Page 27: of Maritime Reporter Magazine (December 2023)

UNDERWATER NOISE

ABB’s DynaFin propulsor will be designd to allow for the use of optimized

ABB trajectories to reduce propeller noise.

There are many technologies available to reduce URN, some of which may also reduce fuel consumption. However, Spence says it’s not just a case of picking out a technology from a shopping list. Vessel designers are in the best position to identify the design features that will work for a given vessel. Some noise control technolo- gies are only effective if the vessel suffers from a particular symptom. For example, applying a technology that would reduce propeller hub cavitation to a vessel that does not have hub cavitation would not improve URN.

Moreover, there are fundamental design decisions that will have a greater impact noise and ef? ciency, such as the shape of the hull form. This will determine the ? ow into the propeller, and ultimately determines what an optimized propeller design will look like. These are factors that need to be decided by the specialists that are working on the vessel design.

There’s a process for ensuring the right decisions are made to control URN along- side other related non-acoustic factors: include an underwater noise limit in the ves- sel speci? cation. This simple act will enable engineers, naval architects and acous- tic specialists to be involved in the design process, working together to develop an effective design. He cautions: “Without having some sort of line in the sand for engineers to design towards, you’re going to make design decisions that are likely to adversely impact URN.” www.marinelink.com 27

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