Note: Descriptions are shown in the official language in which they were submitted.
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PERSONAL ~ATER SURFACE TOWING DEVI OE .
TECHNICAL FIELD
This invention relates to a self powered aquatic device that will tow a
person through and across a water surfsce where in use most of the
persons body is essentially in the water below the surface, but where
the head and arms sre supported above the surface, in a manner that
could be described as a powered alternative to swimming but with a
higher speed capability.
BACKGRûUND ART
There are many varied vehicles or products designed for use on water,
recreational or otherwise, ranging from various types of boats, powered
sailing or rowing, to products towed by boats such as water skis,
towable inflatable products and the like. Various other products powered
or not, SUL~ h ~ jet skis, surfboards, pedaloes, canoes, windsurfing
boards etc. All these products are designed to essentially carry and
propel someone over and across a water surface. There are even products
that still essentially carry and propel a person, although the person is
in contact with the water or partially submerged, such as United States
patents 3543712 or 3716013, or British specification 795194 or P.C.T.
publication WØ84101755.
As opposed to this concept of being carried and propelled over and
across water, there are few products that actually tow a persons body
itself directly in and through a water surface.
The few products designed to tow as exhibited by prior art take various
forms, some of which are, a power unit attached to a framework and held
above the water by a float or floats, towing a person behind (French No
2625684), a power unit enclosed in a boat shaped box or hull, with a
means of holding on (Japanese No 2-12687û or British specification
1545222), or a device which is commercially available, a specially
designed water sealed internal combustion engine operating direct in
water, again with a means of holding on (United States patent No 3630165
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or ~890920). Generally, the majority and the earlier of prior art had
the means of holding and controlling positioned at the rear of the
device. This was a very tiring and sluggish means of steering. Later on
it was found that positioning the means of holding and controlling at
the front of the towing device (United States patent 3890920) was less
tiring and a lot more accurate, despite the fact that with this system
it is necessary to control whether the device is tilted in an upwards or
downwards direction as well as steering from side to side.
Although these and other designs are different from each other, the
basic overall concept of all prior art has been a separate towing
device, towing a person along as a separate entity. Although an
acceptable arrangement at normal swimming speeds, little or no
consideration seems to have been given to the potential or possible
capabilities of a towing device beyond simply motorising a swimmer, and
in fact above normal swimming speeds, the arrangement is inherently
hy'drodynamically inefficient to the point of being self limiting, both
in terms of performance or speed attainable, and also in the leve~ of
energy required from the user for the following reasons.
It is a well known and accepted fact that if a human body lying face
down is moved forwards through water with the arms outstretched and the
head raised above the water surface, most drag or turbulence in the
water will occur around the persons upper chest and shoulders, caused by
the relatively blunt shape of the persons frontal chest area and
shoulders trying to push through the water. This is the reason why even
at speeds as low as normal swimming, all professional and any serious
swi~mer will swim with their head down in an attempt to overcome this
drag effect, only raising it momentarily in order to see and breathe.
Where a towing device is towing a person along as a separate entity, the
necessity of the person being towed holding on to the device and
consequently having their arms and chest submerged in the water while
their head is raised snd tilted upwards in order to see and breathe
creates if any speed is involved, considerable drag or turbulence in the
form of a "bow wave" around the upper chest and shoulders for the
reasons already explained. As speed is increased, the "bow wave" becomes
more pronounced and higher, having the effect of trying to drag the
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person being towed away from the device, tiring the persons arms in the
process and causing the person to attempt to hold their head higher
which creates an even more pronounced and higher "bow wave", the only
solution being to reduce speed.
.
All prior art where the only contact between the device and the person
being towed is the persons hands holding on to the device, is inevitably
tiring in use since any steering or directing, not just left or right
but on some devices up or down as well, in order to maintain a desired
driving angle or distance from the device, can only be accomplished by
using the strength of their hands, wrists or arms.
A related effect which also causes tiring is that in normal sea
conditions where waves exist, the level of the towing device bobbing up
and down and that of the person being towed is constantly changing in
relation to each other. In choppy water conditions, these changing
levels can also mean that the persons body can inadvertently partially
block or get in the way of the propelling stream of water.
