No offence, but that is a little bit wrong. There were originally five "Yamato's" planned, three built, two as battleships, Yamato and Musashi, and one converted to a carrier before completion, the Shinano. Shinano was sunk by an american sub, the largest ship in history sunk by a sub. Musashi was sunk by carrier aircraft, same as Yamato, a few months earlier.
The ship you are thinking of was the Nagato, only capital ship of the japanese navy to survive the war. It was a late ww1 vessel with 8 16"guns. As an older warship, her technical details were studied before using her as a target at bikini.
Technical details of the Yamato class are almost impossible to verify, she was built in total secrecy, and most drawings and build specs were destroyed, prior to the expected invasion of japanese home islands.
At one time it was thought that the only surviving photos of Yamato were taken by the US navy.