Patent Publication Number: US-2023150641-A1

Title: Marine vessel equipped with steering mechanism for marine vessel, and steering handle for marine vessel

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to Japanese Patent Application No. 2021-187173, filed on Nov. 17, 2021. The entire contents of this application are hereby incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a marine vessel equipped with a steering mechanism for a marine vessel, and a steering handle for a marine vessel. 
     2. Description of the Related Art 
     A speed of a marine vessel is adjusted by operating a lever of a remote control switch provided at a maneuvering seat. In recent years, with the aim of reducing the burden on a marine vessel operator or the like, a marine vessel maneuvering system of the marine vessel has been equipped with a constant speed navigation mode that keeps the speed of the marine vessel constant without the marine vessel operator continuing to operate the lever of the remote control switch. For example, as shown in  FIG.  8   , a speed control switch  82  functioning as an operator is provided on the side face of a lever  81  of a remote control switch  80 , and after the marine vessel operator operates the lever  81  of the remote control switch  80  to increase the speed of the marine vessel to a predetermined speed, when the marine vessel operator operates the speed control switch  82 , the marine vessel shifts to the constant speed navigation mode in which the marine vessel continues to navigate at the predetermined speed. Such a speed control switch  82  is provided with up and down buttons (indicated by “+” and “-” in  FIG.  8   ), and by operating the up and down buttons, it is possible for the marine vessel operator to change the speed of the marine vessel navigating in the constant speed navigation mode (For example, see “Helm Master EX”, [online], Yamaha Motor Co., Ltd., [searched on Nov. 8, 2021], Internet &lt;URL: https://www.yamaha-motor.co.jp/marine/lineup/outboard/helmmasterex/&gt;). 
     However, the predetermined speed when the marine vessel is navigating in the constant speed navigation mode is often a relatively high speed, and in order to maintain the course of the marine vessel, the marine vessel operator needs to keep holding a steering wheel. 
     Therefore, in the case of changing the speed of the marine vessel navigating in the constant speed navigation mode with the up and down buttons of the speed control switch  82 , since the marine vessel operator needs to hold the steering wheel with one hand and operate the speed control switch  82  of the remote control switch  80  located away from the steering wheel with the other hand, it is not easy for the marine vessel operator to operate the speed control switch  82  accurately. In addition, since the up and down buttons are provided along with the speed control switch  82 , they cannot be made large, and the operability is not good. That is, there is room for improvement in the operability of the operator for changing the speed of the marine vessel. 
     SUMMARY OF THE INVENTION 
     Preferred embodiments of the present invention provide marine vessels equipped with steering mechanisms, and steering handles that are each able to improve the operability of an operator to change a speed of a marine vessel. 
     According to a preferred embodiment of the present invention, a marine vessel includes a steering mechanism including a steering wheel, a speed increasing paddle to accelerate the marine vessel, and a speed decreasing paddle to decelerate the marine vessel. 
     According to another preferred embodiment of the present invention, a marine vessel includes a steering mechanism including a steering wheel, a speed increasing switch to accelerate the marine vessel, and a speed decreasing switch to decelerate the marine vessel. The steering wheel includes a central portion supported rotatably around a rotation fulcrum with respect to a hull of the marine vessel, a wheel portion having an annular shape, and at least two spoke portions that connect the central portion and the wheel portion. The at least two spoke portions are positioned above a virtual plane extending through the rotation fulcrum and parallel to a left/right direction, and are positioned within an angle range from about 0° to about 60° with respect to the virtual plane in a circumferential direction about the rotation fulcrum. The speed increasing switch and the speed decreasing switch are located on the at least two spoke portions, respectively. 
     According to another preferred embodiment of the present invention, a steering handle for a marine vessel includes a steering wheel, a speed increasing paddle to accelerate the marine vessel, and a speed decreasing paddle to decelerate the marine vessel. 
