the outlet of said muffler means and having the second end thereof extending inwardly through the lower portion of said buoyant housing; and a third segment having a first end thereof in communication with the second end of said second segment and forming an inverted U-shaped loop within said housing and having a second end thereof in communication with said throat portion of said impeller means.
4. A tow-craft as defined in claim 1 wherein the longitudinal axis of said inwardly converging throat portion is inclined at an angle slightly to one side with respect to the axis of rotation of said axial drive impeller, and wherein said outlet vanes are substantially longitudinally aligned with the longitudinal axis of said throat portion.
5. A tow-craft as defined in claim 1 wherein said buoyant housing is characterized further to include: a rigid inner portion of hollow construction; an air-inflatable flotation chamber disposed around the periphery of said inner portion; and means carried by said inner portion for securing said flotation chamber to the periphery of said inner portion.
6. A tow-craft as defined in claim 5 wherein said flotation chamber is toroidal in shape and is received in a circumferential groove formed in the periphery of said inner portion of said buoyant housing.
7. A tow-craft as defined in claim 6 wherein said flotation chamber is a conventional rubber pneumatic tire innertube.
8. A tow-craft as defined in claim 6 characterized further to include: second conduit means interconnecting the lowermost portion of the interior of the inner portion of said buoyant housing and said impeller means for removing therethrough water which may become entrained in the lowermost portion of the inner portion of said housing.
9. A tow-craft as defined in claim 8 wherein said first conduit means is characterized further to include: a first segment having a first end thereof in communication with the exhaust port of said engine means and having the second end thereof extending outwardly through the lower portion of the inner portion of said buoyant housing; muffler means having an inlet and an outlet and disposed without said inner portion of said buoyant housing beneath the surface of the water for muffling and cooling exhaust gases from the engine means with the inlet thereof in communication with the second end of said first segment; a second segment having a first end thereof in communication with the outlet of said muffler means and having the second end thereof extending inwardly through the lower portion of said inner portion of said buoyant housing; and a third segment having a first end thereof in communication therewith the second end of said second segment and forming an inverted U-shaped loop within said inner portion of said housing and having a second end thereof in communication with said throat portion of said impeller means.
10. A tow-craft as defined in claim 9 wherein the longitudinal axis of said inwardly converging throat portion is inclined at an angle slightly to one side with respect to the axis of rotation of said axial drive impeller, wherein said outlet vanes are substantially longitudinally aligned with the longitudinal axis of said throat portion.