were protected by of armor. The transverse bulkheads at the end of her machinery rooms were thick forward and three inches thick aft. The deck over the machinery spaces and steering gear had a thickness of 1.5 inches. The gun turrets were only protected against muzzle blast and the conning tower had 1.5 inches of armor. Milwaukee carried two floatplanes aboard that were stored on the two catapults. Initially these were probably Vought VE-9s, but the ship operated Curtiss SOC Seagulls from 1935 and Vought OS2U Kingfishers after 1940. Wartime changes After 1940 the lower aft six-inch guns were removed and the casemates plated over. The ship's anti-aircraft armament was augmented by two quadruple 1.1-inch gun mounts by early 1942, although these were replaced by twin Bofors 40 mm gun mounts later in the war. At about the same time, Milwaukee received eight Oerlikon 20 mm cannon. Service history Inter-war period The contract for Milwaukee, the third ship named for the city of Milwaukee, Wisconsin, was signed on 27 August 1917, and the ship was laid down by Todd Dry Dock and Construction Company, at their Tacoma, Washington shipyard on 13 December 1918. She was launched on 24 March 1921 and was commissioned on 20 June 1923. During the ship's shakedown cruise, she visited Sydney, Australia, during the Pan-Pacific Scientific Congress which opened on 23 August. With her new depth–finding equipment, Milwaukee surveyed the floor of the Pacific en route. "The Milwaukee Seamounts in the Northern Pacific are named after a set of soundings taken by Milwaukee in 1929." During Fleet Problem VI, she collided with her sister ship in Guantanamo Bay, Cuba, on 1 February 1926, although neither ship was seriously damaged. Milwaukee and the destroyer assisted victims of a fierce hurricane which had devastated the Isle of Pines in October. She was assigned to Cruiser Division 2 of the Asiatic Fleet in 1928. During an engagement with "enemy" cruisers during Fleet Problem IX on 16 April 1930, the ship was ruled to have been knocked out by the exercise's umpires. Three years later, during Fleet Problem XIV, Milwaukee was spotted by fighters from the aircraft carrier and "sunk" by some of the opposing cruisers. In 1933, the ship was assigned to Cruiser Division 3 of the Battle Fleet. After the Panay Incident in December 1937, Milwaukee made a cruise through the Western Pacific from January to April 1938.