Background of the Invention
[0001] The present invention introduces a new category of motorized personal water craft:
a high speed, high thrust, high performance craft with no steering mechanism for turning.
The present invention is a stable, maneuverable, high speed motorized water ski suitable
for use by a single rider standing on a rear deck. The rider may turn the water craft
according to the present invention solely through his body position, stance and weight
distribution. Exceptional speed, maneuverability and rider/craft stability are achieved
by a unique and precisely calculated combination of several design parameters including,
thrust, speed, weight, engine power, buoyancy, placement of mechanical components
to provide a precisely located center of gravity, bottom hull/rail configuration and
hull structure.
[0002] Prior art motorized personal water craft include: (a) high powered, high speed craft
with swivel jet steering mechanisms (devices) for turning; (b) low speed, low performance
craft with rudders and other steering mechanisms for turning; and (c) low speed, low
performance craft with no steering mechanism for turning.
[0003] Many high powered motorized personal water craft that have previously been available
use movable jet nozzles or other mechanisms for turning the craft. Such water craft
may support either a seated or standing rider. The engine position and cockpit structure
of previous motorized aquatic vehicles cause the net center of gravity of the craft
plus rider to be substantially in front of the rider while making a turn. All steering
devices such as directional nozzles and rudders cause the pivot point to be far in
front of the rider, which causes instability. This location of the net center of gravity
causes the pivot point for making turns to also be substantially in front of the rider,
The forward net center of gravity renders these craft unsuitable for high speed or
high performance use by a standing rear mounted rider. In particular, the forward
center of gravity causes rider instability. With such craft it is impossible to make
high speed turns solely under the control of the rider's stance and weight distribution.
[0004] In addition to the very high and forward net center of gravity and extreme forward
pivot point of heretofore available stand-up and sit-down high powered personal water
craft, these craft also have high, slightly curved, vertical side rails. Consequently,
if the rider leans to the side without using a directional nozzle to turn the craft
in a direction opposite to the direction he is leaning, the rider typically loses
his balance and takes an unexpected plunge into the water.
[0005] The inertia of the rider's body causes the rider to tend to travel in a straight
line. As the prior art craft starts to turn, the rider feels it move laterally under
him as he continues to tend to move in a straight line. Therefore, in executing turns
with such personal water craft, the standing rider's body moves from side to side
relative to the craft. Sudden turns can cause the rider to lose his sense of balance.
[0006] A movable pump nozzle is used to turn one type of prior art jet-driven standup water
craft that is commonly referred to as a Jet Ski. The nozzle is directed away from
the longitudinal axis in a plane generally parallel to the water. The nozzle then
causes a torque or moment about a vertical axis through the net center of gravity
of the craft and rider. In operation, if water is propelled to port, the stern of
the craft rotates to starboard while the bow turns to port. This movement of the bow
and stern is due to the fact that the craft will pivot about its net center of gravity,
which is located far forward of the rider.
[0007] Therefore, when the rear mounted rider of this type of personal water craft turns
the pump nozzle, the craft rotates about the forward center of gravity. The rider's
body moves from side to side, which causes a sensory loss of balance or stability.
This is a serious stability problem that is addressed by the prior art by increasing
the size and weight of the craft in order to achieve acceptable stability for the
rider. This also is the reason for the popularity of sit-down craft, which typically
use a directional nozzle for turning. The directional nozzle turns left or right and
causes the tail to slide in the opposite direction. Because the rider is sitting,
he is better able to accommodate instability during turns.
[0008] It also must be appreciated that in today's market, a personal water craft is expected
to attain speeds of between 30 and 55 miles per hour (approximately 50 to 88 km/hr).
A desirable feature of high performance personal water craft is the capability of
turning and maneuvering the craft solely by movement of the rider's body. Currently
available high speed personal motorized water craft do not provide the capability
of being controlled by rider stance and weight distribution. Rather, the body movement
associated with the rider of the present day water craft is only in reaction to the
directional thrust of a water jet or other turning mechanism in order to maintain
stability to prevent the rear mounted rider from being thrown from the craft during
maneuvers.
[0009] Previous attempts to provide a motorized personal water craft for a standing rider
using mechanisms other than swivel jets for turning have been necessarily low speed,
low thrust, low performance craft. Some such craft use rudders for steering. These
craft do not utilize the relationship of the location of the rider to the location
of the center of gravity for negotiating stable turns.
[0010] United States Patent 3,548,778 to Von Smagala-Romanov discloses a self-propelled
surfboard having a propeller that is driven by an internal combustion engine. The
propeller is located in a recess in the bottom of the board. The propeller blade is
housed within a shield to prevent the blade from contacting a swimmer or the rider
if he should fall off the board. The internal combustion engine is mounted within
a cavity located centrally of the front and rear ends of the board. The driving propeller
is mounted closely behind the engine so as to be generally under the deck portion
where a rider would stand.
[0011] Von Smagala-Romanov discloses a low power, low speed craft that cannot be made to
turn without the use of a rudder, movable jet or other mechanical steering apparatus.
Von Smagala-Romanov discloses that his device could be made steerable by incorporating
an optional mechanized fin using appropriate cables controlled by rider. By indicating
that the craft can be made steerable by using a rudder, movable jet, mechanized fin
or other mechanical steering apparatus, Von Smagala-Romanov shows that he did not
consider the location of the center of gravity as being a factor in turning. It is
evident from the disclosure of Von Smagala-Romanov that the location of the net center
of gravity of the craft and rider has nothing to do with the steering or maneuvering
of the Von Smagala-Romanov craft. Furthermore, careful study of the Von Smagala-Romanov
device indicates that it is a low buoyancy craft that would support only a light-weight
rider.
[0012] At best, Von Smagala-Romanov is necessarily a low power, low speed craft incapable
of a speed anywhere near 30 miles per hour. Careful study of the Von Smagala-Romanov
device further indicates that it would accommodate only a small engine that would
provide insufficient thrust to produce short radius turns. The hull structure of Von
Smagala-Romanov is suitable only for low speeds of less than about 8 miles per hour.
Any greater speed would raise a safety issue. The drive mechanism (propeller) in the
Von Smagala-Romanov craft is located under the rider, exterior to the hull and forward
of the stabilizing fin. This underwater location of the drive mechanism would not
be efficient or suitable for placement of a high-thrust jet flow pump.
[0013] Von Smagala-Romanov does not take into account the critical placement of mechanical
components in relationship to the position of its rider in order to achieve acceptable
performance even at low speed. In the position of the rider relative to the position
of the lower weight mechanical components shown, the rider's weight would dominate.
The bow would be raised significantly out of the water, thus producing unacceptable
resistance to forward motion. This type of resistance to forward motion is sometimes
referred to as the "ploughing effect." If the rider were to move forward to level
the craft, assuming there enough flotation for such movement, he would be inconveniently
standing where the vent tube and hand control are located.
[0014] French patent 2,617,793 to Trotet discloses a motorized nautical board. Trotet uses
a low center of gravity that is below the water line to stabilize the board against
overturning. However, like the Von Smagala-Romanov craft, the location of the center
of gravity in Trotet has absolutely nothing to do with the turning or maneuvering
of the craft. Trotet, like Von Smagala-Romanov, teaches the steering and maneuvering
of the craft using a moveable rudder or steering mechanism. In the Trotet craft the
net center of gravity is forward of the rider so that during a turn, the stem slides
to the left or right, depending on the direction of the turn, which thereby destabilizes
the standing rider.
[0015] Trotet, with an 80 cc engine capable of no more than 5 to 8 miles per hour and 50
pounds of thrust, teaches a low speed leisure craft rather than a high speed performance
craft. The rider of the low speed board of Trotet would be unstable during takeoff
while standing on the rear deck. The Trotet board has insufficient thrust for safely
making short radius turns even at low speeds because of its forward pivot point and
large vertical profile keel, which causes increased water resistance during turns.
Replacing the small engine of Trotet with a larger engine, even if the hull were redesigned
to accommodate it, would not enable the Trotet craft to have high speed performance
features.
[0016] The prior art also discloses motorized water craft with no mechanical turning device.
None of these craft are capable of high speed controlled turns or responsive, small
radius, low speed turns.
[0017] United States Patent 3,608,512 to Thompson discloses a boat hull that is provided
with its own propulsion unit and that accommodates a standing rider. Thompson discloses
a substantially flat-bottomed hull filled with buoyant material and having an upwardly
open, longitudinally extending compartment that is open rearwardly at the stern of
the hull for accommodating an operator in a standing position. A pair of elongate,
longitudinally extending singly formed, narrow fins extend laterally of the compartment.
The flat bottom surface merges arcuately into the inner faces of the fins and is preferably
provided with elongate, longitudinally extending grooves intermediate the fins. A
shrouded propeller, jet orifice, or other suitable arrangement is positioned at the
stern directly below the open rear end of the compartment and between the fins. A
well in the hull near the bow in front of the compartment serves to receive an internal
combustion engine. The large bow mounted engine places the net craft plus rear mounted
standing rider such that the pivot point on turns would be far in front of the rider,
which destabilizes him as described previously. Therefore, this relatively bulky craft
would not be capable of executing responsive, stable high speed turns or safe, short
radius low speed turns and maneuvers.
[0018] United States Patent 3,406,653 to Mela discloses a four foot long, nine pound powered
float board which cannot accommodate a standing rider. The engine is relatively openly
exposed to water and has no bilge pump. The Mela device is capable speeds of only
a few miles per hour. Having no sealed engine housing and no bilge pump renders the
disclosed device unsuitable for high performance use. The float board has no rails
that would permit it to make high-speed turns.
[0019] One particular type of motorized personal water craft is sold under the name Surf
Jet. The Surf Jet motorized water craft has a top speed of about 22 miles per hour.
The Surf Jet has a rear-mounted engine in a compartment that extends a considerable
distance above the water line. The heavy, stern mounted engine causes the stem of
this craft to sit very low in the water unless the rider stands a considerable distance
in front of the engine. The center of gravity of this craft is located within about
20% of the total craft length measured from the stern. The rider is forced to stand
at or forward of the craft midlength in order to balance the heavy stern mounted engine
and centrifugal pump and to avoid the large vertical protrusion of the engine housing.
