Foot-operated boat paddle propulsion system

A boat-mounted pedal-driven paddle system for maneuvering a lightweight fishing boat. When employed for movement, a paddle is vertically oriented with its blade parallel to the keel of the boat and removably mounted upon the transom by a manually adjustable C-clamp. A pair of cooperating foot pedals are permanently, pivotally mounted upon a crossbar which transverses the width of the boat and is connected between the boat sides. The foot pedals are operatively linked to the paddle system via a pair of flexible cables guided upon a multiplicity of cooperative pulleys and connected to the pedals via a pivotal cable guide donut. Paddle movement involves three basic motions. First, the paddle is rotatable a limited degree about its longitudinal axis, and the position to which it axially rotates determines blade operative pitch during propulsion. Second, the paddle swings in an arc of roughly 180 degrees, which arc lies in a plane generally parallel with and spaced apart from the boat transom to propel the boat in a direction predetermined by the previously established blade pitch. Third, in response, for example, to underwater obstacles, the paddle may be deflected in an arc occupying a plane generally perpendicular to the transom, and generally coplanar with the longitudinal axis of the boat. The paddle may thus assume a generally horizontal, inclined position well above the surface of the water and be suspended in an out-of-the way position for travel or storage.

BACKGROUND OF THE INVENTION 
The present invention relates generally to paddle or sculling propulsion 
systems for fishing boats. More particularly, the present invention 
relates to an improved foot operated paddle assembly for flat-bottomed 
fishing boats. It is believed that the invention is properly classified in 
U.S. class 115, subclass 125. 
The present device comprises an improvement of the foot-operated boat 
paddle invented by my father, F.L. Stolzer, and disclosed in U.S. Pat. No. 
3,095,850, issued July 2, 1963, which is hereby incorporated by reference. 
As will be appreciated by those skilled in the art, a variety of 
pedal-driven boat paddle devices exist in the prior art. The propulsion 
device proposed by d'Elloy, U.S. Pat. No. 4,353,703 (issued Oct. 12, 
1982), comprises a pair of cooperating vertically-oriented paddles 
operatively associated with a pedal mechanism adapted to be attached to a 
small raft. The mechanical paddle drive includes a pair of guide rudders 
for manually guiding the craft. 
U.S. Pat. No. 3,680,522, issued to Clark on Aug. 1, 1972 generally suggests 
the desirability of providing a pedal-powered boat drive mechanism with a 
drive shaft comprising cooperating clutches for propelling the boat in 
both a forward backward direction. 
Other prior art known to me comprises U.S. Pat. Nos. 4,323,352; 4,345,903; 
3,467,049; 4,172,426; 4,231,309; 3,056,977; 3,038,435. 
None of the prior art devices known to me provides adequately stabilized 
means for dYnamically securing the paddle assembly to the boat. No 
adequate means are suggested in the prior art which permit the paddle to 
smoothly ride over unseen submerged objects, such as tree stumps, fence 
posts, or the like. Frequently, therefore, the paddle will become damaged, 
broken, or dislodged from its mount when it strikes such an object. Other 
prior art pedal-driven paddle devices I have studied do not satisfactorily 
permit the seated user to conveniently manipulate the paddles to 
effectuate forward and backward propulsion. 
The paddle invention of the previous patent, U.S. Pat. No. 3,095,850, fails 
to suggest adequate recoil means for limiting tilt of the paddle relative 
to the boat. The teachings of the patent fail to include any suggestion as 
to the desirability of providing a mechanism for facilitating automatic 
return of the paddle to its normally vertical, upright orientation after 
the paddle recoils. The prior art device disclosed therein forced the user 
to rise from a seated, driving position and balance upon the hull of the 
boat to restore the paddle to its operative position after recoil. 
Moreover, such manual adjustment of the paddle required substantial 
physical strength. Further disadvantages of the previous device include 
inadequate stabilization during operation and noise produced during 
paddling. 
