Control of Ship Radiated Underwater Noise

As human activity in the oceans has grown and scientific understanding of underwater noise has increased, it has been generally accepted that the growth of anthropogenic noise in the ocean has acute, chronic, and cumulative impacts on marine species, most notably marine mammals who depend on sound for foraging, breeding, predator avoidance, navigation, maintaining social bonds, and environmental awareness /1/. Since it was noted that continuous anthropogenic noise in the ocean was primarily generated by shipping /3/, ship radiated underwater noise has gained increased attention. Further, there are certain ship types which require low underwater noise for its function, such as research vessel, seismic vessel and fishing vessel. DNV GL has been working on noise and vibration criteria definition, noise and vibration control, and measurement for shipping industry. DNV GL SILENT criteria, which are the first set for ship's underwater noise, are presented in this paper. To reduce the underwater radiated noise from ship, a thorough process will be needed to cover front-end design, detailed design, construction and verification. The DNV GL Noise and Vibration Control Program, which is developed based on DNV GL's 50 years' experiences in the field, is presented in this paper.