Because of this protrusion, which is about 1.5 feet above the deck, the rider is inconveniently
forced to mount the craft from the side while in the water. The Surf Jet utilizes
a maximum 17 HP vertically mounted engine, vertical drive shaft and an inefficient
(relative to an axial flow pump) centrifugal jet pump that produces a maximum thrust
of about 130 pounds. It is obvious that the center of gravity was not considered in
balancing this craft. Increasing the size of the engine and pump to achieve more thrust
and performance would be impractical because this would further deteriorate the balance
and stability of the craft. Therefore, the Surf Jet design is essentially a low performance
craft because the engine must be small in order to keep the rider from having to stand
near the bow of the craft to balance it and keep the bow from being too high above
the water line. If the net center of gravity is too close to the stern, then at moderate
speeds, the bow begins to lift, which causes instability and the ploughing effect.
[0020] For many water sports enthusiasts, personal enjoyment from the operation of a powered
water craft will be significantly increased if the rider can, at both low and high
speed, turn and control the craft solely by rider stance and weight distribution without
the use of active steering mechanisms. Such enjoyment is presently not achieved with
motorised water craft as it is at lower speeds with non-motorised craft, such as surfboards
and body boards, where personal fulfillment is accomplished through the successful
and skillful control of the rider's body for manipulating the board.
[0021] A motorised surf board that has some but not all of the characteristics of the motorised
water ski of the present invention is disclosed in US-A-3 262 413, over which the
present invention is characterised.
SUMMARY OF THE INVENTION
[0022] A motorized water ski according to the present invention has stability and maneuverability
for a standing rider at both low and high speeds. The motorized water ski according
to the present invention comprises a hull having a bow, a stem, a deck sized to accommodate
the standing rider. The hull further includes a hydroplane surface formed on a bottom
hull surface and a longitudinal axis extending from the bow to the stern. The motorized
water ski also further includes a jet pump fixedly mounted in the stern for discharging
a propelling stream of water outwardly from the stern in a direction fixed to be generally
parallel with the longitudinal axis of the motorized water ski. A motor is disposed
within the hull for driving the jet pump. The motor is mounted in the hull forward
of the deck where the rider stands. The motor and jet pump are mounted within the
hull such that the motorised water ski has a riderless center of gravity that is within
an envelope located beneath the deck and aft of the motor. The location of the riderless
motorised water ski centre of gravity causes the location of the net center of gravity
of the motorised water ski and rider standing on the deck to be within the region
of the envelope of the body of the rider The location of the net center of gravity
of the motorised water ski and rider located on the deck enable the rider to maneuver
and turn the high speed motorised water ski by adjusting his position and weight distribution
on the deck to move the net center of gravity.
[0023] The motorised water ski further comprises a pair of curved side rails formed on opposite
sides of the hull; a hull bottom (58) having a first "V"-shaped portion (194A, 194B)
forward of the widest beam portion (182A, 182B) of the hull (16), the first "V" shape
(194A, 194B) transitioning aft along the hull bottom (58) to a flat keel (17) and
then to a second "V" shaped portion (195A 195B) between the hydroplane surface (180)
and the curved side rails (190A, 190B), the second "V" shaped portion (195A and 195B),
the curved side rails (190A, 190B) cooperating with the riders movement of the net
center of gravity (120) to enable smooth transition from startup to high speed planing
and easy initiation and execution of high and low speed turns;
an intake grate (148) formed in the hull bottom (58);
a hull bottom section forward of the intake grate (148) that blends smoothly into
the second "V" shaped portion (195A, 195B) and connects to the rails (190A, 190B)
to minimize aeration of water entering the pump (100); and
a pair of hydrosteps (183A, 183B) aft of the intake grate (148) that assist in the
efficient release of water as the hull (16) transitions to a hydroplane mode, thus
providing stability and decreased water resistance to the hull (16).
[0024] An appreciation of the objectives of the present invention and a more complete understanding
of its structure and method of operation may be had by studying the following description
of the preferred embodiment and by referring to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025]
FIG. 1 a is a perspective view of the motorised water ski in accordance with the present
invention as it is manipulated through a controlled high speed, high g-force turn;
FIG. 1b is a perspective view of the motorised water ski in accordance with the present
inventeion as it is manipulated through a lower speed, short radius, high thrust turn;
FIG. 1c is a perspective view of the motorized water ski in accordance with the present
invention as it is manipulated through a vertical spin turn maneuver;
FIG. 1d represent a rider in the water mounting the motorised water ski according
to the present invention from the rear
FIG. 2 is a perspective view of the motorised water ski in accordance with the present
invention generally showing a hull having a bow, a stern, a deck portion and an arm
pole;
FIG. 3 is a perspective view of the bottom portion of the hull generally showing interior
vertical walls for support and engine pod mounts;
FIG. 4 is a side view of the hull bottom;
FIG. 5 is a top plan view of the hull bottom;
FIG. 6 is a bottom plan view of the hull bottom;
FIG. 7 is a front view of the hull bottom;
FIG. 8 is a rear view of the hull bottom;
FIG. 9 is an exploded view of the motorised water ski in accordance with the present
invention showing the bottom portion being composed of a bottom shell and a top shell
along with a top and associated covers therefor;
FIG. 10 is a top plan view of an assembled motorized water ski partially broken away
to show the engine pod, engine and associated components;
FIG. 11 is very similar to tat shown in FIG. 10, at a different cross-section, showing
further components;
FIG. 12 is a bottom plan view of the motorized water ski, broken away to show an underside
of the engine pod and associated components;
FIG. 13 is a side view of the motorized water ski, partially exploded and broken away
to show an engine pod cover in relation to the hood of the engine compartment;
FIG. 14 is a side view of the motorized water ski in accordance with the present invention,
illustrating the positioning of the net rider plus craft center of gravity envelope
of the motorized water ski in relation to the rider;
FIG. 15 is a bottom plan view of the motorized water craft showing the position of
the riderless center of gravity and a flat hydroplane surface bounded by a hydrostep;
and
FIG. 16 is a top plan view of a motorized water ski according to the present invention
showing details of the arm pole assembly and controls.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Structure of the Motorized Water Ski
[0026] Referring to FIGS. 1a-1c, there is shown a high speed motorized water ski 10 according
to the present invention as it may be used by a rear mounted standing rider 12. FIG.
1a is a perspective view of the motorized water ski 10 as it is manipulated through
a controlled high speed, high g-force turn at speeds of 30 miles per hour (approximately
50 km/hr) or more. FIG. 1b is a perspective view of the motorized water ski 10 as
it is manipulated through a lower speed, short radius, high thrust turn. FIG. 1c is
a perspective view of the motorized water ski 10 as it is manipulated through a vertical
spin turn maneuver. This turning of the high speed motorized water ski 10 as shown
in FIGS. 1a-1c is initiated and controlled solely by the stance and weight distribution
of the rider 12 upon the water ski 10 and application of thrust as described in detail
subsequently. No prior art personal water craft that does not have a steering mechanism
is capable of these turns and maneuvers with a standing rider.
[0027] Referring to FIGS. 1a-1c, 2, 14 and 16, the motorized water ski 10 generally includes
a hull 16 that has a bow 18, a stem 20 and a rear deck portion 22. The rear deck portion
22 is sized for accommodating a standing rider as shown in FIGS. 1a-1c and 14. The
deck portion 22 has also been designed to accommodate a prone rider 12, shown in Figure
1D, who is able to easily mount the ski in deep water from the stern. The capability
of the rider 12 to mount the motorized water ski 10 from the stern 20 is a significant
advantage over the Surf Jet. Mounting the motorized water ski 10 from the rear decreases
the likelihood that it will turn over during the mounting process. The prior art rear
mounted engine motorized surf board known commercially as the "Surf Jet" cannot be
mounted from the stem because of the vertical protrusion of the motor housing. A chest
cavity depression 23, shown in FIG. 16, is preferably molded in the deck 22, to improve
the comfort of the rider 10 as he operates the craft in a prone position.
[0028] Also shown in FIGS. 1a-1c and 13-16 is a flexible arm pole 26, described hereinafter
in greater detail, along with an engine compartment hood 28, hood latches 30, a fire
extinguisher compartment cover 34, a master power switch 36, a bilge pump outlet 38,
access covers 42A and 42B and fins 44A, 44B, 46A and 46B. The fins 44A, 44B, 46A and
46B may be either fixed or retractable upon impact and may vary in horizontal and
vertical dimension.
[0029] The hull 16 is preferably made from molds (not shown) suitable for fiberglass molding
using appropriate resins. Such molds and techniques for fiberglass molding are well-known
and are therefore not described herein. Referring to FIGS. 2-9, the hull 16 includes
a bottom shell 50, a top shell 52 and a top deck 54. The bottom shell 50, the top
shell 52 and the top deck 54 are all bonded to one another with a suitable bonding
agent to form a monolithic structure when the hull 16 is fully assembled.
[0030] The mold assembly (not shown) includes a bottom mold, an interior mold and a top
deck mold. Referring to FIGS. 3-5, the bottom mold produces a jet pump housing compartment
60 and the entire bottom hull shape 58 from bow 18 to stem 20 and half way up the
entire contoured side rails 190A, 190B at a parting line. The interior mold produces
the entire engine compartment and compartments for other mechanical components described
herein. The contoured compartments 64, 66, 68 are outlined with a continuous vertical
contoured overflowing wall that rises up and over onto the outside complex curved
side rails 190A and 190B, shown in FIG. 6, that meet half way down the rail to the
bottom mold. The unique design precisely locates the mechanical components to obtain
the desired location of the craft center of gravity.