SUMMARY OF THE INVENTION 
The present invention comprises a foot-operated paddle system which enables 
a fisherman to manually propel and maneuver a fishing boat in selected 
directions. A variety of forward, backward, and sideways movements are 
enabled. The system is semi-permanently mounted upon the hull of a 
lightweight, flat-bottomed boat. In the best mode the system comprises a 
rigid paddle dynamically mounted upon the transom and linked to a steering 
control assembly driven by a pair of cooperating foot pedals. 
The system is preferably secured to the hull of a boat by a manually 
adjustable C-clamp mount. Additional reinforcement to prevent deformation 
of the lightweight, usually-aluminum boat body is afforded by a rigid 
mounting plate which is preferably permanently welded to the bow of the 
boat. An elongated, rotatable cylinder preferably links the mount to the 
preferred steering assembly. Steering and propulsion are established by 
foot-driven pedals linked to the paddle through cables. 
A pair of cooperating foot pedals are permanently, pivotally suspended upon 
a rigid, transverse support bar removably mounted between the interior 
sides of the boat. The pedal support bar provides stability to the 
assembly during operation and results in virtually silent operation, which 
is desired to avoid scaring away the fish. The foot pedals are preferably 
operatively linked to the steering assembly via a pair of flexible cables 
made of coated nylon or similar material. The cables are guided upon a 
pair of cooperating pulleys and extend from the pedals to a donut mount. 
The donut can pivot in a plane generally perpendicular to the transom. A 
spring exhibiting a predetermined tension yieldably biases the donut away 
from the transom. The spring may preferably be interchanged with a lighter 
weight spring, so that the device may be more easily manipulated, for 
example, by children. A lighter weight spring also facilitates the change 
from reverse to forward drive. 
Turnbuckle mounts associated with the cables permit manual adjustment of 
the cable length and tension to properly align the paddle and pedal 
assembly for use. The cables are removably mounted to facilitate 
convenient replacement or maintenance as needed. 
Paddle dynamics involve three basic motions. First, the paddle is rotatable 
about its longitudinal axis, and the position to which it axially rotates 
determines its operative pitch. Second, the paddle swings in an arc of 
roughly 180 degrees, which arc lies in a plane generally parallel with and 
spaced apart from the boat transom. The last mentioned plane is generally 
perpendicular to the axis of the boat. By virtue of sweeping arcs struck 
by each stroke of the paddle through the water, the boat may be silently 
sculled in a forward or backward direction at a variable speed. The 
direction of movement will be established by the pitch of the paddle, 
which changes for each stroke. Third, in response to obstacles, the paddle 
may be deflected in an arc occupying a plane generally perpendicular to 
the transom, and generally coplanar with the longitudinal axis of the 
boat. The paddle may thus assume a generally horizontal, inclined position 
well above the surface of the water and be suspended in an out-of-the way 
position for travel or storage. 
A cam assembly facilitates tilting of the paddle during the aforementioned 
third movement along an arc of roughly seventy degrees. The paddle may 
tilt forward or backward in response to an impact from a submerged tree 
stump or the like. When a strike is experienced, a travel-limiting 
follower associated with the cam assembly will become yieldably disengaged 
from a track defined within the cam body while the paddle tilts. The 
paddle is automatically urged back into engagement with the cam body and 
returned to its upright position by the force of water resistance. 
In operation, the paddle is normally oriented in a generally upright 
position with its blade in the water. Peddling sweeps the paddle (i.e. the 
second above mentioned movement) to propel the boat. The direction of 
travel is established by blade pitch (i.e. the first above mentioned 
movement) and pitch is established by blade twisting established by that 
cable which is most tensioned in a given stroke. However, when the sum of 
the tensions on each cable leading to the donut is greater than the 
predetermined spring tension mentioned above, the donut flips over, and 
now each stroke established by the most tensioned cable will first twist 
the paddle to a different pitch than before, reversing the direction of 
boat travel. By thus varying either or both of the difference in tension 
between cables leading to the donut, and/or the total tension transmitted 
by cables to the donut, the fisherman may quickly and easily effectuate a 
change from forward to backward motion. 
