Noise and vibration

Use of OPS will also reduce noise and vibration from ships, benefiting not only crew members on board but also dockside workers and in some cases nearby residents, too.

Ship noise and vibration can originate from a variety of sources, including auxiliary engine exhausts, engine room and hold ventilation systems and container ship reefers. On the largest category of vessels an average sound power level of 110 dB(A) is found.

Implementation of OPS will only eliminate the noise and vibration from the auxiliary engines and it is worth investigating whether (part of) the engine room ventilation can be shut down. Whatever the case, OPS will only reduce some of the noise from ships at berth.

Estimated noise reduction
Based on measurements on several container ships berthed in Amsterdam, the noise from ventilation units equals or even exceeds that from the auxiliary engine exhaust pipe. In these cases, using OPS and shutting down the auxiliary engine will reduce total vessel noise emissions by around 3 dB. If the exhaust pipe is the ships’ predominant noise source, better results will be achieved. The more onboard noise sources that can be shut down or reduced, the greater the reduction that can be achieved, with reductions in the engine room being greatest.