Based on the Coast Guard Historian’s timeline, https://www.history.uscg.mil/research/chronology/
With inspiration from Mike Kelso

April 6

Men killing fur seals on St Paul Island, Alaska, 1890s.

1894  The President authorized the Revenue Cutter Service to enforce the Paris Award, which was concerned with the preservation of fur seals in Alaska.

Miami-class cutter USCGC Tampa photographed in harbour, prior to the First World War. Completed in 1912 as the U.S. Revenue Cutter Miami, this ship was renamed Tampa in February 1916. On 26 September 1918, while operating in the English Channel, she was torpedoed and sunk by the German Submarine UB-91. All 131 persons on board Tampa were lost with her, the largest loss of life on any U.S. combat vessel during the First World War. Official U.S. Navy photo NH 1226 from the U.S. Navy Naval History and Heritage Command

1917  The United States declared war on Germany and joined the Allied Powers in World War I.  The Coast Guard, which at that time consisted of 15 cruising cutters, 200 commissioned officers, and 5,000 warrant officers and enlisted men, became part of the U. S. Navy by Executive Order.  The cutters immediately reported to their assigned naval districts for duty.  Cutters provided armed parties to seize German ships that had been interned in U.S. ports.  Coast Guard aviators were assigned to naval air stations in this country and abroad.  One Coast Guardsman, First Lieutenant (Eng.) Charles E. Sugden, USCG, commanded the Naval Air Station at Ile Tudy, France, and was later awarded the French Chevalier of the Legion of Honor.  Another officer, Second Lieutenant (Eng.) Philip B. Eaton, USCG, commanded Chatham Naval Air Station and he piloted one of two HS-1 seaplanes that attempted to bomb and machine gun a surfaced U-boat off the coast of New England after the U-boat had shelled a tug and barges four miles off Cape Cod.  Eaton’s bombs failed to explode, however, and the U-boat escaped.  One cutter, CGC Tampa, was lost in action with all hands while on convoy duty in British waters.

“HOIST PICK-UP DEMONSTRATION: A Coast Guard HO3S helicopter from the Coast Guard Air Station Elizabeth City, N.C., demonstrates the use of hydraulic hoist to pick up a man from the ground during the American Helicopter Society Show at Anacostia Naval Air Station, Washington, D.C., April 28-29, 1951. The helicopter equipment has proved invaluable in effecting rescues in areas inaccessible by any other means.”; no photo number; April 1951; photographer unknown.
Note the rescue litter basket slung beneath the HO3S’s fuselage.

1949  A U.S. Coast Guard H03S-1 helicopter completed the longest unescorted helicopter ferry flight on record.  The trip from Elizabeth City, North Carolina to Port Angeles, Washington via San Diego, a distance of 3,750 miles, took 10-1/2 days to complete and involved a total flight time of 57.6 hours.