In October 2017, R/V TKK became China’s first scientific research vessel to obtain DNV GL’s SILENT class certificate (Silent R and Silent F, light search). DNV GL, headquartered in Oslo, Norway, is a recognized advisor for the maritime industry and also the first classification society to offer an underwater noise notation.

SILENT Underwater Noise Certificate Delivery Ceremony held in Shanghai

In the ocean, sound is synonymous with life. Since light can only penetrate very limited depth of the ocean surface, sound is the most critical tool that enables us to detect both physical and biological environment in the ocean. However, noise from increasing anthropogenic sources, such as cargo ships, sonar devices, and offshore operations, has become a type of acoustic pollution.

To address the marine noise-related issues, DNV GL issued the SILENT class notation in 2010, which is the first set of rules for underwater noise emission from vessels ever published. The voluntary class notation will ensure vessels with satisfactory realistic underwater noise emissions thereby increasing data quality and catch rates and reducing the environmental footprint.

To ensure the optimal performance of acoustic transducers for the acquisition of high-quality research data and mitigate the underwater radiated noise, R/V TKK is installed with a customized low-noise electric propulsion system, highly skewed fixed pitch propellers and thrusters. Damping techniques for noise and vibration control are also applied to the main equipment and cabins onboard. This is one of the several notable and science-specific design elements featured by the vessel.

Underwater noise measurements were conducted for R/V TKK by engineers from DNV GL

DNV GL awarded SILENT R and F (light search) to R/V TKK on October 23, 2017 in Shanghai after the underwater noise measurements were conducted onboard, verifying that the vessel meets the requirements of certification.

A copy of SILENT Underwater Noise Certificate