1776    World's first submarine attack: the American submersible craft ''Turtle'' attempts to attach a time bomb to the hull of British Admiral Richard Howe's flagship HMS ''Eagle'' in New York Harbor.

1863    American Civil War: The ''H. L. Hunley'', the first submarine to sink a ship, sinks during a test, killing its inventor, Horace L. Hunley.

1864    American Civil War: The {{Ship||H. L. Hunley|submarine|6}} becomes the first submarine to engage and sink a warship, the {{USS|Housatonic|1861|6}}.

1912    In Groton, Connecticut, the first diesel-powered submarine is commissioned.

1915    World War I: German submarine {{SMU|U-20}} sinks {{RMS|Lusitania}}, killing 1,198 people including 128 Americans. Public reaction to the sinking turns many formerly pro-Germans in the United States against the German Empire.

1915    US Navy salvage divers raise F-4, the first U.S. submarine sunk in accident.

1917    World War I: The United States breaks off diplomatic relations with Germany a day after the latter announced a new policy of unrestricted submarine warfare.

1918    A series of accidental collisions on a misty Scottish night leads to the loss of two Royal Navy submarines with over a hundred lives, and damage to another five British warships.

1930    The United Kingdom, Japan and the United States sign the London Naval Treaty regulating submarine warfare and limiting shipbuilding.

1939    The U.S. Navy submarine USS ''Squalus'' sinks off the coast of New Hampshire during a test dive, causing the death of 24 sailors and two civilian technicians. The remaining 32 sailors and one civilian naval architect are rescued the following day.