Underwater Noise from Ships – Causes and General Approaches to Noise Control

Awareness of underwater noise generated from shipping is rising due to environmental concerns in sensitive areas with protected animal species as well as for the world’s oceans as a whole. Individuals interested in underwater noise have attempted to better understand the problem by performing measurements of vessel noise either by direct measurement or by recording sound levels in different oceans over time. These efforts provide insights into noise levels produced by vessels as well as the noise levels produced by shipping in different locations. However, in order to reduce underwater noise the specific causes of noise must first be identified. Various generalities of primary noise sources and radiation mechanisms can be given for different ship types, though in order to actually reduce noise the structural and machinery details of each ship must be known and considered as part of an acoustical design (or re-design) effort. Specific noise control treatments can be optimized to different vessel designs using various computer-aided tools, though in order to make a significant impact on noise in the world’s oceans such efforts should be performed during the design of any new vessel.