US3237582A - Surface piercing concave disc hydrofoil - Google Patents

Description

March 1966 J. A. STURGEON ETAL 3,237,582

SURFACE PIERCING CONCAVE DISC HYDROFOIL Filed June 7, 1965 4 Sheets-Sheet INVENTORS c/OSEPH 4. STUPGEOM,

' March 1966 J. A. STURGEON ETAL 3,237,582 I SURFACE PIERCING CONCAVE DISC HYDROFOIL Filed June 7, 1965 4 Sheets-Sheet 2 March 1, 1966 J. A. STURGEON ETAL 3,237,582

SURFACE PIERGING CONCAVE DISC HYDROFOIL INVENTORS S fl/QGEO 4 Sheets-Sheet 5 c/OSEPH 4. 0%:77 QW25 E STaPGEOA/ Filed June 7, 1965 March 1, 1966 J. A. STURGEON ETAL 3,237,582

SURFACE PIERCING CONCAVE DISC HYDROFOIL Filed June 7, 1965 4 Sheets-Sheet 4 IN V EN TORS 4055 J. 57 R950 7/30/1145 5 ra flea United States Patent 3,237,582 SURFACE PIERCING CONCAVE DISC HY DROFOIL Joseph A. Sturgeon and Thomas E. Sturgeon, Seattle, Wash. Filed June 7, 1965, Ser. No. 470,264 4 Claims. (Cl. 11466.5)

This application is a continuation-in-part application of our application Serial No. 300,507, filed August 7, 1963, and now being abandoned.

The present invention relates to watercraft generally and in particular to a hydrofoil boat having surface piercing concave discs.

-An object of the present invention is to provide a hydrofoil for a watercraft which to a great extent overcomes the problem of skin friction, one which automatically sheds itself of debris such as grass or seaweed when collected on the leading edge of the hydrofoil, one in which the problem of cavitation will be eliminated, and one which is highly effective in action.

:Another object of the present invention is to provide for a watercraft a hydrofoil assembly consisting of four discs arranged two at the forward end of the craft and two at the aft end of the craft, the discs being arranged so as to be tilted toward the craft and also tilted away from the movement of the craft through the water.

.A further object of the present invention is to provide ahydrofoil arrangement which permits a watercraft to travel well in rough water, and one which achieves greater stability of the craft not heretofore possible with present hydrofoil designs.

.A still further object of the present invention is to provide a rotating stabilizer which offers little or no resistance to travel through the water but provides stability for the watercraft on which it is installed while making turns or traveling straight.

Yet another object of the present invention is to provide a hydrofoil arrangement which is useful on all types of watercraft, one in which there are two or more hydrofoil means each individually suspended and resiliently mounted so as to absorb shock, one which is sturdy in construction and of simple structure, and one which is economically feasible.

These and other objects and advantages of the present invention will be fully apparent from the following description when taken in connection with the annexed drawings, in which:

FIGURE 1 is a side elevational view of a boat with a mid-portion broken away, showing the hydrofoil arrangement of the present invention installed thereon, the dotted line showing the raised-out-of-use position of the vertical stabilizer;

FIGURE 2 is a fragmentary front elevational view of the assembly shown in FIGURE 1;

FIGURE 3 is a view in section and on an enlarged scale of the support means for one of the hydrofoils;

FIGURE 4 is a view similar to FIGURE 2 showing a modified form of the invention;

FIGURE 5 is a fragmentary side elevational view of the assembly shown in FIGURE 4;

FIGURE 6 is a view on an enlarged scale taken on the line 6-6 of FIGURE 5;

FIGURE 7 is a view taken on the line 77 of FIG- URE 2;

FIGURE 8 is a front elevational view of a modified form of the invention;

FIGURE 9 is a bottom view of a preferred disc embodying a modification of the invention; and

FIGURE 10 is a front elevational view taken along lines 1010 of FIGURE 9.

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Referring in detail to the drawings in which like numerals indicate like parts throughout the several views, the reference numeral 10 designates generally a boat hull of more or less conventional design for which no invention is claimed.