[0031] The hull design also forms the interior and bottom walls to produce the longitudinal
stiffness and strength of the entire hollow hull 16. The bottom shell 50 and the interior
shell 52 while in their respective molds are injected or poured with close cell foam
and sandwiched or clamped together until cured with the interior flange mold. The
top deck mold produces the entire contoured deck 54 and half of the rails 190A and
190B, minus the engine compartment hood 28. The top deck shell 54 in the mold is adhesively
bonded together with a suitable resin or other adhesive of choice with the bottom
mold. The molds are opened after curing the part. The top deck shell 54, the interior
shell 52 and bottom shell 50 match at the same parting line and become one part. This
produces a finished very high strength, high stiffness monolithic structure integrally
reinforced in both the longitudinal and transverse directions that is not disclosed
or suggested in the prior art.
[0032] The combination of the bonded contoured composite shaped top deck, shell 50 interior
shell 52 and bottom shell 54 seals the entire water craft from any water intake into
the hull foam and gives the hull 16 excellent flotation and strength superior to all
previous motorized personal water craft. This sophisticated light composite shaped
product and mold design allows the craft 10 to be assembled faster on an assembly
line than other motorized high performance personal water craft such as Jet Skis and
sit-down craft. The only assembly steps are drilling holes, tapping threads and inserting
screw-in parts.
[0033] Most of the Jet Skis and sit down craft require additional steps in their assembly.
Typical assembly of prior art watercraft includes gluing top deck, bottom hull and
bulk head compartment walls and adding and gluing the foam in most of their assembly
lines in fiberglass manufacturing.
[0034] Referring to FIGS. 2, 4, 6 and 8 the bottom shell 50 includes a pair of nose rail
rockers 55A and 55B and a pair of curved cross-section side rails 57A and 57B. The
term "rocker" as used herein refers to a vertical upwardly curved structure as viewed
from the side of the craft. Near the stem 20, the bottom shell 50 has a pair of tail
rail rockers 59A and 59B. The front rail rockers 55A and 55B, the side rails 57A and
57B and the rear rail rockers 59A and 59B facilitate making various types of turns
and maneuvers as explained subsequently.
[0035] The strength and stiffness of the foam sandwich composite hull structure 16 is superior
to any prior art personal water craft such as the current swivel jet stand-up (Jet
Ski) and sit-down craft, Surf Jet motorized surfboard, or other lower speed craft
such as those taught by Von Smagala-Romanov and Trotet. The weaker prior art composite
structures typically feature only single composite vertical walls such as in commercial
motorized personal watercraft or only reinforcement localized under the rider such
as proposed by Sajic for a non-motorized paddle board.
[0036] In the current invention the structure of the hull 16 is critical for supporting
the rider 12 and internal components in the craft 10 as it is exposed to the combined
stresses from high normal and torsional loads due to high speed, high g-force turns;
impact loads from the hull interacting with choppy seas at high speeds; high deck
loads from aerial jumps, and vibration loads from the engine 108. In the preferred
embodiment of the current invention, the hull 16 and the side rails 190A and 190B,
best shown in FIGS. 6-8, all are constructed from low density closed cell foam core
encapsulated by continuous fiber reinforced composite materials from bow 18 to stem
20. This unique monolithic curved shell hull assembly 16 is very efficient in reacting
the high internal bending moments, shear and torsion loads of the craft created by
the previously described maneuvers with minimum deflection and cyclic fatigue damage.
[0037] Further features of the invention, not applied in the prior art, are the highly sculptured
interior compartments within the hull 16 that accommodate and precisely locate the
placement of the internal components to achieve optimum location of craft center of
gravity, pivot point and balance while simultaneously acting as internal longitudinal
stiffening ribs. Also, composite reinforced metal mounting plate inserts for all mechanically
attached components are integrally molded into the hull structure 16.
[0038] The lower shell 50 includes a hull bottom 58 and a jet pump compartment 60 (best
shown in FIG. 5). The jet pump drive shaft compartment 61 as shown in FIG. 5 has an
access opening 62 therein as shown in FIGS. 3 and 9. Referring to FIG. 9, the top
shell 52 includes generally vertical interior walls 64, 66 and 68, which provide longitudinal
strength and stiffness to the high speed motorized water ski 10. The interior walls
64, 66, 68 enclose a bilge pump compartment 71, a fire extinguisher compartment 72,
an engine compartment 74, a rear gas tank compartment 76, a rear engine exhaust compartment
77, and engine pod mounts 80 and 82. The fire extinguisher compartment cover 34 and
the access covers 42A and 42B may be secured to the top deck 54 in any conventional
manner. Sealing rings 73 and 75 are preferably included to provide a water-tight closure.
[0039] It should be noted that the forward vertical walls 64 join and are continuous with
the walls 66. The walls 66 are continuous with the rear interior walls 68 to provide
structural strength and stiffness to the water ski 10. The drive shaft compartment
61 is surrounded by a box structure whose top surface bonds in a uniquely strong sandwich
with the deck 22. The deck 22 supports the 1000 to 1500 lb. dynamic (approximately
4450 to 6675 N) load of a rider in high g-force turns. The core of the sandwich is
an advanced continuous fiber "egg-crate" composite material. A further feature of
the structure is the reinforcement of the top deck engine compartment 74 access, utilizing
a novel flanged composite lip 79, along with multiple ply composite reinforcement
on the deck all around the access opening to the rails 190A and 190B and for a distance
of about 6 inches from the bow 18 and stem 20.
[0040] Referring to FIG. 10, formed in the top shell 52 is a mount 84 for a drive shaft
coupler 86. In addition, a forward mount 90 shown in FIG. 5 may be provided for supporting
a battery 92 in a conventional manner by a top plate 94 and bolts 96, best shown in
FIGS. 10 and 11.
[0041] Turning now to FIGS. 11-13, an axial flow jet pump 100, which may be of any suitable
commercial design capable of providing thrust preferably above 240 lb. (approximately
1068 Newtons), is secured within the pump compartment 60 by mounting bolts 102. The
axial flow jet pump is connected by a drive shaft 104 to the drive shaft coupler 86.
An engine drive shaft 106 is also connected to the drive shaft coupler 86. An internal
combustion engine 108 is mounted to an engine pod 110 that is secured to the engine
pod mounts 80 and 82 by bolts 114.
[0042] Preferably, the engine 108 has an output of about 15 to 55 horsepower (approximately
11 to 41 KW) to provide the necessary thrust. The water ski 10 preferably has a dry
weight in the range of about 85 pounds to about 155 pounds (approximately 378 to 690
Newtons). The engine 108 is capable of propelling the water ski 10 at speeds up to
about 35 miles per hour (approximately 56 km/hr) or more.
[0043] The engine pod 110 provides means for mounting the engine 108 below the level of
the deck 22. The engine 108 is located a short distance in front of the deck 22 where
the rider stands. The engine 108, the jet pump 100 and gas tank 115 with recessed
gas cap 117 and exhaust system 136 are positioned in the hull to define a net center
of gravity 120, shown in FIG. 14, beneath the deck portion 22 and rider 12. This location
of the net center of gravity enables the rider 12, standing on the rear deck 22 within
the length A, to turn the motorized water ski 10 solely by a shift in his stance or
weight distribution on the deck portion 22. Careful selection of the location of the
craft center of gravity will be hereinafter discussed in relation to the water ski
length. There is no other high speed personal motorized water craft that can be steered
in this manner by a rear-mounted, stand up rider.
[0044] Referring to FIGS. 14 and 16, in one preferred embodiment the mid-section, or beam,
182 of the motorized water ski 10 is approximately 27 inches (approximately 69 cm.)
wide; and the stern 20 is approximately 15 inches (approximately 38 cm.) wide. In
order to maintain a low profile, it is preferable that the engine 108 have a maximum
height, when mounted, of less than about 10 inches (approximately 25 cm.). The engine
108 may include a conventional pull-start mechanism 124 having a handle 126. The engine
may also include an electric starter 127 and a carburetor 128 having a throttle linkage
130, best shown in FIG. 11.
[0045] After the engine 108 is started, it may be controlled via controls disposed within
a hand grip 132, best shown in FIG. 13. The engine 108 may be controlled through the
flexible arm pole 26 by way of an electrical relay system. The engine 108 may alternatively
have controls that are directly connected to the hand grip 132 by a mechanical cable,
not shown. An exhaust system 136, best shown in FIG.11, is connected to the engine
108 for providing an acceptable sound level at a small exhaust pipe 140 that extends
through an exhaust port hole 19 (FIG. 8). A rubber hose 141 connects the exhaust system
136 to the exhaust pipe 140.
[0046] The engine 108 and exhaust system 136 are cooled by pumping water from the axial
flow jet pump 100. A Venturi intake fitting 101 is connected to a small intake hose
103 and then to another fitting 105 that connects through the rear compartment 76
and then to another fitting 107 on the engine water intake hose 109. The water circulates
through the engine to the exhaust cooling line utilizing fitting 111.
[0047] Referring to FIG. 11, the pump 100 is fixedly mounted in the stern 20 for discharging
a propelling stream of water, as indicated by the dashed lines 142. The propelling
stream of water is discharged outwardly from the stern 20 in a single unchangeable
direction. The direction of the propelling stream of water is directed generally parallel
to the longitudinal axis 144 of the motorized water ski 10. Water intake for the pump
is provided by an intake grate 148 disposed in the hull bottom 58 as shown in FIG.
15. A central fin 149 may also be mounted along the longitudinal axis 144.
[0048] The motorized water ski 10 preferably includes a bilge pump 154 connected to the
bilge pump outlet 38 by a conventional tube 152, as also shown in FIG. 13. Referring
to FIG. 13, an engine pod cover 150 may be provided for further sound attenuation
and additional water sealing of the engine 108 beneath the engine pod hood 28. It
should be appreciated that the engine 108 is sealed within the pod 110 and pod cover
150 to prevent water entrance. Additionally, the pod 110 and cover 150 and the engine
components contained therein are redundantly sealed within the water ski 10 by the
engine compartment hood 28 and latches 30, with an appropriate elastomer or inflatable
water seal 29 being used at the hood-deck interface. Air intake to the engine 108
is provided by an air intake opening 158, which communicates with the forward compartment
72. One way check valves (not shown) may be used for draining water from the internal
cavity without permitting water ingress.
