The Department of the Navy was established on 30 April 1798. Note that there was a Navy during the War for Independence, it was established by the Continental Congress on 13 … October 1775. That date is observed as the official Navy Birthday.That forefather of the Department of the Navy was effectively disbanded at the end of the war.he Continental Navy was established during the American Revolutionary War in 1775. The Continental navy had been essentally a Privateer force and never intended as a permanet organization.