Of all the improbable things to find lying abandoned in the Nevada desert, a gun turret from a World War II era U.S. Navy cruiser might be near the top of the list.
Nevertheless, a turret answering that description can be seen there, rusting in the sun at what used to be called the Nevada Test Site, some 100 miles north of Las Vegas.
On careful examination, the scars of devastating naval battles and frightening kamikaze aircraft attacks are visible on parts of the turret.
No one paid attention to these historical clues until recently. For decades, the purpose of the gun turret would be explained to visitors, but its exact origin was a mystery, a matter of speculation.
The turret's purpose, in the days when nuclear tests were conducted on towers above-ground, was to cut costs by eliminating multiple stations for measuring the gamma ray output of nuclear explosions detonated at different sites.
The late Bill McMaster of Lawrence Livermore National Laboratory saw a way to create a single station that could turn and point its detectors at many sites. He had a surplus Navy gun turret shipped in from Mare Island Shipyard in the Bay Area.
The turret was installed as if aboard ship and fitted with a lead-lined barrel that could be aimed precisely at the top of a 500-foot tower a thousand or more yards away where the burst of gamma rays from a nuclear detonation would indicate its explosive yield.
The turret was used to diagnose three tests in 1957, all part of Operation Plumbbob. Soon after that, the turret was retired, as the U.S. and Soviet Union entered into agreements that led to an end to testing in the atmosphere.
While the turret’s brief role was known and discussed by old timers and tour guides, its deeper history was a mystery. Now it has been revealed through the personal efforts of Rob Hoffman, a theoretical physicist in the Lawrence Livermore National Laboratory weapons program who comes from a Navy family.
The Navy connection is not just a figure of speech. Hoffman’s father and younger brother were both chief petty officers. His uncles served in the Navy as well. His twin brother was a career officer in the Marine Corps and is now an intelligence analyst with the Coast Guard.
With this family background and his work at LLNL, Hoffman took on the historian role almost exactly one year ago after visiting the abandoned turret as part of a tour of the Test Site, now called the Nevada National Security Site.
Since then, he has spent nights and weekends scanning the internet, corresponding with aging Navy veterans and with the Desert Research Institute, and checking archival records at sites around the country, from San Bruno to Washington, D.C.
He continues to make new contacts and uncover new information, but in the meantime he published a historical report at LLNL late last year and has plans for a more formal article, perhaps in a Naval history journal.
The turret is from the 1930s and is known as a Mark 9, he found. It housed three 8-inch guns and was carried by a dozen U.S. ships, 10 of them cruisers, but two aircraft carriers as well.
“The battle history of these ships is a tale of great success and sorrow,” he wrote in the LLNL report. Five were lost to enemy action in battles with names like Sunda Strait, Coral Sea and Guadalcanal that are burned into the memories of those who fought in the Pacific in World War II.
Which of the ships did the turret come from?
Opinions varied among people who had worked at the Test Site. Hoffman eliminated the names of those that were sunk in action. Then he familiarized himself with the battle histories of surviving ships that carried the Mark 9. He studied repair records at places like Pearl Harbor and Mare Island and traveled to the desert to crawl over the turret to compare battle and repair records with scars, misaligned seams and repair welds.
He was able to eliminate from consideration the USS Portland, Pensacola and Salt Lake City. All of these were damaged in battles near Guadalcanal in 1942, but none appeared to sustain damage that would match scars on the Nevada turret in detail.
By contrast, he found a close connection with the damage and subsequent repairs to the USS Louisville, which was hit twice by kamikaze attacks in January 1945 en route to the Lingayen Gulf in the Philippines.
Dozens were killed or wounded. The Louisville was forced to limp back to the Bay Area for repairs at Mare Island Shipyard, arriving a month later.
Repair records from the shipyard match the Nevada turret down to scrapes, scars, bolt and welding patterns and a slightly displaced faceplate where a replacement part was installed.
Hoffman continues to gather new information and interact with historians and others who might shed light on the history of the turret, but for now he is convinced that he has identified the ship that it came from.
The process has been a lot of fun, he said. He was happy to recognize the Louisville for serving her country by contributing to LLNL’s nuclear testing program “long after her last salvo was fired.”