US2887082A

US2887082A - Hydrofoil steering, adjusting and retracting mechanism

Info

Publication number: US2887082A
Application number: US607529A
Authority: US
Inventors: Jr Harold Boericke; Bader John
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-08-31
Filing date: 1956-08-31
Publication date: 1959-05-19
Anticipated expiration: 1976-05-19

Description

May 19, 1959 H, BOERICKE, JR., ETAL 7,

HYDROF OIL STEERING, ADJUSTING AND RETRACTING MECHANISM Filed Aug. 31. 1956 4 Sheets-Sheet 1 INVENTORS HAROLD BOERICKE JR JOHN BADER ATTORNEYS May 19, 1959 H. BOERICKE, JR., ETAL 2,887,082

ADJUSTING AND RETRACTING MECHANISM HYDROFOIL. STEERING,

Filed Aug. 31, 1956 4 Sheets-Sheet 2 INVENTORS HAROLD EOERICKE, JR, JOHN BADER ATTORNEYS y 1959 H. BOERICKE, JR. ETAL 2,887,082

HYDROFOIL STEERING, ADJUSTING AND RETRACTING MECHANISM 4 Sheets-Sheet 3 Filed Aug. 31, 1956 INVENTORS n E R J W m E 7 W m M A m OD 4 BA fi B L N w J y 9, 1959 H. BOERICKE, JR, EFAL 2,887,082

HYDROFOIL STEERING, ADJUSTING AND RETRACTING MECHANISM Filed Aug. 31, 1956 4 Sheets-Sheet 4 S 5 m8 n T N NJ R E 7O VE W NK RR 2 m x A D L N 8 w MJ United States Patet HYDROFOIL STEERING, ADJUSTING AND RETRACTING MECHANISM Harold Boericke, 31"., and John Bader, Washington, D.C.

Application August 31, 1956, Serial N0. 607,529

17 Claims. (ci. 114-665 (Granted under Title as, US. Code 1952 see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. p

This invention relates to improvements in hydrofoil craft and in particularit relates to steering, angle of attack control and indication, and to retraction of hydrofoils.

Existing mechanisms for supporting forward foils on a craft are mounted on the ends of fixed arms extending from the sides of the craft. Such mechanismsmake no provision for steering by the forward foils. With such mechanisms, any adjustment to the angle of attack of the foils is awkward and cumbersome. Such mechanisms are relatively inaccessible and the fixed arms are a constant source of annoyance and damage while the craft is lying alongside a dock or the like. The structures used heretofore allow the foils to be jarred out of adjustment, and no simple check is possible for realignment while waterborne. Realignment is a tedious process which, with existing mechanisms, can be done only after the craft has been hauled out of the water.

With the above in view, a principal object of this invention is the provision of a single, interconnected mechanism for steering, controlling and indicating angle of attack, and

for retracting hydrofoils, which are mounted on the sides of the hull and are accessible from the deck of hydrofoil craft.

Another object of the invention is the provision of automatic angle of attack control for hydrofoils while steering by such foils.

Another object of the invention is the provision for retraction close to the hull and out of the water of'foils of a hydrofoil craft while such craft is waterborne.

Another object of the, invention is the provision of balance of lift and drag foiltorques in hydrofoil craft.

Another objectof the invention is the provision of a safety device for limiting stresses imposed on the mechanism in case of foil impact on a floating object or the like.

A further object of the invention is the provision of synchronizing mechanism for simultaneous movement of hydrofoils mounted on opposite sides of a craft.

The invention, together with the above and other objects and advantages thereof, is set forth in more technical detail in the following description and accompanying drawings, wherein:

Fig. 1 is a schematic top planview, partly in section, of a water craft, showing a pair of hydrofoils attached to opposite sides of the hull near the bow thereof and a hydraulic system for manipulating the foils in accord ance with this invention;

on the gudgeons forrot ation about a near-vertical axis.

ice

Fig. 5 is a top plan view of the structure shown in Fig. 2;

Fig. 6 is a vertical section taken on line 6-6 of Fig. 5;

Fig. 7 is a transverse section taken on line 7--7 of Fig. 6;

Fig. 8 is a transverse section taken on line 8-8 of Fig. 6; and

Fig. 9 is a side elevational view of the structure shown in Fig. 2, and showing in broken lines the relative retracted position of the hydrofoil.

