Mackerel

History: The Mackerel-class submarines were a pair of experimental prototype submarines built just prior to World War II and launched in 1940 and 1941. The two submarines were similar in size and capability to the S-class submarines built at the end of World War I, and had been ordered to test the feasibility of using mass production techniques to build small submarines. Until at least 1940 it was thought that mass production of fleet submarines would be impractical, and in any case small submarines could provide area defense for submarine bases.[3] Once it became apparent that there would be sufficient production of the more capable Gato-class submarines, interest in the design waned and no additional small submarines were ordered. Submarine production standardized during the war on the Gato class and its successors, the Balao and Tench-class submarines. In some references, the Mackerels are called the "M class".

Type: Submarine

Primary Country: The U.S. is a country of 50 states covering a vast swath of North America, with Alaska in the northwest and Hawaii extending the nation’s presence into the Pacific Ocean. Major Atlantic Coast cities are New York, a global finance and culture center, and capital Washington, DC. Midwestern metropolis Chicago is known for influential architecture and on the west coast, Los Angeles' Hollywood is famed for filmmaking.