Aboard the USS Fall River (CA-131), Bikini Atoll,19 Jul 1946, William Day, Test Baker Minus 3 – Today was William Day, the code name for the rehearsal of Test Baker, the second atomic bomb test scheduled for 25 July. The Baker bomb would be the first underwater explosion of an atomic bomb. Nicknamed “Bikini Helen” or “Helen of Bikini”, the 23-kiloton bomb would be lowered in a caisson and submerged 90 feet below the target vessel LSM-60 (Landing Ship, Medium). The arming would be done remotely from a support ship by a sequence of radio impulses. Substitutions were made for the five ships that were sunk and the fourteen that were seriously damaged in Test Able.
Scuttlebutt was the scientists expected the underwater explosion to create far more damage to the target ships than did Test Able on 1 July, an aerial bomb explosion, also 23 kilotons. Some predicted the sea waters of the Bikini Lagoon might roll back like the Red Sea and expose the lagoon’s dry bottom for several seconds before the water rushed back in. Others said the explosion might hurl huge target ships into the air. Still others said the underwater bomb might blast a huge crater in the lagoon floor.
As with the Queen Day rehearsal for Test Able, all went well at the William Day rehearsal for Test Baker, even though the “dummy” bomb — a flash bomb containing no atomic material — exploded prematurely startling everyone.
On 22 July, Test Baker minus three, the Fall River chaplain pulled some strings and booked a USO show on the fantail of the ship. For a few hours, we forgot about Baker and what might happen to us when an atomic bomb was detonated 90 feet underwater in the Bikini Lagoon.
Excerpted from Operation Crossroads, Lest We Forget! An Eyewitness Account, Bikini Atomic Bomb Tests 1946 by William L. McGee with Sandra V. McGee