US3714918A - Air boat with air cushion - Google Patents

Abstract

A WATER SURFACE PLANING CRAFT INCLUDING A HULL HAVING A BOTTOM SURFACE PROVIDED WITH A PLURALITY OF AIR OUTLETS OPENING DOWNWARDLY THERETHROUGH. A MOTOR DRIVEN AIR PROPELLER IS CARRIED BY THE HULL FOR DISCHARGING AIR REARWARDLY PROPELLING THE HULL FORWARDLY. FURTHER, STRUCTURE IS PROVIDED FOR TRAPPING AND DUCTING A PORTION OF THE REARWARD DISCHARGE OF AIR FROM PROPELLER TO THE AIR OUTLETS, WHEREBY THE TRAPPED INDUCTED PORTION OF THE REARWARD AIR DISCHARGED FROM THE AIR PROPELLER IS USED TO FORM AT LEAST A PARTIAL BLANKET OF AIR BETWEEN THE BOTTOM SURFACE OF THE HULL AND THE SURFACE OF THE WATER OVER WHICH THE HULL IS MOVING.

Description

Feb. 6, 1973 J. VAN. VELDHUIZEN 3,714,918

AIR BOAT WITH AIR CUSHION 2 Sheets-Sheet 1 Filed July 6. 1970 VENT OR.

John m Ve/d/ruken 1973 J. VAN. VELDHUIZEN 3,71

AIR BOAT WITH AIR CUSHION Filed July 6. 1970 2 Sheets-Sheet 2 John Van Ve/dhw'zen IN! 'EXTOK.

& BY

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United States Patent 3,714,918 AIR BOAT WITH AIR CUSHION John Van Veldhuizen, Homestead, Fla. (Rte. 2, Box 54, Unionville, Tenn. 37180) Filed July 6, 1970, Ser. No. 52,256 Int. Cl. B63b N38 US. Cl. 114-67 A 12 Claims ABSTRACT OF THE DISCLOSURE A Water surface planing craft including a hull having a bottom surface provided with a plurality of air outlets opening downwardly therethrough. A motor driven air propeller is carried by the hull for discharging air rearwardly propelling the hull forwardly. Further, structure is provided for trapping and ducting a portion of the rearward discharge of air from propeller to the air outlets, whereby the trapped inducted portion of the rearward air discharged from the air propeller is used to form at least a partial blanket of air between the bottom surface of the hull and the surface of the water over which the hull is moving.

The air boat construction of the instant invention has been specifically designed for use in shallow water and travel over marsh and swamp grasses.

The basic configuration and operation of the air boat construction of the instant invention is quite similar to conventional propeller driven air boats provided with generally fiat bottom planing surfaces. However, the air boat of the instant invention is provided with a false bottom planing surface spaced below the air-tight bottom and air outlet holes are provided in the false bottom. An air trapping and ducting structure is provided on the hull and is operable to trap a portion of the rearward discharge of air from the air propeller and duct the trapped air into the area between the water-tight bottom of the hull and the false bottom of the hull for discharge through the holes or openings formed in the false bottom. In this manner, a blanket or thin layer of air is formed between the bottom planing surface of the hull and the surface of the water over which the hull is moving. This of course results in reduced skin friction and slightly higher riding of the boat hull on the water and in turn afiords for higher speed of the hull with less power.

The false bottom surface of the hull is corrugated whereby the air discharged downwardly through the false bottom is for the most part retained in longitudinal downwardly opening channels so as to reduce the amount of air which moves laterally outwardly from the beneath the false bottom of the hull.

The main object of this invention is to provide an air boat construction which will be capable of travel in even shallower water than may be crossed by a conventional air boat and an air boat which at the same time will be capable of higher speeds with less power.

Another object of this invention is to provide an improved air boat construction which may be readily incorporated into the manufacture 'of conventional air boats.

Still another object of this invention is to provide an improved air boat construction which will conform to conventional forms of manufacture, be of simple construction and easy to operate so as to provide a device that will be economically feasible, long lasting and relatively trouble-free in operation.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a longitudinal vertical sectional view taken substantially upon a plane passing through the longitudinal center line of an air boat constructed in accordance with the present invention;

FIG. 2 is a bottom plan view of the air boat construction;

FIG. 3 is a vertical transverse sectional view taken substantially upon the plane indicated by section line 33 of FIG. 1.

FIG. 4 is a transverse vertical sectional view taken substantially upon a plane indicated by section line 44 of FIG. 1; and

FIG. 5 is a fragmentary longitudinal vertical sectional view similar to the lower right-hand portion of FIG. 1 but illustrating the air trapping shutter of the instant invention in a closed position.

Referring now more specifically to the drawings the numeral 10 generally designates an air boat constructed in accordance with the present invention and which includes a hull 12 above whose aft portion a motor 14 is supported in elevated position. The motor 14 includes a rearwardly projecting rotary output shaft 16 upon which an air propeller 18 is mounted. Further, an air shroud 20 is supported from the hull 12 and closely embraces the air propeller 18. In additional, a pair of opposite side air rudders 22 are supported for oscillation about parallel upstanding axes and the air rudders 22 are interconnected for simultaneous and equal oscillation and suitable controls (not shown) are provided for oscillating the air rudders 22.

