Fleet problem Fleet problem was the term used by the United States Navy to describe each of 21 large - scale naval exercises conducted between 1923 and 1940 . They are labeled with roman numerals , from Fleet Problem I through Fleet Problem XXI . A 22nd Fleet Problem exercise , scheduled for 1941 , was canceled because of World War II . The fleet problems were usually once a year exercises in which U . S . naval forces would engage in mock battles . One or more of the forces would play the part of a European or Asian navy . They were the culmination of the Navy ' s annual training maneuvers . Fleet Problems . Fleet Problem I . Fleet Problem I was held in February and March 1923 and was staged off the coast of Panama . The attacking Black force , using battleship s to represent aircraft carrier s , tested the defenses of the Panama Canal . A single plane launched from — representing a carrier air group — dropped 10 miniature bombs and theoretically " destroyed " the spillway of the Gatun Dam . Fleet Problems II , III , IV . Fleet Problems II , III , and IV were held concurrently in January and February 1924 took place in the Caribbean and simulated actions that might occur in the Pacific . Fleet Problem II . Fleet Problem II simulated the first leg of a westward advance across the Pacific . Fleet Problem III . This exercise focused on a defense of the Panama Canal from the Caribbean side . The Blue force was defending the canal from an attack from the Caribbean by the Black force , operating from an advance base in the Azores . It was to practice amphibious landing techniques and the rapidity of transiting a fleet through the canal from the Pacific side . In the exercise , a Black force special operations action resulted in the " sinking " of Blue force battleship in the Culebra Cut which would have blocked the canal . Fleet Problem IV . This problem simulated the movement from a main base in the western Pacific to the Japanese home islands — represented in that case by islands , cities , and countries surrounding the Caribbean . Fleet Problem V . Fleet Problem V was held in March and April 1925 and simulated an attack on Hawaii . The Black force , the aggressor , was given the United States ' first aircraft carrier , along with two seaplane tender s and other ships outfitted with aircraft , while the defending Blue force had no carriers . In addition , aircraft aboard the battleship could not be launched for lack of a working catapult . " Langley " s positive performance helped speed the completion of aircraft carriers and . One aspect of Fleet Problem V was conducted near Guadalupe Island off Baja California and involved attacking a lightly held position and refueling 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 submarine s 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 . 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 " Saratoga " s 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 American 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 . Held in March 1932 . In a simulated naval battle , an outnumbered scouting force inflicted staggering losses on a battle fleet in the first effective demonstration of aircraft carriers against sea - based targets . After - action critiques stressed the growing importance of naval aviation , and an increased need for the construction of aircraft carriers in the event of a war in the Pacific . Fleet Problem XIV . Held in 1933 . Fleet Problem XV . Held in May 1934 in Hawaii , this was a three - phase exercise which encompassed an attack upon and defense of the Panama Canal , the capture of advanced bases , and a major fleet engagement . Fleet Problem XVI . Held in May 1935 in the northern Pacific off the coast of Alaska and in waters surrounding the Hawaiian Islands , this operation was divided into five distinct phases which were thought to be aspects of some real naval campaign of the future in which the U . S . would take the strategic offensive . Fleet Problem XVII . This problem took place off the west coast of the U . S . , Central America , and the Panama Canal Zone in the spring of 1936 . It was a five - phase exercise devoted to preparing the fleet for anti - submarine operations , testing communications systems , and training of aircraft patrol squadrons for extended fleet operations , and pitted the Battle Force against the submarine - augmented Scouting Force . Fleet Problem XVIII . This exercise was held in May 1937 in Alaskan waters and in the vicinity of the Hawaiian Islands and Midway , practicing the tactics of seizing advanced base sites — a technique later to be polished to a high degree into close support and amphibious warfare doctrines . Fleet Problem XIX . This operation in April and May 1938 gave the navy added experience in search tactics ; in the use of submarines , destroyers , and aircraft in scouting and attack , in the dispositions of the fleet and the conduct of a major fleet battle . In addition , the exercise again dealt with the matter of seizing advanced fleet bases and defending them against minor opposition . Fleet Problem XIX also tested the capabilities of the Hawaiian Defense Force , augmenting it with fleet units to help to defend the islands against the United States fleet as a whole . The last phase of the exercise exercised the fleet in operations against a defended coastline . Fleet Problem XX . Took place in February 1939 in the Caribbean and Atlantic , and observed in person by President Franklin Roosevelt . The exercise simulated the defense of the East Coast of the United States and Latin America by the Black team from the invading White team . Participating in the maneuvers were 134 ships , 600 planes , and over 52 , 000 officers and men . Fleet Problem XXI . An eight - phase operation for the defense of the Hawaiian area in April 1940 . Fleet Problem XXII . Scheduled for the Spring of 1941 , but cancelled .