US3761980A

US3761980A - Water ski structure

Info

Publication number: US3761980A
Application number: US00202345A
Authority: US
Inventors: B Silverstein
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-11-26
Filing date: 1971-11-26
Publication date: 1973-10-02
Anticipated expiration: 1990-10-02

Abstract

An improved water ski structure having a conventional ski body with the addition of a pair of parallel depending rails on the lower ski surface defining a central channel therebetween. The forward portions of the rails are of a constant depth and merge at the forward end into the upwardly curved front end of the ski, and the rear portions of the rails are provided with a plurality of short sequential inclined planes having a progressively greater angle of inclination toward the rear end of the ski; the planes being inclined forwardly and upwardly to provide greater lifting power for the ski.

Description

United StatesPat-ent 1 9] Silverstein WATER SKI STRUCTURE [21] Appl. No.: 202,345

[52] U.S. Cl 9/310 A, 114/665 S, 280/1 1.13 Y [51] Int. Cl. A63c 15/00 [58] Field of Search 9/310 R, 310 A-310 E; 280/1 1.13 Y; 114/665 S, 66.5 R

[56] References Cited 7 UNITED STATES PATENTS 1,223,320 4/1917 Curtiss et al 114/665 S 1,620,349 3/1927 Hickman 114/665 S 3,099,025 7/1963 Merkley et al.. 9/310 A 2,143,545 1/1939 Currier 280/11.13 Y 3/1965 Amsbry: 9/310 A Rivard 9/310 A X Pope, Jr. et a1 9/310 A Primary Examiner-Milton Buchler Assistant Exar'ninerPaul E. Sauberer AttorneyCarl F. Geppert [57] ABSTRACT An improved water ski structure having a conventional ski body with the addition of a pair of parallel depending rails on the lower ski surface defining a central channel therebetween. The forward portions of the rails are of a constant depth and merge at the forward end into the upwardly curved front end of the ski, and the rear portions of the rails are provided with a plurality of short sequential inclined planes having a progressively greater angle of inclination toward the rear end of the ski; the planes being inclined forwardly and upwardly to provide greater lifting power for the ski.

10 Claims, 6 Drawing Figures PATENTED I 2 75 WATER SKI STRUCTURE The present invention relates to an improved water ski structure and more particularly to a water ski structure utilizing inclined planes on the bottom surface thereof to provide a greater lifting effect for the ski carrying a skier.

Conventional water skis provide an elongated flat lower surface with an upwardly curved forward end and a foot binding on the flat upper surface. Trick or stunt skis require a flat under surface and conventional skis are often provided with one or a pair of shallow wooden rudders or a deep single metal keel utilized for stability and to enhance the ease of maneuvering the skis while being pulled through the water. However, beginning from a stationary position in the water for the skier to a normal planing position of the skis is difficult to accomplish as both the boat and skier must build up speed from their stationary positions. The present ski structure alleviates this starting problem as well as enhancing the planing position of the skis.

Among the objects of the present invention is the provision of an improved water ski structure providing a distinct catamaran effect. A pair of depending parallel rails or ribs are formed on the undersurface of the ski along the longitudinal edges thereof to define a central open channel. The use of the rails separated by the central channel provides a catamaran effect for the ski in planing position.

Another object of the present invention is the provision of an improved water ski providing a greater lifting effect for starting from a stationary position in the water and an improved planing position. This ski structure permits towing of water skiers utilizing less horsepower for the boat as the inertia, water resistance and towing force are substantially reduced. The parallel depending rails each has a forward portion of a constant depth and a rearward portion having a plurality of inclined planes formed thereon, with each inclined plane being of substantially equal length but of gradually increasing angularity and depth toward the rear end of the ski. The inclined planes on each rail provide a greater lifting effect in starting with the skis and skier in the water and an improved more horizontal planing when the skier is riding on the surface of the water.

A further object of the present invention is the provision of an improved water ski structure where a pair of skis can be used for normal skiing or a single ski can be used as a slalom ski. The parallel rails and'central channel reduces the frictional area of contact with the water and provides greater balance and stability in use. A relatively deep center keel is mounted in the channel adjacent the rear end of the ski to improve stability and maneuverability of the ski.