     According to preferred embodiments of the present invention, although the steering mechanism for the marine vessel includes the steering wheel, the speed increasing paddle to accelerate the marine vessel, and the speed decreasing paddle to decelerate the marine vessel, since the speed increasing paddle and the speed decreasing paddle are able to be configured (made) larger than a speed control switch, it is possible for a marine vessel operator to easily operate the speed increasing paddle and the speed decreasing paddle. Further, since the speed increasing switch and the speed decreasing switch are located on each of the at least two spoke portions of the steering wheel of the steering mechanism for the marine vessel, it is possible for the marine vessel operator to operate the speed increasing switch and the speed decreasing switch without taking his/her hands off the steering wheel. As a result, it is possible to improve the operability of the operator to change the speed of the marine vessel. 
     The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a marine vessel equipped with a steering mechanism according to a preferred embodiment of the present invention. 
         FIG.  2    is a perspective view of a principal portion of a maneuvering seat. 
         FIG.  3    is a block diagram for schematically explaining a configuration of a marine vessel maneuvering system of the marine vessel of  FIG.  1   . 
         FIG.  4    is a view for explaining a configuration of the steering mechanism for the marine vessel. 
         FIG.  5    is a view for explaining the configuration of the steering mechanism for the marine vessel. 
         FIG.  6    is a view for explaining a configuration of a first modified example of the steering mechanism for the marine vessel. 
         FIG.  7    is a view for explaining a configuration of a second modified example of the steering mechanism for the marine vessel. 
         FIG.  8    is a view for explaining a speed control switch of a conventional remote control switch. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 
       FIG.  1    is a perspective view of a marine vessel equipped with a steering mechanism according to a preferred embodiment of the present invention. A marine vessel  1  includes a hull  2 , and a plurality of, for example, two outboard motors  3  that function as marine vessel propulsion devices and are mounted on the hull  2 . It should be noted that the number of the outboard motors  3  provided on the marine vessel  1  is not limited to two, and may be one or three or more. The two outboard motors  3  are mounted side by side on the stern of the hull  2 . Each outboard motor  3  includes an engine (not shown) which may be an internal combustion engine functioning as a power source, and obtains a thrust from a propeller (not shown) which is rotated by a driving force of the corresponding engine. It should be noted that each outboard motor  3  may include an electric motor functioning as the power source, or may include both an engine and an electric motor functioning as the power source. 
     In addition, in the marine vessel  1 , a maneuvering seat  4  is provided on the bow side, which is the front portion of the hull  2 .  FIG.  2    is a perspective view of a principal portion of the maneuvering seat  4 . A steering mechanism  5  for a marine vessel (hereinafter, also simply referred to as “a marine vessel steering mechanism  5 ”) that functions as a steering handle for a marine vessel), a remote control switch  6 , a joystick  7 , a main operation unit  8 , and an MFD (Multi Function Display)  9  are located near the maneuvering seat  4 . 
     The marine vessel steering mechanism  5  enables a marine vessel operator to determine the course of the marine vessel  1 . The marine vessel steering mechanism  5  includes a steering wheel  10  which is rotatably operated, and speed adjusting paddles  11  and  12 . The marine vessel operator is able to turn the marine vessel  1  left or right by rotatably operating the steering wheel  10  left or right. Further, the marine vessel operator is able to increase a rotation speed of the engine of the outboard motor  3  by operating the speed adjusting paddle  11  (a speed increasing paddle) so as to increase a vessel speed of the marine vessel  1 . On the other hand, the marine vessel operator is able to decrease the rotation speed of the engine of the outboard motor  3  by operating the speed adjusting paddle  12  (a speed decreasing paddle) so as to decrease the vessel speed of the marine vessel  1 . 
     The remote control switch  6  includes levers  13  corresponding to the outboard motors  3 , respectively. By operating each lever  13 , the marine vessel operator is able to switch a direction of the thrust generated by the corresponding outboard motor  3  between a forward moving direction and a backward moving direction, and adjust the output of the corresponding outboard motor  3  so as to adjust the vessel speed of the marine vessel  1 . 
