Abstract:
A new and improved leg assisted forward facing rowing system is disclosed wherein a rower applies leg power to propel a boat by means of a rope connected between his or her foot and an oar. A unique feature is a roller, fastened under the heel of the rower&#39;s foot, that rolls along the bottom of the boat supporting the weight of the rower&#39;s leg while the reciprocating motion of the leg is transmitted by rope going through pulleys to reverse the force applied to the oar. The oar is pivoted at the center of the boat above the rower&#39;s knees by a mechanism that includes provision for applying lifting force to support the oar weight thereby holding the oar blade out of the water when no force is applied. The rower&#39;s legs, back and arms simultaneously apply rowing force. Feathering at the end of a stroke and squaring action at the beginning are provided by wrist action to rotate the oar blade. Ergonomically good features of a conventional sliding seat racing scull rowing are thereby incorporated into a forward facing rowing apparatus.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/570,824, filed May 14, 2004, the disclosure of which is hereby incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   The ergonomics of conventional scull and shell rowing, where a rower&#39;s arms, legs and back apply propelling force to the oars, are very good. The rower grasps the oars with his hands while sitting on a sliding seat facing the rear of the boat with his feet fastened in boots on the bottom of the boat. At the start of the power part of the stroke, the seat is located toward the rearward end of its motion with the rowers legs flexed, the rower lifts the oar handle to place the blade of the oar in the water, and the legs, then the back and finally the arms supply force to the oar as the rowers legs extend to slide the seat toward the forward end of its motion, propelling the boat forward. At the end of the stroke the rower uses wrist action to rotate the oar, thereby “feathering” it so that water force on the blade lifts the oar out of the water. The rower presses down on the oar handle to hold the oar out of the water during the recovery phase in which the rower legs are flexed to cause the seat to slide toward the rear of the boat. The momentum generated by moving the body and arms rearward toward the bootstraps brings the oar back to the starting position. Wrist action then rotates the oar blade, thereby “squaring” it, and upward arm motion then “plants” the oar in the water as the pulling force is once again applied. 
   A long-standing desire has been for a rowing apparatus which will incorporate these actions while the rower faces forward; i.e., faces in the direction in which the scull, shell, or other rowed vessel or boat is propelled. Facing forward is more pleasant and is better for keeping the boat on a proper course. Every backward facing rower has experienced serious safety concerns after encountering unexpected obstacles, even when mirror arrangements are used to look ahead. 
   Various attempts have been made in the prior art to provide a forward-rowing system, with varying success. For example, some rowing apparatus inventions disclose a sliding seat with feet fixed in bootstraps for leg assistance. Systems where the seat is fixed and the feet move can give better ergonomics, however, since the leg force transmitted to the oar need not go through the arms and back and the possibility of balancing the leg effort with that of the arms and back by separate connection to the oars becomes possible. Fixed seat systems may be found in the prior art. One such system provides footrests that slide in a track and are connected by ropes to oars in a normal, backwards facing rowboat, but this system does not require fastening of the feet to a foot support, does not have free foot movement, and more importantly does not have favorable foot ergonomics. In other systems, the entire oar rigging, including its full weight, must also be moved forward and backward with each stroke, thus increasing the required force and effort of the user. In still other systems, a configuration is provided where the feet rest on a swinging arm device to provide added power. The swinging arm motion has poor ergonomics, however, because of the unnatural relationship in the positioning and relative motion between the legs with the rest of the body. The principal focus of some devices is to provide a hands free rowing apparatus that automatically feathers, returns the oar to the starting position, squares it and finally lowers it into the water, whereupon force generated entirely by the legs is applied to the oars. Other prior art discloses a sliding foot support in a guiding track member to provide the transfer of leg effort by a complex pulley system to an oar movement mechanism. Such systems suffer from undue mechanical complications, with much inherent friction, and probable unreliability in a wet environment. 
