During the late 1960’s, the USS New Jersey was a beast of the Battleship. She was part of the proud Iowa Class Battleships and served during the Vietnam war. Her 40mm guns were removed during a refit before deployment and the empty gun tubs were then painted blue, piped and turned into swimming pools. War with luxury people, war with luxury.
Check out this PDF containing the history. “Some of the gun tubs—left empty when the 40-mm antiaircraft guns were removed during reactivation—still remained in place. Snyder directed that two of them in the superstructure be painted light blue inside, and he dubbed them swimming pools. Once he had a ―pool‖ filled and then playfully donned his swimming trunks and rode an air mattress atop the water.”