Decarbonization Co-Benefits

June 23, 2026

An update on underwater radiated noise research at Robert Allan Ltd.

Giorgio Burella, P.Eng., Ph.D. | Project Manager | Naval Architect | Noise & Vibration

In 2024, HaiSea Wamis, a battery-electric tug from the Robert Allan Ltd-designed and Sanmar-built ElectRA 2800 series, received a low underwater radiation noise notation from the American Bureau of Shipping (ABS UWN). Wamis is the first tug in the world to receive such a notation certifying superior performance for low underwater radiated noise (URN) emissions.

The ABS UWN notation was obtained after an extensive sea trials campaign spearheaded by Robert Allan Ltd. to systematically measure underwater radiated noise signatures in an effort to better understand the noise generation and transmission from onboard sources to underwater noise. In the summer of 2023 Robert Allan Ltd. conducted sea trials to collect URN data on three vessels, including two traditional diesel-mechanical azimuthing stern drive tugs and the Wamis. Simultaneously, our trials team collected noise and vibration data onboard. The URN measurement campaign was supported by the Quiet Vessel Initiative (QVI) program from Transport Canada’s Innovation Centre.

The measurements from the sea trials show that the Wamis is so quiet that it would take 10x similar battery electric tugs running side-by-side to produce the same underwater noise as a single conventional diesel tug.

Robert Allan Ltd. has been leveraging the data collected from the trials to continue the development of predicting models to guide the reduction of URN from our designs to the benefit of marine fauna worldwide. In recent months, our engineers have been busy developing high-fidelity Finite Element and Statistical Energy Analysis (FEA/SEA) models to predict the machinery noise contributions to URN. Being able to make these predictions is a fundamental step in including URN reduction considerations in our present and future designs. Stay tuned for future updates as our team works hard to develop the quiet tugs of the future!