Referring now to Fig. 1 of the drawing wherein for purposes of illustration there is shown the forward portion of a water craft 10 having a pair of forward hydrofoil mechanisms 12 and 12' mounted on opposite sides of the hull near the bow thereof. Suitable aft hydrofoil mechanisms, not shown, may be mounted, near the stern of the craft. The

hydrofoil mechanisms

12 and 12'. are operated by a pair of hydraulic rams 14 and 14', respectively, which rams are connected by pairs of

conduits

16, 16' and 18, 18' to opposite ends of a pair of

hydraulic steering cylinders

20 and 20, respectively. The hydraulic steering cylinders are mounted on opposite sides of a control box 22 and are provided with

pistons

24, 24 and

piston rods

26, 26, which piston rods are connected to opposite ends of a gear rack 28 for reciprocation therewith. A pinion gear 30, mounted on the forward end of a steering shaft 32, meshes with rack 28. The steering shaft is journaled on the control box and has a steering. wheel 34 mounted on the aft end thereof. A' solenoid-operated retracting plunger 36 is mounted Within the control box and includes a piston 37 mounted within a hydraulic cylinder 33, which cylinder has conduits 40 and 42 connected to opposite ends thereof. Conduit 40 is provided with a solenoid-operated valve 41 having a pair of branches a and 4012 leading therefrom andconnected, respectively, to conduits 16 and 16'. Conduit 42 is provided with a solenoid-operated valve 43 having a pair of branches 42a and 42b leading therefrom and connected, respectively, to conduits 18 and .18.

Plunger 36, when deenergized, is spring-biased to the inner position shown in Fig. l, and when energized, piston 37 is forced outwardly of cylinder 38. Solenoidoperated valves 41 and 43 are biased to closed position when deenergized and are open when energized. So that the plunger and the solenoid valves may be operated simultaneously, they are wired in series in an electric circuit. This circuit includes a lead wire 45 leading from a suitable source of current, a switch 46, solenoid plunger 36, solenoid valve 43, solenoid valve 41 and a return wire 47 back to the source of current. A switch bridge 48 for closing switch 46 is mounted on rack 28 and is positioned in a manner to close the switch terminals and thereby energize the plunger and valves when the steering wheel is rotated clockwise beyond a given steering range. For preventing accidental rotation of the steering wheel beyond this steering range, a suitable stop mechanism, not shown, may be provided. Thus, as will be described in detail hereinafter, the

hydrofoil mechanisms

12 and 12 aresimultaneously moved to their retracted position by clockwise rotation of the steering wheel-beyond its steering range. Hydrofoil mechanisms 12 and 12' are similar, but of opposite hand, therefore, only one such mechanism 12, will be described in detail.

Referring now to Figs. 2, 5 and 6, hydrofoil mechanism 12 includes a substantially triangular-shaped frame 50 mounted on the hull of the craft by a pair of

gudgeons

51 and 52. Frame 50 includes a near-vertical tubular inemberSS, a horizontal tubular-member 54 and connecting

struts

55 and 56. A near-vertical shaft 58, that passes through tubular member 53, mounts the frame H 'A horizontal shaft 59 passes through tubular member 54 of the frame and has a hydrofoil 60 rigidly attached thereto for rotation therewith. A bevel gear 62 attached to the inboard end of horizontal shaft 59 meshes with a segment of a companion bevel gear 63 formed on a lower portion of near-vertical shaft 58.

The hydrofoil 60 may be of any desired form, however, ,for purposes of illustration, it is shown here as a diamend-shaped foil in accordance with the invention of Harold Boericke, In, one of the joint inventors herein, and described in his application, Serial No; 555,212, filed December 23, 1955.

