The Fleet Landing Exercises, or FLEX were amphibious landing exercises conducted by the United States Navy and United States Marine Corps between 1935 and 1941. The purpose of these exercises was to formulate a workable amphibious warfare doctrine. The development of the necessary craft and other equipment, and the proper tactical deployment of them were also results. Finally, the exercises demonstrated the usefulness of a standing body of Marines, the Fleet Marine Force, specially prepared for amphibious expeditions. Origins The history of amphibious warfare predates Greek antiquity. In United States history, early in the Revolution, Colonial marines were used to conduct amphibious landings and raids such as the Battle of Nassau, and the Penobscot Expedition. Amphibious operations were mounted in the American Civil War, and also prominently in the Spanish–American War. Though this history produced a system of landing procedures, the advent of the motor vehicle (the tank in particular) and the airplane required planners to think more critically about the feasibility of amphibious operations. In Panama, during the 1920s, the Marine Corps conducted a few modest experiments concerning modern amphibious warfare. At the beginning of the 1930s American defense policy shifted as the threat of the expansionist Japanese Empire became more apparent. The establishment of the Fleet Marine Force and greater concentration on the feasibility of amphibious assault were the direct result. Developing the ability to capture Japanese held islands during a Pacific war against Japan was a vital part of US war contingency plans; War Plan Orange. It was not until these contingency plans described the necessity of amphibious capability that testing key maneuvers in amphibious landings was funded. History After the First World War and until the mid-1930s, appropriations for the United States Navy were small. Ships fitted as troop transports were not priorities for the Navy in fact or in theory, so as a stop-gap measure the responsibility fell to battleships and cruisers to lift Marine landing forces. As a consequence of the standard davits on Navy ships, a length of 30’, the spacing of the davits fitted to these ships, and a weight of 5 tons (the maximum capacity of the davits) were imposed as basic requirements for all new landing craft Soon after the formation of the Fleet Marine Force, plans were made for training the FMF in landing operations in the Caribbean. The northwest peninsula of Culebra Island was chosen as the training