Abstract: A gyrostabiliser assembly for a marine vessel comprising: a housing defining a chamber for supporting at least a partial vacuum; a flywheel mounted within the chamber for rotation about a spin axis at the partial vacuum; a flywheel shaft upon which the flywheel is supported and mounted in the housing for rotation of the flywheel about the spin axis, the flywheel shaft being rotatably supported by a first spin bearing located at one end region of the shaft and a second spin bearing located at an opposite end region of the shaft; and a lubrication system configured to circulate lubricant to the spin bearings from a lubricant reservoir. The reservoir is arranged in or on the housing to collect lubricant from the spin bearings under gravity and the first and second spin bearings are arranged in the housing for operation under the partial vacuum.

Abstract: A vessel stabilizer control system (12) includes a sensor fault detection means (16) which senses the availability of sensing signals from a gyrostabilizer precession motion sensor (10) and a vessel roll motion sensor (14). The control system (12) controls the action of a gyro-actuator (8) which is mechanically coupled to a gyrostabilizer (4). The benefit of employing fault sensing of the sensors providing the process control variables is that the sensed number of available process control variables (or sensors) can be used to activate a tiered system of control modes. Each tiered control mode is designed to utilize the available process control variables to ensure safe and effective operation of the gyrostabilizer (4) that is tolerant of sensor faults and loss of power supply. A control mode selector (18) is provided for selecting the appropriate control mode based on the number of available process control variables.

Abstract: A gyrostabilizer control system and method for stabilizing marine vessel motion based on precession information only. The control system employs an Automatic Gain Control (AGC) precession controller (60). This system operates with a gain factor that is always being gradually minimized so as to let the gyro flywheel (12) develop as much precession as possible—the higher the precession, the higher the roll stabilizing moment. This continuous gain change provides adaptation to changes in sea state and sailing conditions. The system effectively predicts the likelihood of maximum precession being reached. Should this event be detected, then the gain is rapidly increased so as to provide a breaking precession torque. Once the event has passed, the system again attempts to gradually decrease the gain.

Abstract: A gyrostabiliser control system and method for stabilising marine vessel motion based on precession information only. The control system employs an Automatic Gain Control (AGC) precession controller (60). This system operates with a gain factor that is always being gradually minimized so as to let the gyro flywheel (12) develop as much precession as possible—the higher the precession, the higher the roll stabilising moment. This continuous gain change provides adaptation to changes in sea state and sailing conditions. The system effectively predicts the likelihood of maximum precession being reached. Should this event be detected, then the gain is rapidly increased so as to provide a breaking precession torque. Once the event has passed, the system again attempts to gradually decrease the gain.

Abstract: A vessel stabiliser control system (12) includes a sensor fault detection means (16) which senses the availability of sensing signals from a gyrostabiliser precession motion sensor (10) and a vessel roll motion sensor (14). The control system (12) controls the action of a gyro-actuator (8) which is mechanically coupled to a gyrostabiliser (4). The benefit of employing fault sensing of the sensors providing the process control variables is that the sensed number of available process control variables (or sensors) can be used to activate a tiered system of control modes. Each tiered control mode is designed to utilise the available process control variables to ensure safe and effective operation of the gyrostabiliser (4) that is tolerant of sensor faults and loss of power supply. A control mode selector (18) is provided for selecting the appropriate control mode based on the number of available process control variables.