at sea. Fleet Problem VI Held off the west coast of Central America in early 1926. Fleet Problem VII This fleet problem was held March 1927 and involved defense of the Panama Canal. The highlight of the exercise was ’s successful air raid on the Panama Canal. Fleet Problem VIII Held in April 1928 between California and Hawaii and pitted Orange, a cruiser force from Pearl Harbor, versus Blue, the Battle Force. It also involved a convoy search and anti-submarine operations. Fleet Problem IX This scenario in January 1929 studied the effects of an attack upon the Panama Canal and conducted the operations necessary to carry out such an eventuality, and pitted the Battle Fleet (less submarines and Lexington) against a combination of forces including the Scouting Force (augmented by Lexington), the Control Forces, Train Squadron 1, and 15th Naval District and local army defense forces. These forces represented a significant commitment of the total US Navy: 72% of the fleet's battleships, 68% of the destroyers, and 52% of modern combat aircraft were involved in the scenario. In a daring move, Saratoga was detached from the fleet with only a single cruiser as escort to make a wide sweep to the south and "attack" the Panama Canal, which was defended by the Scouting Fleet and Saratogas sister ship, Lexington. She successfully launched her strike on 26 January and, despite being "sunk" three times later in the day, proved the versatility of a carrier-based fast task force. Fleet Problem X Held in 1930 in Caribbean waters. This time, however, Saratoga and Langley were "disabled" by a surprise attack from Lexington, showing how quickly air power could swing the balance in a naval action. Fleet Problem XI Held in April 1930 in the Caribbean. Fleet Problem XII Held in 1931 in waters west of Central America and Panama. Black, attacking from the west, was to land forces and establish bases in Central America and destroy the Panama Canal, while Blue defended with an aviation-heavy fleet. Blue's two carrier groups, centered on Saratoga and Lexington, attacked the invasion fleets but failed to stop the landings and got too close to the Black fleets. Fleet Problem XIII Fleet Problem XIII began in March 1932, one month after Army/Navy Grand Joint Exercise 4. Blue, based in Hawaii, was to sail east and invade three "enemy" ports on the North American Pacific coastline to try to