USS Eagle 56 (PE-56) was a United States Navy World War I-era patrol boat that remained in service through World War II. On 23 April 1945, while towing targets for US Navy bomber exercises off the coast of Maine, Eagle 56 was sunk by the German submarine U-853. Only 13 of the 67 crew survived. The loss was classified as a boiler explosion until 2001 when historical evidence convinced the US Navy to reclassify the sinking as a combat loss due to enemy action.