As'shown in Fig. 2, the hydrofoil comprises a unitary structure including an upper or inverted V-shaped foil 64, a lower V-shaped foil 65 and a horizontal foil and brace 66. The hydrofoil is attached to the outboard end of shaft 59 by a strut 67, which, as shown in Figs. and

9, extends upward and aft from the top V and terminates in a collar rigidly secured to shaft 59, and at the inboard corner, the hydrofoil is supported by a strut 68 also rigidly secured to the shaft. Thus, as shown in Figs. 5 and 9, the hydrofoil is supported on a horizontal axis on a line to the rear of the plane of the foils so that the lift forces of the foils tend to rotate the bottom of the hydrofoil forward. This tends to counter-balance the effects of drag forces of the hydrofoil tending to rotate the bottom of the hydrofoil aft. In this manner, hydrodynamic balance is obtained. For a more detailed description of the diamond-shaped hydrofoil and modifications thereof, reference may be had to the above patent application of Harold Boericke, Jr., Serial No. 555,212.

' Returning to Figs. 2 and 6, the frame 50, and hydrofoil 60 attached thereto, is made to rotate with and about 'the near-vertical shaft 58 by a steering arm 70, as dejjscribed hereinafter. Arm 70 has an outboard end thereof keyed, as by keys 71, to the upper portion of frame member 53 and an inboard end pivoted, as by pivot pin 72 (Fig. 5), to a bifurcated end 73 of a piston rod 74, which piston rod is attached to a piston 75 within a cylinder 76 of hydraulic ram 14. So that the cylinder of the hydraulic ram may be free to move with movement of the piston and piston rod, the cylinder is pivoted to the deck of the craft by a pivot connection 78.

An arm 80, for adjusting the angle of attack of the hydrofoil, is mounted on top of steering arm 70 and has an outboard end thereof that surrounds shaft 58 and is releasably attached thereto by a clutch member 90. The inboard end of arm 80 is formed as a segment of a gear 82 (Fig. 7) that meshes with a worm gear 84. Gear 84 is provided with a shaft 85 journaled in a pair of supports 86 formed on steering arm 70. A crank 87, for manually rotating the worm gear and through it the adjusting arm '80, is mounted on one end of shaft 85.

The upper portion of near-vertical shaft 58 is formed 'with a portion 58a (Figs. 3 and 6) of reduced diameter upon which is mounted a splined sleeve 91. A safety or rotation therewith.

As shown in Figs. 2 and 7, clutch member 90 is formed with a pair of keys or projections 93 on the lower face thereof, which keys fit into keyways 94 in the upper face of adjusting arm 80. For moving the clutch member 90 vertically relative to the adjusting arm and thereby disengagingthe adjusting arm from shaft 58, a roller 95 -is mounted on one side of the clutch member in position to ride upon a ramp surface 96a of a cam member 96,

which cam member forms a part of the upper gudgeon 51 (Figs. 2 and 3). Clutch member 90 is formed with an upper portion 90a of reduced diameter (Fig. 6) for the reception of a coil spring 97, which spring. releasahly v, 4 urges the clutch member into engagement with the adjusting arm and is itself held under compression by a washer 98 and a nut 99, the latter screw-threaded upon the upper end 58a of shaft 58. A stop 52a, formed on lower gudgeon 52 (Figs. 2 and 4), contacts a vertical surface 63a formed on bevel gear 63 and thereby limits forward rotation of the combined frame and hydrofoil mechanism 12 within the forward steering range thereof. The stop 52a, upon stopping forward rotation of the frame and hydrofoil mechanism, also initiates the retraction of the hydrofoil, as pointed out hereinafter.

In operation, with the hydrofoils athwartship,as shown in Fig. l, clockwise rotation of the steering wheel, through the rack and pinion, causes piston 24 to be moved inward of cylinder 20 and hydraulic fluid to be forcedfrom the cylinder through conduit 18 into hydraulic ram 14 behind the piston therein, with the result that the piston is forced inwardly of the cylinder and hydrofoil mechanism 12 is rotated aft of the craft. Simultaneously with the forcing of fluid from cylinder 20, fluid is forced from cylinder 20' through conduit 16' into hydraulic ram 14 in front of the piston therein, with the result that this piston is forced outwardly of the cylinder and hydrofoil mechanism 12' is rotated forwardly to the craft; thus, the craft makes a starboard turn. Counterclockwise rotation of the steering wheel causes forward rotation of hydrofoil mechanism 12 and aft rotation of hydrofoil mechanism 12'; whereupon, a port turn is maneuvered. The steering range of the hydrofoil mechanisms is approximately eight degrees fore and aft of athwartship. It will be noted that each of the hydraulic systems thus far described constitutes a closed circuit so that the forcing of fluid from one end of a cylinder causes fluid to flow into the opposite end thereof, and vice versa. -Since valves 41 and 43 are closed during steering maneuvers, fluid cannot by-pass through branch conduits 40a, 405 or 42a, 42b. 1