[0049] It should be appreciated that any suitable construction materials may be utilized
in the fabrication of the motorized water ski 10, with appropriate methods and materials
for joining components as necessary. As noted herein above, fiberglass, graphite fiber,
polyester or epoxy resin and polyurethane or polystyrene foam are suitable materials
of construction.
[0050] It is necessary to access the tail section of the hull inside the back wall of the
exhaust 77 and gas tank compartment 76. This access is required for fitting and clamping
of hoses and other components under the deck 22. All of the above-mentioned fittings
for hoses, exhaust bilge pump, and water drainage have to be connected to mechanical
components through the jet pump compartment housing walls 61 on both sides inside
the hull exhaust compartment.
[0051] The clamping of these necessary mechanical components cannot be completed from the
engine compartment 74 because of the required length of the gas tank 77, drive shaft
104, and exhaust chamber 76. Therefore, as shown in FIG. 9, there may be a pair of
small openings 41A and 41B in the deck 22. These openings may be sealed by a corresponding
pair of O-ring sealed deck plates 42A and 42B that may be removed for providing access
to mechanical components under the deck 22. The size of the deck plates 42A and 42B
should be only large enough to accommodate a person's hand or hands and tools for
clamping these components properly. The design allows a rider to stand and jump on
the entire rear deck area 22 at dynamic forces of up to 1500 lb. (approximately 6675
N) during turning or jumping without damaging the deck plates. The small size of these
hand access deck plates coupled with the structural design of the inside walls of
exhaust 77, drive shaft 60, and gas tank 76 water tight compartments allows convenient,
water tight, high strength access for maintenance and installation never before achieved
in the personal water craft art.
[0052] Turning to FIG. 13, an arm pole air intake 160 communicating with the forward compartment
72 through a tube 162 and fitting 164 provides means for introducing air to the engine
108. The arm pole air intake 160 disposed in the arm pole 26 at a point elevated from
the bow, for example, up to 12 inches or more to prevent the entry of water during
use. Hence, the motorized water ski 10 may be completely submerged during operation
up to the arm pole air intake 160 without the introduction of water into the forward
compartment 72 or the engine compartment 74. Further protection for the engine is,
of course, provided by the sealed arrangement between the pod 110 and pod cover 150
and redundantly by the sealed engine hood 28. Any water entering the forward engine
compartment 72 is removed by the bilge pump 154 before it reaches the air intake 158
of the engine pod cover 150. In addition, the arm pole air intake 160 is rearwardly
facing to reduce water entry during operation of the water ski 10. Manual one-way
drain valves 21A and 21B may also be provided.
[0053] Referring still to FIG. 13, also fitted to the bow 18 is a replaceable safety nose
piece 165 preferably formed from rubber or silicone. The nose piece 165 is fitted
to the bow 18 by a tongue-in-groove fitting 166 which may be secured by screws or
the like (not shown). This a unique feature that is not shown in the prior art.
[0054] The arm pole 26 terminates in the universal left or right hand grip 132 which includes
finger controls 170, preferably a thumb-actuated throttle 170A, a starter 170B and
a stop switch 170C connected to the engine 108 either mechanically or electrically
for controlling engine speed. The hand grip is configured to be suitable for operation
by one hand of the rider 12. The thumb-actuated throttle 170A is a unique safety feature
that prevents the rider 12 from inadvertently depressing the throttle if he loses
his balance while gripping the hand grip 132 with his other four fingers. The one
handed universal left or right hand grip 132 differs from the grips used in the prior
art personal watercraft where two-handed handles are required for control and balance.
In water skiing a two handed grip is required so that the rider can maintain stability
throughout a sharp turn. In the present invention the free hand can be used for balance
and leverage while making turns as shown in FIGS. 1a-1c.
[0055] In addition, a dead man switch 172 is attached by a cord 174 to the rider's wrist
176 to cause the engine 108 to turn off should the rider 12 fall from the water ski
10. The details of the dead man switch are not shown here because this is a well-known
conventional feature mandated by law in most jurisdictions.
[0056] As shown in FIG. 15, the craft center of gravity 121 of the empty, riderless motorized
water ski 10 in accordance with the present invention is disposed behind the beam
182A, 182B. The beam is defined as the widest portion of the motorized water ski 10
when it is seen in a plan view. The shape and weight distribution of the hull 16 and
the locations of the jet pump 100, the engine 108, gas tank 115, exhaust system 136
and other components of the motorized water ski 10 are selected and formed so that
the craft center of gravity 121 is located on a vertical plane lying on the craft
longitudinal axis 144, shown in FIG. 11, within the length Z of FIG. 15.
[0057] The craft center of gravity 121 (FIG. 15) is determined by the structure of the hull
16 and placement of internal components. The structure of the motorized water ski
10 is designed so that its center of gravity 121 falls within an envelope or range
located above the flat keel 17 portion (FIG. 4) of the hull 16. Therefore, at high
speeds of up 30 miles per hour (approximately 50 km/hr) or more, directional control
of the motorized water ski 10 is accomplished by a change in the rider's stance or
weight distribution while he is positioned in a preferred location that is approximately
over the net center of gravity 120 of the rider 12 and motorized water ski 10.
[0058] Referring to Figure 14, when the rider 12 stands on the deck 22, the net center of
gravity 120 of the motorized water ski 10 and rider 12 is rearward of the craft center
of gravity 121 (shown in FIG. 15) of the riderless motorized water ski 10. It is assumed
that the average rider will weigh between about 80 pounds and 250 pounds (approximately
356 to 1112 Newtons). The range, or envelope, of the position of the net center of
gravity 120, depending on the rider's weight and position, is shown by the double
headed arrow A in FIG. 14. The arrow A represents a range of locations of about 70%
to 100% of the length of the motorized water ski 10 measured from the bow 18 and bounded
laterally by the side rails 190A and 190B. It has been found that the riderless center
of gravity 121 preferably is disposed more than 50 percent of the length of the water
ski 10 from the bow 18 approximately on the longitudinal center line 144. Placement
of the craft center of gravity 121 should be in the range or envelope indicated by
the double headed arrow Z shown in FIG. 15 which lies behind the bow 18 at least a
distance Y. The total length of the water ski is represented by the length of the
lines Y + X. The ratio of
is preferably between 0.50 and 0.75. Therefore, when the rider of average weight
stands on the deck 22, the net center of gravity will lie in the general region of
the rider and above the hydroplane surface 180. The structure of the motorized water
ski 10 that allows the longitudinal and transverse coordinates of the net center of
gravity to lie below the rider is an important feature that permits a change in position
and weight distribution of the rear mounted standing rider 12 to be effective in initiating
and maintaining a turn of a desired radius in water without the use of a mechanical
turning device. This is described in detail subsequently.
[0059] Another feature of the present motorized water ski 10 is a low profile. Particularly,
the profile of the top deck at the stern 20 and deck portion 22 enables a rider to
board the motorized water ski while it is in water as shown in FIG. 10.
[0060] The combination of design features of the bottom hull 58 and side rails 190A as shown
generally in FIG. 6, has never before been used in personal water craft, and are a
novel part of this invention. These features, in conjunction with the placement of
the craft center of gravity and control of thrust, enable the rear mounted standing
rider to select a variety of operating characteristics for maximum control and stability
during straightway high and low speed cruising and during high and low speed turns.
[0061] The side rails 190A and 190B run the entire length of the craft and bound the hull
bottom 58 on both port and starboard as best shown in FIGS. 7 and 8, and provide the
rider stability and precise control during turns as shown in FIGS. 1A and 1B. The
rails have complex curve cross-sections 57A and 57B, that assist the rider 12 in achieving
the desired sharpness of turns and setting the angle of thrust during turns as explained
subsequently. The rails 190A and 190B also have vertical upward curvatures or front
rail rockers 55A and 55B at the bow 18 and rear rail rockers 59A and 59B near the
stem 20, as shown best in FIG. 6. The front rail rockers 55A and 55B act to decrease
drag at low speeds prior to hydroplaning and assist in controlling the sharpness of
high speed turns. The rear rail rockers 59A and 59B assist in the control of the sharpness
of lower speed, small radius thrust assisted turns.
[0062] Referring again to FIG. 6, 7 and 8, the hull bottom 58 features forward soft low
angle "V" surfaces 194A and 194B extending from the bow 18 to the beam 182 and 182
B, which reduce straightway cruising drag at lower speeds prior to hydroplaning. The
rear "V' surfaces 195A and 195B extend aft from the beam 182 at an increasingly higher
angle to the stern, where they connect the side rails 190A and 190B with the hydrostep
183A and 183B which bound the flat hydroplane surface 180. The forward end of the
rear "V' surfaces located between the beam 182 and the beginning of the sharply defined
hydrostep 183A and 183B facilitates executing partial sharp zig-zag maneuvers, while
the sharp rear portions of the 'V" surfaces 195A and 195B provides leverage for the
rider 12 to move from the hydroplane surface 180 to the selected rail 190A or 190B
to initiate turns.
[0063] Referring again to Figure 6, the hydroplane surface 180, located directly under the
deck 22 is bounded by a blended radius with the rear "V" 195A and 195B surfaces forward
of the pump water inlet 148 in order to minimize aeration, with the abrupt hydrostep
183A and 183 B beginning aft of the inlet 148 to achieve rapid release of water during
transition of the craft 10 to high speed hydroplaning. The hydroplane surface 180
provides stability and low drag efficient operation as soon as the pump 100 provides
sufficient thrust to achieve hydroplaning speeds above about 10 miles per hour. In
addition the position of the net center of gravity, 120 under the rider 12 as shown
in FIG. 14, enables the ski 10 to come to speed without the rider leaning forward
with his weight to stabilize the craft from porpoising as is necessary in prior art
watercraft with standing rear mounted riders. The flat center keel 17, shown in FIG.