     The joystick  7  is operable to be tilted forward, backward, leftward and rightward, and also operable to rotate about an axis. By operating the joystick  7 , the marine vessel operator is able to navigate the marine vessel  1  with a course corresponding to a tilting direction of the joystick  7  and a thrust corresponding to a tilting amount of the joystick  7 . In a normal mode, the outboard motor  3  works mainly according to an operation of the marine vessel steering mechanism  5  and an operation of the remote control switch  6 . On the other hand, in a joystick mode, the outboard motor  3  works mainly according to an operation of the joystick  7 . It is possible to switch between the normal mode and the joystick mode by a change-over switch (not shown). 
     The main operation unit  8  includes a main switch  14  and an emergency switch  15 . The main switch  14  (one main switch  14 ) is provided in common for the outboard motors  3  (respective outboard motors  13 ). The main switch  14  is an operator to collectively start and collectively stop the engines of the outboard motors  3  (the respective outboard motors  13 ). 
     The MFD  9  is, for example, a color LCD display. The MFD  9  functions as a display that displays various kinds of information, and also functions as a touch panel that accepts inputs from the marine vessel operator. For example, the MFD  9  displays the rotation speed of the engine of each outboard motor  3  and the vessel speed of the marine vessel  1 , and as will be described below, accepts settings to change functions assigned to the speed adjusting paddles  11  and  12 . 
       FIG.  3    is a block diagram for schematically explaining a configuration of a marine vessel maneuvering system of the marine vessel  1 . As shown in  FIG.  3   , in addition to the outboard motors  3 , the marine vessel steering mechanism  5 , the remote control switch  6 , the joystick  7 , the main operation unit  8 , and the MFD  9  that are described above, the marine vessel maneuvering system of the marine vessel  1  includes a GPS (Global Positioning System)  16 , an HS (Heading Sensor)  17 , a remote control ECU (Engine Control Unit)  19  functioning as a controller, SCUs (Steering Control Units)  20 , and a steering shaft sensor  21 . 
     The GPS  16  obtains the current position of the marine vessel  1  and transmits the current position of the marine vessel  1  to the remote control ECU  19  as position information. The HS  17  incorporates direction sensors (azimuth sensors) such as a yaw sensor, a roll sensor, and a pitch sensor, an acceleration sensor that measures an acceleration of the marine vessel  1  in a front-rear direction (a longitudinal direction), an acceleration sensor that measures an acceleration of the marine vessel  1  in a left/right direction, and an acceleration sensor that measures an acceleration of the marine vessel  1  in a vertical direction. The HS  17  transmits a direction of the marine vessel  1  and the respective accelerations (movement) of the marine vessel  1  to the remote control ECU  19 . 
     The remote control ECU  19  is a main controller of the marine vessel maneuvering system, and controls operations of respective components of the marine vessel maneuvering system according to digital signals that will be described below, and various kinds of programs. In addition, the remote control ECU  19  controls the engine of each outboard motor  3  according to the operation of each lever  13  of the remote control switch  6 . The SCU  20  is provided corresponding to each outboard motor  3 , and controls a steering unit (a steering mechanism) that horizontally turns the corresponding outboard motor  3  with respect to the hull  2  of the marine vessel  1  so as to change an acting direction of the thrust of each outboard motor  3 . The steering shaft sensor  21  detects a rotation angle (an operation angle) of the steering wheel  10  of the marine vessel steering mechanism  5 . 
     In the marine vessel maneuvering system, the respective components are connected to each other by a CAN (Control Area Network)  22  that is a network in which a plurality of nodes are individually connected to a bus. In the CAN  22 , operation inputs to the respective components are transmitted as the digital signals to the remote control ECU  19  via the bus. 
     In addition, in the marine vessel maneuvering system, the remote control switch  6  is connected to the remote control ECU  19  not only by the CAN  22  but also by individual wiring (see a broken line in  FIG.  3   ), and the main operation unit  8  is connected to the remote control ECU  19  not by the CAN  22  but by individual wiring (see a broken line in  FIG.  3   ). The operation input to each lever  13  of the remote control switch  6  is transmitted also as an analog signal to the remote control ECU  19 , and the operation input to the main switch  14  of the main operation unit  8  and the operation input to the emergency switch  15  of the main operation unit  8  are also transmitted as analog signals to the remote control ECU  19 . 