With the clutch 90 engaged, as shown in Figs. 2 and 6. frame 50, near-vertical shaft 58, horizontal shaft 59,

bevel gears

62 and 63, and hydrofoil are held fixed relative to each other, so that through the steering range of approximately eight degrees fore and aft of athwartship these components rotate about the near-vertical axis as a unit. The steering range of movement of the piston 75 fore and aft the cylinder 76 of hydraulic ram 14 is approximately that shown'in Fig. 5. That is, the capacity of hydraulic cylinder 20 (Fig. 1) is such that, with maximum clockwise movement of the steering wheel in the steering range, sufficient fluid is forced from cylinder 20 through conduit 18 into cylinder 76 to force piston 75 from the position shown in Fig. 5 to the inner end of the cylinder. Conversely, with maximum counterclockwise rotation of the steering wheel in the steering range, sufficient fluid is forced from cylinder 20 through conduit 16 into cylinder 76 to force piston 75 from the position shown in Fig. 5 a like distance outwardly of the cylinder. This latter movement of piston 75 causes steering arm to rotate frame and hydrofoil mechanism 12 forwardly about the near-vertical axis until the vertical surface 63aon bevel gear 63 contacts stop 52a on gudgeon 51 which limits this forward movement and positions the mechanism 12 for retraction of hydrofoil 60.

In retracting the hydrofoils, the steering wheel is rotated clockwise beyond the steering range and until bridge member 48 closes the electric circuit through switch terminals 46, the solenoid-operation valves 41 and 43 (Fig. l) in

conduits

40 and 42, which. are closed during steering maneuvers, are energized and'opened and the solenoid-plunger 36 is energized so that now hydraulic fluid is forced from cylinder 38 through conduit 40, branches 40a and 40b, and

conduits

16 and 16 into the cylinders of rams 14 and 14', respectively, in front of the pistons therein. In the meantime the steering wheel and its rack and pinion will have been locked by suitable mechanism, not shown, so that the forcing of fluid from retraotingcylinder 38: \vilLhaveno effect on the position; of thepistonsin steering. cylinders. 20=and 20. It may be statech that the. retracting; maneuver. is. best: initiated with the frame and. hydrofoil mechanisms positioned. athwartship, asshown in; Fig. 1.

Withthe frame and hydrofoil mechanism so positioned and hydraulic fluid being forced. from; cylinder. 38 into the cylinders of rams 14 and.14, as just described, the pistons ofsuch cylinders are moved outwardly thereof (aft of the craft) Whereuponthe frame and

hydrofoil mechanisms

12 and 12 are each rotatedabout its near-vertical axis forwardly of the craft. The capacity of cylinder 33 is such that now the pistons of

rams

14 and 14. are moved beyond the forward steering range to the aft end of their cylinders.-

In tracingtheretracting movement of frame and hydrofoil mechanismlZ, for example, the.above extrememovement of. piston 75 causes arm 70 to rotate the frame and hydrofoil, mechanism forward of the craft as a unit. As frame Stlmoves beyond the forward end of the steering range, theverticalsurface. 63a on bevel gear 63, strikes the stop 52a on the lower gudgeon (Figs. 2 and 4) causing gear. 63 and consequently shaft 58 to be held stationary. At thisipoint the roller 95 on clutchmember 90-ridesup the ramp 96:: (Fig. 3) of cam 96 which disengages the clutch and: allows the frame 50 torotaterelative to bevel gear 63 and shaft 58. As the ram continues .torotatethe frame forward, the now stationary bevel gear 63, through the meshing gear 62, causes horizontal shaft 59'to rotate hydrofoil 60 backwards and upwards at a rate, determined by the gear ratio, of slightly morethan twice that of the frame. Thus, as aresult of a frame rotationof 80 forward, the hydrofoil rotates 180 backwards and upwards, describing a simultaneous and combined rotation. At the end of this travel, the foil frame retracts to a forward position, against the hull of the craft, whereas: thehydrofoil itself rotates into a. nearly-vertical up-side down position in line with the near-vertical axis of rotation of the foil frame, as shown in broken lines in Fig. 9.

