US3148392A

US3148392A - Jumping water skis

Info

Publication number: US3148392A
Application number: US217258A
Authority: US
Inventors: William N Bennett
Original assignee: CYPRESS GARDENS SKIS Inc
Current assignee: ERO Industries Inc; CYPRESS GARDENS SKIS Inc
Priority date: 1962-08-13
Filing date: 1962-08-13
Publication date: 1964-09-15
Anticipated expiration: 1981-09-15

Description

P 1964 w. N. BENNETT 3,148,392

JUMPING WATER SKIS Filed Aug. 13, 1962 3 Sheets-Sheet 1 WELLEAM BENNETT BY 1H2 ATTORNEY P 1964 w. N. BENNETT 3,148,392

JUMPING WATER SKIS Filed Aug. 13, 1962 3 SheetsSheet 2 FIG. 3

INVENTOR WILLIAM N. BENN ET T ATTORNEY Sept. 15, 1964 w. N. BENNETT JUMPING WATER SKIS 3 Sheets-Sheet 3 Filed Aug. 13

FIG. II

FIG.

FIG. I5

VIIILLIAM N. BENNETT IYZZ ATTORNEY FIG. I4

United States Patent 3,143,392 JUMPING WATER SKIS Wiiiiam N. Bennett, Winter Haven, Fla, assigner to Cypress Gardens Skis, Inc., Cypress Gardens, Fla. Filed Aug. 13, 1%2, Ser. No. 217,258 8 Claims. (Cl. 9-4910) This invention relates to water sports of various kinds including water skiing and to accessories and equipment employed in such sports and which are of interest and usefulness to competitive participants and attention attracting and interest evoking to spectators.

The invention relates particularly to water ski jurnping where the skier travels at high speed up a ramp in making the jump and lands with terrific impact upon the water, and to skis employed in such jumps which are subjected to extraordinary stresses and strains.

Until this date, water skis in general have been designed by trial and error methods with personal opinions used as a medium of research. Basically, a water ski as it is known today, is flat on the riding surface, with tips of various arcs or radii. Water ski jumping is entirely different from open water skiing, inasmuch as a ramp is employed as a means of obtaining both altitude and distance. Skis have been specially designed for this purpose, with emphasis on the reduction of breakage. The present invention, based on scientific research, has brought to light the fallacy in the present designs of jumping skis.

Heretofore in water ski jumping where the jumps were made at high speeds and covered substantial distances the ski have been short-lived due to the punishment of the force of impact upon movement from the water onto an ascending ramp, and great force of the landing impact accentuated at times by the lack of proper balance on the part of the jumper. Breakage of jumping skis always has been attributed to the shock in landing on fiat water, and efforts have been made to reinforce skis to withstand the impact forces to which they were subjected, however little or no consideration has been given to the impact of the ski with the ramp. The skill of the individual jumper has been greatly impaired because of inaccurate designs.

It is an object of the invention to provide skis particularly designed for use in water ski jumping which are comfortable, of any desired weight and have other physical characteristics which render them capable of withstanding the extreme forces to which they are subjected thereby rendering them exceedingly durable and longlived.

Another object of the invention is to provide water skis particularly designed for jumping and other drastic use, which skis are of material of such stiffness, configuration, and surface finish that they have an exceedingly durable exterior capable of withstanding the weather, and with a combination and arrangement of materials, curvatures and configuration that they can be used repeatedly for a long period of time for the purpose for which they were produced.

A further object of the invention is to provide a laminated ski produced in an electronic press in an exceedingly short time instead of the many hours ordinarily required in the production of skis, and at the same time to provide skis which will not split, crack or break upon contact at high speed with a ramp on take-01f or on impact with the water on landing, as well as skis under the rear of which are a pair of widely spaced fins rather than a single fin to facilitate the maintenance of balance by the jumper, on the ramp and in the water.