Additionally, the paddle may be rotated roughly ninety degrees to a 
horizontal position and thus secured, when it is desired to disengage the 
assembly entirely. Thus, the assembly may be mounted together with a power 
motor or hand oars. When the paddle strikes an unseen underwater object 
such as a tree or post, it will tilt or recoil from its upright position 
so that it will smoothly "ride over" the obstruction without being broken, 
damaged, or dislodged from its mounting. After recoil, the paddle may be 
quickly automatically returned to its upright position by manipulation of 
the pedals. 
Thus it is a broad object of the present invention to provide a 
pedal-driven paddle system for propelling a boat through the water either 
forwards or backwards. 
Another fundamental object of the present invention is to provide an 
improved foot-powered boat paddle system of the nature described which is 
adapted to "ride over" submerged obstacles without sustaining damage or 
becoming dislodged from its mount. 
A similar object is to provide a boat-paddle system which may be 
conveniently, automatically restored to its upright, operative position 
after it strikes a submerged object. 
A still further object of the present invention is to provide a 
foot-powered boat paddle of the nature described which includes improved 
stress joint means to facilitate restoration of the paddle to its original 
upright operating position after overstress is experienced. 
Another object of the present invention is to provide an improved 
foot-powered boat paddle of the character described which is lighter in 
weight and more easily installed than known prior art boat paddles. 
Yet another object is to provide a boat paddle system of the nature 
described which may be manually adjusted to compensate for the weight load 
in the boat. 
A further object of the present invention is to provide a boat paddle 
system which can be easily adapted for operation by different users, 
including children. 
A still further object of the present invention is to provide a boat paddle 
assembly of the character described which includes improved pedal mounting 
means for improved stabilization and quiet operation. 
Another object of the present invention is to provide a boat paddle 
assembly of the character described which includes means for manually 
setting and adjusting the orientation of the paddle relative to the 
pedals. 
Yet another object of the present invention is to provide a boat paddle 
assembly of the character described which may be easily and conveniently 
disengaged from operation when not in use and hence may be used as an 
auxiliary to a power motor or hand oar system. 
These and other objects and advantages of the present invention, along with 
numerous features thereof, will appear or become apparent in the course of 
the following descriptive sections.

DETAILED DESCRIPTION 
With reference now directed to the appended drawings, the best mode of my 
improved foot-powered boat paddle assembly is generally designated by the 
reference numeral 10. The assembly 10 may be mounted upon hull 12, 
preferably on transom 13, of a fishing boat 15. As described in detail 
hereinafter, assembly 10 permits the seated fisherman to silently maneuver 
the boat forwards or backwards through the water while fishing. Assembly 
10 is powered and controlled solely by the feet 18 of a fisherman or other 
operator, so that the fisherman's hands are free during use to manipulate 
other devices, such as fishing rods and tackle, guns, or other sporting 
gear. Additionally, the fisherman may selectively elevate the paddle 
system 24 out of the water to a generally horizontal position when, for 
example, use of an outboard motor is desired for high-speed travel. 
Paddle system 24 responds to cable pressures transmitted from the foot 
pedals to effectuate three basic motions. As a preliminary matter, the 
paddle responds to both the total pressure in the control cables, and to 
the difference in pressure between the cables. All cable pressures result 
from pedaling. As used herein the term "first motion" refers to limited 
paddle rotation about its longitudinal axis when one cable overpressures 
the other, as happens each time one pedal is depressed. Paddle orientation 
after torsional rotation determines its operative pitch and thus the 
direction of boat propulsion. 
The term "second motion" refers to the swinging of the paddle in an arc of 
roughly 180 degrees, which arc lies in a plane generally perpendicular to 
the longitudinal axis 13A of the boat. This second motion, the "power 
stroke," results when one cable overpressures the other, and it 
operatively occurs immediately after the paddle first axially rotates in 
the above first motion in response to differential pressure. 
