Ship control system

Claim 1

A MARINE VESSEL POSITIONING SYSTEM COMPRISING: AT LEAST TWO PROPULSION MEANS LOCATED ON SAID VESSEL AT SEPARATE POSITIONS SPACED FROM THE CENTER OF ROTATION OF SAID VESSEL, FIRST CONTROL MEANS COUPLED TO EACH OF SAID SEPARATE PROPULSION UNITS FOR DIRECTING THE THRUST EFFECT OF SAID PROPULSION UNITS IN A HORIZONTAL PLANE, SECOND CONTROL MEANS COUPLED TO EACH OF SAID SEPARATE PROPULSION UNITS TO VARY THE THRUST EFFECT OF SAID PROPULSION UNITS; LOCATION MEANS DISPOSED ON THE VESSEL FOR DETERMINING ITS ACTUAL LOCATION AND HEADING RELATIVE TO ITS DESIRED LOCATION AND HEADING; A THIRD CONTROL MEANS COUPLED TO SAID LOCATING MEANS TO DETERMINE THE DIFFERENCE BETWEEN THE ACTUAL LOCATION AND HEADING OF THE VESSEL AND THE DESIRED LOCATION AND HEATING OF THE VESSEL MEANS GENERATING CONTROL SIGNALS RELATED TO SAID DIFFERENCE; ACTUATING MEANS COUPLED TO SAID THIRD CONTROL MEANS TO ACTUATE SAID FIRST AND SECOND CONTROL MEANS FOR POSITIONING SAID FIRST AND SECOND CONTROL MEANS IN RESPONSE TO THE CONTROL SIGNALS.