The United States Navy

The current naval jack of the United States is the First Navy Jack, traditionally regarded as having been used during the American Revolutionary War. On 31 May 2002, Secretary of the Navy Gordon England directed all U.S. naval ships to fly the First Navy Jack for the duration of the "War on Terror". Many ships chose to shift colors later that year on the first anniversary of the September 11, 2001 attacks. The previous naval jack was a blue field with 50 white stars, identical to the canton of the ensign (the flag of the United States) both in appearance and size, and continues to remain in use with vessels of the U.S. Coast Guard and National Oceanic and Atmospheric Administration. A jack of similar design was used in 1794, though with 13 stars arranged in a 3–2–3–2–3 pattern. When a ship is moored or anchored, the jack is flown from the bow of the ship while the ensign is flown from the stern. When underway, the ensign is raised on the mainmast. The First Naval Jack, however, has always been flown on the oldest ship in the active American fleet, currently the USS Constitution.
Notable sailors
Many past and present United States historical figures have served in the Navy. Notable officers include John Paul Jones, John Barry (Continental Navy officer and first flag officer of the United States Navy), James Lawrence (whose last words "don't give up the ship" are memorialized in Bancroft Hall at the United States Naval Academy), Stephen Decatur, Jr., David Farragut, David Dixon Porter, Oliver Hazard Perry, Commodore Matthew Perry (whose Black Ships forced the opening of Japan), and Chester Nimitz, Admiral of the Pacific Fleet in World War II.