The term "third motion" refers to movement of the paddle in an arc 
occupying a plane generally coplanar with the longitudinal axis of the 
boat, and generally perpendicular to the aforementioned second motion 
plane. The third motion allows the paddle to "give" in response to contact 
underwater obstacles, and it allows fisherman 11 to move the apparatus to 
a convenient out-of-the-way storage or transportation position. All three 
of these motions may operate substantially concurrently, and the hardware 
to be disclosed enables the different movements to occur in harmony with 
one another. 
With primary reference now directed to FIGS. 1 and 2, assembly 10 
preferably comprises an elongated, rigid paddle assembly 24 which moves 
the boat. It is operatively associated with a mechanical control system, 
generally designated by the reference numeral 34, which utilizes cables to 
interconnect the paddle system with foot pedals. The frame of the assembly 
is operatively, pivotally mounted on transom 13 by an adjustable clamp 38. 
To prevent the lightweight, aluminum body of the conventional 
flat-bottomed fishing boat 15 from being damaged or warped as a result of 
hard impacts or of the constant force of water resistance against the 
assembly 10, a rigid reinforcement plate 92 is preferably permanently 
mounted by means of welding, heavy duty bolts, or the like to the hull of 
boat 15. Reinforcement plate 92 extends from the floor of boat 15 up over 
the rim of the hull to providing an undergirding for clamp 38. 
Control system 34 comprises a pair of cooperating foot pedals 44 linked by 
a pair of flexible control cables 54A and 54B to the paddle assembly 24. 
The control cables are trained over front guide pulleys 48 and rear guide 
pulleys 50. Pulleys 48 are mounted at the sides of the boat rear by rigid 
legs 53. The cables terminate at one end at a guide donut assembly 56 
which controls paddle assembly 24, and their opposite ends are connected 
to the pedals 44. Cables 54A, 54B are preferably removably attached to the 
base of pedal plates 113 by means of an eyelet hook or the like (not 
shown). Foot pressure transmitted to the paddle system 24 from cables 54A 
and 54B controls the paddle. Blade pitch changes whenever the pressure in 
one cable is greater than the other (i.e. immediately after the actuation 
of a particular pedal commensurate with a foot stroke.) 
Pulleys 50 are preferably positioned approximately even with the 
fisherman's side and suspended from turnbuckles 117 associated with the 
sides 63 of the boat. Turnbuckles 117 may be conveniently adjusted to 
remove slack and properly tension cables 54A, 54B for smooth operation. 
Pulleys 48 are supported upon a rigid, elongated support arm 53 associated 
with control system 34 and maintained such that the cable ends extend 
toward the blade system in substantial axial alignment, occupying a line 
parallel with and spaced apart from the transom 13. Arm 53 is operatively 
joined at its outer ends to guide pulleys 48. 
Foot pedals 44 are preferably suspended for rotation about a rigid crossbar 
59 positioned near the operator's feet 18 and semi-permanently secured 
between the sides 63 of the boat 15 by braces 61. The pedals 44 are linked 
to the steering assembly by a pair of cooperating cables 54A, 54B 
preferably comprising equal lengths of aircraft stranded steel covered 
with a waterproof jacket of nylon or similar material. Each foot pedal 44 
comprises a rigid pedal plate 113 swiveled to an L-shaped crank 118 which 
upwardly terminates in a tubular crank bearing 123 mounted on crossbar 59. 
Each crank bearing 123 is slidably, rotatably fitted to crossbar 59 at a 
desired position comfortable to fisherman 11. When foot pressure is 
applied, bearings 123 tend to move outwardly towards the sides of the 
boat. They are laterally held in position by an adjoining collar and set 
screw assembly 125 which limits bearing travel along shaft 59. Assemblies 
125 may be loosened to permit slidable adjustment of the cranks and pedals 
longitudinally along crossbar 59. Because the foot pedals 44 are suspended 
upon crossbar 59 at a distance well above the floor of the boat and spaced 
apart from the sides 63 of the boat, the operation of the assembly 10 is 
virtually silent. Thus there is less likelihood that fish in the area will 
be frightened away. 