   SUMMARY OF THE INVENTION 
   Briefly, and in accordance with the present invention, the difficulties encountered in prior front-facing rowing systems are overcome by the provision of a new and improved leg assisted system wherein a rower applies leg power to an oar by means of a flexible cable, or rope, connected to a platform, or shoe, such as a boot which is engaged by the rower&#39;s foot. The weight of the shoe and of the rower&#39;s foot is supported by a wheel or slider attached to the shoe, for example at the region of the rower&#39;s heel. The rower&#39;s leg reciprocates back and forth during the rowing strokes while his foot freely rolls or slides on the floor of the boat. The force generated by the rower&#39;s leg is transmitted through the shoe and the cable to the oar by way of the ball of the foot, as is the case with a sliding seat scull or bicycle pedal. The inner end of the oar is pivoted at the center of the boat, above the rower&#39;s knees, to allow back and forth and up and down oar movement. The weight of the oar is balanced by a spring so that the neutral point of the oar blade is a few inches out of the water. The oar has two coaxial, relatively rotatable segments with a rotational joint between the location of the pivot point and a handle to allow a simple wrist action to rotate the oar blade as required for oar feathering and squaring. The rower grasps the oar using the handle which is loosely connected to the oar, to impart the needed actions of pulling and pushing the oar and also of feathering, squaring and raising and lowering the oar out of and into the water. 
   More particularly, the rowing system of the invention includes an oar having a first, or inner, portion pivotally mounted on a pivot support and a second portion coaxial with and rotatable with respect to the first portion, a handle pivotally secured to the second portion; a stationary seat for a rower, and a movable foot-operated shoe connected to the handle by a flexible cable or rope extending through one or more pulleys. The pivot support preferably comprises a horizontal platform supported in front of the seat by a bridge structure or by a cantilever, and incorporates a tower supported for rotation in the platform. A horizontally extending pivot bracket is fixed to the tower and supports the oar on a pivot pin for motion in a vertical plane, with rotation of the tower permitting pivotal motion of the oar in a horizontal plane. The pivot pin is spaced from the inner end of the oar, and the inner end is secured to a yoke having a vertical shaft that extends into the tower. A coil spring surrounds and is adjustably secured to the shaft to counterbalance the weight of the oar so that it normally is supported in a generally horizontal rest position. 
   The handle includes a rod portion that is pivotally engaged at one end to the oar and is secured at its opposite end to the flexible cable. A grip is secured to the rod at an angle of about 60° to allow a rower to grasp the handle to manipulate the oar in forward (recover) and rearward (power) strokes. The pivotal connection of the handle also allows the rower to pivot the handle in one direction to rotate the oar to feather it for the return stroke and to pivot the handle in the opposite direction to rotate the oar to square it for the power stroke by simple wrist motions in synchronism with the foreward and rearward motion of the oar. 
   The movable shoe which is engaged by the foot of the rower is moved forward and back in synchronism with the power and return strokes, respectively, of the oar, with the cable being connected to the shoe by way of a suitable harness to transfer the motion of the shoe to the oar. The shoe may be in the form of a boot, a sole plate, or other similar structure that receives and secures the rower&#39;s foot to permit a transfer of power from the rower&#39;s leg to the oar. The shoe preferably includes a set of wheels or rollers of nylon or similar material at the heel region to support the rower&#39;s leg, allowing the shoe to roll back and forth on a floor surface during rowing. Tracks may be provided on the floor surface to guide this reciprocating motion. Wheels may also be provided at the toe end of the shoe, if desired. Alternatively, sliders in the form of stainless steel tubes or nylon slides may be mounted on the shoe to engage the floor surface or tracks. 
   The shoe is connected to the oar by way of a cable passing over one or more pulleys mounted, for example, behind the seat. The cable extends from the shoe, back under the seat, through the pulleys, and forward to the oar handle so that forward motion of the shoe produces rearward motion of the handle and oar during the power stroke. 