Although in FIGURE 1 only two hydrofoil assemblies 12 and 14 are shown, it is to be understood that there are two on each side of the hull 10 with the assembly 12 positioned outwardly of and adjacent the forward end of the hull 10 and the assembly 14 positioned adjacent the aft end of the hull 10.

As the assemblies 12 and 14 are nearly identical, they will be described with reference to the assembly 12.

As shown in FIGURE 2, the assembly 12 includes a strut 16 and a shaft 18 rotatably mounted in the lower end of the strut 16. The disc 20 of the present invention is fixedly secured by welding or other means to the lower end of the shaft 18.

As shown most clearly in FIGURE 3, bearing assemblies 22 and 24 support the shaft 18 for rotation relative to the strut 16, the bearing assemblies 22 and 24 being mounted in a housing 26 which is provided with a pair of trunnions 28 on the lower end thereof for mounting of the strut 16 on the hull 10 with the support brackets 28 and 30, as shown most clearly in FIGURE 1.

The upper end of the strut 16 is connected by a nut or bracket assembly 32 to the hull 10 for limited upward and downward movement as controlled by a shock absorber assembly 34 interposed between the housing 26 and another portion of the hull 10.

An important feature of the present invention resides in the fact that the disc 20 is concave and has its concave face facing downwardly, as shown most clearly in FIG- URE 7. It is to be understood that the curve shown in FIGURE 7 is not necessarily a limitation on the invention and other shapes of concavity may be employed as desired.

Another feature of the invention resides in the provision of a vertical stabilizer assembly 36 consisting of a rotatable disc 38 mounted on a stub shaft 40, the stub shaft 40 being suspended from a yoke 42 pivotally connected to the underside of the hull 10, as shown in FIGURE 2.

The hull 10 is provided with a well, indicated by dotted lines at 44, into which the disc 38 may be moved from the full line position shown in FIGURE 1 to the dotted line position shown in FIGURE 1.

With reference to the modified form of the invention shown in FIGURE 4, the assembly 12 includes the disc 20 and a vertical stabilizer disc 38' carried on one end of a strut 46. The strut 46 projects horizontally from the lower end of the strut housing 48 which is mounted for limited resilient movement upward and downwardly, as described above with reference to the assembly 12.

The disc 20 is rotatably mounted on the strut housing 48 for free rotation about the strut housing 48 as an axis.

In FIGURE 8, a modified form of the invention is shown in which the disc 20 is rotatably mounted on the lower end of a shaft 50 which has its upper end portion telescopingly mounted within oleo strut assembly 52 which provides a resilient mount for the disc 20,

As shown most clearly in FIGURES 1 and 2, each disc 20 is disposed at a lateral angle with respect to the hull 10 and also at a fore and aft angle with respect to the path of movement of the hull 10 through the water.

The amount of this angle is such that a portion of the periphery adjacent the forward end of the boat of each disc 20 is out of the water, as shown in FIGURE 1. Traveling movement of the hull 10 through the water by a conventional drive means (not shown) causes each disc 20 to rotate and to thereby lessen the friction of the disc in the water.

The same applies to the vertically disposed disc 38 which serves as a stabilizer and, as shown in FIGURE 1, only a portion of the disc periphery is emersed in the water so that it too will be caused to rotate by the friction of the discs passing through the water.

It' is.to beunderstood that the invention is not to be limited by the angle of the discs, size of the discs, or its relative position to the hull as illustrated in the accompanying drawings. Nor is the shape of the concave face of the discs to be limited to that illustrated.

It will be seen therefore that the rotating disc 20 and the rotating disc 38. will be free of any debris-catching characteristics because of the rotation of the disc in the water..

Theiprovision of the resilient mounting of each of the discs provides for absorption of shock transmitted through rough water or for other reasons.