With primary reference now to FIG. 5, paddle assembly 24 comprises an upper 
portion, generally designated by the reference numeral 68, and a lower 
blade unit 23 which may be removed. Lower unit 23 preferably comprises a 
rigid, generally planar, wooden board 80 made from a conventional oar and 
having a rounded base and a narrow, pointed top 83. Shaft 28 is mated to 
blade 80. Blade top 83 is permanently secured to a rigid, preferably 
metallic cap 85 extending from shaft 28 by a multiplicity of rivets 88. 
Shaft 28 has a larger diameter upper end 93 which terminates in a collar 
95 having an interior 96 generally in the form of an inverted truncated 
cone. It is mated to a similarly profiled bearing fitting 197 at the 
bottom of upper unit 68. When fitting 197 is mated to collar 95, orifices 
98A and 98B will align, so that a suitable cotter pin may secure the two 
together to secure the blade 80 to the apparatus. Preferably a slot 99 is 
defined across fitting 95 to provide clearance for an additional fastener 
pin 97. 
In FIG. 5A, it is seen that an arcuate slot 197A in bearing 197 registers 
with a follower 197B projecting downwardly from cam 150. Relative rotation 
between the cam and the blade is thus limited to approximately ninety 
degrees, so that during the first motion the blade can be rotated between 
attack pitches of plus and minus forty five degrees relative to the 
longitudinal axis of the boat. 
A control donut 56 is disposed at the top of the upper unit 68 of the 
paddle assembly 24. The donut preferably comprises a donut shaped head 131 
having a central stem 132 coupled to annular bearing 133, which is 
concentrically mounted within the receptive annulus of lower donut collar 
134. A flat, generally rectangular tab 134T projects downwardly from 
collar 134 towards bearing sleeve 135 and is pivotally coupled thereto 
with a screw 136. 
Thus donut head 131 and collar 134 can pivot about screw 136 relative to 
sleeve 135 (i.e. to the left or to the right as viewed in FIG. 5). In 
addition, head 131 is rotatable relative to collar 134 because of roller 
bearing 133. Control cables 54A, 54B pass through the center 55 (FIGS. 6, 
7) of donut head 131 through side orifice 130 in collar 134 and are 
terminated by set screw assembly 120. Sleeve 135 mounts a downwardly 
projecting shaft 198 which is concentrically mated to it with a pin 135B. 
As best viewed in FIG. 5, a recoil spring 71 extends lengthwise from screw 
eyelet 207 secured to blade shaft end 93 and is adapted to be coupled to 
screw eyelet 211 in collar 134. Spring 71 normally biases cable guide 
donut 56 to the right (as viewed in FIG. 5). When total tension applied by 
cables 54A, 54B by manipulation of foot pedals 44 exceeds the tension in 
spring 71, the donut flips over, as will be seen by comparing FIGS. 6 and 
7. 
The upper unit 68 of the paddle assembly 24 also comprises a cam 150 which 
is disposed between sleeve 135 and fitting 197. Cam 150 is generally 
D-shaped, and its outer, arcuate cam surface 151 projects towards the 
boat. The cam is penetrated by rotatable shaft 198 which extends between 
the doughnut assembly and the lower fitting 197. The cam facilitates the 
third motion mentioned above, enabling deflection of the paddle 24 to 
prevent the paddle from becoming damaged or dislodged from its mount 38 
when it strikes an unseen submerged object such as a tree stump, fence 
post, or the like. After such a strike occurs, the cam apparatus permits 
the automatic return of the paddle to an upright position for continued 
normal operation. 
The cam is grasped within the fork of a mounting bracket 164 which mounts 
the entire paddle assembly to the C-clamp 38 secured to the boat transom. 