     Furthermore, in the marine vessel steering mechanism  5 , the speed adjusting paddles  11  and  12  are connected to the CAN  22  via a steering substrate (not shown) of the marine vessel steering mechanism  5 . The operation inputs to the speed adjusting paddles  11  and  12  are transmitted as the digital signals to the remote control ECU  19  via the steering substrate. 
     It should be noted that in the marine vessel maneuvering system, the respective components may be connected to each other not by the CAN but by a LAN (Local Area Network) such as Ethernet (registered trademark) that performs connecting via a network device, or the respective components may be directly connected to each other. Also in this case, the operation inputs to the respective components are transmitted as the digital signals to the remote control ECU  19 . 
       FIG.  4    and  FIG.  5    are views for explaining a configuration of the marine vessel steering mechanism  5 .  FIG.  4    shows a case in which the marine vessel steering mechanism  5  is viewed opposite from the side of the marine vessel operator, and  FIG.  5    shows a case that the marine vessel steering mechanism  5  is obliquely viewed from the opposite side of the marine vessel operator. It should be noted that a vertical direction and a left/right direction of  FIG.  4    correspond to the vertical direction and the left/right direction of the marine vessel  1 , the depth side of  FIG.  4    is the bow side of the marine vessel  1 , and the front side of  FIG.  4    is the stern side of the marine vessel  1 . 
     As shown in  FIG.  4    and  FIG.  5   , the marine vessel steering mechanism  5  includes the steering wheel  10 , the speed adjusting paddles  11  and  12 , and a column portion  27  that pivotally and rotatably supports the steering wheel  10 . The steering wheel  10  includes a central portion  29  that is supported rotatably around a rotation fulcrum (a steering shaft)  28  with respect to the column portion  27 , a wheel portion  30  that has an annular shape, and at least two spoke portions, for example, three spoke portions (spoke portions  31 ,  32 , and  33 ) that connect the central portion  29  and the wheel portion  30 . 
     The speed adjusting paddle  11  is a substantially T-shaped lever, and protrudes rightward from the column portion  27  when viewed opposite from the side of the marine vessel operator. Furthermore, the speed adjusting paddle  12  is also a substantially T-shaped lever, and protrudes leftward from the column portion  27  when viewed opposite from the side of the marine vessel operator. On the other hand, the steering wheel  10  is provided on the stern side of the column portion  27 . That is, the speed adjusting paddle  11 , the speed adjusting paddle  12 , and the steering wheel  10  are separate from the column portion  27 . It is preferable that both the speed adjusting paddle  11  and the speed adjusting paddle  12  are located within a range that fingers of the marine vessel operator who is gripping the wheel portion  30  are able to reach. 
     The column portion  27  supports the speed adjusting paddles  11  and  12  so that they are able to be tilted substantially forward and backward, respectively. Each of the speed adjusting paddles  11  and  12  accepts the operation when the marine vessel operator pulls the respective speed adjusting paddles  11  and  12  toward the front side once. The operations of the speed adjusting paddles  11  and  12 , that is, the tilting or moving of the speed adjusting paddles  11  and  12  toward the front side of the marine vessel operator are/is converted into analog signals by, for example, a potentiometer, and transmitted to the steering substrate of the marine vessel steering mechanism  5 . It should be noted that the speed adjusting paddle  11  (the speed increasing paddle) may protrude leftward from the column portion  27  when viewed opposite from the side of the marine vessel operator, and the speed adjusting paddle  12  (the speed decreasing paddle) may protrude rightward from the column portion  27  when viewed opposite from the side of the marine vessel operator. 
     When the steering wheel  10  is at a position that makes the marine vessel  1  move straight, the spoke portion  31  is positioned below a virtual plane  34  extending through the rotation fulcrum  28  and parallel to the left/right direction, and extends downward from the rotation fulcrum  28 . 
