Underwater Noise Study Completed for Washington State Ferries
A Massachusetts-based acoustical engineering consulting firm recently completed an underwater radiated noise study to quantify noise, potential impacts to orcas and other marine life, and methods of reducing noise for Washington State Ferries (WSF).
Noise Control Engineering (NCE), a subsidiary of naval architecture and marine engineering firm Glosten, said its study included measurement of nine vessels representing all seven operating classes of WSF vessels. The firm specializes in noise and vibration design, measurement and control for marine, industrial and commercial applications.
NCE utilized its Buoy Acoustic Measurement System (BAMSTM) to perform vessel noise measurements in general accordance with ANSI S12.64 while allowing the vessels to maintain their normal operating schedule. Simultaneously, vessel operational and environmental data was collected allowing for assessments of noise at varying propeller RPMs, operating powers and speeds.
The information was compiled into a database which was used to calculate ‘source levels’ and identify impacts to marine life using NMFS guidelines. The measurement data was also used to identify causes of noise ranging from propeller cavitation to specific machinery items. NCE’s decades of experience in quiet ship design was used to identify potential methods of reducing underwater noise.
“This work provides the information that WSF needs to take the next steps towards operational and engineered mitigation measures to reduce the impact of underwater radiated noise from our vessels on marine life, particularly the critically endangered Southern Resident Killer Whale,” said Kevin Bartoy, Environmental Stewardship & Sustainability Program Manager, Washington State Ferries.
“This was a great project for NCE. The opportunity to measure and assess noise across an entire fleet was fantastic, and could not be done without the direct engagement of WSF personnel. We are grateful to have been part of this effort,” said Jesse Spence, President of NCE.