Bracket 164 has similar rigid sides extending on opposite sides of the 
cam, and their rounded ends 165 are suitably apertured to register with 
orifice 205 in cam projection 204. A nut and bolt assembly 168 penetrates 
orifice 205 in cam body 150 (FIG. 5.) to pivotally couple cam 150 and 
bracket 164. Orifice 205 establishes the pivot point enabling the third 
movement discussed above. 
Cam bracket 164 is coupled to rigid, cylindrical shaft 144 adapted to be 
rotatably received within a fixed sleeve 137. Sleeve 137 comprises an 
elongated tube having an integral mounting tab 153, and as best seen in 
FIG. 3, sleeve 137 is coupled to rigid brackets 125 which are pivoted with 
bolt 129 to C-clamp 38. Sleeve 137 is pivoted between brackets 125 (FIG. 
3) via captured lower tab 153. Reduced diameter shaft end 144A rotatably 
received within sleeve 137 is secured by a conventional stud 155, and ease 
of rotation is maintained by the washers 157. 
An interior bore 176 within shaft portion 144A coaxially receives spike 186 
which is biased by an internal spring 189. Spike 186 includes a rigid tip 
which fits within a corresponding angular channel 194 defined within cam 
body 150. Bore 176 further receives an insert 171 which can be adjusted to 
vary spring pressure. Spike 186 is thus biased against cam surface 150, 
and its outer tip 194 will normally seat within a suitable groove formed 
in the cam surface 151. 
OPERATION 
In operation, the assembly 10 permits a fisherman to maneuver the 
watercraft forward or backward through the water in response to 
manipulation of the foot pedals 44, while the fisherman's hands remain 
free for operation of other fishing or sporting equipment. For optimum 
control and proper operation, it may be necessary for the fisherman to 
"set up" the assembly by assuring that the paddle is fully upright or 
vertical positioned and that tension is evenly distributed between the 
cables by simple adjustment of turnbuckles 117. 
To effectuate forward movement of the watercraft, the fisherman simply 
applies moderate, even pressure to each pedal during the power strokes. 
With the first application of pedal pressure, the first blade motion 
commences, and the blade rotates axially a limited amount until the 
follower is stopped (see FIG. 5A) to assume a desired pitch. With 
reference to FIGS. 6 and 7, if cable 54A is tensioned first, the blade 
rotates in the first motion until the follower limits travel (FIG. 5A) and 
then pressure experienced subsequently effectuates the second motion. The 
blade is then arced through the water at a preestablished pitch to 
effectuate propulsion. 
Boat propulsion is thus effectuated by the propeller-like action when the 
paddle swings in its limited arc through the water when pressure is 
applied by the cables (i.e. the second motion). The direction of boat 
travel is first determined by the position of doughnut 56, since its 
position will determine the paddle twist direction (i.e. the pitch) when a 
given cable force is applied. In other words, shifting of the donut 
reverses the torsional displacement of the paddle which a given cable 
tension will produce. A comparison of FIGS. 6 and 7 clarifies this 
function. Spring 71 maintains the doughnut in a position where the cables 
(i.e. FIG. 4) are tilted over the axis of the paddle 28. 
When the total pressure supplied concurrently by both cables is sufficient 
to overcome bias from spring 71, the donut flips over from the position in 
FIG. 7 to the position of FIG. 6. Thereafter when the same cable is 
tensioned, since its has in effect been moved across the center 55 of the 
donut, its torsional forces will now rotate the blade in the opposite 
direction from that indicated by arrow 301 in FIG. 7. Then, when torsional 
travel is limited (FIG. 5A) the paddle is again pivoted in a generally 
semi-circular arc through the water. This time, however, the pitch has 
been changed during the first motion, and the second motion now propels in 
an opposite direction from before. If both pedals are pushed in at once, 
doughnut 56 "flips over" across the center line of paddle 28 in response 
to the combined translational forces exerted by both cables against 
pressure from spring 71. 