     Further, when the steering wheel  10  is at the position that makes the marine vessel  1  move straight, the spoke portion  32  (the other spoke portion) is positioned above the virtual plane  34 , and extends from the rotation fulcrum  28  so as to be positioned within an angle range from about 0° to about 60°, for example, clockwise with respect to the virtual plane  34  in a circumferential direction about the rotation fulcrum  28  (within an angle range indicated by θ1 in  FIG.  4   ), preferably, so as to be positioned within an angle range from about 20° to about 40°, for example, clockwise with respect to the virtual plane  34  in the circumferential direction about the rotation fulcrum  28  (within an angle range indicated by θ2 in  FIG.  4   ). 
     Furthermore, when the steering wheel  10  is at the position that makes the marine vessel  1  move straight, the spoke portion  33  (one spoke portion) is positioned above the virtual plane  34 , and extends from the rotation fulcrum  28  so as to be positioned within an angle range from about 0° to about 60° counterclockwise with respect to the virtual plane  34  in the circumferential direction about the rotation fulcrum  28  (within an angle range indicated by θ3 in  FIG.  4   ), preferably, so as to be positioned within an angle range from about 20° to about 40° counterclockwise with respect to the virtual plane  34  in the circumferential direction about the rotation fulcrum  28  (within an angle range indicated by θ4 in  FIG.  4   ). 
     In the marine vessel steering mechanism  5 , when the steering wheel  10  is viewed from the marine vessel operator, the spoke portion  32  and the speed adjusting paddle  12  are located so as to overlap each other, and the spoke portion  33  and the speed adjusting paddle  11  are located so as to overlap each other. 
     When the marine vessel  1  is navigating, sometimes the marine vessel operator grips the wheel portion  30  while standing, at that time, since the marine vessel operator holds the wheel portion  30  from above, the marine vessel operator grips the upper half of the wheel portion  30 , particularly grips the vicinity where the wheel portion  30  intersects the spoke portions  32  and  33 . Therefore, since the marine vessel operator is able to operate the speed adjusting paddle  11  and the speed adjusting paddle  12  with his or her fingers without regripping the wheel portion  30 , the operability of the speed adjusting paddles  11  and  12  is improved. 
     In addition, the speed adjusting paddles  11  and  12  are attached to the column portion  27  so as to rotate in the same manner as the steering wheel  10  rotates. Therefore, even in the case that the steering wheel  10  rotates, when the steering wheel  10  is viewed from the marine vessel operator, the spoke portion  32  and the speed adjusting paddle  12  remain overlapped, and the spoke portion  33  and the speed adjusting paddle  11  remain overlapped. It should be noted that the speed adjusting paddles  11  and  12  may be fixed to the column portion  27  with respect to a rotational operation direction of the steering wheel  10  so that even in the case that the steering wheel  10  rotates, the speed adjusting paddles  11  and  12  do not rotate. 
     As described above, in the CAN  22 , the operation input to the speed adjusting paddle  11  and the operation input to the speed adjusting paddle  12  are transmitted as the digital signals to the remote control ECU  19  via the steering substrate of the marine vessel steering mechanism  5 . When the remote control ECU  19  receives a digital signal indicating that the speed adjusting paddle  11  has been operated, the remote control ECU  19  transmits a control signal to an ECU (not shown) of each outboard motor  3  to increase the rotation speed of the engine of each outboard motor  3  by a predetermined rotation speed, for example, about 50 rpm. In addition, when the remote control ECU  19  receives a digital signal indicating that the speed adjusting paddle  12  has been operated, the remote control ECU  19  transmits a control signal to the ECU of each outboard motor  3  to decrease the rotation speed of the engine of each outboard motor  3  by a predetermined rotation speed, for example, about 50 rpm. 
     In a preferred embodiment of the present invention, the number of times of operations of the speed adjusting paddles  11  and  12  that are able to change the vessel speed of the marine vessel  1  is limited, for example, the number of times of the operations of the speed adjusting paddles  11  and  12  is limited to 10 times. In this case, the marine vessel operator is able to increase or decrease the rotation speed of the engine by up to about 500 rpm by operating the speed adjusting paddles  11  and  12 . 
