Naval Warfare

Sonar Technician explains why talking normally while aboard a US Navy Submarine on silent running can compromise the boat’s stealthiness

Submarine on Silent Running

Silent running (or ultra-quiet) is a stealth mode of operation for submarines.

During silent running, the propellers have a characteristic RPM band in which no cavitation noise arises. Since this rotation speed is usually relatively low, the first electric submarines had special “silent running” engines designed for optimum performance at reduced speed.

Nuclear submarines can run even more quietly, at very low speeds only, by turning off active reactor cooling during silent running. The reactor is then only cooled by natural convection of the water.

The aim of silent running (a protocol that has been in use since the latter part of World War I, when hydrophones were invented to detect U-boats) is to evade discovery by passive sonar by eliminating superfluous noise: nonessential systems are shut down, as explained above speed is greatly reduced to minimize propeller noise and the crew is urged to rest and refrain from making any unnecessary sound.

As already explained (CLICK HERE to read the article) ‘Being “quiet” is more than not talking.

This article was edited because because it contained sensitive information.

The Los Angeles-class fast attack submarine USS Toledo (SSN 769) transits through the Arabian Gulf.

Stay tuned for additional updates if further details on this story had to come to light!

Photo credit: Mass Communication Specialist 2nd Class Jonathan W. Hutto, Sr. / U.S. Navy

Sailors share a moment before getting underway aboard the Virginia-class attack submarine USS Virginia (SSN 774). Submariners are a small community with the average command about 135 Sailors.
Dario Leone

Dario Leone is an aviation, defense and military writer. He is the Founder and Editor of “The Aviation Geek Club” one of the world’s most read military aviation blogs. His writing has appeared in The National Interest and other news media. He has reported from Europe and flown Super Puma and Cougar helicopters with the Swiss Air Force.

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  • The USN nuclear submarine force was once "defeated" in a war game by some other nations diesel electric subs operating in battery only mode. There's USN silent and then there's battery silent.

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