4, extends from forward of the beam 182, then aft to merge with the flat hydrostep
182 which begins at a point forward of the pump inlet grate 148 and proceeds aft in
a "mini surfboard" shape as shown best in FIG. 6. The flat center keel 17 helps prevent
porpoising of the ski 10 in the water.
[0064] The unique design of the hull 58, combined with the side rails 190A and 190B and
the low net center of gravity 12 positioned underneath the rider 12 provides unique
stability for a rear mounted beginning rider. For example if an inexperienced rider
leans, by accident, left or right while planing, there is no unstable abrupt tipping
from side to side or unstable sliding left or right of the stem 20 which would cause
loss of balance and perhaps throwing of the rider off the ski. The craft smoothly
transitions from the hydroplane surface 180, through the side "V" surfaces 195A or
195B to the rails 190A or 190B and a gradual sliding turn of the ski is negotiated
under control of the rider 12.
[0065] This novel combination of bottom hull and side rail configuration in conjunction
with the location of the net center of gravity and proper application of thrust allows
the rider to have precise control of the craft as described subsequently.
[0066] Also providing stability are the fins 44A, 44B, 46A, 46B and 149 which minimize lateral
sliding of the water ski 10 in turns. As best seen in FIG. 15, the fins 44A, 44B,
46A, 46B and 149 are disposed in slots 204A, 204B 206A, 206B and 208, respectively,
and may be pivotally mounted or spring mounted, not shown, for enabling the fins 44A,
44B, 46A, 46B and 149 to retract into the rear compartments 76 as a safety feature
and to enable ramp jumping with the motorized water ski 10.
Method of Operation of the Motorized Water Ski
[0067] The high performance operation of the craft 10 is directly related to the application
of a unique combination of structural features. These feature include thrust, engine
power, buoyancy, precisely located craft center of gravity, bottom hull design and
side rail design. To obtain the required high speed performance, the axial flow water
jet pump 100 in the current invention must deliver sufficient thrust to rapidly accelerate
the craft 10 and maintain its speed, which is preferably from 30 miles per hour (approximately
50 km/h) to in excess of 40 miles per hour (approximately 64 km/h). To overcome both
the resistance of the water acting on the craft 10 and the resistance of air on the
rider and the craft 10, the required thrust for achieving this range of speeds was
calculated to be in the range from 130 pounds (approximately 580 Newtons) to about
330 pounds (approximately 1468.5 Newtons). In a preferred embodiment of the invention,
a craft speed of 32 to 35 miles per hour (approximately 51 to 56 km/h) was measured
on flat water at a measured pump thrust of about 240 to 265 pounds (approximately
1068 to 1179 Newtons).
[0068] The engine 108 must have sufficient power to propel the craft 10 and rider at the
desired range of speeds stated above. The required engine power depends on the energy
consumed per second to move the mass of the rider plus craft 10 through the water
at the desired speed. This power is a function of the kinetic energy of the craft
10 and rider plus the work done in overcoming drag forces from the air and water and
the efficiency of the jet drive pump system. For the desired range of speeds and applicable
range of rider plus craft 10 weights of from about 250 pounds (approximately 1112
Newtons) minimum to about 400 pounds (approximately 1780 Newtons) maximum, engine
powers of from 14 HP (approximately 10.4 KW) to about 55 HP (approximately 41 KW)
are required.
[0069] In one preferred embodiment of the invention, a craft 10 plus rider with a total
weight of about 350 pounds (approximately 1560 Newtons) achieved a constant measured
speed of above 32 to 35 miles per hour (approximately 51 to 56 km/h) with an engine
108 rated at 25 HP (approximately 18.6 KW) output power, The relatively high weight
of the required highly powered engine 108 ranges from 30% to 50% of the total weight
of the craft 10, which requires careful placement of the engine 108 within the hull
to allow a rear mounted rider to pivot the craft 10 and perform stable turns without
the use of a steering mechanism.
[0070] The buoyancy of the craft 10 is designed to neutrally support a rider of up to about
250 pounds (approximately 1112 Newtons) while simultaneously supporting an additional
90 to 150 pounds (approximately 400 to 667.5 Newtons) of weight from the craft 10
structure and mechanical components, without submerging the top of the engine compartment
hood 28. This is achieved by a precisely calculated craft 10 volume, weight and center
of buoyancy relative to the location of the center of gravity 121 of the craft 10.
Once hydroplaning is achieved, the natural (static) buoyancy becomes less important,
being dominated by the vertical hydrodynamic components of force on the rear of the
craft 10, controlled by the thrust and speed.
[0071] The center of gravity 121 of the craft 10 is critical to performance, stability and
the ability of a rear mounted rider to initiate and negotiate controlled low speed
and high speed turns (FIGS. 1a and 1b) without the use of a turning mechanism. This
control by a rider mounted on the rear deck is achieved by positioning, the center
of gravity 121 of the craft 10 on the craft 10 longitudinal center line 144 in front
of the rider and at a horizontal distance in the range of about 50% to 75% from the
bow.
[0072] The weight of a typical rider is in the range of 1.0 to 1.75 times that of the craft
10. As the typical rider 12 stands in a sideways stance on the rear deck 22, the net
center of gravity 120 of the rider plus craft 10 moves to a preferred position on
the longitudinal center plane of the craft 10. The longitudinal and transverse coordinates
of the net center of gravity 120 typically are located in the region beneath the rider
and between the position of his front and back feet. In this case the net center of
gravity 120 is referred to as an "intelligent CG" because the rider is able to easily
move the net center of gravity 120 forward, aft, left or right to control the craft
10 by only slight body movement or weight shift.
[0073] For example during take off, the rider leans forward in a standing position or lies
on the craft 10 with his chest just behind the engine 108 to move the net center of
gravity 120 forward toward the location of the mechanical center of gravity 121 and
applies thrust, thus facilitating rapid transitioning of the craft 10 to a hydroplaning
condition. Then the rider leans back if standing (or stands up if lying down) to move
the net center of gravity 120 in a projected area near his feet for stable high speed
straight line operation. The rider turns the craft 10 by slightly adjusting his weight
distribution or position of his rear foot generally forward and in a transverse direction
to the craft's longitudinal axis 144 in the direction of the desired turn. This moves
the net center of gravity 120 slightly forward and in the direction of the desired
turn (left or right), and places the pivot point inside the selected rail 194A or
194B in the region of the rider, thus producing a stable turn. The rider can adjust
the angle of the turn by the degree to which he shifts his body weight rearward and
to the left or right of the longitudinal centerline 144. The rider 12 can negotiate
both high speed, high g-force turns and low speed turns as described later.
[0074] Precisely locating the craft 10 center of gravity 121 and the net craft 10 plus rider
12 center of gravity 120 is a key element of this invention. A large number of calculations
and experiments regarding hull structure, placement of mechanical components and position
of the rider 12 were required to achieve the preferred embodiment. These calculations
and experiments took into account both the weight and weight distribution of the empty
hull 16 structure and the weight and location of the mechanical components within
the craft 10 and the weight range and location of the rider 12.
[0075] Unlike the prior art craft 10 with no steering mechanisms, for the considerably higher
powers and thrusts required in this invention, the total weights of the mechanical
components including engine 108 assembly, jet pump assembly 100 and fuel tank 114
are generally equal to or greater than the weight of the craft 10 structure. This
is shown below for a range of intended models and one specific preferred embodiment.
Unlike the previous art, the high power engine 108 dominates the weight of the mechanical
components and its placement in front of the rider dominates the calculation of the
center of gravity 121 of the craft 10, determined by calculating, for each of three
mutually orthogonal directions, the summation of the product of the individual masses
times the distances from a reference datum divided by the sum of the masses. Table
I gives representative values of the weights of various components of the craft 10
along with values for a specific preferred embodiment.
TABLE I
Component |
Weight Range (Lb.) |
Pref. Embodiment (lb.) |
Empty Hull |
35-60 |
55 |
Engine & Pod |
30-80 |
59 |
Battery & Housing |
5-15 |
13.5 |
Jet Pump Assembly |
7-20 |
12 |
Fuel Tank |
2-5 |
4 |
Exhaust System |
3-8 |
4.5 |
Arm Pole Assembly |
6-12 |
11 |
[0076] Even slight variations of the positions of heavy components of the craft 10 has a
significant effect on the location of the center of gravity of the craft 10. Slight
variations in component position also have significant effects on the performance
and handling of the craft 10. In one preferred embodiment of the invention, the approximately
59 pound (approximately 263 Newton), 25 HP (approximately 18.6 KW) engine assembly
and the mechanical components are positioned in the craft 10 such that the center
of gravity 121 of the craft 10 is positioned at a distance of 62.5% of the total length
from the bow, about 1.5 ft. (approximately 0.45 m) in front of the net center of gravity
120 when a rear mounted rider of average adult body weight is in a typical position
for straightway high speed planing. As discussed previously, in order to achieve the
desired handling characteristics and provide stability and speed for a rear mounted
rider experiments showed that the center of gravity 121 of the craft 10 must be located
in the range of 50% to 75% of the total craft 10 length measured from the bow on the
longitudinal axis of the craft 10 and about midway between the top shell 52 and bottom
shell 50 on the vertical axis.
[0077] The coordinated design of the hull bottom 58 and side rails 190A and 190B in the
present invention is critical to achieving both high speed, controlled high g-force
turns and low speed turns without the use of any turning mechanism or variable-direction
jet. The hull 16 features a unique combination of the flat hydroplane surface 180
near the stem 20 that transitions laterally through "V" shaped surfaces 195A and 195B
to the outer curved cross section rails 190A and 190B. This hull-rail design operates
in conjunction with the net center of gravity 120 of the craft 10 and rider to enable
a stable transition from low speed startup to high speed straight planing and easy
initiation and execution of smooth and controllable high and low speed turns. The
unique combination of bottom hull 58 and rail 190A, 190B design features offers the
rider optimum choices for operation in a variety of modes. During start-up the abrupt
hydrostep 183A, 183B bordering the hydroplane surface 180 facilitates release from
the water on application of thrust, which results in the rapid transition to stable
high speed hydroplaning where both the wetted hull surface and resultant drag forces
are minimized. The hydrosteps 183A, 183B vary from negligible height at the forward
initiation point of the hydroplane surface 180 to a maximum height at the stem 20
of 1 to 4 inches (approximately 2.5 cm to 10.0 cm) high, depending on desired responsiveness
during turns or maneuvers.
