Naval Warfare

US Navy submariner recalls when while his boat was on silent running engineering watchstanders had to bang wrenches on metal for half an hour before other subs and ships could find it during drills

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.

Slamming hatches and banging wrenches on metal

‘As a US Navy nuke, we loved rig for ultra-quiet,’ Michael Denney, former US Navy submariner, says on Quora.

‘A normal nuke day is 6 hours standing watch, 6 hours maybe off, theoretically 6 hours in the rack, and repeat. If any maintenance was due, it happened during the 6 hours ‘off’. Any ship wide evolutions (drills or all hands clean up) could come during your rack time. During ultra-quiet, if you weren’t on watch it was sweet, sweet bunky time.

‘I’ll leave it to the sonar techs to say how much they could hear, but at the end of every war game with other subs and ships, if it was time for the other guys to find us, the engineering watchstanders would roam around slamming hatches and banging wrenches on metal.’

Denney concludes;

‘They’d usually find us after a half hour of this, but certainly didn’t inspire us to tiptoe on a regular basis.’

Virginia class submarine

Photo credit: U.S. Navy

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.

View Comments

  • I served on the USS Briscoe DD977. I was pleasantly surprised to see the picture of my ship.

  • I was a sonar tech on USS Nicholson DD-982. The 963 class ships main mission was ASW and we did plenty of it. The 973 class ship were a great platform for paving the way for our latest generation of Sonar systems.

Recent Posts

The story of why the German Air Force and German Navy dubbed the F-104 Starfighter “Widow Maker”

The F-104 Starfighter Designed as a supersonic superiority fighter, the F-104 Starfighter was produced in… Read More

1 hour ago

Video shows C-130 Hercules “Buddy Start” (engine start utilising the propeller blast of another aircraft to effect engine starting)

The C-130 Hercules The C-130 Hercules primarily performs the tactical portion of the airlift mission.… Read More

1 hour ago

Legendary F-14 pilot Joe “Hoser” Satrapa tells the story of the gun kill on an F-15 that almost sold Tomcats to Japan

Joe “Hoser” Satrapa No dissertation on present-day section tactics, or on naval aviation in general,… Read More

1 day ago

Marine Infantry Rifleman tells why (except the VH-60 White Hawks flown by HMX-1) the USMC doesn’t use the Black Hawk Multirole Helicopter

The Black Hawk Multirole Helicopter The Black Hawk is the military's most versatile helicopter, suited… Read More

1 day ago

USAF reveals AGM-183A ARRW with live warhead in Guam during hypersonic weapon training

AGM-183A ARRW with live warhead in Guam Andersen Air Force Base (AFB) on Feb. 27,… Read More

2 days ago

Operation Tamouré: the only time a French Air Force Mirage IV strategic bomber dropped a live nuclear bomb

The Mirage IV The Suez crisis in October 1956 prompted France to look into setting… Read More

2 days ago