High maneuverability steering system for work boats and other watercraft

Abstract

A combined Kort nozzle and rudder steering system for vessels requiring a high degree of maneuverability. A Kort nozzle is mounted around the propeller to direct the wash to generate a first turning source, and a rudder is mounted behind the Kort nozzle to react with the wash exiting the nozzle to produce a second turning force. The nozzle and rudder are pivoted in the same directions simultaneously, but with the rudder being pivoted at a faster rate than the nozzle. The nozzle is pivoted to an optimal maximum angle relative to the wash generated by the propeller and the rudder is pivoted to an optimal maximum angle to the wash exiting the nozzle.

What is claimed is: 
     
         1 . A steering apparatus for a water-borne vessel, said steering apparatus comprising:
 a steerable Kort nozzle mounted above a propeller that directs wash from the propeller to generate a first turning force;   a propeller mounted behind said Kort nozzle that reacts with said wash of said propeller exiting said Kort nozzle to produce a second steering force; and   a mechanism that pivots said Kort nozzle and said rudder in the same direction simultaneously, with said rudder pivoting at an angle greater than said Kort nozzle;   to a predetermined optimal maximum angle of said Kort nozzle to said wash generated by said propeller and a predetermined optimal maximum angle of said rudder to said wash exiting said Kort nozzle.   
     
     
         2 . The steering apparatus of  claim 1 , wherein said predetermined optimal maximum angle of said Kort nozzle to said propeller is about 35°, and said predetermined optimal effective angle of said rudder to said discharge of said Kort nozzle is about 25° and therefore about 60° to said propeller. 
     
     
         3 . The steering apparatus of  claim 2 , wherein said mechanism that pivots said Kort nozzle and said rudder comprises:
 a linkage that interconnects said Kort nozzle and said rudder, said linkage having a geometry selected to pivot said rudder at a predetermined angular rate greater than said Kort nozzle so that said rudder and said Kort nozzle arrive substantially simultaneously at said predetermined optimal maximum angles.   
     
     
         4 . The steering apparatus of  claim 3 , wherein said linkage that interconnects said Kort nozzle and said rudder comprises:
 a first tiller member mounted to a vertical pivot shaft of said Kort nozzle;   a second tiller member mounted to a vertical pivot shaft of said rudder;   said first and second tiller member each having connection portions extending laterally of said pivot shafts;   first and second linkage rods mounted to said connection portions of said tiller members on opposite sides of said pivot posts;   forward ends of said linkage rods being mounted to said connection portions of said nozzle tiller member at pivot connections spaced relatively farther from said pivot post of said Kort nozzle, and rearward ends of said linkage rods being mounted to said connection portions of said rudder pivot post at pivot connections spaced relatively closer to said rudder pivot post;   so that in response to rotation of said Kort nozzle post by said Kort nozzle tiller said rudder pivot post is rotated at a greater angular rate by said rudder tiller.   
     
     
         5 . The steering apparatus of  claim 4 , wherein said Kort nozzle tiller comprises:
 an extension portion having an end of a steering ram mounted thereto, so that said Kort nozzle tiller and said rudder tiller rotate in a first direction in response to extension of said steering ram, and rotate in an opposite direction in response to retraction of said steering ram.   
     
     
         6 . The steering apparatus of  claim 2 , wherein said mechanism that pivots said Kort nozzle and said rudder comprises:
 a flexible power transmission interconnecting said Kort nozzle and said rudder, said flexible power transmission having a ratio selected to pivot said rudder at a predetermined angular rate greater than said Kort nozzle so that said rudder and said Kort nozzle arrive substantially simultaneously at said predetermined optimal maximum angles.   
     
     
         7 . The steering apparatus of  claim 6 , wherein said flexible power transmission that interconnects said Kort nozzle and said rudder comprises:
 a pulley and cable mechanism.   
     
     
         8 . The steering apparatus of  claim 6 , wherein said flexible power transmission that interconnects said Kort nozzle and said rudder comprises:
 a sprocket and chain mechanism.   
     
     
         9 . The steering apparatus of  claim 2 , wherein said mechanism that pivots said Kort nozzle and said rudder comprises:
 a gear train interconnecting said Kort nozzle and said rudder, said gear train having a ratio selected to pivot said rudder at a predetermined angular rate greater than said Kort nozzle so that said rudder and said Kort nozzle arrive substantially simultaneously at said predetermined optimal maximum angles.   
     
     
         10 . A steering apparatus for pivoting a steerable Kort nozzle mounted about a propeller that directs wash from the propeller to generate a first turning force in conjunction with a rudder mounted behind said Kort nozzle that reacts with said wash exiting said Kort nozzle to produce a second turning force, said apparatus comprising:
 a mechanism that pivots said Kort nozzle and said rudder in a same direction simultaneously and with said rudder pivoting at an angular rate greater than said Kort nozzle;   a predetermined optimal maximum angle of said Kort nozzle to said wash generated by said propeller and a predetermined optimal maximum angle of said rudder to said wash exiting said Kort nozzle.   
     
     
         11 . The steering apparatus of  claim 10 , wherein said predetermined optimal maximum angle of said Kort nozzle to said wash generated by said propeller is about 35°, and said predetermined optimal maximum effective angle of said rudder to said wash exiting said Kort nozzle may be about 25° and therefore about 60° to said propeller. 
     
     
         12 . The steering apparatus of  claim 10 , wherein said mechanism that pivots said Kort nozzle and said rudder simultaneously may comprise a linkage that interconnects said Kort nozzle and said rudder, said linkage having a geometry selected to pivot said rudder at a predetermined angular rate greater than said rudder so that said rudder and said Kort nozzle arrive simultaneously at said predetermined optimal maximal angles. 
     
     
         13 . A method for steering a water borne vessel having a steerable Kort nozzle mounted about a propeller that directs wash from said propeller with said wash exiting said Kort nozzle to produce a second turning force, said method comprising the steps of:
 pivoting said Kort nozzle in a first direction at said first rate in response to a helm input;   pivoting said rudder in said first direction at a second, greater rate in response to said helm input;   to a predetermined optimal angle of said Kort nozzle to said wash generated by the propeller and a predetermined optimal maximum angle of said rudder to said wash exiting said Kort nozzle.   
     
     
         14 . A method for pivoting a steerable Kort nozzle mounted about propeller that directs wash from the propeller to generate a first turning force in conjunction with a rudder mounted behind said Kort nozzle that reacts with said wash exiting said Kort nozzle to produce a second turning force, said method comprising the steps of:
 pivoting said Kort nozzle in a first direction at a first rate in response to a helm input; and   pivoting said rudder in said first direction at a second, greater rate in response to said helm input;   to a predetermined optimal angle of said Kort nozzle to said wash generated by the propeller and a predetermined optimal maximum angle of said rudder to the wash exiting said Kort nozzle.