[0078] The hydroplane surface 180 is generally shaped like a miniature surfboard. The hydroplane
surface 180 begins well in front of the pump intake 148 and mates with the center
of keel 17 which proceeds aft without any rocker (or vertical curve) and acts to resist
vertical porpoising of the craft 10 while lowering drag and stabilizing the craft
10 during high speed operation. The "V" surfaces 195A and 195B to the side of the
hydroplane surface 180 connect the base of the hydroplane surface 180 with the outer
rails. The interface lines of the "V"- shaped surfaces 195A and 195B and the hydroplane
surface 180 are blended smoothly forward of the jet pump intake 148 to minimize aeration
into the pump 100. Sharp edges 183A and 183B in the hydrostep begins at the forward
edge of the jet pump intake 148 and proceeds aft, thus promoting hydrodynamic release
of the water off the sharp edges thereby reducing drag. The full "V" shaped hull portions
194A and 194B forward of the hydroplane surface 180 assists the rider in initiating
rapid zig-zag turn maneuvers with minimum effort.
[0079] When the rider shifts his weight left or right to initiate a full turn, the craft
10 rolls from the flat hydroplane surface 180, to the adjacent "V" surfaces 195A and
195B, which increase in angle towards the bow 18 and provides the rider 12 with leverage
to submerge the curved rails 190A and 190B by means of his weight shift on the deck
22, thus initiating a turn. The rider 12 then glides on the selected rail 190A or
190B, proceeding from the stern portion to the mid portion of the rail for high speed
turns and remaining on the stern rocker portion of the rail 59A, 59B in lower speed
turns where thrust is used to change the direction of the craft 10. The hydrodynamic
drag forces on the submerged portion of the rail, in conjunction with the position
of the net center of gravity 120 and pre-defined pivot point under the rider 12, produce
controlled smooth high speed and low, speed turns with no abrupt movement to destabilize
the rider 12. The side rail rockers 59A, 59B that curve vertically upwards near the
stern 20 enable the rider 12 to use his weight shift to control the speed of response
of the craft 10 during turns. In high speed turns the complex curved cross section
rail surfaces 57A and 57B acts like a motorcycle tire in setting the final angle and
direction of the turn. The fins 44A, 44B, 46A, 46B and 149 act to prevent over-rotation
of the hull and prevent sliding during both low speed and high speed turns. One to
five fins suitably placed fins may be used, depending on the required performance
characteristics. As an alternative, low profile retractable "Bonsai" type fins can
be used.
[0080] During low speed, short radius turns as shown in FIG. 1B at speeds between 5 to 10
miles per hour (approximately 8 to 16 km/h), the rider 12 shifts the net center of
gravity 120 aft and in the direction of the desired turn. This sinks the aft rocker
end of the rails 59A, 59B, and the rider 12 simultaneously uses high thrust bursts
of the water jet to accelerate through the short radius turn having a radius typically
in the range of 3 to 4 feet (approximately 0.9 to 1.2 m) with high stability. In this
type of turn the craft pivots wound the net center of gravity 120 without the use
of a steering mechanism or maneuverable jet as required by the prior art. A more extreme
spin maneuver shown in FIG. 1C can also be achieved in which a major portion of the
craft is lifted out of the water by the rider 12 shifting his weight and net center
of gravity 120 even further aft toward the stern 20 by leaning backwards and by applying
maximum thrust of greater than 200 lb. (approximately 890 Newtons). This results in
a significant component of thrust in the vertical direction that lifts much of the
craft 10 out of the water while pivoting the craft 10 and rider 12.
[0081] The unique combination of high thrust, precision craft center of gravity 121 positioning
and bottom hull/rail configuration enables the craft 10 and rear mounted standing
rider 12 to negotiate stable controlled high speed turns never before achievable on
a stand up, rear mounted personal water craft with non-directional thrust. The rider
12 experiences peak forces of between 3 and 6 times the force of gravity during such
turn as measured with one preferred embodiment of the invention as listed in Table
II.
TABLE II
Turn Radius (ft) |
Max. Tangential Speed (mph) |
Peak Centripetal Force (g's) |
25 |
34 |
3.1 |
15 |
32 |
4.6 |
10 |
30 |
6.0 |
[0082] The high centripetal force allows the rider 12 to negotiate high speed turns at approximate
angles of his body axis to the water surface of 15 to 20 degrees, as he is stabilized
by both the upward vertical component of the reaction force and the friction force
of his feet on the deck 22 acting against the vertically downward force of his weight.
For example, a 200 pound rider 12 would experience the following forces acting against
the vertically downward 200 pound force of his weight, thus preventing him from falling
or slipping off the craft 10 as he negotiates a high speed turn. Table III gives forces
on the rider 12 for two different angles between the rider's body and the water during
a turn of the watercraft according to the present invention.
TABLE III
Angle of Body to Water Surface |
Peak Centripetal Force (g's) |
Vertical Force (lb.) |
Friction Force (lb.) |
20° |
3 |
205 |
120 |
15° |
4 |
207 |
160 |
[0083] The controlled and stable high g-force turns that can be performed by a standing
rider 12 without an active mechanical steering mechanism by a rear mounted standing
rider 12 with the present invention have never been achieved in personal water craft
or in water skiing where the tension on the rope connected to the boat and the skier's
arm tends to produce destabilizing forces on the skier.
1. A high speed motorized water craft (10) that includes a hull (16) having a bow (18),
a stern (20), a deck (22) sized for accommodating the standing rider (12); a hydroplane
surface (180) formed on the hull (16) and a longitudinal axis (144) extending from
the bow (18) to the stern (20); a jet pump (100) for discharging a propelling stream
of water outwardly from the stern (20) in a direction fixed to be generally parallel
with the longitudinal axis (144) of the high speed motorized water craft (10); a motor
(108) disposed within the hull (16) for driving the pump (100), the motor pump (100)
being mounted within the hull (16) such that the high speed motorized water craft
(10) has a riderless center of gravity (121) that is within an envelope located beneath
the deck (22) and aft of the motor (108), enabling the rider (12) located on the deck
(22) to be in an essentially neutral position with respect to the net center of gravity
(120) of the high speed motorized water craft (10) plus rider (12), thus allowing
the rider (12) to maneuver and turn the high speed motorized water craft (10), without
the use of a mechanical turning device, by a shift in his stance or weight distribution
on the deck (22) that moves the net center of gravity (120) of the high speed motorized
water craft (10) about an approximately vertical axis of rotation that is approximately
coincident with the location of the rider (12) to facilitate maintenance of balance
and stability of the rider (12) while riding the high speed motorized water craft
(10) and while turning it about an approximately vertical axis,
characterised in that the watercraft is a water ski, the jet pump is fixedly mounted in the stem (20),
the motor (108) is mounted in the hull (16) forward of the deck (22), thus enabling
easy deep water mounting of the high speed motorized water ski (10) by the rider (12)
from the stern (20), and the riderless centre of gravity is aft of the motor (108),
and in that the craft further comprises a pair of curved side rails (190A and 190B)
formed on opposite sides of the hull (16); a hull bottom (58) having a first "V"-shaped
portion (194A, 194B) forward of the widest beam portion (182A, 182B) of the hull (16),
the first "V" shape (194A, 194B) transitioning aft along the hull bottom (58) to a
flat keel (17) and then to a second "V" shaped portion (195A 195B) between the hydroplane
surface (180) and the curved side rails (190A, 190B), the second "V"-shaped portion
(195A and 195B), the curved side rails (190A, 190B) cooperating with the rider's movement
of the net center of gravity (120) to enable smooth transition from startup to high
speed planing and easy initiation and execution of high and low speed turns;
an intake grate (148) formed in the hull bottom (58);
a hull bottom section forward of the intake grate (148) that blends smoothly into
the second "V" shaped portion (195A, 195B) and connects to the rails (190A, 190B)
to minimize aeration of water entering the pump (100); and
a pair of hydrosteps (183A, 183B) aft of the intake grate (148) that assist in the
efficient release of water as the hull (16) transitions to a hydroplane mode, thus
providing stability and decreased water resistance to the hull (16), whereby the high
speed motorised water craft has stability and manoeuvrability for a rear mounted rider
(12) at both low and high speeds.
2. The high speed motorised water ski (10) of claim 1, further comprising:
an arm pole (26) attached to the hull (16) adjacent the bow (18); and a hand grip
(132) connected to the flexible arm pole (26), the arm pole (26) and hand grip (132)
being configured such that the rider (12) may stand on the deck portion (22) and grasp
the hand grip (132) with one hand and use the hand grip (132) and arm pole (26) to
achieve additional stability and manoeuvrability of the high speed motorised water
ski (10).
3. The motorised water ski of claim 2 wherein the hand grip is a universal single handed
right/left hand grip (132) configured for one-handed operation.
4. The motorised water ski (10) according to claim 1 wherein the riderless center of
gravity (121) of the motorised water ski (10) is disposed more than 50% of the length
of the hull (16) from the bow (18).
5. The motorised water ski (10) according to claim 1, wherein the riderless center of
gravity (121) of the motorised water ski (10) is disposed more than 25% of the length
of the hull (16) from the stem (20).
6. The motorised water ski (10) according to claim 2, further including an air intake
(160) formed in the arm pole (26) for introducing intake air to the engine (108),
the air intake (160) being disposed in the arm pole (26) at a point spaced apart and
elevated from the bow (18).