Further objects are to provide a construction of maximum simplicity, efficiency, economy and ease of assembly and operation, and such further objects, advantag'es and capabilities as will later more fully appear and are inherently possessed thereby.

In the drawing:

FIG. 1 is a side elevational view of the improved water ski structure of the present invention.

FIG. 2 is a bottom plan view of the water ski structure.

FIG. 3 is a perspective view of the water ski structure.

FIG. 4 is an end elevational view taken from the rear end of the ski.

FIG. 5 is a vertical cross sectional view taken on the line 55 of FIG. 1.

FIG. 6 is a vertical cross sectional view taken on the line 6--6 of FIG. 1.

Referring more particularly to the disclosure in the drawing wherein is shown an illustrative embodiment of the present invention, FIGS. 1, 2 and 3 disclose a water ski 10 having a generally flat upper surface 11 and an upwardly curved forward end or toe portion 12. This ski may be one of a pair of identical skis for a water skier; however, the present ski is shown as a slalom ski utilized for single ski operation. Thus, on the upper ski surface 1 1 is positioned a stationary toe piece 13 formed of a flexible piece of rubber or similar resilient material secured at its edges to the ski by a pair of metal bars 14,14, and a flexible adjustable heel piece 15 formed of the same resilient material is mounted on a plate 16 to cooperate with the toe piece to receive one foot of the skier; the plate 16 having an adjustment slot 17 in the rear portion cooperating with a clamping screw 18 for anchoring in adjusted position. A rear toe piece 19 clamped onto the ski by metal bars 21,21 is stationary to receive the toes of the rear foot of the skier and is also formed of flexible material as is conventional in water ski construction.

Depending from the flat undersurface 22 of the ski are a pair of generally parallel integral elongated rails or

ribs

23,23 at the outer edges of the ski 10. Each rail extends from a curved surface 24 merging into the undersurface 22 of the ski adjacent the curved forward end 12 to the rear ene 25 of the ski; the rails defining a central longitudinal channel 26 therebetween of a substantially constant width. Mounted in the channel 26 adjacent the rear end 25 is a relatively deep keel or rudder 27 which extends for approximately two-thirds of its depth below the

rails

23,23 at its deepest point. The keel or rudder 27 is advantageous in providing for stability against excessive lateral movement of the ski and prevents any fishtailing action of the ski. The rails 23 and the central channel 26 therebetween provides a catamaran effect to enhance balance and stability of the ski and provide better weight distribution of the skier.

The forward approximately one-third of each rail 23 is of a constant depth as at 28 and the rearward approximately two-thirds of each rail is provided with a plurality of

inclined planes

29, 31, 32, 33, 34 and 35 of substantially equal length. However, each plane is of a slightly greater angularity than the previous plane to wards the rear end 25 of the ski, and each

shoulder

36,37,38,39 and 41 and the rear edge 42 of the last plane are progressively deeper.

As seen in FIG. 1, the dotted line 44 passes through and discloses that the deepest point of each shoulder lies in a common plane parallel to both the lower surface 22 of the ski and the channel 26 and the upper surface 11. Thus the shoulder 36 indicates the shallowest inclined plane 29, while the

shoulders

37, 38, 39 and 41 increase in depth by a substantially constant increment, with the angularity of each

plane

31, 32, 33, 34 and 35 also increasing by a substantially constant increment. The shoulder 43 between the lower surface 28 of the forward portion of the rail 23 and the inclined plane 31 extends to the common plane 44 of the bases of the shoulders and is of a depth of slightly less than or equal to the depth of the shoulder 36.

The center channel 26 has a width of approximately 20 to 25 percent of the total width of the ski at its maximum width and insures direction during skiing. This channel provides a passage for air to move under the ski and produces an aerodynamic lifting action on the ski, which raises the ski to the surface of the water. The most common method of starting on water skis for the skier is to start in the water in a crouched position with the skis parallel and pointing upward at a steep angle; the tow rope from the boat passing between the upper ends of the skis with the tow bar grasped by the skier. As the boat is started from its stationary position to obtain proper speed for skiing, the flat bottom surfaces of conventional skis provides a high resistance force as the skis and skier are pulled through the water until the skis reach a planing position at a slight rearward angle from the horizontal as the skier leans away from the force of the boat. For novices, the high resistance in starting from a position in the water provides the greatest deterrent to actual skiing, as most falls occur during starting.