     Furthermore, when the vessel speed of the marine vessel  1  is high, since it is difficult to feel a change in the vessel speed even in the case that the vessel speed changes slightly, it is preferable that the width of the vessel speed that changes by one operation of the speed adjusting paddle  11  or the speed adjusting paddle  12  is large. On the other hand, when the vessel speed of the marine vessel  1  is low, since even a slight change in the vessel speed can be felt, it is preferable that the width of the vessel speed that changes by one operation of the speed adjusting paddle  11  or the speed adjusting paddle  12  is small. In response to this, in a preferred embodiment of the present invention, the rotation speed of the engine, which is changed by one operation of the speed adjusting paddle  11  or the speed adjusting paddle  12 , may be changed according to the vessel speed of the marine vessel  1 . For example, when the vessel speed of the marine vessel  1  is high, the rotation speed of the engine, which is changed by one operation of the speed adjusting paddle  11  or the speed adjusting paddle  12 , may be set to be larger than about 50 rpm, and when the vessel speed of the marine vessel  1  is low, the rotation speed of the engine, which is changed by one operation of the speed adjusting paddle  11  or the speed adjusting paddle  12 , may be set to be smaller than about 50 rpm. As a result, the marine vessel operator is able to naturally accelerate and decelerate the marine vessel  1  by operating the speed adjusting paddles  11  and  12 . 
     In a preferred embodiment of the present invention, although the remote control ECU  19  changes the rotation speed of the engine by the predetermined rotation speed according to the operation of the speed adjusting paddle  11  or the speed adjusting paddle  12 , the remote control ECU  19  may monitor the vessel speed of the marine vessel  1  based on the position information from the GPS  16 , and may control each outboard motor  3  so as to change the vessel speed of the marine vessel  1  by a predetermined amount according to the operation of the speed adjusting paddle  11  or the speed adjusting paddle  12 . Specifically, when the remote control ECU  19  receives the digital signal indicating that the speed adjusting paddle  11  has been operated, the remote control ECU  19  transmits the control signal to the ECU of each outboard motor  3 , and controls each outboard motor  3  so as to increase the vessel speed of the marine vessel  1  by the predetermined amount. Furthermore, when the remote control ECU  19  receives the digital signal indicating that the speed adjusting paddle  12  has been operated, the remote control ECU  19  transmits the control signal to the ECU of each outboard motor  3 , and controls each outboard motor  3  so as to decrease the vessel speed of the marine vessel  1  by the predetermined amount. Also in this case, a change amount of the vessel speed due to one operation of the speed adjusting paddle  11  or the speed adjusting paddle  12  may be changed according to the vessel speed of the marine vessel  1 . For example, when the vessel speed of the marine vessel  1  is high, the predetermined amount, which is the change amount of the vessel speed due to one operation of the speed adjusting paddle  11  or the speed adjusting paddle  12 , is set to be large, and when the vessel speed of the marine vessel  1  is low, the predetermined amount, which is the change amount of the vessel speed due to one operation of the speed adjusting paddle  11  or the speed adjusting paddle  12 , is set to be small. 
     Since the speed adjusting paddles  11  and  12  transmit the digital signals according to the operation inputs, by assigning arbitrary functions to these digital signals it is possible to change functions executed by the operations of the speed adjusting paddles  11  and  12 . For example, the function of changing the rotation speed of the engine by the predetermined rotation speed according to the operation of the speed adjusting paddle  11  may be changed to the function of changing the vessel speed of the marine vessel  1  by the predetermined amount according to the operation of the speed adjusting paddle  11 . This change is realized by the marine vessel operator using the MFD  9  to change an assignment of functions to the digital signals with respect to the operation inputs to the speed adjusting paddles  11  and  12 . 