Finally, with prior art, the person's head is not positively supported
above the water surface. In conditions not anticipated, such as rough
sea, cramp, illness, fatigue, sickness or injury, the person must still
make the relevant effort to hold their head above water.
ln conclusion, although some are better than others, at any speed
significantly above normal swimming speeds, all prior art requires
considerably more energy and effort than necessary from the user, in
order to steer or control, and to overcome the drag or turbulence around
the person's chest area, in achieving what can only be a comparatively
modest increase in speed before the self limiting effect inherent in the
concept of a separate towing device and a separate user takes over.
DISCLOSURE AND ADVANTAGES OF lNVENTION
ln the following description of the present invention, it will be seen
that the disadvantages mentioned of prior art have been overcome, and it
is believed a unique benefit added, by adopting an essentially different
concept, which is to regard the towing device and the person being towed
as a single overall hydrodynamically streamlined entity.
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This concept was arrived at by considering the basic example mentioned
earlier of a human body lying prone in water with the arms outstretched
in a substantially parallel manner and the head raised above the water
surface and the best way to streamline it. The ultimate example of hydro
dynamic streamlining considered was a dolphinlike shape. Accordingly,
the principal object of the present invention is to go beyond simply
motorising a swimmer at normal swimming speeds and emulate as far as
possible the streamlining and effortless manner in which a dolphin moves
and manoeuvres through water and to impart to the user of the towing
device its sense of freedom, albeit only on the water surface.
For the sense of freedom, it is an important feature of the present
invention that most of the persons body, at least from the chest down,
is essentially in the water unencumbered by contact with the towing
device but in a manner still consistent with efficient streamlining.
This is accomplished by supporting the outstretched srms on a hydro-
dynamically streamlined buoyant body that fills in or spans the space
between the arms, going some way in front beyond the hands to be able to
incorporate a n~ wed streamlined nose, and continuing a streamlined
shape rearwards on the under surface to skim the water, and shaping the
rear end of the device to merge and blend hydrodynamically with the
upper chest area of the user. Since the buoyancy of the towing device is
higher than the person being towed, this area of merging and blending is
held a close fit by the buoyancy of the device pushing upwards and the
body weight of the person pushing downwards. The overall effect of
combining the towing device and user in this manner produced the desired
result of a single overall hydrodynamically streamlined shape that
diverts or guides water underneath or around the users chest area in a
smooth flow. It was also decided that any substantial weight including
the motor or power means and propulsion means, should be underslung
beneath the device body and water surface for maximum stability and so
that the deck of the towing device could be substantially flat and clear
of obstructions for good visibility. The towing device body was kept the
same or similar width as the user partly for hydrodynamic reasons, but
also so that the towing device would roll easily, with a self levelling
effect caused by the underslung weight, so that manoeuvring or steering
would simply be a matter of leaning or applying body weight with the
upper arms and shoulders to the relevant side, with very little conscious
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effort required.
All the various criteria has been met and the objects of hydrodynamic
streamlining, effortless manoeuvring and a sense of freedom achieved,
and it is believed, the present invention is a significant advance over
prior art.
Consequently, according to the present invention there is provided, a
self powered water surface towing device, that tows a person by their
hands through and scross a water surface, comprising a buoyant
hydrodynamically streamlined body , motive power means, handlebars and
control levers or other means of holding and controlling the towing
device situated at or towards the forward end of the towing device and
where the rear end of the towing device is adapted and shaped to blend
hydrodynamically with the upper chest area of a person being towed and
is such a width that the upper arms and shoulders of the person can be
supported over and on top of the rear end of the towing device. A motor
or power means and a propulsion means are situated on the underside of
the towing device below the water surface. In use, the motGr u~ power
means drives the propulsion means, which expels or drives a water jet or
jets rearwards and underneath the body of the person being towed. Most
of the persons body from the chest down is essentially in the water,
below the surface, unencumbered by contact with the towing device. The
towing device is such and is so shaped and adapted that together with
the person being towed, they form an essentially single combined
hydrodynamically streamlined shape, that diverts or guides surrounding
water underneath or around the persons chest area in a smooth flow and
as speed is increased the towing device and the person being towed ride
progressively higher over or through the water surface and assume the
angle of least resistance in relation to overall water drag.
