(WHTM) — April 11 is National Submarine Day, commemorating the day in 1900 that the U.S. Navy purchased the U.S.S. Holland, their first practical submarine. The key term here is “practical.” The U.S. Navy owned three submarines before Holland. In the 1860s, during the Civil War, the Union Navy had the U.S.S. Alligator, a 47-foot-long […]