A still further object of the invention is to provide a ski having a bottom rounded or curved along its length,

3,148,392 Fatented Sept. 15, 1ti4 a sharp edge at the junction of the sides and bottom, a sharp edge at the heel or trailing edge, and composed of laminations with cross shims and all of which are joined or bonded together by an adhesive and controlled electronically applied heat and provided with a clear durable surface coating.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a bottom perspective of a ski used on water for jumping;

FIG. 2, a top exploded perspective of the several lay ers of lamina employed in the production of the ski;

FIG. 3, a side elevation of the ski of FIG. 1;

FIG. 4, an enlarged fragmentary section on the line 44 of FIG. 3;

FIG. 5, a transverse section on the line 5-5 of FIG. 3;

FIGS. 6 and 7, fragmentary views of a similar ski with an insert or modified side edge;

FIG. 8, an enlarged fragmentary bottom perspective of the rear portion of the ski with guide runners attached;

FIG. 9, an enlarged section on the line 9-9 of FIG. 8;

FIG. 10, a perspective of a guide runner of FIG. 8;

FIG. 11, a perspective illustrating the use of the ski in a manner to obtain accelerated speed;

FIG. 12, a side elevation of the skier making a turn as illustrated in dot and dash lines in FIG. 11;

FIG. 13, a section on the line 1313 of FIG. 12;

FIG. 14, a side elevation of a skier approaching a ramp used in jumping;

FIG. 15, a side elevation of the skier immediately before engagement of the skis with the ramp of FIG. 14;

FIG. 16, a side elevation with the full weight of the skier on the skis in contact with the ramp; and

FIG. 17, a side elevation of a skier using conventional flat bottom skis as the forward portion of the skis strike the ramp.

Briefly stated, the present invention is a ski created to provide the ultimate in comfort, lightness of weight, practicality, durability, as well as for facilitating maintenance of balance on a ramp and on the water, and comprises a ski in which the bottom is provided with a reverse camber or has a uniformly slight curve near its bottom on an are described from a point a substantial distance above the ski to obtain a slight curvature with such curvature extending from the rear end of the ski to a location along the forward portion where the ski begins to extend upwardly, the tip being shaped to conform with the approach angle of the ramp on impact of the ski with the latter to cause the ski to be eased upon the ramp rather than with a sudden drastic impact and a rapid change in center of balance which tends to throw the skier off balance. The ski is formed of three laminae having lengthwise grain and constituting the bottom, top, and intermediate layers thereof, and with a lamina having crosswise grain between the intermediate and outer layers, such laminae being bonded together by an adhesive at a controlled temperature, moisture and pressure, in a press having the desired configuration and electrically operated, after which the skis are provided with a clear durable surface coating.

In addition the design of the skis incorporates the use of a sharp side edge along the bottom biting edge of the ski in direct contact with the water, and a sharp trailing edge to minimize turbulence in the water. The sharp side edge allows the skier to hold a more accurate cut toward the ramp while moving over the surface of the Water at an angle to the propelling craft, whereby speeds greater than that of the craft are achieved via angular movement.

In the drawings, certain of the figures are made from excerpts of high speed research films of jumping on water skis in which modern distance jumping is done with the aid of an inclined ramp normally made of flooring, ordinarily of wood, with such ramp usually about 10 to 12' wide and 24' long and of which 20' is exposed from the water line to the top front edge or lip located 5 to 6 above the water line.

In water ski jumping, boat speeds are consistent for the particular class of skiers and tow ropes are of a specified length. In competition the skier is judged for both distance and form. A greater or lesser speed than the propelling craft is obtainable by varying from a straight line as illustrated in FIG. 11. Tournament jumpers use a variation of a double-wake cut and attain speeds approaching a mile a minute. At such speeds, a skier must be able to hold the angle of approach once it has been selected, and it is because of this that the application of sharp edges and runners or keels is made. The skier must ascend the ramp at top speed with minimum resistance and damage to the skis. This is the reasoning behind the particular shape of ski. On leaving the forward edge or tip of the ramp, skis having single runners tend to cause twisting of the jumpers ankle in view of which it has been found desirable to employ spaced double runners which also aid greatly in cutting across the wa er at a sharp angle in approaching the ramp.