   The system may be constructed in any rowable vessel, such as a scull, shell, rowboat or canoe, and thus fabricated as a permanent part of the vessel. Alternatively, the system may be constructed as an insert, in which case it is constructed as a unitary front-rowing assembly that can be mounted in and removed from a suitable vessel. Although the system has been described above in terms of a single oar, it will be understood that in most instances it will be fabricated with two oars mounted at the centerline of the system for use by a single operator. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     The foregoing, and additional objects, features and advantages of the present invention will be more fully understood from the following detailed description of preferred embodiments thereof, wherein: 
       FIG. 1  is a perspective view of a preferred embodiment of the rowing system of the present invention; 
       FIG. 2  is a perspective view of a second embodiment of the rowing system of the present invention; 
       FIGS. 3A–3D  are diagrammatic side view illustrations of the operation of the rowing system of the invention; 
       FIGS. 4A–4D  are diagrammatic front views of the illustrations of  FIGS. 3A–3D , respectively; 
       FIG. 5  is a partial cross-sectional view of the pivot mounting of oars utilized in the systems of  FIG. 1  and  FIG. 2 ; 
       FIG. 6  is a top plan view of the pivot mounting of  FIG. 5 ; 
       FIG. 7  is a top plan view of an oar utilized in the systems of  FIGS. 1 and 2 , illustrating a handle for manipulating the oar; 
       FIG. 8  is a cross-sectional view taken at lines AA and of the structure of  FIG. 7 ; 
       FIG. 9  is a partial elevation taken at lines BB of  FIG. 8 ; 
       FIG. 10  is a cross-sectional view of the oar and handle of  FIG. 7 , taken at lines CC of  FIG. 7A ; 
       FIG. 11  is a side elevation of a wheeled movable shoe for use in the systems of  FIG. 1  and  FIG. 2 ; 
       FIG. 12  is a side elevation of a movable shoe incorporating slides; 
       FIG. 13  is a bottom plan view of the shoe of  FIG. 12 ; 
       FIG. 14  is an end view of the shoe of  FIG. 12 ; 
       FIG. 15  is an exploded, partial view of another embodiment of the pivot mounting for the oars; and 
       FIG. 16  is a cross-sectional view of the pivot mountings of  FIG. 15 . 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   Turning now to a more detailed description of the invention,  FIG. 1  illustrates a first embodiment of a front-rowing system in the form of a unitary “drop in” rowing apparatus  10  mounted in a suitable boat hull  12 . Although the boat hull is illustrated as a canoe, it will be understood that it may take any desired form, and that a canoe is illustrated for purposes of convenience. It will also be understood that for purposes of the following description, the system is illustrated as a unitary assembly capable of being mounted in any suitable boat hull, but that it is often preferable to incorporate the system of the invention as an integral part of the boat design. A second embodiment of the invention is illustrated in  FIG. 2  at  14 , wherein the forward-facing rowing apparatus incorporates a modified oar support apparatus, to be described in greater detail below. In both embodiments, similar features are identified by the same reference numerals. 
   The self-contained, or unitary, front facing rowing apparatus  10  of  FIG. 1  includes a pair of oars  16  and  18  pivotally mounted at their inner ends on a pivot support generally indicated at  20 . Oars  16  and  18  incorporate corresponding inner portions  22  and  24 , respectively, and corresponding coaxial outer end portions  26  and  28 , respectively, with the outer portions being relatively rotatable with respect to their inner portions about their common axes. Handles  30  and  32  are pivotally secured to the outer portions  26  and  28  of oars  16  and  18 , respectively, for use in manipulating the oars during rowing. The rowing apparatus  10  further includes a stationary seat  34  for the rower located behind the pivot support  20 , and a pair of movable, foot-operated shoes  36  and  38  located on the floor  40  of the apparatus in front of the seat. The shoes  36  and  38  are connected to the handles  30  and  32 , respectively, through flexible cables, or ropes  42  and  44  which extend from the shoes back under the seat  34  and around suitable pulleys such as the pulley indicated at  50  in  FIG. 1  and then forwardly to their corresponding handles. 
   The pivot support  20  preferably comprises a horizontal platform  52  supported in front of the seat by a bridge structure  53  that includes arms  54  and  56  secured to sides  46  and  48  of the insert assembly  10  and arching over the floor  40  in front of seat  34 , meeting at platform  52  over the centerline of the boat hull  12 . In the structure of  FIG. 2 , the arching bridge formed by arms  52  and  56  is replaced by a cantilevered arm  60  secured to the forward end of the insert  10  and extending rearwardly toward the seat to position the platform  20  in front of, and above the legs of, the rower. The arched bridge structure  53  is preferred since the arms  54  and  56  may be constructed to produce a stronger and more rigid support for the oars than is practical for the cantilever, as by the use of rearwardly extending braces  62  and  64 , for example. 
   The inner ends  22  and  24  of the oars are supported for pivotal motion on platform  52  by means of corresponding U-shaped brackets  70  and  72 , which are mounted to be pivotal about a vertical axis to allow forward and backward motion of the oars, with each oar being secured to its respective bracket by horizontal pins  74  and  76  to allow pivotal motion of the oars in a vertical direction. 