The advantages of the present invention over prior art can now be seen
to be, number 1, the drag factor and self limiting eftect caused by the
persons arms, shoulders and chest being in the water has been overcome.
Number 2, with the present inventions single entity concept, its
closeness and overlapping with the person being towed is such that
steering is executed with the shoulders or upper arms, not the hands, by
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leaning or applying body weight to the relevant side of the rear end of
the towing device. The "handlebars" are in a fixed position and their
function is simply a means of holding the towing device, and operating
the control levers. It has been found in fact that in use the hands
wrists and arms can be relaxed completely, consistent with the fingers
remaining curled around the handlebars. Therefore the tiring effect with
prior art of having to steer and direct continuously with hand, wrist or
arm pressure has also been overcome.
Number 3, the related tiring effect in rough water conditions, or water
conditions where waves exist, of the level of the towing device and the
level of the person constantly changing in relation to each other is
substantially reduced since the hands, arms, shoulders, chest and head
of the person being towed and the said towing device, move up and down
together, either up together or down together.
Number 4, where with prior art, the head is not positively supported
above the water surface, with the present invention, when the person is
holding the handlebars or me~ns of ;~oidi"g in the normal operating
position, even if the person is incapacitated or semi-conscious for any
reason, their head would still be positively supported above the water
surface, both with the towing device moving or stationary.
Number 5, The unique benefit believed to be added, mentioned earlier,
which could be the present inventions most important advantage, is a
variable stretching or extending force applied to the torso and spine of
the person being towed. This is caused by the propulsion force of the
towing device pulling the hands, arms, and shoulders of the person in a
forward direction, the lack of, or neutrality of water drag around their
chest area, so that the force of the water drag pulling rearwards on
their lower body, from the waist down, caused by the propelling water
jet and surrounding water, is substantially greater than any water drag
on their upper body. The force of the water drag on their lower body can
be increased or decreased simply by varying the angle and position of
their feet in relation to the propelling water jet, instead of just
letting them trail in line. Coupled with the degree of relaxation and
infinitely variable movement possible in water, either from steering
from side to side or the movement up and down created by waves, the
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.
overall effect has been found to be of significant benefit in reducing
back pain in a person who suffers with this condition.
In conclusion, the present invention provides a water surface towing
device that is not limited by poor hydrodynamic efficiency, and
therefore has the capability to travel considerably faster thsn prior
art in a smooth relaxed manner, with effortless steering snd
significantly less overall physicsl effort required and since the head
is always supported, with a high degree of safety. It is fun to use, and
should prove to be a vsluable therspeutic aid.
DESCRIPTION OF THE DRAWINGS
FIG.1 is a side view of the water surface towing device and a person
holding the device in the normal operating position with a typical water
level while stationary, indicated by the horizontal dotted line, and
also the path of the propelling water jet, with the persons feet in the
normal trailing position and also angled downwards to incresse water
drag on their lower body.
FIG.2 illustrates in perspective the water surface towing device.
FIG.3 shows a top view of the water surface towing device viewed from
the rear, illustrating the chamfered and dished rear end shape.
FIG.4 is the same illustrstion as fig.3, but with a person in the
normal operating position to illustrate the dimensional relationship and
how steering is executed with the upper arms and shoulders.
FIG.5 is a side view of the self contained engine unit.
MODE FOR CARRYING OUT THE INVENTION
This particular example is intended as a light, quickly detachable,
easily transportable interpretation of the basic concept, comprising
three main component parts. A self contained engine unit, a main body
sssembly and a hsndle bsr snd control lever sssembly.