7. The high speed motorised water ski (10) of claim 2, further comprising a thumb-actuated
throttle (170A),, a starter (170B) and a stop switch (170C) in the hand grip (132),
the thumb-actuated throttle (170A), starter (170B) and stop switch (170C) being located
such that the rider (12) may conveniently and safely control starting of the motor
(108) and speed of the motor (108) by actuating the thumb-actuated throttle (170A),
starter (170B) and stop switch (170C) with this thumb only, such that acceleration
of the high speed motorised water ski (10) while the rider grips the hand grip (132)
does not further open the throttle.
8. The motorised water ski (10) according to claim 1, further including a chest depression
(23) formed in the deck (22) near the stern (20) for accommodating the chest of the
rider (12) as he mounts the motorised water ski (10) from the water over the stern
(20).
9. The motorised water ski (10) according to claim 1 wherein the side rails (190A, 190B)
extend the full length of the hull (16) and have complexly-curved cross section portions
(57A, 57B) and vertically upward curved portions (55A, 55B) near the bow (18) and
vertically upward curved portions (57A, 57B) near the stern (20) that enables the
rear mounted rider (12) to turn the motorised water ski (10) at high or low speeds
according to the angle and sharpness of turn preferred by the rider.
10. The motorised water ski (10) according to claim 1 wherein the "V" shaped surfaces
(195A, 195B) on either side of the hydrosteps (183A, 183B) provide the rider (12)
with leverage to facilitate transitioning of the high speed motorised water ski (10)
from straight line cruising to turning modes.
11. The motorised water ski (10) according to claim 1 wherein the hull (16) is formed
such that the net center of gravity (120) of the high speed motorised water ski (10)
and rider (12) is between the side rails (190A, 190B) while the rider steers the high
speed motorised water ski (10) through a banked turn,
12. The motorised water ski (10) of claim 1, further comprising:
an engine pod (110) that provides a stable engine platform, a structural load path
from the motor to the hull and maintains alignment of the engine (108) with a drive
shaft (104) and the jet pump (100); and
an engine pod cover (150) that cooperates with the engine pod (110) to form a water-tight
enclosure for the motor (108).
1. Hochleistungs-Motorwasserfahrzeug (10), das folgende Komponenten einschließt: einen
Rumpf (16), der einen Bug (18), ein Heck (20), ein Deck (22), das für die Aufnahme
eines stehenden Fahrers (12) bemessen ist; eine hydroplane Oberfläche (180), die auf
dem Rumpf (16) gebildet wird, und eine Längsachse (144) hat, die sich vom Bug (18)
zum Heck (20) erstreckt; eine Strahlpumpe (100) zur Abgabe eines antreibenden Wasserstromes
vom Heck (20) nach außen in eine Richtung, die allgemein parallel mit der Längsachse
(144) des Hochleistungs-Motorwasserfahrzeugs (10) fixiert ist; einen Motor (108),
der innerhalb des Rumpfes (16) angeordnet ist, um die Pumpe (100) anzutreiben, wobei
die Motorpumpe (100) derartig innerhalb des Rumpfes (16) angeordnet ist, daß das Hochleistungs-Motorwasserfahrzeug
(10) einen Schwerpunkt (121) ohne Fahrer hat, der sich innerhalb einer Verkleidung
befindet, die unter dem Deck (22) und hinter dem Motor (108) angeordnet ist, wodurch
der Fahren (12), der sich auf dem Deck (22) befindet, in die Lage versetzt wird, eine
im wesentlichen neutrale Position im Verhältnis zum Nettoschwerpunkt (120) des Hochleistungs-Motorwasserfahrzeugs
(10) plus Fahrer (12) einzunehmen, was es dem Fahrer (12) erlaubt, das Hochleistungs-Motorwasserfahrzeug
(10) ohne Benutzung einer mechanischen Lenkvorrichtung zu manövrieren und zu wenden,
allein durch eine Verlagerung seines Standes oder seiner Gewichtsverteilung auf dem
Deck (22), durch die der Nettoschwerpunkt (120) des Hochleistungs-Motorwasserfahrzeugs
(10) um eine annähernd senkrechte Rotationsachse bewegt wird, die annähernd mit dem
Standort des Fahrers (12) übereinstimmt, um die Erhaltung des Gleichgewichts und der
Standfestigkeit des Fahrers (12) zu erleichtern, während dieser das Hochleistungs-Motorwasserfahrzeug
(10) fährt und während er dieses um eine annähernd senkrechte Achse wendet, dadurch
gekennzeichnet, daß das Wasserfahrzeug ein Wasserski ist, die Strahlpumpe feststehend
im Heck (20) angebracht ist, der Motor (108) im Rumpf (16) vor dem Deck (22) angebracht
ist, wodurch in tiefem Wasser ein leichtes Besteigen des Hochleistungs-Motorwasserskis
(10) durch den Fahrer (12) vom Heck (20) her ermöglicht wird, und sich der Schwerpunkt
ohne Fahrer hinter dem Motor (108) befindet, und dadurch, daß das Fahrzeug außerdem
folgendes aufweist: ein Paar gebogener Seitschienen (190A und 190B), die auf gegenüberliegenden
Seiten des Rumpfes (16) gebildet werden; eine Rumpfunterseite (58), die einen ersten
V-förmigen Abschnitt (194A, 194B) vor dem breitesten Trägerabschnitt (182A, 182B)
des Rumpfes (16) hat, wobei der erste V-förmige , Abschnitt (194A, 194B) nach hinten
längs der Rumpfunterseite (58) in einen flachen Kiel (17) und dann in einen zweiten
V-förmigen Abschnitt (195A, 195B) zwischen der hydroplanen Oberfläche (180) und den
gebogenen Seitschienen (190A, 190B) übergeht, wobei der zweite V-förmige Abschnitt
(195A und 195B), die gebogenen Seitschienen (190A, 190B) mit der Bewegung des Nettoschwerpunkts
(120) durch den Fahrer zusammenwirken, um den ruhigen Übergang vom Anfahren zum schnellen
Gleiten und das leichte Einleiten und Ausführen von schnellen und langsamen Wenden
zu ermöglichen;
ein Einlaufgitter (148), das in der Rumpfunterseite (58) gebildet wird;
einen Teilabschnitt der Rumpfunterseite vor dem Einlaufgitter (148), der gleitend
in den zweiten V-förmigen Abschnitt (195A, 195B) übergeht und mit den Schienen (190A,
190B) verbunden ist, um die Durchlüftung des Wassers, das in die Pumpe (100) eintritt,
auf ein Minimum zu senken: und
ein Paar Hydrostufen (183A, 183B) hinter dem Einlaufgitter (14), die das wirksame
Abheben vom Wasser unterstützen, wenn der Rumpf (16) in einen Hydrogleitmodus übergeht,
um so dem Rumpf (16) Stabilität und einen geringeren Wasserwiderstand zu geben, wodurch
das Hochleistungs-Motorwasserfahrzeug sowohl bei niedrigen als auch bei hohen Geschwindigkeiten
einem im hinteren Teil stehenden Fahrer (12) Stabilität und Manövrierfähigkeit bietet.
2. Hochleistungs-Motorwasserski (10) nach Anspruch 1, der außerdem folgendes aufweist:
eine Armstange (26), die angrenzend an den Bug (18) am Rumpf (16) angebracht ist;
und einen Handgriff (132), der mit der flexiblen Armstange (26) verbunden ist, wobei
die Armstange (26) und der Handgriff (132) derartig konfiguriert sind, daß der Fahrer
(12) auf dem Deckabschnitt (22) stehen und den Handgriff (132) mit einer Hand fassen
und den Handgriff (132) und die Armstange (26) dafür nutzen kann, zusätzliche Stabilität
und Manövrierfähigkeit des Hochleistungs-Motorwasserskis (10) zu erreichen.
3. Motorwasserski nach Anspruch 2, bei dem der Handgriff ein universeller Einhandgriff
(132) für die rechte/linke Hand ist, der für die Einhand-Handhabung konfiguriert ist.
4. Motorwasserski (10) nach Anspruch 1, bei dem sich der Schwerpunkt (121) ohne Fahrer
des Motorwasserskis (10) um mehr als 50% der Länge des Rumpfes (16) vom Bug (18) entfernt
befindet.
5. Motorwasserski (10) nach Anspruch 1, bei dem sich der Schwerpunkt (121) ohne Fahrer
des Motorwasserskis (10) um mehr als 25% der Länge des Rumpfes (16) vom Heck (20)
entfernt befindet.
6. Motorwasserski (10) nach Anspruch 2, der außerdem einen Lufteinlaß (160) einschließt,
der in der Armstange (26) gebildet wird, um Ansaugluft in den Motor (108) einzuführen,
wobei der Lufteinlaß (160) an einer Stelle in der Armstange (26) angeordnet ist, die
im Abstand zum und oberhalb des Bugs (18) angeordnet ist.
7. Hochleistungs-Motorwasserski (10) nach Anspruch 2, der außerdem eine daumenbetätigte
Drosselklappe (170A), einen Starter (170B) und einen Stoppschalter (170C) im Handgriff
(132) aufweist, wobei die daumenbetätigte Drosselklappe (170A), der Starter (170B)
und der Stoppschalter (170C) so angeordnet sind, daß der Fahrer (12) bequem und sicher
nur mit diesem Daumen das Starten des Motors (108) und die Drehzahl des Motors (108)
durch Betätigung der daumenbetätigten Drosselklappe (170A), des Starters (170B) und
des Stoppschalters (170C) steuern kann, derartig, daß durch die Beschleunigung des
Hochleistungs-Motorwasserskis (10) die Drosselklappe nicht weiter geöffnet wird, während
der Fahrer den Handgriff (132) hält.
8. Motorwasserski (10) nach Anspruch 1, der außerdem eine Brust-Vertiefung (23) aufweist,
die im Deck (22) in der Nähe des Hecks (20) gebildet wird, um die Brust des Fahrers
(12) aufzunehmen, wenn dieser den Motorwasserski (10) über das Heck (20) vom Wasser
her besteigt.
