<hi style=afpcap>Several commercial designs were adopted for military use when it became clear to the US Government that it should increase the size of its armed forces as a precaution as the German and Japanese influence spread in Europe and the Pacific respectively. Prior to these two factions beginning their offensive, the Grumman G.21 amphibian was acquired in 1938 with 26 being allocated the designation OA-9. Others were obtained from private owners as the OA-13, while a few Navy versions were transferred to the Army.</hi>