Referring to Fig 5, the self contsined engine unit is a single cylinder
internal combustion engine with a recoil starter 1 and a msgneto 2 of
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orthodox design facing forwards and an enclosed propeller (not shown)
mounted on the mainshaft facing rearwards, drawing in water at the front
3 and expelling a water jet rearwards through a tunnel 4. The engine
unit includes and is attached to a one piece molded plastic tank 5 that
incorporates an sir tsnk 6 with a snorkel 7 at the front, through which
the carburetor breathes, and a separate fuel tank 8 at the back. Access
to the spark plug 19 i8 through a hole molded in the center of the tank
5. The engine unit also includes a cradle 9, that attaches the front of
the tank 5 to engine mounts located at the bottom of the crankcase
magneto housing 10. This engine unit is of the type fully described in
~nited States patent 3890920 snd any further description is thought not
to be necessary.
Referring to the drawings, the main body 11 is a hydrodynamically
stresmlined component manufactured from a plastic foam which is light,
durable, possesses a high degree of buoyancy, is rigid enough to
maintain its shape, but is comfortable in use and energy absorbing in
the event of a collision. It is one metre long, .4 metre wide at the
rear, narrowing towards the front with a rounded streamlined nose. Ihe
rear is chamfered snd dished in shape 12 to merge and blend with the
upper chest area of the person being propelled. There is a large hole
(not shown) aproximately in the middle, shaped to be a close fit over
and around the fuel/air tank 5 of the engine unit. There is a top plate
13 manufactured from rigid plastic sheet fixed to the top of the main
body 11 with four nylon screw type fixings 14. The top plate has two
holes (not shown), one that locates around the air tank threaded top 15
and the other that locates around the fuel tank threaded top 16.
Screwing down the snorkel air tank cap 17, and the fuel tank cap 18,
fixes the top plate 13 and therefore the main body 11, to the fuel/air
tank 5 of the engine unit. There is a larger hole (not shown) in the top
plate 13 between the other two, that gives access to the engine units
spark plug 19. To complete the main body assembly, there is a top pad 20
made from the same material as the main body 11, which acts as a spacer
between the main body and the handle bar assembly, covers the snorkel
cap 17, the spark plug access hole, and the fuel cap 18. It also adds
extra buoyancy and provides a comfortable chin or head support for the
person being towed. There is a nylon securing strap 21, that wraps under
the fuel tank 8, goes right through the main body 11 and top plate 13
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and buckles over and retains the top pad 20.
The handlebar assembly consists of a set of handlebars 22, a control
lever on each end 23 and 24, a support bracket on either side 25, a
decorative central cover 28 and a control cable 26 and 27 from each
control lever. The support brackets are fixed to the handlebars at a
slightly greater width than the width of the main body top pad 20. The
handlebar assembly is fitted to the towing device by pushing each
support bracket 25 through a hole (not shown) in the forward end of the
main body top plate 13, one on either side of the top pad 20, right
through the main body 11, and sliding them into a spring loaded retaining
clip 29 screwed and fixed on each side of the engine unit cradle 9. The
right hand control lever 24 and its control cable 26, are connected to
the accelerator lever on the carburetor. The left hand control lever 23
and its control cable 27, is a safety device that in the event of the
person being towed, inadvertently letting go of the towing device, would
either cause the towing device to go round in a continuous circling
motion, or alternatively would stop the engine. The preferred method
would be to have the lever and cable collneu~ed to a spring loaded rudder
(not shown) so that when the lever is pulled right back to the handlebar,
the rudder would be in a straight line with the towing device, and if
the lever was accidentally released, the rudder would spring to one side
out of line causing the towing device to move in a continuous circle
until retrieved by the user.
It should be noted that the basic and essential concept of the present
invention of regarding the towing device and the person being towed as a
single entity for hydrodynamic purposes, is capable of interpretation in
various ways, including different constructions and materials and
ranging from sophisticated permanently assembled examples to relatively
simple, light, quickly detachable, easily trasportable examples.
Therefore, while a relatively simple, quickly detachable example has
been illustrated herein, it is appropriate that the appended claims be
construed broadly and in a manner consistent with the spirit and scope
of the invention herein.
