By contrast, the more deliberate pace set by the still-neutral US military saw their construction in Newfoundland planned for a much more substantial investment, intended to last the length of the 99-year lease. Wartime operations Lt. Col. J.J. Yates assumed command of Fort Pepperrell on November 28, 1941 and was replaced on December 2 by Colonel Paul N. Starling. Troops of the United States Army Coast Artillery Corps manned two coast defence batteries and some anti-aircraft batteries at Fort Pepperrell. In January 1941 part of Battery A, 57th Coast Artillery (Tractor Drawn) (TD) Regiment with two mobile 155 mm guns probably arrived on USAT Edmund B. Alexander. On 1 May 1941 part of Battery D, 52nd Coast Artillery (Railway) Regiment arrived with two 8-inch M1888 railway guns. A command known as the Harbor Defenses of Argentia and St. John's was established in January 1941 to coordinate US coast defence activities in Newfoundland, under the Newfoundland Base Command. On 12 February 1942 Battery D, 52nd CA was redesignated as Battery D, 24th Coast Artillery (Harbor Defense) (Composite) Regiment, which was assuming control of US coast defense assets in Newfoundland. By 1942 the battery of two 155 mm guns of Battery A, 53rd Coast Artillery (Tractor Drawn) Regiment (redesignated from the 57th CA on 20 July 1941 and on 16 February 1942 made part of the 24th CA) had three prepared positions featuring Panama mounts at Signal Hill, Middle Cove, and Manuels. The 8-inch battery was initially at Signal Hill, but relocated to Red Cliff circa 1943. Also in the area was a Canadian-manned battery of two Lend-Lease 10-inch M1888 guns at Fort Cape Spear; the gun barrels remained there as of 2017. Other Canadian-manned guns included at least two QF 4.7-inch B Mark IV* guns at Fort Amherst; these were former field guns converted to fixed mountings. A Royal Canadian Navy-manned indicator loop station was at St. John's; this detected submarines via their magnetic signature. Fort Pepperrell expanded significantly after the United States entered the war with the attack on Pearl Harbor in December 1941. During late 1941 and early 1942, multiple units left the temporary tent city to fill the new military base until capacity was reached on February 27, 1942 when the final unit, the headquarters of Newfoundland Base Command, moved from temporary facilities at 44 Rennie's Mill Road. The base held approximately 5,500 personnel and it, along with