With reference to FIGS. l-10, a water ski is provided having a relatively thin body 8 of generally uniform thickness and having a sharply curved higher front end or shovel portion 9. The main portion of body 8 is curved slightly from end to end on an arc described from a point a substantial distance above the ski to provide a reverse camber. The body is constructed of a plurality of laminations 1t), 11, 12, 13, and 14 in which the grain of

laminae

10, 12 and 14 is generally lengthwise of the body and the grain of

laminae

11 and 13 is generally crosswise thereof. As illustrated in FIGS. 2 and 4-7, the

cross-grain laminae

11 and 13 are interposed between the

longitudinal grain laminae

10, 12, and 14 and such laminae are bonded together by a waterproof adhesive under controlled temperature, moisture and pressure conditions. A pair of widely spaced runners or keels 15 are connected to the bottom of the body 8 adjacent to the rear edge thereof by bolts 16 and securing nuts 16' Each of the runners 15 is vertically tapered from the front to the rear thereof at an angle such that the bottom surfaces of both runners lie in a plane which is substantially coincident with the upper surface area of the ski body 8 lying between the binder plate 24 and the base of the sharply curved front end portion 9 of the ski. The rear or trailing edge of each runner is tapered inwardly at 15' substantially to a vertical line to reduce turbulence and drag as the ski moves over the water.

Noting FIGS. 5, 8 and 10 with respect to FIG. 3 it is clearly apparent that when runner mounting bolts 16 which are spaced along the length of the relatively rigid elongate runners or keels 15 of generally rectangular section as shown in FIG. 10 are inserted through the ski laminations 10-14 and nuts 16' are screwed down on the bolts into intimate contact with the top surface of the ski body 8, all of the laminations 10-14 in the immediate area of the runners is thereby placed under relatively high compressive stress. Moreover the intimate bearing of the runners 15 against the bottom surface of the rearward end portion of the ski body thereby rigidifies or stiifens this end portion. These combined effects, by strengthening, stiffening and generally reinforcing the rearward end portion of the ski body, minimize the splitting and other destructive tendencies of impact forces acting on the ski body when it is thrust at high speed against the inclined ramp 31 by the skier and subsequently drops onto the water surface under the weight of the skier.

The

laminae

10 and 14 form the top and bottom surfaces of the ski, the lamina 12 forming the intermediate portion, and the

laminae

11 and 13 forming the shims or cross laminae. The exposed bottom surface of the ski instead of being fiat is scientifically designed especially for jumping with a bottom or running surface that employs a reverse camber or is gently upwardly rounded lengthwise from the heel or rear end of the ski to and smoothly merging into the shovel or sharply curved forward end.

In the fabrication of the ski a press is provided having a slight end to end curvature terminating at the forward end in a sharply curved radius. As illustrated in FIG. 5, the bottom lamina 14 has sharp edges 14 at the junction between the sides and the bottom. If desired, an insert 17 (FIG. 6) having a square edge 17' may be molded into the laminae of the ski.

In order to integrate the insert 17 with the side of the ski, a groove 18 is milled in the bot-tom laminae 14 and the insert 17 is secured therein by a waterproof adhesive. Such insert preferably is of plastic or other nongrain material to provide a permanent sharp edge.

Instead of the relatively rectangular insert 17, a modified insert 29 having a slightly angular edge 20' may be provided in which the parts are correspondingly formed. As illustrated in FIG. 7 a groove 21 is milled in the bottom laminae 14 on an angle relative to the bottom and side edges thereof and the insert 20 is secured therein by a waterproof adhesive. Such insert is in the shape of a parallelogram and is preferably constructed of plastic material or the like. The insert 20 is located in a position such that the included angle at the junction of the bottom and side of the ski is less than The outer bottom edge of the insert is adapted to extend slightly below the bottom surface of the ski so that a permanent sharp edge is maintained. These

inserts

17 and 20 are in direct contact with the water allowing the skier to hold a more accurate out toward the jump and give a better intimacy between the ski and the water since the surface of the water is hard to penetrate at high speeds and any slip adds to the hazard of control.

With particular reference to FIGS. 8 and 9, the heel or rear end of the ski is provided with a reinforcing sealing plate 22 attached to the ski by screws 23 and adhesive 23'. The plate 22 is provided with a sharp edge 22' along the junction between the bottom and the rear thereof to reduce turbulence within the water when the ski passes therethrough. The plate 22 is of plastic construction or the like to prevent abuse and scratching in sand and on cement when the ski is not actually in use. Likewise the plate will preserve the watertight integrity of the ski and not permit water to enter the wood grain even if the plastic plate is abused.

