Former US Navy Submarine Officer explains why the periscope is raised when submarines dive

Nuclear Submarine Officer recalls when his submarine had to do an emergency deep dive after the periscope came up inside a cardboard box while the boat was coming to periscope depth

By Dario Leone
May 12 2023
Share this article

‘Apparently, the scope came up inside the box. Not so much a needle in a haystack, more like threading a needle in a haystack,’ John Hartzog, former US Navy Nuclear Submarine Officer.

The periscope is the eye of the submarine. It was invented and developed solely for the purpose of providing a means to view the surface without fear of detection by surface craft.

Have submarines coming to periscope depth ever hit something?

John Hartzog, former US Navy Nuclear Submarine Officer, recalls on Quora;

‘While on patrol in the central Mediterranean on a fast attack one day in the early 90s, we were coming to periscope depth to get a satellite fix, get our radio traffic, etc. It was one of those rare days, when the water is flat as a pond, and no one else was within 20 miles. Sunny, gorgeous summer day. We made routine preparations for coming to, including clearing baffles. Once we start driving the ship up, the periscope is raised, and the Officer of the Deck [OOD] trains the scope upward, and starts scanning the underside of the surface, looking for “shapes and shadows”, while continually announcing, “no shapes or shadows.”

‘Just as we approached the depth where the scope is breaking the surface, he yells, “emergency deep” … this gets everyone’s pucker factor up quickly, as it implies, we were about to co-occupy a volume with something else, i.e, hit it. Now, sonar had not heard anything, but passive sonar has its limitations. A sail boat on sail without an engine or generator running is pretty much impossible to hear, for instance. Emergency deep results in the control room crew immediately and automatically bringing the sub to a safe-from-being-hit depth… rapidly.’

Hartzog concludes;

‘So, we get to our safe depth (simply deep enough to pass under the deepest draft ship in existence, with some margin). The OOD explains that the scope went black dark just as it broke the surface. We again clear baffles. Nothing heard. So, we circle around where we previously attempted to come to up, and finally try again. When we get there, a cardboard box is floating upside down. Apparently, the scope came up inside the box. Not so much a needle in a haystack, more like threading a needle in a haystack.’

Former US Navy Submarine Officer explains why the periscope is raised when submarines dive
The Los Angeles Class Attack submarine USS Key West at periscope depth.

Photo credit: Photographer’s Mate 1st Class Kevin H. Tierney / U.S. Navy


Share this article

Dario Leone

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.
Share this article


Share this article
Back to top