InFIGURES 9 and 10 there is shown a modified or alternative. and preferred embodiment of the disc that is capable of being used in the present invention. The disc 70' is adapted to be. rotatably mounted from a rotatable shaft 82 in which the upperend thereof is telescopically mounted, as shown in FIGURE 8, for rotation. The disc 70' is.of circular configuration, as shown in FIGURE 9, but the crossasectional;configuration thereof is shown so that it is. evident the cross-sectional curvature changes substantially'rapidly as it approaches the peripheral portion, asshown as curve 84. The intermediate portion of theinner face of: the disc 70 is'a curve generally shown as 86, and is substantially linear in cross-section to provide the generally, planar section formed by the surface of revolution of the curve 86. It is foundthat the construction of the disc. 70 provides the optimum characteristics in supporting anddriving a hydrofoil by means of the concave construction that is exemplified in FIGURES 9 and 10.

The fore and' aft angle of shaft 82. with respect to the path of movement of the hull through the water is generally that ofthe embodiments shown in FIGURES 1-8.

Although the invention is not to be limited by the angles-or the. configuration of the concave disc, it is to be understoodthat the concavity described and shown in the illustration .of the invention in FIGURES 9 and 10 is intended to show. what has been found to be the ultimate and. optimum characteristics of the preferredand best modeiof the invention.

Additional embodimentsof the invention in this specification will occur to others and therefore it is intended that the scope of the invention be limited only by the appended claims and not by the embodiments described hereinabove. Accordingly, reference should be made to the following claims in determining the full scope of the invention.

What is claimed is:

1. In at least a watercraft having a hull, a pair of downwardly and outwardly extending struts secured to said hull with one strut on each side thereof, a shaft freely rotatively journaled in each strut and extending downwardly therefrom in diverging relation to the hull, a disc mounted on the lower end of each shaft, each disc having a concave lower surface with the axis of rotation thereof converging upwardly and rearwardly in relation to the boat hull and also inwardly toward the centerthereof, whereby the wetted surfaces of the disc will movein rotation with the flow of water reducing skinfriction.

2. In at least a watercrafthaving a hull, a pair=of=downwardly and outwardly extending struts secured tosaid hull with one strut on each'side thereof, a shaft freely rotatively journaled in each strut and extendingdowmwardly therefrom in diverging relation tothe hull," a-

concave disc mounted'on the lowerend of each'shaft, the concavity of the disc being of such a radiusiofcurvature that the concavity increases attheper-ipheral portions of the disc, and ismore generally planar at'theintermedi ate and central portions-of the disc, whereby the wetted surfaces of the disc will move in rotation with'the flow of water reducing skin friction and providing improved support and operation of the hydrofoil.

3. The invention according to claim 1 wherein the concavity of the lower surface of the disc is generally planar throughout the central and intermediate portions of the disc, and is sharply contoured toward the-peripheral; portions thereof.

4. The invention according to claim 1 wherein the intermediate and central lower surface of the concave-disc is generally planar throughout these'portionsb No references cited.

MILTON BUCHLER, Primary-Examiner.

ANDREW H FARRELL, Examiner.

Claims (1)

1. IN AT LEAST A WATERCRAFT HAVING A HULL, A PAIR OF DOWNWARDLY AND OUTWARDLY EXTENDING STRUTS SECURED TO SAID HULL WITH ONE STRUT ON EACH SIDE THEREOF, A SHAFT FREELY ROTATIVELY JOURNALED IN EACH STRUT AND EXTENDING DOWNWARDLY THEREFROM IN DIVERGING RELATION TO THE HULL, A DISC MOUNTED ON THE LOWER END OF EACH SHAFT, EACH DISC HAVING A CONCAVE LOWER SURFACE WITH THE AXIS OF ROTATION THEREOF CONVERGING UPWARDLY AND REARWARDLY IN RELATION TO THE BOAT HULL AND ALSO INWARDLY TOWARD THE CENTER THEREOF, WHEREBY THE WETTED SURFACES OF THE DISC WILL MOVE IN ROTATION WITH THE FLOW OF WATER REDUCING SKIN FRICTION.

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