2025_programme: The impact of electric propulsion systems on underwater radiated noise from small vessels

• Day: June 19, Thursday
    Location / Time: A. TERPSIHORI at 17:40-18:00
• Last minutes changes: -
• Session: 27. Radiated noise from Ships and Surface Platforms
  Organiser(s): N/A
  Chairperson(s): Andreas Grech La Rosa
• Lecture: The impact of electric propulsion systems on underwater radiated noise from small vessels
  Paper ID: 2121
  Author(s): Andrea Grech La Rosa, Tom Smith, Peng Wu
  Presenter: Andrea Grech La Rosa
  Abstract: Electric propulsion systems are becoming more widespread on marine vessels, from small vessels with electric outboards to ferries. There is considerable interest in understanding the acoustical impact of such systems, particularly if it can be shown that they can lead to meaningful reductions in URN. It is sometimes assumed that electric propulsion systems will be quieter than their combustion counterparts. However, there is only limited data on their overall impact on URN available at present and this paints a complex picture. For example, if propeller noise and cavitation dominate, changes to the machinery noise will have a minimal effect. \nOn smaller vessels, research has shown that engine noise due to combustion processes can dominate over a larger speed range. Electric propulsion may therefore be of greater benefit here than for large ships. Combustion outboard engines also typically expel their exhaust gases through the propeller hub, which is a significant source of low-frequency broadband noise. However, depending on the power electronics and propulsion architecture, electric motors can produce high amplitude high-frequency tonal noise which can be very detrimental to many marine mammals. \nIn this work, the impact of marine electrification on underwater radiated noise is discussed for small craft. Trials data are presented for two vessels: one powered by a conventional outboard engine and the other by an electric motor. The electric vessel is found to be significantly quieter, with a broadband reduction of 29 dB re 1μPa m. Compared to the conventional outboard, this is due to a lack of combustion noise and no exhaust gases. Crucially, the motor does not radiate high frequency tonal noise into the water. \nThis work demonstrates that electric propulsion systems can be significantly quieter but that care must be taken to ensure that high-frequency noise from the motor does not radiate into the water. \n
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  This paper is a candidate for the "Prof. John Papadakis award for the best paper presented by a young acoustician(under 40)"
• Corresponding author: Dr Andrea Grech La Rosa
  Affiliation: University College London
  Country: United Kingdom