WO2017218642A1

WO2017218642A1 - Short hydrodynamic designed water ski

Info

Publication number: WO2017218642A1
Application number: PCT/US2017/037429
Authority: WO
Inventors: Peter G. Ifju; Alexander MCGHEE; Luis CANTU
Original assignee: University Of Florida Research Foundation, Inc.
Priority date: 2016-06-16
Filing date: 2017-06-14
Publication date: 2017-12-21
Also published as: EP3472039A1; EP3472039A4; US20190308697A1

Abstract

A compact water ski having a top surface, a bottom surface and a rocker with an overall length of less than 36 inches and a means to secure a foot to the top surface. The ski can be with or without a fin. The bottom surface of the water ski can be decorated with strakes and/or channels to allow for greater maneuverability and stability.

Description

DESCRIPTION

SHORT HYDRODYNAMIC DESIGNED WATER SKI

CROSS-REFERENCE TO A RELATED APPLICATION This application claims the benefit of U.S. Provisional Application Serial No. 62/350,791, filed June 16, 2016, the disclosure of which is hereby incorporated by reference in its entirety, including all figures, tables and drawings.

BACKGROUND OF INVENTION

Water skiing originated on June 28, 1922 at Lake Pepin in Lake City, Minnesota by Ralph Samuelson when Ralph discovered that leaning backwards with ski tips up leads to successful water skiing with barrel staves. Ralph fashioned the first dedicated water skis from lumber with leather strips for bindings. The first patented water skis, Waller, U.S. Patent 1,559,390 October 27, 1925, attached the tow rope to a bridle attached to the tips of the skis and from the tips to a handle for the skier. From that inception, the sophistication of water skis advanced for specialized or general use. The most common skis used are known as combination pairs that can be used as a pair or where one ski can be used for slalom skiing. Combination skis have relatively wide tips for control and are generally between 5 and 6 feet in length, 6 to 8 inches in width, and 1/2 to 3/4 inches in thickness, although lengths of as little as 4 feet are commercially available for children.. Slalom skiing is carried out with a single ski designed to make sharp turns and reach high speeds, tending to have wide tails and flat bottoms but more advanced slalom skiers use skis with more tapered tails, beveled edges, and have concave or tunnel concave bottoms. Trick skis are relatively short, generally 40 to 48 inches in length and are relatively wide, generally 10 to 12 inches in width where the skier uses a single ski that lacks a fin. Long and wide ski pairs are manufactured for jumping. The most extreme water skiing is barefoot, without any skis. Because of the extreme lack of surface area on the water, the typically barefoot skiers must ski at speeds of at least 35 miles per hour to achieve sufficient lift.

Water skis are designed to be flexible, having a concave shape with bevel edges that have a degree of rocker, which is its tip to tail curvature. Typically, the concave shape spans the entire bottom surface of the water ski. More concave surfaces stabilize the ski at the cost of speed. Bevels can be sharp and flat or soft and rounded for stability and speed or control in turns, respectively. A highly flexible, or soft-flex, ski turns easily and rides smoothly in rough water. A stiffer flex allows for speed on flat water but is more challenging to turn. The outside shape and width of a ski from tip to tail is important with wider skis being more stable and easier to engage in deep water, but more difficult to control in turns relative to a narrower ski. Skis with less rocker are fast but require longer turning radii.

The concave base of skis normally has a "V-Bottom" with a center rib from the tip of the ski to allow an easy maintenance of a straight trajectory and to provide a pivot point to transfer weight from edge to edge for beginners. A tunnel-concave design employs a center concave having flat spots on each side of the edge that act like pontoons. A full concave from edge to edge allows a quick transition from edge to edge and holds strongly in a turn, and is employed by competition and higher level skiers.

The sport of water skiing lacks a ski that is designed to handle choppy water at speeds below 25 mph. To this end a design suited for speeds of about 20 mph or less would be desired, yet at such speeds a maneuverable ski would need to be small.

BRIEF SUMMARY

Embodiments of the invention are directed to short hydrodynamic water skis that permit use at low speeds. These compact water skis are less than 36 inches in length with widths in excess of five inches, though less than 15 inches. These compact water skis can include one or more fins on the bottom surface or the skis can be Unless. The water skis can be decorated with strakes and/or channels to enhance stability and maneuverability.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a top view and side view of a compact water ski, according to an embodiment of the invention where the water ski includes a fin in the tail.

FIG. 2 show cross-sections of the ski with a flat top and various possible shapes of the bottom of the water ski, according to embodiments of the invention, where the water ski includes a fin.

FIG. 3 A shows a bottom view of a finless water ski having parallel strakes and/or channels, according to an embodiment of the invention; and FIG. 3B shows a bottom view of a finless water ski having non-parallel strakes and/or channels, according to an embodiment of the invention. FIG. 4 shows cross-sections of a water ski with a flat top and various possible shapes of the bottom of the water ski, according to embodiments of the invention, where the water ski lacks a fin.

FIG. 5 shows a photographic reproduction of water skis with a fin and equipped with a wakeboard boot according to an embodiment of the invention.

FIG. 6 shows mechanical drawings of the tip, profile, cross-section, and bottom of the water ski shown in FIG. 5, without illustration of the fin.

