To commemorate September 11, 2001 and those who died, all U.S. Navy ships will replace the normal Union Jack flag (showing fifty white stars on a blue background)

with the First Navy Jack (a rattlesnake, superimposed across 13 horizontal alternating red and white stripes with the motto "don't tread on me.")

The First Navy Jack was first used by Commodore Esek Hopkins in late 1775, as he gathered the continental navy in the Delaware river for operations against British shipping and warships (mostly the former). The First Navy Jack was also used by American privateers (non Navy ships commissioned by the Continental Congress to prey on British merchant shipping.) For the rest of the War on Terror, US Navy ships will fly the First Navy Jack.