   Rotation of the outer portions  26  and  28  of the oars with respect to the coaxial inner portions  22  and  24  is accomplished by means of handles  30  and  32 , wherein each handle incorporates a rod portion  80  and grip portion  82 . The grip portion is secured to the rod at an angle of approximately 60° to enable a rower to grasp the grip portion and pivot the rod portion up and down by wrist action. The distal end of the rod portion  80  is connected to the outer portion of the oar through a pivotal connection  84 , to be described in greater detail below, while the near end of the rod  80  is fastened through a connector  86  to the corresponding one of cables  42  or  44 . This handle enables a rower to grasp the grip portion to move the oar back and forth horizontally and up and down vertically in a rowing motion while tilting the rod portion to controllably rotate the outer portion of the oar to control feathering and squaring of the oar blade in synchronism with the rowing motion. At the same time, the rower engages the shoes  36  and  38  with his feet to slide the shoes forwardly and rearwardly with respect to the stationary seat in synchronization with the rowing motion to assist in the power stroke of the oars. 
   As more clearly illustrated in  FIG. 2 , the rowing insert  10  of the present invention incorporates a floor portion  40  between side rails  46  and  48  and front and rear rails  104  and  106 . Seat  34  is adjustably positioned on the side rails  46  and  48  and is secured in place by clamps, pins, or other suitable fasteners. As illustrated, the shoes  36  and  38  may be in the form of lace-up boots, and in accordance with the invention, the shoes incorporate corresponding wheels or rollers  110  and  112 , preferably located in the heel region of the shoes. These rollers, which may be nylon wheels, for example, engage the floor  40  of the insert assembly  10  to enable the roller to easily move the boots forwardly and rearwardly during the rowing motion, with the rollers supporting the weight of the shoes and of the rollers&#39; legs. Suitable harnesses  114  and  116  ( FIGS. 1 and 2 , respectively) are secured to the boots and are fastened to the connector cables  42  and  44 , respectively, by corresponding fasteners  118  and  120 . 
   It will be understood that if the rowing system of the invention is built into a boat hull, a separate floor  40  might not be needed, in which case the rollers would engage the interior surface of the hull in which the system is installed. As will be described in greater detail below, it may be desirable to mount guide tracks on either the floor  40  or the interior surface of the hull for receiving the rollers. Additionally, in some cases it may be desirable to replace the wheels with bars or plates which will slide along the insert floor or hull surface. 
   As further illustrated in  FIG. 2 , the cables  42  and  44  are directed rearwardly under the seat  34  to pass around a pair of pulleys such as the pulleys  130  and  132  provided for cable  42 . These pulleys are secured to the rear rail  106  of the insert, with the pulley  132  being secured to an extension arm  134  which positions pulley  132  outwardly in closer alignment with the direction of motion of handle  30 . Although the single pulley  50  illustrated in  FIG. 1  may be used instead of pulleys  130  and  132 , the configuration illustrated in  FIG. 2  is preferred. 
   The operation of the front facing rowing system of the present invention is illustrated diagrammatically in  FIGS. 3A through 3D , which show the rowing sequence in side view, and corresponding  FIGS. 4A through 4D , which show the same rowing operation in a front view. To start the rowing sequence, an operator, or rower  150  positioned on stationary seat  34 , pushes the oars  16  and  18  forwardly by leaning forward, extending his arms  152  and flexing, or retracting, his legs  154 . The bending or flexing of the legs brings the shoes  36  and  38  back toward the seat  34 , releasing the tension on cables  42  and  44  and allowing the oars to be moved forwardly by means of handles  30  and  32 . As he moves to this position, the rower tilts his wrists upwardly to pivot the grips  82  in a clockwise direction, as illustrated in  FIG. 3A , thereby pivoting the rods  80  upwardly, rotating the outer portions  26  and  28  of the oars in a counterclockwise direction (as viewed in the Figures) and feathering the blades  156  and  158  as the oars are moved forward. 
