Kongsberg Maritime’s rim-drive azimuth thruster has achieved Silent-E notation from DNV, believed to be the first of its kind to receive this certification.
Installed on a new Commissioning Service Operation Vessel (CSOV), Norwind Hurricane, and its sister vessels, the thruster demonstrated significant reduction of underwater noise pollution during a recent trial.
Underwater noise is seen as a growing concern for the marine ecosystem, impacting marine life and disrupting delicate underwater habitats. Kongsberg Maritime’s rim-drive thruster, said to be noted for its energy efficiency, has now proven its acoustic performance, which according to Kongsberg sets a new industry benchmark.
To assess the noise levels of the Norwind Hurricane, an extensive underwater noise study was conducted using hydrophones placed on the seabed. The results confirmed the effectiveness of the rim-drive thruster in reducing underwater noise.
Roy Ove Standal, COO Norwind Offshore, said: “The rim-drive propulsion system stands out for its ability to reduce the need for additional support systems, leading to notable energy savings. It also contributes to increased onboard comfort due to its lower noise levels. Achieving the Silent-E notation further demonstrates our commitment to protecting the marine environment.”
Leif Vartdal, hydrodynamics specialist, Kongsberg Maritime, explained: “Rim-drive thrusters are inherently quieter than conventional thrusters due to their simpler design with fewer moving parts and excellent hydrodynamic characteristics. The Silent-E notation underscores Kongsberg Maritime’s dedication to developing environmentally friendly solutions and this achievement marks a significant step towards a quieter and more sustainable future for the offshore industry. Hydrodynamically induced noise, primarily caused by tip vortex cavitation from propeller blade tips, is a major challenge in traditional thruster designs. Rim-drive thrusters eliminate this issue by using a ring propeller that lacks blade tips, thereby significantly reducing noise generation.”
The benefits of rim-drive technology are said to extend beyond noise reduction. The thrusters offer energy savings and reduced maintenance costs due to the simplified propulsion system with fewer mechanical components. This translates to enhanced operational efficiency and a lower total cost of ownership, aligning with Kongsberg Maritime’s commitment to providing sustainable and cost-effective solutions for the maritime industry.
Image: ‘Norwind Hurricane’ (source: Kongsberg Maritime)