The hull 12 includes a sealed forward chamber 24 and a sealed longitudinally extending main hull chamber 26 forward of whose front end of the bow chamber 24 is disposed.

The bow and main hull chambers 24 and 26 include coextensive upper walls or deck surfaces 28 and 30 and the motor 14 and shroud 20 are supported from the deck surface 30. An upstanding partition 32 separate the bow chamber 24 from the main hull chamber 26 and the rear end of the main hull chamber 26 is closed by means of a rear wall 34. The bow chamber 24 includes an upwardly curving transverse bottom surface or wall 36 and the main hull chamber 26 includes a bottom wall 38 whose forward end is stepped above the rear end of the bottom wall 36. Of course, the hull 12 includes opposite side walls 40 and 42 interconnecting corresponding marginal edge portions of the walls 30 and 38 and the bow compartment 24 also includes side wall portions extending between the walls 28 and 36.

The rear ends of the side walls 40 and 42 include extensions 44 which project rearwardly of the rear wall 34 and the rear ends of the extensions 44 are interconnected by means of a transverse upstanding wall 46 which curves forwardly at its upper end portion as at 48. It will be noted that the wall 46 projects upwardly above the top deck or wall 30 of the main hull chamber 26 and also above the lower peripheral portion of the air propeller 18.

A partial cylindrical air shutter or gate 50 is pivotally secured to the upper marginal edge portion of the wall 46 by means of a hinge construction 52 and an extendable fluid motor 54 is operatively connected between the wall 34 and the air shutter 50 and may be extended and retracted to raise and lower the air shutter 50 between the upper open position thereof illustrated in FIG. 1 of the drawings and the lowered closed position thereof illustrated in FIG. 5 of the drawings.

From FIG. 5 of the drawings it may further be seen that the extensions 44 include upper portions 44' which conform to the upper open position of the air shutter 50 in order to define a forwardly opening air duct immedi-. ately behind the lower peripheral portion of the air propeller 18. Further, from 'FIGS. 1 and 5 of the drawings it may be seen that the free swinging edge portion of the air shutter 50 forms a reasonably good seal with the rear marginal edge portion of the top deck or wall 30 when the air shutter 50 is in the closed position.

The hull 12 includes a corrugated false bottom wall 56 disposed beneath the bottom wall 38 and the false bottom wall 56 includes a plurality of side-by-side upwardly opening and longitudinally extending semi-cylindrical members '58 secured to the bottom wall 38. The semi-cylindrical members 58 extend rearwardly of the rear transverse wall 34 and thus open up into the air plenum defined between the extensions 44, the wall 46 and the wall 34. The semi-cylindrical members 58 also form a bottom for the plenum and each of the semi-cylindrical members 58 has a plurality of air outlet openings 60 formed therein through which air may be exhausted from within the semi-cylindrical members 58 outwardly through the false bottom 56.

The rear ends of the semi-cylindrical members 58 are closed by means of an upstanding transverse flexible panel member or flap 62 hinged along its upper marginal edge portion as at 64 to the wall 46 a spaced distance above the lower marginal edge portion thereof. The flap 62 terminates downwardly in a horizontal plane generally aligned with the lower extremities of the semi-cylindrical members 58. Although it will be noted from FIG. 4 of the drawings that the lower extremities of the semi-cylindrical members 58 are disposed along a transversely bowed path extending longitudinally of the hull and opening downwardly. This disposition of the lower extremities of the semi-cylindrical members 58 further insures that most of the air discharged from the opening 60 will be trapped between the extreme opposite side semi-cylindrical members 50.

In operation, when the hull 12 is being propelled at high speeds by the air propeller 18, variable portions of the rear discharge of the air from the air propeller 18 may be trapped and ducted into the plenum disposed rearwardly of the wall 34 and into the rear ends of the upwardly opening semi-cylindrical members 58 for forward movement therein and outward discharge through the various openings 60 formed in the semi-cylindrical members 58. The amount of air to be trapped and ducted into the semi-cylindrical members 58 may of course be controlled by actuation of the extendable fluid motor 54. A maximum amount of air is ducted to the semicylindrical members 58 with the air shutter 50 as in the raised opened position illustrated in FIG. 1 of the drawings and substantially no air is trapped and ducted to the semi-cylindrical members 58 when the air shutter 50 is in the closed position illustrated in FIG. 5 of the drawings.

It will of course be noted that only the lower portion of the rear discharge of the air from the air propeller 18 can be trapped and ducted to the semi-cylindrical members 58. Accordingly, a great majority of the rearward discharge of air from the air propeller 18 is still utilized for forward propulsion of the boat 10. However, the quantity of air which is trapped and ducted to the semi-cylindrical members 58 when the air shutter '50 is in the open position thereof illustrated in FIG. 1

of the drawings is sufficient to cause a considerable discharge of air to be passed through the opening 60 and beneath the false bottom wall 56 in order to form an air blanket or layer between the false bottom 56 and the surface of the water over which the boat 10 is planing.