     Also, like the speed control switch  82 , the speed adjusting paddles  11  and  12  function as switches to shift the marine vessel  1  to a constant speed navigation mode in which the marine vessel  1  continues to navigate at a constant speed. For example, in the case that the navigation mode of the marine vessel  1  is not the constant speed navigation mode, when the marine vessel operator operates the speed adjusting paddle  11  or the speed adjusting paddle  12  once, in response to this operation, the remote control ECU  19  shifts the marine vessel  1  to the constant speed navigation mode in which the vessel speed at that time is maintained. After the marine vessel  1  shifts to the constant speed navigation mode, when the operation of only the speed adjusting paddle  11  or the speed adjusting paddle  12  is newly accepted, in response to this newly accepted operation, the remote control ECU  19  accelerates or decelerates the marine vessel  1  as described above. Furthermore, in a preferred embodiment of the present invention, when the marine vessel operator simultaneously operates the speed adjusting paddle  11  and the speed adjusting paddle  12 , the remote control ECU  19  releases the constant speed navigation mode of the marine vessel  1 . 
     It should be noted that shifting to the constant speed navigation mode may be performed according to the operation of a speed control switch located on the lever  13  of the remote control switch  6 , and releasing of the constant speed navigation mode may be performed according to the operation of the lever  13  of the remote control switch  6  (movement of the lever  13  from its current position to another position). 
     According to a preferred embodiment of the present invention, although the speed adjusting paddle  11  to increase the vessel speed and the speed adjusting paddle  12  to decrease the vessel speed are located on the marine vessel steering mechanism  5 , the speed adjusting paddles  11  and  12  may be made larger than the speed control switch of the remote control switch  6 . In particular, in the marine vessel steering mechanism  5 , in the case that the speed adjusting paddles  11  and  12  are located within the range that the fingers of the marine vessel operator who is gripping the wheel portion  30  are able to reach, the marine vessel operator is able to operate the speed adjusting paddle  11  and the speed adjusting paddle  12  with his or her fingers without regripping the wheel portion  30 . As a result, the marine vessel operator is able to easily operate the speed adjusting paddles  11  and  12 , and it is possible to improve the operability of the speed adjusting paddles  11  and  12 . Furthermore, since the marine vessel operator is able to operate the speed adjusting paddles  11  and  12  without taking his/her hands off the wheel portion  30 , for example, in the case that the sea is rough with waves, since the marine vessel operator does not need to take his/her hands off the wheel portion  30  when adjusting the vessel speed of the marine vessel  1 , the marine vessel operator is able to maintain the course of the marine vessel  1  even in rough weather. 
     Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described preferred embodiments, and various modifications and changes can be made within the scope of the gist thereof. 
     For example, although when the speed adjusting paddle  11  is operated, the vessel speed of the marine vessel  1  increases, and when the speed adjusting paddle  12  is operated, the vessel speed of the marine vessel  1  decreases, the marine vessel maneuvering system may be configured so that when the speed adjusting paddle  11  is operated, the vessel speed of the marine vessel  1  decreases, and when the speed adjusting paddle  12  is operated, the vessel speed of the marine vessel  1  increases. 
     In addition, functions other than the function of adjusting the vessel speed of the marine vessel  1  may be assigned to the speed adjusting paddles  11  and  12 . For example, in the case that the marine vessel  1  navigates at an extremely low speed, a function of moving the marine vessel  1  forward at an extremely low speed during operation may be assigned to the speed adjusting paddle  11 , and a function of moving the marine vessel  1  backward at an extremely low speed during operation may be assigned to the speed adjusting paddle  12 . In this case, when the marine vessel  1  is not navigating at the extremely low speed, as described above, the function of adjusting the vessel speed of the marine vessel  1  is assigned to the speed adjusting paddles  11  and  12 . Settings of these functions are realized by the marine vessel operator using the MFD  9  to perform assignment of respective functions to the digital signals with respect to the operation inputs to the speed adjusting paddles  11  and  12 . 
     Furthermore, as shown in  FIG.  6   , instead of the wheel portion  30  that has the annular shape, the steering wheel  10  of the marine vessel steering mechanism  5  may be provided with handlebars  37  and  38 , which are located on the right and the left, respectively. In this case, when the steering wheel  10  is viewed from the marine vessel operator, the speed adjusting paddle  11  is located so as to overlap a spoke portion  39  that connects the handlebar  37  located on the starboard side and the central portion  29 , and the speed adjusting paddle  12  is located so as to overlap a spoke portion  40  that connects the handlebar  38  located on the port side and the central portion  29 . 