To move in a constant direction with both swings of the arc, blade pitch 
must be reversed in each half cycle. The paddle is pivoted so that it 
twists immediately prior to being deflected in its arc, and it will 
automatically twist to an opposite deflection just before pressure on the 
opposite pedal moves the arc in the opposite direction. In the forward 
mode both pedals must be pushed at once to deflect doughnut 56 over center 
(i.e. against tension from spring 71). When this occurs, it will be 
apparent that when cable 44, for example, is tensioned the paddle will 
twist in a direction opposite from the direction of twist when the 
doughnut was flipped over. Continued pressure on the cable will still 
deflect the paddle in the same arc through the water as before, but 
because of reversing in the twisting action caused by the deflection of 
the doughnut 56, each power stroke will now force the boat in the opposite 
direction. 
It will be appreciated that a great deal of effort is not required for 
routine operation of the device, since a full seven-inch foot stroke will 
rotate the paddle one full forty-five degree stroke. A full stroke will 
propel the boat at a relatively high speed. For operation at normal 
trolling speeds or low speeds for operation in densely vegetated waters, 
it is necessary to rotate the pedals alternatively only two to three 
inches. 
When the paddle strikes an unseen submerged object, it will automatically 
be urged to tilt to ride over the object. When resistance from the object 
is experienced, the cam will rotate about bolt 168 until the rigid spike 
follower stud spike 186 within sleeve 137 becomes disengaged from a 
transverse channel defined within the cam body 150. Thus the paddle is 
permitted to freely tilt and "ride over" the submerged object without 
breaking or becoming damaged. As the paddle tilts forward to ride over the 
object, spring 71 is greatly expanded. Once the object is safely avoided, 
tension in spring 71 will be released, and the spring will retract, 
automatically urging the paddle to return to its upright, substantially 
vertical position. If complete reset does not occur, then cable tension 
from both pedals will assist in returning the paddle assembly to the 
normally vertically upright position depicted in FIG. 5. 
If extreme tilt is experienced, the paddle may not easily return to its 
upright position. However, by creating tension on one of the cables by 
manipulation of its corresponding foot pedal and thus employing the force 
of water resistance against the paddle, the fisherman can easily "pull" 
the paddle back into position. In the prior embodiment of the invention, 
the fisherman would have to leave the seated position and stand in the 
rear of the boat to manually pull the paddle back into a vertical 
orientation. In applying such force, the fisherman might easily lose his 
balance and topple out of the boat into the water. Also, if the 
lightweight boat were already loaded, exerting additional weight at the 
rear of the boat might allow water to seep in. If the tension on spring 
189 is too light the spike will not adequately engage the channel and the 
fisherman will experience limited control during normal forward or 
backward travel, due to excessive "play" in the paddle in its upright 
position. Then insert 171 (FIG. 5) must be adjusted to vary spring 
tension. 
When it is desired to raise the paddle up out of the water in order to 
position the paddle for trailering or for use of a power motor or similar 
alternative propulsion device, the paddle may be pulled upwardly ninety 
degrees and set to rest on the top of guide pulleys 48. 
Thus forward and reverse propulsion of the boat is accomplished by lateral 
sweep or "sculling" of a paddle positioned generally parallel to the 
transom of the boat. The arc of rotation or "sweeping" of the paddle is 
not the only paddle movement. The paddle also torsionally rotates each 
time it is tensioned by a cable, to assume a new pitch. The motion of the 
paddle in water is analogous to the motion of an airplane prop in the air. 
However, it moves in arcs approximating a half of a circle, and it 
constantly reverses direction as alternating pedals are pushed. Thus it is 
twisted to maintain the correct "power thrust" each time. 
From the foregoing, it will be seen that this invention is one well adapted 
to obtain all the ends and objects herein set forth, together with other 
advantages which are inherent to the structure. 
It will be understood that certain features and subcombinations are of 
utility and may be employed without reference to other features and 
subcombinations. This is contemplated by and is within the scope of the 
claims. 
As many possible embodiments may be made of the invention without departing 
from the scope thereof, it is to be understood that all matter herein set 
forth or shown in the accompanying drawings is to be interpreted as 
illustrative and not in a limiting sense.