Test Baker: Nuclear Bomb Testing, Original footage

In Baker, the weapon was suspended beneath landing craft LSM-60 anchored in the midst of the target fleet. Baker was detonated 90 feet (27 m) underwater at 0835 25 July.[1]

The crews of the target ships that had been remanned following Able were evacuated before Baker to the support fleet east of the atoll. Baker sank eight ships and damaged more ships than Able. The detonation generated unexpectedly intense radioactivity[1] and caused most of the target fleet to be bathed in radioactive water spray and radioactive debris from the lagoon bottom. With the exception of 12 target vessels anchored in the array and the landing craft beached on Bikini Island, the target fleet remained too radiologically contaminated for several weeks for more than brief on-board activities.

Twenty pigs and 200 white rats had been placed aboard four target ships. The number was smaller than during test Able because the heat and blast effects were anticipated to be less significant. Radiation sickness was fatal to all the pigs because of residual radioactivity of contaminated water remaining aboard the ships.
Operation Crossroads was a series of nuclear weapon tests conducted by the United States in the summer of 1946. The series consisted of two detonations, each with a yield of 23 kilotons.

Able detonated at an altitude of 520 feet (158 m) on 1 July 1946; Baker detonated 90 feet (27 m) underwater on 25 July 1946. A third planned burst, Charlie, was canceled. The Crossroads tests were the fourth and fifth nuclear explosions done by the USA (following the Trinity test and the bombings of Hiroshima and Nagasaki).

They were the first nuclear tests held in the Marshall Islands, and the first to be publicly announced beforehand.