   At the beginning of the power stroke, illustrated in  FIG. 3B , the operator rotates his wrists downwardly to pivot the grips  82  in a counterclockwise direction, as indicated by arrow  159 , thereby rotating the outer ends  26  and  28  of the oars in a clockwise direction to square the blades  156  and  158 . The oars are then lowered, as indicated by arrow  160 , to dip the blades below the level of the water, illustrated at  162  in  FIG. 4B , and the power stroke begins. As illustrated in  FIG. 3C , during the power stroke, the operator  150  pulls on the oars with his back, while simultaneously pressing on the shoes  36  and  38  with his legs and, as the end of the stroke is near, continues the power stroke by flexing, or bending, his arms. The motion of the shoes  36  and  38  in a forward direction transmits the power of the legs through cables  42  and  44  to the handles  30  and  32  and thus to the oars  16  and  18 . By properly synchronizing the leg, back and arm motion, the maximum amount of power is applied to the oar during the power stroke. 
   At the end of the stroke, illustrated in  FIG. 3D , the wrists are tilted in a clockwise direction illustrated by arrow  162 , as the oars are raised out of the water, to feather the blades  156  and  158  for the return stroke, which ends in the position illustrated in  FIG. 3A . The pivoting of handle  30  is facilitated by the flowing of water past the boat, as the oar is lifted, thereby making the feathering motion a natural part of the rowing motion. Synchronization of the clockwise and counterclockwise rotation of the oar, produced by tilting the handle  30 , with the forward and rearward motion of the oar during the return and power strokes provides an easy and natural motion for rowing. 
   The pivot support  20  shown in  FIGS. 1 and 2  is illustrated in greater detail in  FIGS. 5 and 6 , to which reference is now made. The platform  52 , which is supported by bridge arms  54  and  56 , may be generally oval in shape, and may support a single oar, or as in the illustrated embodiment, may support a pair of oars  16  and  18  for pivotal motion, as discussed above. The oars are supported at their inner ends  22  and  24  by corresponding pivot towers  170  and  172 , respectively, which are, in turn, supported in corresponding apertures  174  and  176  which extend vertically through the platform  52  at spaced apart locations. The pivot towers  170  and  172  are substantially identical, and thus will be described in what follows only with respect to tower  170 . In the illustrated embodiment, pivot tower  170  consists of a tube  180  which is partially closed at its upper and by a top plate  182  having a diameter greater than the diameter of tube  180  to provide and outwardly-extending shoulder portion  184 . The top plate also incorporates a central aperture  186  axially aligned with tube  180 . The tube  180  is rotatably secured in aperture  174  by upper and lower bushings  188  and  190  having outwardly extending flanges and which are secured, as by a suitable adhesive, to the exterior surface of tube  180 , with the top bushing  188  engaging the lower surface of shoulder portion  184 . The tube  180  may be stainless steel, aluminum, or the like, with stainless steel being preferred, while the bushings  188  and  190  preferably are nylon. The bushings are spaced apart so that their flanges engage the upper and lower surfaces of platform  52  to secure the tube  180  in aperture  174  for rotation about a vertical axis. 
   The generally U-shaped bracket  70  is secured to the top plate  182  on tube  180 , with the closed end  192  of the bracket surrounding aperture  186  and with generally parallel bracket arms  194  and  196  extending in a horizontal direction and opening outwardly to receive the inner end  22  of oar  16 . Inner end  22  is mounted on pivot pin  74  which extends through the oar and is secured in the arms  194  and  196  of bracket  70 , with the pin being spaced away from the axis of tube  180  and permitting pivotal motion of the oar  16  in a vertical plane. This pivotal motion is dampened by means of a yoke  200  having a U-shaped bracket portion  202  having upwardly extending spaced arms which receive the innermost end  204  of oar  16 . The yoke, which is pivotally secured to the oar by a pin  206 , includes a vertical stem  208  that extends through aperture  186  and axially into the interior of tube  180 . A coil spring  210  surrounds the stem  208 , with the upper end of the spring engaging a recess  212  in the lower surface of plate  182  for centering the spring. The lower end of the spring engages a generally cylindrical receiver cup  214  slideably mounted within the interior of tube  180  to center the spring within the tube. A threaded lower end of stem  208  threaded extends through the receiver  214 , with an adjustment lock nut  216  on stem  208  being movable to engage the lower surface of receiver  214 . Loosing or tightening of lock nut  216  on stem  208  lowers or raises the receiver  214  to adjust the compression of spring  210 . The spring is adjusted to counterbalance the oar  16  about pivot point  74  and preferably is adjusted so that when the oar is at rest, the blade  156  ( FIG. 1 ) is slightly above the water level when the system is at rest. The up and downward motion of the innermost end  204  of the oar is limited by an adjustment bolt  220  which is threaded through the oar so that its lower end  222  engages the upper surface of plate  182 . The bolt can be secured in its adjusted position by a lock nut  224 . 
