What does the red mean?

[v0031]

USS Missouri was the last battleship commissioned into the United States Navy, although not the last laid down. Like her sisters USS Iowa, USS New Jersey, and USS Wisconsin, she displaced 45,000 tons, carried nine 16”/50 guns in three triple turrets, and could make over 30 knots. Missouri entered service in June 1944 and joined the forward elements of the U.S. Pacific Fleet in January. Like other fast battleships, she served as part of Task Force 58, the carrier force that constituted the core of U.S. naval power in the last two years of the war. Missouri participated in several operations in the last year of the war, including the bombardments of Iwo Jima, Okinawa, and Japan. For the rest of the time, she escorted U.S. carrier groups, protecting them from air (and potentially surface) attacks.

[True Federalist (진정한 연방 주의자)]

A ship is said to be "laid down" when the construction of the ship's keel is begun. There were six Iowa-class battleships authorized to be built, but the last two were never finished.  The terminology 16"/50 indicates a gun whose caliber is 16" and has a barrel that is 50 calibers long. It was the largest gun ever used by the US Navy.