China’s super-quiet submarine tech halves engine noise detection range: study

Researchers say they have developed a way to dampen the underwater vibrations that can be picked up by sonar systems

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Chinese scientists said that laboratory tests on a scaled-down prototype achieved a striking reduction in the engine noise that makes underwater submarines detectable by sonar systems. Photo: Shutterstock

Published: 6:00am, 27 May 2025Updated: 9:43am, 27 May 2025

A research team in Shanghai has unveiled a vibration-damping technology that could significantly improve the stealth of submarines during covert operations, according to a peer-reviewed study published in the Chinese journal Noise and Vibration Control.

Zhang Zhiyi and his team of researchers, from Shanghai Jiao Tong University’s State Key Laboratory of Mechanical Systems and Vibration, said their innovation could theoretically cut the detection range of hostile sonar systems by more than half.

The technology is intended to replace traditional rigid engine mounts with a hybrid active-passive vibration isolation system that would reduce the engine noise transmitted through submarine hulls by up to 26 decibels (dB), according to the paper.

It combined a steel-rubber-steel “sandwich” ring to dissipate vibrations, and an active layer with 12 piezoelectric actuators arranged radially around the engine to further reduce the noise, it said.

These electrically-powered actuators can neutralise the engine’s micron-level movements with strong control forces through precision lever mechanisms.

“Research indicates that a mere 10dB reduction in underwater vehicle noise can decrease its detectable range by 32 per cent,” according to the paper, published in April.

“During low-speed navigation, mechanical noise generated by power equipment operation constitutes the primary noise source for underwater vehicles, serving as their key acoustic signature for detection – typically manifested as a series of low-frequency tonal components,” the researchers said.