Fort Brooke was a United States Army post established on 3 March 1943 under General Order Number 10 during World War II after the German U-boat attacks of 1942 on the Caribbean Basin in conjunction to Operation Z. Early years During the early years, Puerto Rico played a leading role as the operations center in the Antilles Screen against German U-boats, whose attacks reached an alarming peak in 1942 with the sinking of 336 ships in the Caribbean area. Ships sailing from South American ports carried such strategic products as gasoline, oil derivatives, and bauxite for aluminum production, and their losses were serious. Puerto Rico provided support for U.S. naval forces charged with controlling the Caribbean; it served as a base for air protection for ships, other outposts in the region, and the approaches to the Panama Canal; and it was an important link in the transport and ferrying route for aircraft, personnel, and cargo going to Africa and Middle East. In May 1942, U-boats sunk 56 ships totaling more than 248,000 tons of shipment in the space of 4 months all throughout the Caribbean Sea Frontier west of the shipping control line. By the middle of the month, 22% of the bauxite fleet had been destroyed, 20% of the ships in the Puerto Rican run had been lost, and of 74 vessels allocated to the Army for the month of 17 July had already been sunk. Formation Anxious at the beginning of World War II to avoid raising fears of the U.S. expansion in the hemisphere through the creation of military bases in Latin America, President Roosevelt concentrated instead on strengthening defenses at both ends of the U.S. Canal Zone, and establishing an air base and other military installations on the island of Puerto Rico, the major U.S. territory in the Caribbean Basin. In the President's opinion, expressed in a bill that failed to pass in the U.S. Senate in 1943, the chain of islands running in a great arc from New Orleans to the shoulder of South America, enclosing the Caribbean Basin, formed a vast natural shield for the Panama Canal, suited in distance and conformation to the uses of the military plane. And of this island shield, Puerto Rico is the center. Order 10 General Order No. 10 read: The Headland Castle at Old San Juan will be named Fort Brooke in memory of United States Army