As illustrated in FIGS. 3 and 4, a jump binder plate 24 is fastened to the upper portion of the body 8 and substantially centrally of the opposite ends thereof so that such plate is located at the lowermost point of the upper surface of said body. In this position, the skier will be disposed substantially radially of said body. In order to attach the plate 24 to the ski 10, such ski has a plurality of openings 25 in which a tubular insert 26 is permanently attached. The insert 26 has a central opening 27 in which a fiat headed screw 28 is received and such screw extends upwardly through an opening 29 in the plate 24 and is firmly attached thereto by a nut 30. The insert 26 is attached by means of waterproof adhesive so that water cannot enter the opening 25 and the grain of the wood.

It will be understood that the Width and length of the jumping ski as well as the type of straight edges, normally square back, and tapered low wide fins is designed for strength in landing and to enable better control and balance, as well as durability. Also, the material of which the edges are formed may be varied to suit the needs or requirements as to forces to which the ski will be subjected.

FIGS. 12-17 are reproductions of high speed films of a water skier approaching and moving onto a jumping ramp 31. FIGS. 11, 12 and 13 are illustrative of the skier cutting across the wake of the boat to gain speed.

These figures demonstrate the advantage of a sharp edge for added control in approaching the ramp.

FIGS. 14, 15 and 16 are side elevations of a skier approaching the ramp 31 and moving thereonto. In FIG. 14, the front of the ski is forcing a small amount of water 32 onto the ramp and in FIG. 15 the skier is riding the crest of water 32 immediately prior to contact between the ski and the ramp. In FIG. 16 the ski has been eased onto the ramp with the full weight of skier supported thereby.

By reason of the rearward end portion of the ski 10 being appreciably stiffened by means of runners or keels 15, as previously explained, as the ski ascends the inclined surface of ramp 31 it contacts the ramp surface in three areas two of which comprise the bottom surface of each runner and the lowermost area of the underside of the arcuate or cambered portion of the ski body disposed substantially directly below the binder plate 24. Accordingly, the ski has only a relatively restricted area, or, in a broad sense, a three-point support when on the ramp 31. By reason of this the relatively small contact area of the ski with the ramp minimizes resistance to movement and damage to the ski when ascending the ramp and there is a minimum of shifting of the center of balance of the ski body 8 which, correspondingly, tends to minimize associated loss of balance by the skier during such movement.

FIG. 17 illustrates a skier using conventional fiat bottom skis approaching a ramp. The skis force a small amount of water 32 onto the ramp and when the skier is riding the crest of water, the forward portion or tip of the ski strikes the ramp and causes a bowing up in the center area 33. This bowing up is caused by the flattening of the tip of the ski and the shifting of the center of balance of the skier when the ski contacts the ramp. The bowing up of the ski weakens or fractures the ski so that upon impact with the water on landing such ski will break.

It will be obvious to one skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is illustrated in the drawings and described in the specification, but only as indicated in the accompanying claims.

What is claimed is:

1. A water ski constructed for use in jumping to withstand the forces to which it is subjected during impact with a jumping ramp on take-off and thereafter with the water on landing, comprising an elongated relatively thin body of a plurality of wood laminations having the grain thereof extending in one direction and separated by laminations having the grain extending normal to the first laminations, said body being of substantially uniform thickness throughout its entire length, said laminations being intimately bonded together under predetermined moisture, temperature and pressure conditions to form a unitary structure, said body being slightly upwardly arcuately curved to provide a reverse camber throughout the major linear portion thereof extending from the rearward end of the body forwardly to near the front end thereof, the remaining linear portion of said body comprising a sharply upwardly curved shovel-like portion merging smoothly into the forward end of said arcuately curved ski body portion, a pair of relatively short runners of generally rectangular section mounted in laterally and symmetrically spaced relation on the rear portion of the bottom of said body and extending in close proximity to the rear end thereof, means rigidly securing said runners on said body and operative to maintain the rearward end of said ski body under compression and reinforce the said end against the effects of any impact and splitting forces applied thereagainst, said runners each being tapered vertically from front to rear at an angle such that the bottom surfaces thereof lie in a plane substantially coincident with the upper surface area of the ski lying adjacent said sharply curved forward end thereof, a reinforcing protective and sealing plate means compressively secured to the rear ends of said wood laminations and forming the heel of said ski and having means thereon to minimize turbulence of water in moving contact therewith when waterborne, and insert means in the bottom surface of said ski body extending longitudinally thereof, said insert means forming sharp peripheral edge means on said bottom surface and adapted to maintain a more accurate cut of the ski through the water when moving at relatively high speed in an oblique direction toward a ramp for jumping purposes.