The lower plate of the clutch is apart of the angleof attack control arm 80 that is regulated by the worm gear 84. The upper plate of the clutch is restrained in rotation by the splined sleeve 91 on the near-vertical shaft 58', and it is restrained in, vertical motion by compression spring97 acting on its upper surface. The safety pin 92. (Fig. 3) is incorporated between the. splined. sleeve 91 of the upper clutch plate and the reduced portion 58a of shaft 58 to limit impact on the foil. That is, should the foil strike a floating object,'the pin 92 is sheared, thereby relieving the mechanism of undue strain. To realign the hydrofoil, it is required only to use a portable wrench on the top of shaft 58 to reset the foil and replace the safety pin. This operation can be performed'while afloat.

The angle of attack of hydrofoil 60 may bechanged with respect to the frame 50 by means of worm gear 8.4, attachedto arm 80. Rotation of the wormgear by crank 37rotates arm 80, clutch 90 and shaft 58, with respect to frame 50. Through

bevel gears

62 and 63, shaft 58 rotates shaft 59 and thus hydrofoil 60. All this takes place while frame 50 is held in one position by arm 70 and ram-14. A feature which permitsautomatic angle of attack change for controlof the bankwhile turning is the, inclination of the near-vertical shaft 58 up and outboard (Figs. 2 and 6). While steering, the hydrofoil on the outside of the turn moves forward, and the (hydrofoil'on the inside of the turn moves aft. The up and outboard inclinations. ofjthe vertical; axis: of the hydrofoil frames, cause the foil angle of. attackto; increase-. on the outboard side of" the turn and decrease on the inboard side, thus increasing the lift on the outboard foil and decreasing it on the inboard foil. The difference in the lift forces on the two foils causes an inboard-banking moment which opposes the outboard-banking moment on inboardhydrofoil while maneuvering the-boat stcentrifugalforce on the turn. The. angle. which this. axis of; rotation makes with/the. vertical determines the: amountfofinboard-banking moment of the foils,,a nd sodeterminesv howmuch the boat. banks. inboard. or out;- boardI onr a: turn.

A. featurewhich reduces. the size of the shafts, bevel gearsand, clutch members, is the torquevbalancing effect of the foils forward of the foil frame. In flight,. the forward-rotating moment of. the lift causedby the. offset strut 6.7 counteracts, or more. than. counteracts the aft? rotating moment about a horizontal: axis in the foil frame of the drag, thusleaving a small residual. momentto. be controlled. by, the gears 82 and84, noted above. If the. lift torque, forward. more. than countenbalances the. dragtorque ate, the net torque is then forward, and it provides a ,cushionfor, impact on the foils. The impact, when-the foils strike an object, has first to overcome the nettorque forward before it acts on.the shear pin.

As. will nowbe seen, the hydrofoil steering, retracting and adjusting mechanismis relatively compact in.con-. figuration, allowing. thefoils to retract close to the hull out of the water and thus avoid damage to such foil mechanism. Themechanism is. integratedto a degree of allowing all necessary functions to be accomplished with. less. parts thanheretofore required. The mechanism distributes the lift forces andmoments of the foils to the hull in a wider and more effective manner, 'utilizingsexisu ing structural members ofthe hull to full advantage. Also, the angle of attack and position ofthe foils is adjusted and indicated. in a positive manner from the deck of the boat while. waterborne.