9. Motorwasserski (10) nach Anspruch 1, bei dem sich die Seitschienen (190A, 190B) über
die volle Länge des Rumpfes (16) erstrecken und komplex gebogene Querschnittsabschnitte
(57A, 57B) und senkrecht nach oben gebogene Abschnitte (55A, 55B) in der Nähe des
Bugs (18) und senkrecht nach oben gebogene Abschnitte (57A, 57B) in der Nähe des Hecks
(20) haben, was es dem hinten stehenden Fahrer (12) ermöglicht, den Motorwasserski
(10) bei hoher oder niedriger Geschwindigkeit, entsprechend dem Winkel und der Spitze
der Wende, die vom Fahrer bevorzugt werden, zu wenden.
10. Motorwasserski (10) nach Anspruch 1, bei dem die V-förmigen Flächen (195A, 195B) auf
beiden Seiten der Hydrostufen (183A, 183B) dem Fahrer (12) eine Hebelwirkung vermitteln,
um den Übergang des Hochleistungs-Motorwasserskis (10) vom Geradeausmodus zum Wendemodus
zu erleichtern.
11. Motorwasserski (10) nach Anspruch 1, bei dem der Rumpf (16) derartig geformt ist,
daß der Nettoschwerpunkt (120) des Hochleistungs-Motorwasserskis (10) und des Fahrers
(12) zwischen den Seitschienen (190A, 190B) leigt, während der Fahrer den Hochleistungs-Motorwasserski
(10) durch eine überhöhte Wende steuert.
12. Motorwasserski (10) nach Anspruch 1, der außerdem folgendes aufweist:
eine Motorbasis (110), die eine stabile Motorplattform, einen strukturellen Lastweg
vom Motor zum Rumpf darstellt und die Ausrichtung des Motors (108) mit einer Antriebswelle
(104) und der Strahlpumpe (100) gewährleistet; und
einen Motorbasisdeckel (150), der mit dem Motorbasis (110) zusammenwirkt, um ein wasserdichtes
Gehäuse für den Motor (108) zu bilden.
1. L'embarcation à moteur rapide (10) englobant une coque (16) comportant une proue (18),
une poupe (20), un pont (22), dimensionné de sorte à recevoir un skieur debout (12);
une surface hydroglissante (180) formée sur la coque (16) et un axe longitudinal (144),
s'étendant de la proue (18) vers la poupe (20); une pompe à jet (100) pour décharger
un courant d'eau propulseur vers l'extérieur de la poupe (20) dans une direction fixe
généralement parallèle à l'axe longitudinal (144) de l'embarcation à moteur rapide
(10): un moteur (108) agencé dans la coque (16) pour entraîner la pompe (100), la
pompe à moteur (100) étant montée dans la coque (16), de sorte que l'embarcation à
moteur rapide (10) a un centre de gravité, n'englobant pas le skieur (121), situé
dans une enveloppe agencée au-dessous du pont (22) et à l'arrière du moteur (108),
permettant au skieur (12) se tenant sur le pont (22) d'occuper une position essentiellement
neutre par rapport au centre de gravité net (120) de l'embarcation à moteur rapide
(10) et du skieur (12), permettant ainsi au skieur (12) de manoeuvrer et de faire
tourner l'embarcation à moteur rapide (10) sans utiliser un mécanisme de rotation
mécanique, par un déplacement de la position de son corps ou une distribution du poids
sur le pont (22), déplaçant le centre de gravité net (12) de l'embarcation à moteur
rapide (10) autour d'un axe de rotation à peu près vertical, coïncidant à peu près
avec l'emplacement du skieur (12) pour faciliter le maintien de l'équilibre et de
la stabilité du skieur (12) manoeuvrant l'embarcation à moteur rapide (10) et la faisant
tourner autour d'un axe à peu prés vertical, caractérisé en ce que l'embarcation est
un ski nautique, la pompe à jet étant montée de manière fixe dans la poupe (20), le
moteur (108) étant monté dans la coque (16) à l'avant du pont (22), permettant ainsi
un montage facile du ski nautique motorisé rapide (10) dans l'eau profonde par le
skieur (12) à partir de la poupe (20), le centre de gravité n'englobant pas le skieur
étant situé derrière le moteur (108), et en ce que l'embarcation comprend en outre
une paire de rails latéraux courbés (190A et 190B) formés sur les côtés opposés de
la coque (16); un fond de coque (58) comportant une première partie en V (194A, 194B)
à l'avant de la partie de barrot la plus large (182A, 182B) de la coque (16), la première
partie en V (194A, 194B) s'étendant à l'arrière le long du fond de la coque (58) vers
une quille plate (17) et ensuite vers une deuxième partie en V (195A, 195B) entre
la surface hydroglissante (18) et les rails latéraux courbés (190A, 190B), la deuxième
partie en V (195A et 195B) et les rails latéraux courbés (190A, 190B) coopérant avec
le mouvement du skieur du centre de gravité net (120) pour permettre une transition
en douceur du démarrage vers le planage rapide et une initiation et une exécution
faciles de virages à faible vitesse et à vitesse élevée;
une grille d'entrée (148) formée dans le fond de la coque (58);
une section de fond de coque à l'avant de la grille d'entrée (148), convergeant en
douceur dans la deuxième partie en V (195A, 195B) et connectée aux rails (190A, 190B)
pour réduire au minimum l'aération de l'eau entrant dans la pompe (100); et
une paire de gradins hydrauliques (183A, 183B) à l'arrière de la grille d'entrée (148)
facilitant le dégagement efficace de l'eau lors de la transition de la coque (16)
au mode hydroglisseur, assurant ainsi la stabilité de la coque (16) et une résistance
réduite à l'eau de celle-ci, l'embarcation à moteur rapide étant ainsi stable et pouvant
être manoeuvré par un skieur monté à l'arrière (12) en présence de vitesses réduites
et élevées.
2. Ski nautique motorisé rapide (10) selon la revendication 1, comprenant en outre: une
perche (26), fixée à la coque (16) près de la proue (18); et une poignée (132) connectée
à la perche flexible (26), la perche (26) et la poignée (132) étant configurées de
sorte que le skieur (12) peut se tenir sur la partie de pont (22) et saisir la poignée
(132) avec une main et se servir de la poignée (132) et de la perche (26) pour assurer
une stabilité additionnelle et pour manoeuvrer le ski nautique motorisé rapide (10).
3. Ski nautique motorisé rapide selon la revendication 2, dans lequel la poignée est
une poignée universelle à actionnement par une seule main, par la main droite/la main
gauche (132), configurée pour une commande à une seule main.
4. Ski nautique motorisé (10) selon la revendication 1, dans lequel le centre de gravité
n'englobant pas le skieur (121) du ski nautique motorisé (10) se situe sur plus de
50% de la longueur de la coque (16) à partir de la proue (18).
5. Ski nautique motorisé (10) selon la revendication 1, dans lequel le centre de gravité
n'englobant pas le skieur (121) du ski nautique motorisé (10) se situe sur plus de
25% de la longueur de la coque (16) à partir de la poupe (20).
6. Ski nautique motorisé (10) selon la revendication 2, enlobant en outre une admission
d'air (160) formée dans la perche (26), pour introduire l'air d'admission dans le
moteur (108), l'admission d'air (160) étant agencée dans la perche (26) au niveau
d'un point espacé et surélevé par rapport à la proue (18).
7. Ski nautique motorisé rapide (10) selon la revendication 2, comprenant en outre un
papillon des gaz à actionnement par le pouce (170A), un démarreur (170B) et un interrupteur
d'arrêt (170C) dans la poignée (132), le papillon des gaz à actionnement par le pouce
(170A), le démarreur (170B) et l'interrupteur d'arrêt (170C) étant agencés de sorte
que le skieur (12) peut contrôler aisément et de manière sûre le démarrage du moteur
(108) et la vitesse du moteur (108) en actionnant le papillon des gaz à actionnement
par le pouce (170A), le démarreur (170B) et l'interrupteur d'arrêt (170C) avec son
seul pouce, de sorte que l'accélération du ski nautique motorisé rapide (10) n'ouvre
pas davantage le papillon des gaz lorsque le skieur saisit la poignée (132).
8. Ski nautique motorisé (10) selon la revendication 1, englobant en outre un creux pour
le thorax (23) formé dans le pont (22) près de la poupe (20) pour recevoir le thorax
du skieur (12) montant le ski nautique motorisé (10) de l'eau au-dessus de la poupe
(20).
9. Ski nautique motorisé (10) selon la revendication 1, dans lequel les rails latéraux
(190A, 190B) s'étendent sur l'ensemble de la longueur de la coque (16) et comportent
des parties à section transversale à courbure complexe (57A, 57B) et des parties courbées
verticalement vers le haut (55A, 55B) près de la proue (18) ainsi que des parties
courbées verticalement vers le haut (57A, 57B) près de la poupe (20), permettant au
skieur monté sur l'arrière (12) de faire tourner le ski nautique motorisé (10) à des
vitesses réduites ou élevées en fonction de l'angle et du serrage de l'angle du virage
préféré par le skieur.
10. Ski nautique motorisé (10) selon la revendication 1, dans lequel les surfaces en V
(195A, 195B) de chaque côté des gradins hydrauliques (183A, 183B) fournissant au skieur
(12) un bras de levier pour faciliter la transition du croisement en ligne droite
vers des modes de prise de virages du ski nautique motorisé rapide (10).
11. Ski nautique motorisé (10) selon la revendication 1, dans lequel la coque (16) est
formée de sorte que le centre de gravité net (120) du ski nautique motorisé rapide
(10) et du skieur (12) se situe entre les rails latéraux (190A, 190B) pendant que
le skieur manoeuvre le ski nautique motorisé rapide (10) à travers un virage incliné.
12. Ski nautique motorisé (10) selon la revendication 1, comprenant en outre;
une carène du moteur (110) établissant une plate-forme de moteur stable, une trajectoire
de charge structurale du moteur vers la coque, et maintenant l'alignement du moteur
(108) avec un arbre de commande (104) et la pompe à jet (100); et
un couvercle de la carène du moteur (150) coopérant avec la carène du moteur (110)
pour former une enceinte étanche à l'eau du moteur (108).