Gun turret’s origin a mystery, but it solved nuclear test problem


This story originally aired on KLAS-TV in Las Vegas on August 3, 2017.

MYSTERY WIRE — The code name was Operation Plumbbob. Atomic fireballs shredded the sky almost weekly. The security of the planet hung in the balance. These explosions obliterated pretty much anything within range, almost. 

Livermore Lab physicist Rob Hoffman first saw an odd relic two years ago during a tour of the Nevada National Security Site. “I thought it was a pretty funny looking trailer, as matter of fact. But the closer I got to it, the more I decided, geez, that looks like something that might have belonged aboard a ship sometime,” Hoffman noted.

Hoffman, who’s from a Navy family was right. It’s a gun turret from a heavy cruiser.

During World War II heavy cruisers were often in the thick of the deadliest sea battles. So what’s it doing in the desert of Area 2, in a spot that 60 years ago would have been battered by multiple atomic blasts?

The barrel isn’t a gun, it’s a detection device designed to collect and analyze light.

“The idea behind it was to try and figure out how well a nuclear weapon design actually functioned,” Hoffman said.

The turret was the answer to an engineering challenge.

During Plumbbob’s frequent tests, Test Site workers had to build detection bunkers filled with equipment for each blast. They dug trenches, some 20 feet wide, 20 feet deep and up to a mile long for coaxial cable that connected to the detection gear. The trenches were then refilled to protect the cable from being vaporized.

Irv Woodward
Irv Woodward, a contractor, had the idea of placing sensor equipment inside the turret.

A contractor named Irv Woodward had the bright idea. “That if he could make a reusable line of sight with something that could protect the detectors and yet be able to point at each of the devices, as they were scattered around the site here, then they wouldn’t have to lay so much cable, they wouldn’t have to make so many special purpose bunkers, they wouldn’t have to deploy as many instruments and they might even save some money,” Hoffman said.

They laughed about it at the time.

Woodward and colleagues went to the Mare Island Naval Shipyard in San Francisco, found a couple of turrets sitting on a dock and chose this one. It was transported south by ship, then loaded onto trucks. It likely generated plenty of stares as it traveled the new Interstate 15 highway to the Nevada Test Site.

It had to be modified considerably. The eight-inch gun barrels were removed and the assembly was mounted on a foundation that allowed it to rotate 360 degrees, “This would be pointed at a device sitting on top of a tower, and then light would shine straight down through this tube all the way into the detectors, which would be housed inside the turret safely from the blast wave that was eventually going to get here from less than a mile away,” said Hoffman.

Diablo was the first, an atomic device detonated from a tower north of the turret, followed by Shasta to the south and Whitney to the west. In between, the turret collected data from the Smoky Test, uncorked in Area 9, miles further away.

A Navy ship gun turret at the Nevada Test Site. (KLAS-TV)

The Series

  1. Gun turret’s origin a mystery, but it solved nuclear test problem
  2. Scars from kamikaze attack proof of Navy ship gun turret’s origin

“Worked like a charm. It was fantastic. Got great data out of it,” Hoffman noted.

The turret survived the test and the elements. it still sits in obscurity, home to ferocious Test Site termites and other curious critters.

In the ‘90s, Test Site archaeologists collected information about the turret, but there was one big question that remained unanswered.

“But they couldn’t tell me what ship it came off of,” Hoffman said. “And being a bit of a Navy history buff and from a Navy family, it just kind of caught my imagination.”

That question is answered in Part 2.

Next story: Scars from kamikaze attack proof of Navy ship gun turret’s origin — Part 2

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