Without further descriptiomit is thought that the fear. tures and advantages, oftheinvention will be readilyapparentto. those. skilled in. the art to. which thisinventiou appertainsand, it will, of course, be understood that; while.but.-,oue. embodiment of the invention has been lllUSr trated. and. described herein, changes in form, proportions andminon details. of construction may be resorted to .with. outdepartingfrom the spirit of the invention and, scope of the claims.

Whatis claimed is:

l. A hydrofoil craft comprising a hull, a pair of hydro.- foilsfor supporting the craft in motion, means mounting said hydrofoils onopposite sidesof the hull for rotary,

movement fore and. aft thereof, steering mechanism mounted on the craft, and means connecting thesteering mechanism to each of the hydrofoils in a manner as to rotate the hydrofoilsin opposite directions fore and aft, of the hull'with movement of the steering mechanismtothereby. steer. the craft by the hydrofoils.

2. A hydrofoil craft as set forth in claiml which ineludes means for changing the angle of attack of the; hydrofoils. while steering therewith and in a manner as to increase the angle of attack ofthe forwardly moving or outboard hydrofoil and to decrease the angle of at-i tack on the aft moving or inboard hydrofoil, thus increas-:

ing, lift, of. the outboard hydrofoil and. decreasing liftof the inboard hydrofoil while maneuvering a turn.

31 A hydrofoil craft as set forth in claim 1 wherein the means rotatably mounting the hydrofoils include a rotatable frame mounted on a near-vertical axis upward. and outboard of .the hull at each side thereof, whereby the. angle of attack is increased on the forwardly movingqor outboard hydrofoil and isdecreased on the aft moving or a turn.

4. A hydrofoil craft as set forth in claiml whereinthe. means rotatably mounting the hydrofoils and the steering. mechanism include means operative to limit. thefore and aft movement of the hydrofoils. within a steering range.

5. A hydrofoil craft as set forth in claim l wherein'the. means rotatably mounting the hydrofoils include means for retracting the hydrofoil mechanisms clear of a body of water upon which the craft is borne.

6. A hydrofoil craft comprising a hull including a deck, a pair of hydrofoil mechanisms rotatably mounted on opposite sides of the hull, said hydrofoil mechanisms being similar but of opposite hand, steering mechanism mounted on said deck, and means connecting the steering mecha- 'nism-to each of the pair of hydrofoil mechanisms in a manner as to rotate said hydrofoil mechanisms in opposite directions fore and aft of the hull with movement of the steering mechanism to thereby steer the craft by the hydrofoil mechanisms.

7. A hydrofoil craft comprising a hull, a pair of hydrofoils, means rotatably mounting the hydrofoils one on each side of the hull for rotary movement in opposite directions about near-vertical axes fore and aft of the hull, means mounting the hydrofoils for rotary movement about horizontal axes, steering mechanisms mounted on the craft, and means connecting the steering mechanism to each of the hydrofoils in a manner such that movement of the steering mechanism through a predetermined steering range effects opposite fore and aft movement respectively of said pair of hydrofoils for steering the craft, whereas movement of the steering mechanism beyond the predetermined steering range effects rotation of the hydrofoils about the horizontal axes to thereby retract the hydrofoils to positions above the surface of a body of water upon which the craft is borne.

8. A hydrofoil craft as set forth in claim 7 wherein the means connecting the steering mechanism to the hydrofoils includes means for simultaneously rotating each of the hydrofoils backward and upward relative to the bull to thereby retract the hydrofoils in an up-side-down position substantially in alignment with the sides of the hull.

9. A hydrofoil craft comprising a hull, a pair of hydrofoils for supporting said craft in motion, means mounting the hydrofoils on forward portions of the hull on opposite sides thereof for rotary movement in opposite directions fore and aft of athwartship, said hydrofoils each having a predetermined angle of attack when positioned athwartship, steering mechanism mounted on the craft, and means connecting the steering mechanism to each of the hydrofoils in a manner as to rotate the hydrofoils in opposite directions fore and aft of athwartship by movement of thesteering mechanism to thereby steer the craft by movement of the hydrofoils.

10. A hydrofoil craft as set forth in claim 9 which includes manually operative means for separately adjusting the angle of attack of each of the hydrofoils while the craft is in motion.