The present water ski design overcomes this problem by the use of the

inclined planes

29, 31, 32, 33, 34 and 35 on the rails 23. Rather than the water pushing against a single flat surface of a conventional ski, the water is pushingagainst the six inclined planes of progressively increasing angularity. As these planes are inclined to the lower surface of the ski, the action of the water on these planes acts to quickly urge the ski towards a horizontal position with less effort. Thus the ski achieves a planing position much quicker and under less pulling force than a conventional ski.

Once a planing position has been reached, the inclined planes act to provide a more nearly horizontal position for better planing with less effort so that the skier does not tire in the back and shoulders as readily as with conventional skis. If the improved ski structure is used as a single ski, the greater horizontal planing position produces very little spray, and, when the skier crosses the wake of the boat in maneuvering the ski, the lifting action of the rear inclined planes can affect the ski to leave the crest of the wave and become momentarily airborne. Also, the present design reduces the frictional area of contact between the ski surface and the water and thus reduces the force required for the boat towing the skier.

Although the

rails

23,23 are disclosed to be integral with the body of the water ski 10', conventional water skis can be readily altered to the present design by the attachment of a pair of rails of the proper configuration to the undersurface of the skis by any suitable securing means. Also, although a single deep keel 27 is shown mounted in the center channel 26, my invention comprehends the use of additional rudders on the rear portion of each rail in addition to or as a substitute for the center keel.

I claim:

1. A water ski having an elongated ski body and a pair of substantially parallel rails depending from the undersurface of the ski body and extending longitudinally along the edges thereof, said rails defining a central channel therebetween of a substantially constant width and opening into the rear edge of the ski, cach rail including a forward portion of a substantially constant depth and merging at the front end into the undersurface of the ski at a point spaced from the forward end thereof, and a rear portion extending to the rear end of the ski, said rear portion having a plurality of inclined planes separated by trailing edges forming shoulders of progressively increasing depth, the planes being of progressively increasing angularity toward the rear end of the ski.

2. A water ski as set forth in claim 1, in which said inclined planes are all of substantially equal length.

3. A water ski as set forth in claim 1, in which said forward portion of each rail is approximately one-third the total length of the rail and the rear portion is approximately two-thirds the total length thereof.

4. A water ski as set forth in claim 1, in which a shoulder separates the forward rail portion providing a stabilizing surface from the adjacent inclined plane of least angularity on the rear rail portion, said planes being inclined downwardly and rearwardly away from the forward rail portion.

5. A water ski as set forth in claim 4, in which the points of intersection of each shoulder with the next succeeding inclined plane all lie in a common horizontal plane parallel with the upper surface of the ski.

6. A water ski as set forth in claim 5, in which said center channel is as deep as the rails and is deeper than the common horizontal plane defining the intersections of the shoulders with the inclined planes.

7. A water ski as set forth in claim 1, in which said center channel is of a width equal to approximately 20 to 25 percent of the maximum width of the ski.

8. A water ski as set forth in claim 1, including at least one rudder on the undersurface of the ski to provide lateral stability thereto.

9. A water ski as set forth in claim 8, in which a single relatively deep rudder is mounted in the center channel adjacent the rear end of the ski and depends for at least half of its maximum depth below the rails.

10. A water ski as set forth in claim 1, in which said rails are formed integral with the ski, said ski having an upwardly curved forward end, and the forward portion of each rail having a curved forward end merging into the ski adjacent the curved forward end of the ski.

I? t: 3 k t

Claims

1. A water ski having an elongated ski body and a pair of substantially parallel rails depending from the undersurface of the ski body and extending longitudinally along the edges thereof, said rails defining a central channel therebetween of a substantially constant width and opening into the rear edge of the ski, each rail including a forward portion of a substantially constant depth and merging at the front end into the undersurface of the ski at a point spaced from the forward end thereof, and a rear portion extending to the rear end of the ski, said rear portion having a plurality of inclined planes separated by trailing edges forming shoulders of progressively increasing depth, the planes being of progressively increasing angularity toward the rear end of the ski.