It will also be noted that the greater air pressure within the semi-cylindrical members 58 is realized at the rear ends of the members 58 and therefore that a greater amount of air will be discharged from the rear opening 4 60 than will be discharged from the forward opening 60. Inasmuch as the boat 10, when planing over the water at high speeds, has a major portion of its weight supported by its aft end, this greater amount of air discharged through the aft openings 60 compensates for the heavier loading of the boat 10 at its rear end.

The shutter or flap 62 is utilized to restrict the flow of air outwardly from beneath the rear ends of the semi-cylindrical members 58. However, the flap is pivoted rearward as the boat 10 planes over the water at high speeds and only the extreme lower marginal edge portion of the flap 62 contacts the water with the result that the flap 62 does not offer appreciable drag on the boat 10, even though urged toward a closed position by spring 66.

As hereinbefore set forth, the powering and controlling of the boat 10 may be substantially the same as the powering and control of a conventional air boat, except for actuation of the extendable fluid motor 54 which may be accomplished by any suitable fluid pressure system (not shown).

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. An air boat construction comprising a hull including a false bottom adapted to plane over the surface of a body of water, said false bottom having a plurality of air outlets opening downwardly therethrough, air propulsion means carried by said hull for discharging propulsion air rearwardly from said hull, and means operati-ve to trap and duct a portion of the rear discharge of propulsion air from said air propulsion means to said air outlets, whereby said trapped and ducted portion of the rear discharge of air from said air propulsion means may be used to form at least a partial blanket of air between the surface of said water and the bottom surface of said hull, said false bottom being longitudinally corrugated.

2. The combination of claim 1 wherein said air outlets open downwardly through said false bottom above the lowest depending ridges defined by said corrugated false bottom.

3. The combination of claim 2 wherein said hull includes a water-tight inner bottom structure above said false bottom. 4. The combination of claim 1 wherein the depending ridge forming portions of the corrugated false bottom disposed adjacent and extending along the opposite side longitudinal marginal portions of said false bottom project downwardly below the other ridge forming portions of said corrugated false bottom.

5. The combination of claim 2 wherein said hull includes a water-tight inner bottom structure above said false bottom, said false bottom projecting rearwardly of said inner bottom, said means comprising an upstanding air plenum disposed behind said inner bottom closed at its lower end by means of said false bottom and including a forwardly opening upper end disposed in horizontal registry with and behind the lower portion of the rear discharge of propulsion air.

6. The combination of claim 5 wherein said forwardly opening upper end of said plenum includes gate means shiftable between open and closed positions opening and closing the upper end of said plenum.

7. The combination of claim 6 wherein said gate means, when in said open position, comprises an upper extension of the rear wall of said plenum.

8. An air boat construction comprising a hull including a false bottom adapted to plane over the surface of a body of water, said false bottom having a plurality of air outlets opening downwardly therethrough, air propulsion means carried by said hull for discharging propulsion air rearwardly from said hull, and means operative to trap and duct a portion of the rear discharge of propulsion air from said air propulsion means to said air outlets, whereby said trapped and ducted portion of the rear discharge of air from said air propulsion means may be used to form at least a partial blanket of air between the surface of said water and the bottom surface of hull, an upstanding flap member carried by the rear end of said hull and extending transversely thereacross, the lower marginal edge portion of said flap member projecting slightly below at least portions of the rear marginal edge portion of said false bottom.

9. The combination of claim 8 wherein the upper marginal edge portion of said :flap member is pivotally supported from said hull for swinging about a horizontal transverse axis, whereby the lower free edge portion of said flap member may be swung rearwardly and upwardly to at least a partially retracted position in response to rapid forward movement of said hull over water.

10. The combination of claim 9 wherein said flap is constructed of resilient material and is spring urged toward a fully extended position abutting at least portions of the rear marginal edge of said false bottom.

11. An air boat construction comprising a hull including a bottom adapted to plane over the surface of a body of water, said bottom having a plurality of air outlets opening downwardly therethrough, air propulsion means carried by said hull for discharging propulsion air rearwardly from said hull, and means operative to trap and duct a portion of the rear discharge of propulsion air from said air propulsion means to said air outlets, whereby said trapped and ducted portion of the rear discharge of air from said air propulsion means may be used to form at least a partial blanket of air between the surface of said water and the bottom surface of said hull, said bottom being longitudinally corrugated, said means operative to trap and duct a portion of the rear discharge of propulsion air including an upstanding air plenum having a forwardly opening upper end disposed in horizontal registry with and behind the lower portion of rear discharge of propulsion air, the lower end of said plenum being communicated with said air outlets, and gate means operatively associated with the forwardly opening upper end of said plenum shiftable between open and closed positions opening and closing the upper end of said plenum.

12. The combination of claim 11 wherein the opposite side marginal portions of said bottom include portions thereof extending longitudinally of said hull which project downwardly and define barriers to lateral outward movement of air from beneath said bottom.

References Cited UNITED STATES PATENTS 1,307,135 6/1919 Lake ll467A 3,398,809 8/1968 Wood et al. l124 X 1,469,796 10/ 1923 Lake 1l4-67 A ANDREW H. FARRELL, Primary Examiner

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