LSM-60

LSM-60 was a Landing Ship Medium of the United States Navy that served during the final months of World War II. It is historically significant for its unique role in Operation Crossroads, the first postwar nuclear weapon tests conducted at Bikini Atoll. The vessel was specifically modified to serve as the detonation platform for the second test, Test Baker, an underwater explosion.

Design and specifications

The vessel was a member of the LSM-1-class landing ship medium, a class of amphibious assault ships designed to transport medium tanks and troops directly onto beaches. Built by Brown Shipbuilding in Houston, Texas, its design followed standard wartime specifications for the type. Key features included a large bow ramp for disembarkation, a flat bottom for beaching, and a displacement of approximately 1,095 tons fully loaded. Armament typically consisted of various anti-aircraft guns, including 40mm and 20mm cannons, for defense against enemy aircraft. Propulsion was provided by General Motors Cleveland diesel engines, granting a top speed of around 13 knots.

Service history

Following its commissioning in early 1945, the ship conducted standard shakedown and training exercises along the U.S. West Coast under the Pacific Fleet. With the war in the Pacific Theater concluding, it did not see combat deployment to active battlefronts like Okinawa or Iwo Jima. In 1946, it was selected for a highly specialized mission as part of Joint Task Force 1 for Operation Crossroads. For the Baker test, the vessel was stripped of its armament and extensively modified. It was positioned directly above the submerged "Gilda" atomic bomb suspended from its hull, acting as the zero-point platform for the historic underwater detonation on July 25, 1946. The ship was vaporized in the massive explosion, which produced a characteristic Wilson cloud and a massive radioactive spray, contaminating the target fleet.

Decommissioning and fate

As the vessel was destroyed during the test, it was administratively struck from the Naval Vessel Register shortly thereafter. Wreckage from the ship, along with other contaminated target vessels like the USS ''Arkansas'' and the USS ''Saratoga'', settled to the bottom of Bikini Lagoon. The site remains a popular destination for technical diving expeditions to explore the nuclear test fleet. Its role in Operation Crossroads provided critical data on the effects of nuclear weapons on naval vessels, influencing future defense strategies and arms control discussions during the early Cold War.

See also

* Operation Crossroads * Baker (nuclear test) * LSM-1-class landing ship medium * Ghost fleet of Bikini Atoll * Nuclear weapons testing

Category:Landing craft of the United States Category:Ships sunk by nuclear weapons Category:World War II amphibious warfare vessels of the United States Category:Operation Crossroads