Dutch navy ships are designed and built to have a low underwater signature. For low frequencies however, tonal vibrations of a gearbox can occur, which might lead to increased acoustic signatures. These vibrations are hard to reduce by passive means. To investigate the possibilities of active vibration control to reduce the underwater signature, a full scale experiment was performed with an active vibration control system on board of a navy ship. For this purpose six special, high efficiency, actuators were built and mounted on the gearbox. A MIMO adaptive feedforward control system was used to reduce the tonal vibrations of the gearbox which were excited by the diesel engine. Vibrations onboard and underwater acoustic pressures were used to monitor the performance of the system during full scale runs on the underwater acoustic range in Bergen, Norway. It can be concluded that the system is able to reduce the vibration and the acoustic signature significantly.
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