   The pivot tower  170  thus provides a simple yet effective mounting for the oar  16  to provide pivotal motion of the oar  16  in a vertical plane about pin  74 , with the downward motion of the innermost end  204  being limited by adjustment bolt  220 . The tower also provides unlimited pivotal motion of the oar in a horizontal plane about the axis of tube  180 . The balance provided by the spring  210  facilitates lifting and lowering of the oar during rowing, while the adjustment bolt  220  prevents the outer end of the oar from rising too far above the water level so that the oar acts as an outrigger to stabilize the boat in which it is mounted. 
   The inner and outer ends  24  and  28  of oar  18  are illustrated in greater detail in  FIGS. 7 through 9 , to which reference is now made. It will be understood that oar  16  is substantially identical, and thus will not be described here. The outer portion  28  of the oar, which carries the oar blade  156  at its outermost end, is generally tubular, with its inner end  228  being coaxial with and telescoping over the inner shaft portion  24 . Nylon bushings  230  and  232  are secured at spaced apart locations on the inner shaft  24  to receive the outer tube  28  to hold the tubes in coaxial alignment, and to facilitate rotation of the outer tube with respect to the inner tube. The inner tube may be of wood, metal, or the like, as desired, while the outer tube preferably is plastic, a metal such as aluminum, or other suitable material. 
   To prevent longitudinal motion between the inner and outer proportions  24  and  28 , a pin  234  is secured in the oar portion  24  (see  FIG. 8 ) and extends through elongated apertures  236  and  238  formed in the outer tube  28 . The elongated apertures are vertically aligned and have a width substantially equal to or slightly greater than the diameter of pin  234  to prevent longitudinal motion of the outer tube with respect to the inner portion of the oar, while permitting relative rotation of the inner and outer oar portions  24  and  28 . This arrangement allows the outer oar portion  28  to be rotated to feather or to square the oar blade  156 , as described above, while the inner portion  24  of the oar provides pivotal support at pivot tower  172 . 
   Rotation of the outer portion of the oar with respect to the inner portion is accomplished by handle  32 , which is illustrated in greater detail in the top plan view of  FIG. 7  and the side view of  FIG. 10 . As described with respect to  FIG. 1 , the handle  32  incorporates a rod  80  and a grip  82  connected to oar  18  through a pivotal connection  84  which may be in a form of a universal joint to allow relative motion between handle  32  and oar  18 . The connection  84  may incorporate, for example, a clamp  240  secured to the outer oar tube  28  as by a clamping bolt  242 . The clamp incorporates an ear portion  244  incorporating an aperture  246  that extends through the ear in a direction generally parallel to the oar  18 . A pulling eye  248 , which may be in the form of a stainless steel U-shaped bolt, passes through aperture  246  and is secured in a connecting block  250  which, in turn, is secured to an end of rod  80 . The clamp  240  may be of nylon, while the block  250 , the rod  80 , and the pulling handle  82  preferably are of wood, with the parts being glued together with a suitable epoxy, or the like. 
   At the end of rod  80  adjacent and behind the grip  82  is a second connector block  252  which may also be secured to the end of rod  80 , as by glueing. Connector  252  incorporates a rearward-facing slot  254  that receives a connecting pin  256  for securing the cable  44 . A cable connector such as a length-adjustment chain  258  and a hasp  260  may be used to couple cable  44  to the handle. Chain  258  may be plastic, for example, and may be of an adjustable length suitable for connecting the cable  44  for transferring motion from boot  38  to the oar  18 , in the manner described above. It will be understood that the handle  30  on oar  16  is substantially identical to the handle  32 , and thus is not described here. 
   As described above, the handle  32  is rotated in clockwise or counter-clockwise directions by the rower to twist the outer oar portion  28  in a counter-clockwise or clockwise direction, respectively, to control the feathering of the blade, as discussed above. 
