BC Ferries Case Study: Lessons Learned in Setting Underwater Radiated Noise Targets
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Photo by Daniella K.
As described in a recent article in MarineLink, BC Ferries has some key findings to pass along to other vessel operators considering the implementation of underwater radiated noise targets. Important lessons were learned during investigations of how they might reduce the noise from their passenger ferries transiting the Salish Sea, which is home to the endangered southern resident killer whales (SRKWs).
In 2015, the Vancouver Fraser Port Authority’s Enhancing Cetacean Habitat and Observation (ECHO) program, with equipment and data analysis support from JASCO Applied Sciences, began monitoring underwater noise from commercial vessel traffic in the Strait of Georgia using a cabled listening station installed beneath the international shipping lanes. JASCO’s results showed that the highest noise levels were strongly correlated with BC Ferries’ operating schedule between Vancouver and Nanaimo, a busy route spanning some 70 km of open water between the Canadian mainland and Vancouver Island.
Sound pressure levels (SPL) measured in the Strait of Georgia during a typical day.
Between 2015 and 2017, BC Ferries tasked JASCO with performing dedicated vessel sound levels measurements to supplement the monitoring afforded by the listening station. These measurements would be at the core of the formulation by BC Ferries of underwater radiated noise (URN) performance requirements in the specifications for a major vessel procurement intended to replace its existing C-Class ferries.
The MarineLink article documents BC Ferries’ endeavours in setting targets for underwater radiated noise particularly in the frequency ranges used by SRKWs, modelling propeller designs to reduce their noise signatures (rather than solely optimizing them for performance, as is typical) and working with vessel designers to reduce the overall radiated noise. These efforts have yielded key lessons for other vessel operators considering a similar task, from conducting baseline noise measurements to engaging underwater radiated noise experts to assess design impacts and conduct trade-off analyses.
Simulation modelling of propeller cavitation.
“JASCO is pleased to have supported BC Ferries and the ECHO program by performing the high-resolution ship underwater radiated noise level measurements for this study. We’re excited that our results are enabling reductions in noise emissions of future vessels, especially for vessels destined for the Salish Sea which is an important habitat for SRKWs. ”
In 2020 JASCO, supported by Transport Canada and the Vancouver Fraser Port Authority, installed the successor to the Strait of Georgia listening station: the Boundary Pass Underwater Listening Station. The combined database of acoustic profiles collected over time from these two listening stations now contains more than 20,000 individual measurements of ferries and large commercial vessels including bulk carriers, tankers and container ships, with approximately 20 new measurements added each day.
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Boundary Pass Underwater Listening Station
JASCO Projects | 2020–2023
JASCO’s world-class listening station for Transport Canada. Detects and tracks endangered whales. Catalogs underwater noise emissions of thousands of commercial vessels.
OceanObserver Underwater Listening Stations
JASCO Products | Based on the OceanObserver
Cabled observatory solutions for real-time ocean monitoring.