- 1-1. A hydrofoil craft as set forth in claim 9 which includes means operative by the fore and aft movement of the hydrofoils for automatically changing the angle of attack of each of the hydrofoils in a manner as to increase the angle of attack of the forwardly moving or outboard hydrofoil and to decrease the angle of attack of the aft moving or inboard hydrofoil, thus increasing lift of the outboard hydrofoil and decreasing lift of the inboard hydrofoil while maneuvering a turn, thereby establishing a difference in lift forces of the two hydrofoils which difference causes an inboard-banking moment which opposes an outboard-banking moment of the crafts centrifugal force on the turn.

1 12. A hydrofoil craft as set forth in claim 9 wherein the means mounting the hydrofoils include means limiting stresses imposed thereon by impact of the hydrofoils with a foreign object.

13. A hydrofoil craft comprising a hull, a pair of hydrofoil mechanisms mounted on near-vertical axes on opposite forward sides of the hull, each of the hydrofoil mechanisms including a frame, a near-vertical shaft mounting said frame on the side of the hull, means releasably securing said frame to the near-vertical shaft for rotary movement therewith and relative thereto, a substantially horizontal shaft rotatably mounted on said frame for rotary movement therewith and relative thereto, a hydrofoil mounted on said horizontal shaft for rotary' movement therewith, steering mechanism mounted on said craft, and means operatively connecting the steering mechanism to each of the hydrofoil mechanisms in a manner such that movement of the steering mechanism in one direction causes forward rotary movement of one hydrofoil mechanism about its near-vertical axis and aft rotary movement of the other hydrofoil mecha- -nism about its near-vertical axis, whereas movement of the steering mechanism in an opposite direction causes opposite fore and aft movements of the hydrofoil mechamsms.

14. A hydrofoil craft as set forth in claim 13 wherein the means releasably securing the frame to the nearvertical shaft includes means operable upon rotation of such shaft beyond a predetermined steering range for releasing the securing means and thereby afford rotary movement of the frame about the near-vertical shaft, means included in the steering mechanism for rotating the frame about the near-vertical shaft, and means operable upon movement of the frame about the near-vertical shaft for rotating the horizontal shaft and attached hydrofoil relative to the frame to thereby retract the hydrofoil to an up-side-down position clear of a body of water upon which the craft is borne.

15. A hydrofoil craft as set forth in claim 13 wherein the steering mechanism includes a steering Wheel, and wherein the means connecting the steering mechanism to each of the hydrofoil mechanisms includes a hydraulic system having means incorporated therein for moving the hydrofoils through a predetermined steering range fore and aft of the hull upon predetermined rotation of the steering wheel and for retracting the hydrofoils upon rotation of the steering wheel beyond the steering'range.

16. A hydrofoil craft comprising a hull, a pair of hydrofoils for supporting the craft in motion, means mounting said hydrofoils on opposite sides of the hullfor rotary movement in opposite directions fore and aft of athwartship, steering mechanism mounted on the craft, means connecting the steering mechanism to each of said hydrofoils for simultaneous movement thereof fore and aft of athwartship to thereby steer the craft by the hydrofoils, each of said hydrofoils bein ositioned in a common near-vertical plane when athwartship, and said mounting means including a support attached to an upper portion of each of the hydrofoils and extending aft of the near-vertical plane, the construction and arrangement of the hydrofoils and the mounting means being such that in flight the lift forces of each of the hydrofoils tend to rotate the bottoms thereof forward to thereby counterbalance the effect of drag forces tending to rotate the bottoms aft thereby providing a cushion effect for impact on the hydrofoils.

17. A hydrofoil craft as set forth in claim 16 wherein the mounting means include yieldable means for limiting impact stresses on the hydrofoils and mounting means resulting from impact of the hydrofoils with foreign objects.

References Cited in the file of this patent UNITED STATES PATENTS 1,095,166 Richardson Apr. 28, 1914 2,708,894 Hook May 24, 1955 2,795,202 Hook June 11, 1957 FOREIGN PATENTS 738,333 Great Britain Oct. 12, 1955