   As described with respect to  FIGS. 1 and 2 , movement of the oars is assisted by a pair of movable foot-operated shoes  36  and  38  connected to the oars by way of cables  42  and  44 . This connection may be carried out by way of a suitable shoe harness, such as that illustrated at  114  in  FIG. 1  for shoe  38 . This harness incorporates a line  270  secured around the boot  38  and fastened, for example, to eyelets on the boot. Alternatively, the line may be secured to the sole of the boot near the ball of the foot of the user. The line  270  passes through opposite ends of a spanner  272  that is secured, in turn, to line  44 . Another form of the harness is illustrated in  FIG. 2  at  116 , in which line  270  is secured to opposite ends of spanner  272 . An eye  274  is secured to the spanner and the cable  44  is connected to the eye by means of clip  120 , other methods for securing cable  44  to the boot  38  and for securing cable  42  to boot  36  will be apparent. 
   In another embodiment of the invention, the shoes  36  and  38  may be in the form of a light weight wooden or plastic base  278  such as that illustrated in  FIG. 11 . The base includes a sole plate  280  sized to receive the foot of a rower, and may incorporate a pair of hook and loop fasteners  282  and  284  secured to the base and adjustable to extend over the rower&#39;s foot  286  to secure it. The base may include a heel portion  288  to which the cable  42 , for example, may be fastened either by a harness similar to one of those illustrated in  FIGS. 1 and 2 , or by simply tying or otherwise securing the cable to the heel portion. In the illustrated embodiment, the shoe base  278  incorporates rear and forward sets of wheels  290  and  292  to facilitate the motion of the shoe along the floor  40  of the insert or along the floor surface of a boat hull in which the rowing assembly is mounted. These wheels may be of the type found on conventional roller blades or rollers skates, and may be of nylon or other suitable material. 
   Another embodiment of the shoes  36  and  38  is illustrated at  300  in  FIGS. 12 and 13 ,  FIG. 12  being a side elevation view, and  FIG. 13  being a bottom view of the shoe. This shoe incorporates a base  302  which is similar to that illustrated in  FIG. 11 , the difference being that in place of wheels  290  and  292 , a hardened stainless steel skid tube  304  is secured at the heel of the device and a stainless steel skid pad  306  is secured in the toe region of the device. The skid tube will slide on the floor  40  of the insert, or on the floor surface of the hull in which the system of the invention is installed to facilitate forward and rearward motion of the rower&#39;s feet. 
   In still another embodiment of the invention illustrated in  FIG. 13 , the stainless steel skid tube  304  may be extended across of a pair of tracks such as spaced oils impregnated nylon skids  310  and  312  fastened to the floor  40  of the insert or to the floor of the boat hull. A spacer  314  may be secured to the bottom of base  302  to fit between the skids  310  and  312  to guide the boot along the track. Similar tracks may also be used in combination with the wheel sets illustrated in  FIGS. 1 ,  2  and  9 , if desired. 
   Another embodiment of a pivot tower assembly  330  for pivotally supporting the oars for vertical and horizontal motion is illustrated in  FIGS. 15 and 16 , to which reference is now made. In this embodiment, the assembly  330  includes a pair of pivot towers  332  and  334  mountable in a pivot support platform  336 . The platform may be secured to a cantilever arm  338  such as that illustrated at  60  in  FIG. 2 , or may be secured in a bridge structure of the type illustrated in  FIG. 1 . As illustrated, the support platform includes upper and lower spaced plates  34 - and  342  secured at the end of arm  338 . Apertures  344  and  346  are located in plate  340  and are vertically aligned with apertures  348  and  350 , respectively, for receiving and rotatably holding, pivot tower  332  and  334 . The towers are substantially identical, and will be described below with reference to pivot tower  332 . 
   The pivot tower  332  is fabricated from a tube  356 , which may be of stainless steel, aluminum, or other suitable material. The tube extends through the apertures  344  and  348  and is secured in place by an internally threaded plug  360  that is held in the tube by epoxy or other adhesive. The plug incorporates an outwardly extending flange  362  that extends beyond the top edge of the tube to rest on the top surface of plate  340 . Preferably, a washer  364  of nylon or other suitable material is interposed between the flange  362  and plate  340  to facilitate rotation of the tube  356  with respect to plate  340 . 
