ten cutters to protect the new nation's revenue.
According to the Wikipedia entry for Coast Guard Day, the service got its present name in 1915 when Congress "merged the Revenue Cutter Service with the U.S. Life-Saving Service, and provided the nation with a single maritime service dedicated to saving life at sea and enforcing the nation's maritime laws."
For years a creature of the Treasury Department, the Coast Guard was transferred to the U.S. Department of Transportation in 1967 and then, after 9/11, to the Department of Homeland Security. According to the Coast Guard website, on this day in 1949 Congress "confirmed that the Coast Guard was a branch of the armed forces of the United States, confirmed it in its general functions of marine safety, maritime law enforcement, and military readiness to operate as a service in the Navy upon declaration of war or when the president directs."
Fair warning: Celebration of Coast Guard Day is not likely to be accepted as an excuse should you and yours be accused of boating under the influence today.