2. A water ski used for jumping comprising a relatively thin elongated ski body of bonded laminated construction having substantially parallel upper and lower surfaces, said ski body being slightly upwardly and arcuately curved to provide a reverse camber throughout the major linear portion thereof extending from the rear end of the ski body forwardly to near the front end thereof, the remaining forward linear portion of said ski body comprising a sharply and upwardly curved forward end portion extending relatively high above the said major portion of the ski body, binder plate means mounted on the upper surface of said ski body and located at the lowermost portion of said upper surface intermediate the length of said ski body, a pair of relatively short runners mounted in transversely spaced relation on the bottom surface of said ski body and positioned adjacent said rear end thereof, said pair of runners extending longitudinally of said ski body and positioned relatively close to the side edges thereof, means rigidly securingsaid runners to said ski body and operative to rigidify and place the rear end of said laminated ski body overlying said runners under compression, each of said runners extending downwardly from said ski body and of such shape that the bottom surfaces thereof lie in a plane substantially coincident with the upper surface area of the ski lying adjacent the sharply curved forward end thereof, protective plate means mounted on the rear end of said ski body and having a lower surface forming a reinforcing continuation of the lower surface of the ski body, said protective plate means having a sharp lower trailing edge to minimize turbulence when waterborne during skiing, said protective plate means and said securing means of said runners reinforcing the rearward end of said ski body against impact and splitting forces to which the ski is subjected during its intended use.

3. The water ski as defined in claim 2 wherein the normally vertical lateral sides of the rearward ends of each runner are inwardly tapered to form a substantially line-like trailing edge whereby to m nimize turbulence and drag as the ski moves forwardly through the water when waterborne.

4. The water ski as defined in claim 2 wherein said laminated ski body is of substantially uniform thickness th oughout its entire length.

5. A water ski for use in relatively high speed ramp jumping and adapted to withstand the destructive forces occurring during impact with the ramp on contact therewith, take-oif therefrom, and with the water after takeoff, said ski comprising a relatively long and thin body comprised of a plurality of integrally bonded laminations and having substantially parallel upper and lower surfaces, said body having a protective heel member at one end thereof with a sharp-edged lower surface forming a continuation of said lower surface, said laminated body at the opposite end thereof being sharply curved to provide a shovel forward end, the portion of said laminated body intermediate said heel and said sharply curved shovel forward end having a slight reverse camber lying along an arc, binder means mounted on the upper surface of the lowermost portion of said reversely cambered body portion intermediate the length thereof for securing a skier thereon, a plurality of transversely spaced relatively short and elongate runners secured to the rearward bottom surface portion of said laminated body and positioned with one end of each disposed adjacent said heel member, said elongate runners being tapered vertically throughout their length at an angle such that the bottom surfaces thereof lie in an inclined plane substantially coincident with the upper surface of said ski body portion extending between said binder means and said sharply curved forward end of the ski.

6. A water ski as defined in claim 1 wherein the trailing edge of each of said runners is inwardly tapered subtantially to a vertical line to reduce turbulence and drag when the ski is moved forwardly while waterborne, said insert means being comprised of a non-wood material.

7. A Water ski as defined in claim 5 wherein each of said spaced elongate runners extend longitudinally of said ski bottom surface, each of said plurality of elongate runners being secured to said rearward bottom surface of said laminated ski body by bolt means spaced along the length of the runner, said bolt means extending through to the upper surface of said ski body, and nut means on each of said bolt means and disposed adjacent said upper surface for rigidly securing the runner on said bottom of said laminated ski body and simultaneously compressing and rigidifying said rearward laminated ski body portion whereby said rearward laminated ski body portion is reinforced against damage under impact against the ramp when brought into contact therewith and with the surface of the water when landing thereon at relatively high speeds.

8. A .water ski as defined in claim 7 wherein said plurality of elongate spaced runners comprise a pair of runners of equal length symmetrically positioned on said rearward bottom surface portion of said laminated body, said pair of symmetrically positioned runners and said lowermost portion of the bottom surface of said reversely cambered body portion underlying said means for securing a skier on the said upper surface being adapted to provide substantially a three-point support for said ski and skier when in motion on the jumping ramp thereby minimizing the danger in the loss of balance by the skier and the danger of injury to the body portion of the skier attached to the ski, as well as minimizing resistance to movement of the ski up the ramp.

