her boiler and engine rooms and steering gear 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 not armored and only provided protection against muzzle blast. The conning tower had 1.5 inches of armor. Marblehead carried two floatplanes aboard that were stored on the two catapults. Initially these were probably Vought VE-9s until the early 1930s when the ship may have operated the OJ-2 until 1935 and Curtiss SOC Seagulls until 1940 when Vought OS2U Kingfishers were used on ships without hangars. Armament changes During her career Marblehead went through several armament changes, some of these changes were to save weight, but others were to increase her AA armament. The lower torpedo tube mounts proved to be very wet and were removed, and the openings plated over, before the start of World War II. Another change made before the war was to increase the 3-inch guns to eight; all were mounted in the ship's waist. After 1940, the lower aft guns were removed and the casemates plated over for the same reason as the lower torpedo mounts. During the Battle of Makassar Strait, Marblehead had seven 3-inch/50-caliber guns and eight .50 caliber machine guns, four mounted atop the foremast and another four aft. The ship's anti-aircraft armament were augmented by three twin Bofors guns along with twelve Oerlikon cannons by the end of the war. Inter-war period After commissioning, Marblehead departed Boston for shakedown in the English Channel and Mediterranean. In 1925, she visited Australia, stopping en route in the Samoan and Society Islands and, on her return, in the Galápagos Islands. A year after her return, Marblehead was underway again on an extended voyage. Early in 1927, she cruised off Bluefields and Bragman's Bluffs, Nicaragua, her mission there to aid American efforts to bring together and reconcile the various political factions then fighting in that country. With one exception, Augusto César Sandino, faction leaders agreed to the terms of the Peace of Tipitapa on 4 May 1927, and the United States was requested to supervise elections in 1928. Marblehead next sailed for Pearl Harbor, where she joined and and headed for Shanghai, China. Upon arrival there she contributed to the show of force aimed at the