DETAILED DISCLOSURE

A water ski design, according to embodiments of the invention, is compact with lengths ranging from about 12 inches to 36 inches and widths from 5 inches to 15 inches. With such a design, extreme maneuvering is possible due to a small inertia and swing-weight. The compact water skis use traditional waterski bindings, foot-straps or wakeboard boots as a means to secure the skier's feet. In one embodiment of the invention, the ski incorporates one or more fins. In an embodiment of the invention the ski is fmless for starting from flat surfaces, jumping ramps, and grinding rails.

The ski's outline shape can vary, where: the tip can be pointed, rounded, faceted or a combination shape; the rail, or sides can be parallel, concave, or convex; and the tail can be square, rounded, pointed, faceted or a combination, for example, as shown in FIG. 1 for an exemplary embodiment of the invention, a rounded tip with concave rails extend to a tail that has a rounded point and an included fin. The ski can have an asymmetric shape along the center line or mid- line where one ski is the mirror image of the other ski. In an embodiment of the invention, as shown in FIG. 1 , the rocker-line has some scoop in the front and becomes flat in the back, although the amount of scoop can vary significantly. It can also have rocker along the entire length without any flat. The length can be 12 to 36 inches, 12 to 30 inches, 12 to 24 inches, 16 to 30 inches, 16 to 24 inches, 20 to 30 inches, or 20 to 24 inches. The width can be 5 to 15 inches, 5 to 10 inches, 7 to 15 inches, 8 to 15 inches, 9 to 15 inches, or 9 to 12 inches.

In embodiments of the invention, the fore-section can be narrower than the mid- section and the aft-section can be narrower than the mid-section. In an embodiment of the invention, the fore-section can be narrower than the mid-section and the aft-section can be broader than the mid-section. In an embodiment of the invention, the fore- section can be narrower than the mid-section and the aft-section can be about equal in width to the mid- section. In an embodiment of the invention, the fore-section can be broader than the midsection and the aft-section can be about equal in width to the mid-section. In an embodiment of the invention, the fore-section can be broader than the mid-section and the aft-section can be narrower than the mid-section. The fore-, mid- and aft-sections can be about one quarter to about one half of the length of the water ski.

The bottom portion, according to embodiments of the invention, can have a myriad of shapes, as illustrated in FIG. 2 for skis with fins. The skis with fins can have a flat, vee shape, double concave, inverted vee, single concave or a multiple concave shape, as indicated in FIG. 2. In an embodiment of the invention, as shown in FIG. 3, the water ski can be without a fin but can have features for the stabilization of the ski while in use. In an embodiment of the invention, the water skis without a fin can incorporate one or more strakes and\or one or more channels that run parallel or non-parallel to the length of the ski, as indicated in FIG. 4. The strakes and/or channels can be included with one or more fins if desired. In an embodiment of the invention, the strakes and/or channels extend from about the mid-section through the aft-section. In an embodiment of the invention, the strakes and/or channels extend trough the fore-section and through the aft-section. In an embodiment of the invention, the strakes and/or channels extend through the fore-section and to the aft- section. In an embodiment of the invention, the strakes and/or channels extend from the fore- section through the aft-section. The number of strakes and/or channels can range from one to about 20, for example, but not limited to three strakes and/or channels, four strakes and/or channels, five strakes and/or channels, six strakes and/or channels, or seven strakes and/or channels. The height and depth of the strakes and channels, respectively, can vary over the length of the ski, for example, but not necessarily, the strakes and channels can gradually increase in height and depth towards the back of the ski. The shapes of the strakes and channels can vary over the width of the ski and these features can be of unequal sizes and can be symmetric or asymmetric in shape, though generally, but not necessarily, the features will be symmetrically positioned relative to the center line of the ski. Combinations of strakes and/or channels with skis with bottoms tat are overall vee, flat, or concave, can expand the range of ski performance. These can affect maneuverability, the ability to resist horizontal loading without loss of traction, ability to handle choppy water, interaction with ramps and rails and the overall rigidity of the ski.

Top surfaces of the water skis, according to embodiments of the invention, can be flat or can be convex or concave. The surface can also include channels and/or strakes to direct water from the top surface. The rocker can extend over the entire length of the water ski, or can extend only to or through the mid-section.

METHODS AND MATERIALS

A compact water ski with a fin was constructed, as photographically shown in FIG. 5. The dimensions of the water ski, absent its fin, are given in FIG. 6. An expert water-boarder was able to use the compact ski, having a width at approximately the mid-line of about 10 inches and a length of about 24 inches, at speeds below 20 mph.

It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application.

Claims

CLAIMS We claim:

1. A compact water ski, comprising a top surface, a bottom surface and a rocker, wherein the length is about 12 inches to about 36 inches and the width is about 5 inches to about 15 inches and the top surface has a means to secure a foot.

2. The compact water ski according to claim 1, wherein the bottom surface comprises one or more fins.

3. The compact water ski according to claim 1, wherein the bottom surface lacks a fin.

4. The compact water ski according to claim 1, wherein the bottom surface comprises one or more strakes and one or more channels.

5. The compact water ski according to claim 1, wherein the bottom surface comprises one or more strakes.

6. The compact water ski according to claim 1 , wherein the bottom surface comprises one or more channels.