   The lower end of the tube  356  is secured in aperture  348  of lower plate  342  by a second plug  366  having an outwardly extending flange  368  which engages the lower surface of plate  342 . Plug  366  may be secured in tube  356  by suitable fasteners such as screws  370 . 
   A U-shaped bracket  380  is secured to tube  356 , as by welding. The bracket has a closed end  382  which engages the tube and has a pair fo arms  384  and  386  which extend outwardly to receive and support the inner end  388  of an oar  390 . The oar is secured between arms  384  and  386  by a pivot pin  392  which may be removable to allow the oar to be disconnected from the pivot tower. The pin allows motion of the oar in a vertical plane, while rotation of tube  356  allows motion of the oar in a horizontal plane. 
   The oar is counterbalanced by an adjustable mandrel  394  located in, and axially aligned with, the tube  356 . The mandrel includes a coil spring  396  surrounding a central plunger  398  that is mounted for axial motion in the tube. The upper end of plunger  398  extends through a central aperture  400  in a guide plug  402  that is threaded into plug  360 , so that the plunger is vertically movable in the guide plug. The upper end of the coil spring  396  engages the bottom of guide plug  401 , while the lower end of the spring is held on the plunger by a suitable fastener such as an acorn nut  404 . Tightening or loosening of the fastener  404  preloads the spring  396 , and thus adjust the amount of force required to move plunger  398  upwardly into the guide plug  402 . 
   A support bracket  410  is secured to the innermost end of the oar  390  and extends through an aperture  412  in tube  356 . The bracket incorporates a detent  414  that engages the fastener  404  so that pivoted motion of the oar is counterbalanced by mandrel  394 . The vertical locator of the mandrel and thus the rest position of the oar in the vertical plane, is adjustable by threading the guide plug  402  into or out of the tube  356 , and vertical motion of the oar is limited by the top and bottom edges of the aperture  412 . 
   As discussed above, in operation of the rowing system of the present invention, a rower moves his arms and body forward while lifting on the gripping handles  30  and  32 . Wrist imparted lifting action on the gripping handles, together with water action on the oar blades, feathers the oar blades into a horizontal orientation. Releasing the pulling force on the oar, which has a downward component due to the relative height of the guide pulleys for cables  42  and  44 , allows springs  210  to hold the oars horizontally without further arm support during the recovery part of the stroke. During the recovery, the height of the oar above the water is determined by adjustment of the preloaded spring. The forward, recovery motion of the oars is provided by forward body momentum transmitted through the arms and hands to the gripping handles  30  and  32  and then to the oar shafts. When large waves are present, keeping the oars out of the water by lifting the grip handles  30  and  32  is easy because of the spring-provided counterbalance. At the end of the recovery stroke the rower first rotates his wrists down to rotate the oar blades to squaring them. The grip handles  30  and  32  are then pushed down to “plant” the oar blades in the water with upright orientation. As soon as the oar is firmly “planted” the rower pulls with the arms and back and legs for the powering part of the stroke. The downward components of the pulling cables and a slightly non-vertical orientation of the oar blade, determined by the rotation limit of the pin  234  and slot  236  combination holds the oar at the proper depth in the water during this part of stroke without concentration by the rower. 
   The variable lengths of the connecting cables  42  and  44  and the movable seat  34  allow the system of the invention to be adjusted to a particular rower for comfort and for maximum efficiency. As a result, during the powering part of the stroke, the leg and arm and back motion are coordinated. The forces applied to the oars by the arms and back are independent of each other and these two forces add. In a conventional sliding seat rower the opposite is true, for these the force stress of the legs equals that of the arms. The consequence of this is that relative travel of the hands with conventional sliding seat rowing is almost double that of the forward facing rower disclosed herein. In conventional sliding seat rowing, the action of the legs, back and arms occur sequentially because of the relative strength of each. This leads to a lower stroke rate, for a given effort, than for the rowing apparatus disclosed herein, where the action of the legs and of the arms and back are simultaneous. The resulting intrinsically higher stroke rate of the rowing action is better matched to the body. It is generally accepted that an optimum stroke rate in a conventional sliding seat scull is around 25 strokes per minute; however, in the rower disclosed herein it is somewhat over 30 strokes per minute. 
   Although the invention has been described in terms of preferred embodiments, it will be understood that numerous modifications and variation may be made without departing from the true spirit and scope thereof, as set for in the following claims.