     Furthermore, although the marine vessel steering mechanism  5  includes the speed adjusting paddles  11  and  12 , instead of the speed adjusting paddles  11  and  12 , speed adjusting levers having the same functions may be located on the marine vessel steering mechanism  5 . As with the speed adjusting paddles  11  and  12 , when the steering wheel  10  is viewed from the marine vessel operator, the speed adjusting levers are also located so that the spoke portions  32  and  33 , and the speed adjusting levers overlap, respectively. 
     Furthermore, as shown in  FIG.  7   , instead of the speed adjusting paddles  11  and  12 , the marine vessel steering mechanism  5  may include a speed adjusting switch  35  (a speed increasing switch) that increases the vessel speed of the marine vessel  1  by operation thereof, and a speed adjusting switch  36  (a speed decreasing switch) that decreases the vessel speed of the marine vessel  1  by operation thereof. The speed adjusting switch  35  is located on the spoke portion  33 , and the speed adjusting switch  36  is located on the spoke portion  32 . It is preferable that both the speed adjusting switch  35  and the speed adjusting switch  36  are located within the range that the fingers of the marine vessel operator who is gripping the wheel portion  30 , for example, thumbs, are able to reach. 
     In the CAN  22 , an operation input to the speed adjusting switch  35  and an operation input to the speed adjusting switch  36  are transmitted as digital signals to the remote control ECU  19 . Upon receiving a digital signal indicating that the speed adjusting switch  35  has been operated, the remote control ECU  19  performs the same process as when receiving the digital signal indicating that the speed adjusting paddle  11  has been operated. Furthermore, upon receiving a digital signal indicating that the speed adjusting switch  36  has been operated, the remote control ECU  19  performs the same process as when receiving the digital signal indicating that the speed adjusting paddle  12  has been operated. 
     In addition, as with the operation inputs to the speed adjusting paddles  11  and  12 , the change amount of the rotation speed of the engine or the change amount of the vessel speed of the marine vessel  1  corresponding to the operation input to the speed adjusting switch  35  or the operation input to the speed adjusting switch  36  may be changed according to the vessel speed of the marine vessel  1 . 
     Furthermore, as with the speed adjusting paddles  11  and  12 , the speed adjusting switch  35  and the speed adjusting switch  36  may function as switches to shift the marine vessel  1  to the constant speed navigation mode. In this case, in the case that the navigation mode of the marine vessel  1  is not the constant speed navigation mode, when the marine vessel operator operates the speed adjusting switch  35  or the speed adjusting switch  36  once, the marine vessel  1  shifts to the constant speed navigation mode, and after the marine vessel  1  shifts to the constant speed navigation mode, when the marine vessel operator simultaneously operates the speed adjusting switch  35  and the speed adjusting switch  36 , the constant speed navigation mode of the marine vessel  1  is released. 
     As described above, in the case that the speed adjusting switch  35  and the speed adjusting switch  36  are located on the spoke portion  33  and the spoke portion  32 , respectively, the marine vessel operator gripping the wheel portion  30  is able to easily operate the speed adjusting switch  35  and the speed adjusting switch  36 , and it is possible to improve the operability of the speed adjusting switch  35  and the speed adjusting switch  36 . It should be noted that in order to prevent erroneous operations, the speed adjusting switch  35  and the speed adjusting switch  36  may be slightly recessed from the surface of the spoke portion  33  and the surface of the spoke portion  32 , respectively. 
     Although the marine vessel steering mechanism  5  according to preferred embodiment of the present invention is applied to the marine vessel  1  including the two outboard motors  3 , there is no limitation on the type of the marine vessel to which the marine vessel steering mechanism  5  is applied, and it may be applied to a marine vessel equipped with inboard/outboard motors or inboard motors. 
     While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.