Patent ID: 9522723
Filing Date: 2016-12-20
CPC Classification: B63H

Claim Text:
1. A method for controlling movement of drive units on a marine vessel, the marine vessel having a hull with a horizontally extending longitudinal axis and each drive unit having a respective vertically extending steering axis, the method being carried out by a control circuit and comprising: receiving an operator request for a desired steering angle; setting a steering angle of a first drive unit equal to the desired steering angle; determining a midpoint of a wetted surface area of the hull; defining a pivot line extending laterally through the midpoint and perpendicular to the longitudinal axis; determining a first intersection point of the pivot line and a line extending horizontally through the first drive unit's steering axis and parallel to the longitudinal axis; determining a second intersection point of the pivot line and a line representing perpendicular application of hydrodynamic force on the first drive unit; setting a steering angle of a second drive unit such that a line representing perpendicular application of hydrodynamic force on the second drive unit intersects the pivot line at the second intersection point; and sending control signals to actuate the first and second drive units to their respective steering angles.