A boat includes a planing hull, a propeller, a main rudder, and a pair of flanking rudders. The planing hull has port and starboard sides, a transom, a hull bottom, and a centerline running down the middle of the boat, halfway between the port and starboard sides. The propeller is positioned forward of the transom and beneath the hull bottom. The main rudder is positioned aft of the propeller. The main rudder has a rotation axis about which the main rudder rotates. The flanking rudders are positioned forward of the propeller. One of the flanking rudders is positioned on the port side of the centerline, and the other flanking rudder is positioned on the starboard side of the centerline.

A steering system for a marine vessel comprises a helm, a control head, and a joystick. The helm and control head may respectively provide user inputted steering commands and user inputted shift and throttle commands on a first CAN network. The joystick and the control head may respectively provide user inputted steering commands and user inputted shift and throttle commands on a second CAN network. The helm may provide user inputted steering commands on the first CAN network. The control head may provide user inputted shift and throttle commands on the second CAN network. The joystick may provide user inputted steering commands and user inputted shift and throttle commands on either the first CAN network or the second CAN network.

A boat includes a planing hull, a propeller, a main rudder, and a pair of flanking rudders. The planing hull has port and starboard sides, a transom, a hull bottom, and a centerline running down the middle of the boat, halfway between the port and starboard sides. The propeller is positioned forward of the transom and beneath the hull bottom. The main rudder is positioned aft of the propeller. The main rudder has a rotation axis about which the main rudder rotates. The flanking rudders are positioned forward of the propeller. One of the flanking rudders is positioned on the port side of the centerline, and the other flanking rudder is positioned on the starboard side of the centerline.

A steering device in which a rudder plate is vertically suspended at a positive minimum distance from an outer edge of a propeller having a radius R from a steering shaft which is biaxially arranged and symmetrically rotates around a screw shaft within a propeller radius R from a screw shaft center, on a propeller rotation plane, and can be turned from aside of a propeller to a downstream of the propeller by rotation of the steering shafts, each of which is driven independently by two hydraulic driving mechanisms, and the steering device is characterized in that the steering action is divided into two modes: the two-independent mode and the two-same direction modes, and each mode is adapted as follows: at the time of ahead condition, each one of the two rudder plates is retained on both sides of a propeller parallel with a ship axis, and at the time of veering of the two-same direction mode, a rudder plate opposite to a veering direction turns 45 from aside of the propeller to the downstream of the propeller, and the other rudder plate turns 45 from aside of the propeller to the upstream of the propeller, and at the time of veering of the two-independent mode, the rudder plate opposite to a veering direction turns 45 from aside of the propeller to the downstream of the propeller, and simultaneously, the other rudder plate turns from aside of the propeller to the upstream of the propeller to take a rudder angle of 90 or more, to generate a thrust flow, and a method for steering the same to enhance a thrust flow by increase in a propeller rate.

A hull motion control unit performs steering for a pinwheeling swing such that a bow distance and a stern distance that are measured by a quay separation distance measuring device are made equal to each other and the fore-and-aft direction of a ship is parallel to a target quay, and then the ship is caused to laterally approach and dock in the target quay while keeping the parallel state.

Provided is a rudder assembly producing significant thrust to reduce energy consumption of vessels during voyage. The rudder assembly is formed of first/second rudder units arranged on both sides of first/second propellers. As seen from rear, each first/second rudder unit is formed of left/right rudders arranged on the left/right of the first/second propeller. Each left/right rudder of the first/second rudder units is formed of a first left/right rudder portion extending in the right-left direction, a second left/right rudder portion curved from the left/right end of the first left/right rudder portion toward lower left/right, and a third left/right rudder portion extending downwards from the lower end of the second left/right rudder portion. The first left/right rudder portions of the first/second rudder unit are arranged spaced upwardly apart from the upper edge of the tip circle of the first/second propeller for a distance of 10-20% of the diameter of the first/second propeller.

To provide a gate rudder capable of reducing energy consumption during a voyage of a ship. A gate rudder including a pair of rudders including a left rudder and a right rudder disposed left and right, respectively, of a propeller at a stern, wherein each of the rudders includes a first rudder portion extending in a horizontal direction and a second rudder portion linearly extending in a vertical direction in rear view, wherein a rudder chord length of the second rudder portion in a front-rear direction is 40 to 100% of a diameter of the propeller, wherein the propeller is provided within a range of 15 to 65% of the rudder chord length from a front edge of the second rudder portion in side view, and wherein a rudder shaft that drives each of the rudders is provided at a position within a range of 30 to 50% of the rudder chord length from the front edge of the second rudder portion in side view.

A steering system for a marine vessel, the steering system comprises a first steering apparatus having a first steering actuator for steering the first steering apparatus and a second steering apparatus having a second steering actuator for steering the second steering apparatus. There is a mechanical steering linkage operatively connecting the first steering apparatus to the second steering apparatus so the steering apparatuses are steered synchronously. A user input device provides user inputted steering commands. A control apparatus operatively connects to the actuators and to the user input device. The control apparatus controls the steering of the steering apparatuses so both of the steering apparatuses are simultaneously steered the same amount.