References Cited in the file of this patent UNITED STATES PATENTS 2,184,791 Broome Dec. 26, 1939 2,817,101 Chaifee Dec. 24, 1957 2,918,684 Sackett Dec. 29, 1959 3,056,148 Abbott Oct. 2, 1962 FOREIGN PATENTS 1,013,462 France Apr. 30, 1952 1,058,791 France Nov. 10, 1953 446,579 Italy Mar. 21, 1949 490,873 Canada Mar. 3, 1953 250,679 Switzerland June 16, 1948 198,168 Austria June 10, 1958

Claims

1. A WATER SKI CONSTRUCTED FOR USE IN JUMPING TO WITHSTAND THE FORCES TO WHICH IT IS SUBJECTED DURING IMPACT WITH A JUMPING RAMP ON TAKE-OFF AND THEREAFTER WITH THE WATER ON LANDING, COMPRISING AN ELONGATED RELATIVELY THIN BODY OF A PLURALITY OF WOOD LAMINATIONS HAVING THE GRAIN THEREOF EXTENDING IN ONE DIRECTION AND SEPARATED BY LAMINATIONS HAVING THE GRAIN EXTENDING NORMAL TO THE FIRST LAMINATIONS, SAID BODY BEING OF SUBSTANTIALLY UNIFORM THICKNESS THROUGHOUT ITS ENTIRE LENGTH, SAID LAMINATIONS BEING INTIMATELY BONDED TOGETHER UNDER PREDETERMINED MOISTURE, TEMPERATURE AND PRESSURE CONDITIONS TO FORM A UNITARY STRUCTURE, SAID BODY BEING SLIGHTLY UPWARDLY ARCUATELY CURVE TO PROVIDE A REVERSE CAMBER THROUGHOUT THE MAJOR LINEAR PORTION THEREOF EXTENDING FROM THE REARWARD END OF THE BODY FORWARDLY TO NEAR THE FRONT END THEREOF, THE REMAINING LINEAR PORTION OF SAID BODY COMPRISING A SHARPLY UPWARDLY CURVED SHOVEL-LIKE PORTION MERGING SMOOTHLY INTO THE FORWARD END OF SAID ARCUATELY CURVED SKI BODY PORTION, A PAIR OF RELATIVELY SHORT RUNNERS OF GENERALLY RECTANGULAR SECTION MOUNTED IN LATERALLY AND SYMMETRICALLY SPACED RELATION ON THE REAR PORTION OF THE BOTTOM OF SAID BODY AND EXTENDING IN CLOSE PROXIMITY TO THE REAR END THEREOF, MEANS RIGIDLY SECURING SAID RUNNERS ON SAID BODY AND OPERATIVE TO MAINTAIN THE REARWARD END OF SAID SKI BODY UNDER COMPRESSION AND REINFORCE THE SAID END AGAINST THE EFFECTS OF AN IMPACT AND SPLITTING FORCES APPLIED THEREAGAINST, SAID RUNNERS EACH BEING TAPERED VERTICALLY FROM FRONT TO REAR AT AN ANGLE SUCH THAT THE BOTTOM SURFACES THEREOF LIE IN A PLANE SUBSTANTIALLY COINCIDENT WITH THE UPPER SURFACE AREA OF THE SKI LYING ADJACENT SAID SHARPLY CURVED FORWARD END THEREOF, A REINFORCING PROTECTIVE AND SEALING PLATE MEANS COMPRESSIVELY SECURED TO THE REAR ENDS OF SAID WOOD LAMINATIONS AND FORMING THE HEEL OF SAID SKI AND HAVING MEANS THEREON TO MINIMIZE TURBULENCE OF WATER IN MOVING CONTACT THEREWITH WHEN WATERBORNE, AND INSERT MEANS IN THE BOTTOM SURFACE OF SAID SKI BODY EXTENDING LONGITUDINALLY THEREOF, SAID INSERT MEANS FORMING SHARP PERIPHERAL EDGE MEANS ON SAID BOTTOM SURFACE AND ADAPTED TO MAINTAIN A MORE ACCURATE CUT OF THE SKI THROUGH THE WATER WHEN MOVING AT RELATIVELY HIGH SPEED IN AN OBLIQUE DIRECTION TOWARD A RAMP FOR JUMPING PURPOSES.