Was this the test where a decommissioned battleship was blow vertical standing up in the water?................
I vaguely recall the USS Pennsylvania was used in an atomic test. Various types of livestock were also placed on the ship as well.
No, that was the Baker test at Bikini Atoll in 1946.
A Fatman type bomb was exploded underwater. On pictures of the test, on one side of the mushroom cloud there’s a dark smear caused by the Battleship USS Arkansas being lifted about 300’ out of the water.
One more note about the Baker test: the bomb expended used the “Demon Core” plutonium core that was involved in two separate fatal laboratory accidents.
No. That was Operation Crossroads-Baker, an underwater shot performed much earlier in 1946.