Pre-war Dione departed Manitowoc the same day she was commissioned—5 October 1934. She passed through the
Great Lakes and docked in
Ogdensburg, New York for repairs to her oil purifier on 15 October. The cutter traveled up through the remainder of the river and through the
gulf of the same name.
Dione stopped in
Philadelphia on 30 October to be outfitted with her weaponry, and docked at the Coast Guard base on the
Elizabeth River on 1 November in order to take on fuel and provisions.
Dione was stationed in
Norfolk, Virginia. The cutter primarily operated in a
search and rescue capacity, responding to vessels that had signaled that they were in distress, taking injured seamen to Norfolk, and locating the wreckage of downed planes. She also operated in various miscellaneous capacities, such as breaking through ice to allow ships access to the
Smith and
Tangier Islands in February 1936 and accompanying vessels participating in a
Hampton One-Design race in August 1941. In November 1937,
Dione joined the search for survivors of the sunken cargo ship , which had sunk in a storm off
Hatteras, North Carolina, on the night of 12–13 November. Multiple lifeboats were found empty, but 15 survivors were eventually found clinging to wreckage by the cutter and were subsequently taken to Norfolk.
World War II Following the beginning of
World War II,and the
Eastern Sea Frontier, a Navy operational command. On 1 November 1941, President
Franklin D. Roosevelt signed
Executive Order 8929, which transferred control of the Coast Guard from the Department of the Treasury to the Navy "for the duration of the emergency." Sometime in 1941, the cutter's two guns were removed. Installed were two racks to hold
depth charges and a
Y-gun depth charge launcher,
Second Happy Time January–February of the Fifth Naval District off North Carolina and Virginia which
Dione patrolled during the Second Happy Time|alt=A map showing the shoreline of Virginia and North Carolina The waters off the Outer Banks of North Carolina are nicknamed the "
Graveyard of the Atlantic" due to the high number of ships lost at sea off the coast. The
sandbars shift due to rough waves and unpredictable weather.) due to the high number of U-boats patrolling off the Outer Banks. During the time period that lasted from January to June 1942 and was referred to as the "
Second Happy Time" by
Kriegsmarine officers as well as
Karl Dönitz—
Admiral of the and in charge of U-boats, 397
Allied ships were sunk by U-boats. in charge of the Eastern Sea Frontier, compiled a group of twenty ships to help defend the
East Coast of the United States. This consisted of
Dione, six
Active-class patrol boats, four
cruiser submarines built before World War I, three
Eagle-class subchasers, two
gunboats from 1905, and four large
yachts that had been converted for military service. In addition to being the fastest vessel of the fleet,Sometime at the end of January,
Dione dropped six depth charges after her sonar operator reported an "underwater object" off
Oregon Inlet. Two airplanes made several runs on a rapidly spreading patch of oil. They reported to McCormick that they saw something long and narrow. An oar and a boat hook eventually surfaced from the object, and when brought aboard were found to have been from the shipwreck of the
oil tanker ; the tanker had been sunk by on 27 January.
Dione set off for
Cape Henry late at night on 27 February to assist the torpedoed
freighter North Sea. The freighter was found by
Dione early the next morning. Reportedly, a U-boat's attack on
North Sea had been halted due to a storm that had tossed the U-boat about, preventing it from accurately aiming its
deck gun and shelling the freighter.
Dione towed the damaged freighter to
Little Creek, as
North Sea had lost her steering capabilities in the attack, and arrived by the end of the day.
Dione rescued the crew of the storage tanker
Acme early in the morning of 18 March. The tanker had been torpedoed by
U-124 west of the
Diamond Shoals Light Buoy just before midnight the previous day. The cutter also picked up the survivors of the Greek freighter , which had been torpedoed by the same U-boat that attacked
Acme just after midnight on 18 March. On 20 March,
Dione's sonar made contact with a U-boat. A Coast Guard airplane from the
Elizabeth City Air Station dropped two depth charges. Three days later, on 26 March, the crew of
Dione spotted flames from the oil tanker and traveled several miles to investigate. The tanker's survivors had already been rescued by the destroyer , and the cutter encountered nothing but debris.
Dione then headed south to the waters off Hatteras, North Carolina.
Dione dropped depth charges on the U-boat which reportedly almost hit, though
U-552 managed to escape. No ships were lost to U-boats near
Cape Hatteras or
Cape Lookout after the establishment of the "bucket brigade" convoy system. On 24 June, at 1900 hours, the cutter made an underwater contact and conducted escort duty in the
North Atlantic Ocean, escorting HK convoys going from New York to Key West and KN convoys heading from Key West to New York. She was based out of
Tompkinsville, Staten Island from December 1943 Thompkinsville was the site of an Eastern Sea Frontier Base.
1945 In 1945,
Dione underwent a major refit. Her 3-inch/23-caliber gun was removed. In addition to her Y-gun and two depth charge racks, the cutter was fitted with two single-mount
3-inch/50-caliber guns, two single-mount
20 mm/80 cannons, two
"Mousetrap" anti-submarine rocket launchers, and an additional Y-gun. Her wireless set and World War I-era sonar system was replaced with an SF
radar system and a QCN-1 sonar system. On 17 May,
Dione rendezvoused with , a U-boat that had fled to Allied waters following the German surrender.
Dione escorted the U-boat into Portsmouth later that day.
Dione was sent back to the Fifth Naval District in June, where she was assigned to
air-sea rescue duty. From 1945 to 1947,
Dione was used by the Coast Guard for
law enforcement and search and rescue. where she spent several years
laid up in storage due to a lack of personnel. after a
shakedown cruise in the
Caribbean. Starting in 1952,
Dione was assigned to the
Eighth Coast Guard District and based in
Freeport, Texas; she was the first cutter to be based in the city. The cutter was originally scheduled to arrive on 13 March 1952 but was delayed until 19 March due to rough weather on her shakedown cruise. She was met with a yacht escort upon her arrival in Freeport that day. Local schools were closed so students could visit
Dione, and an enlisted men's dance and officer's dinner was held. Among many other incidents, the cutter responded to the distress signal of a Mexican motor vessel in 1956, towed the disabled in 1957, helped put out a fire that had started aboard the Freeport sulfur
barge FS-20 in 1959, and towed a fishing vessel after a false emergency signal in 1962. In 1953, per international rules, the cutter was required to install a forward masthead light above the hull, and install an after range lightthe horizontal distance had to be . She was also the first of five -long cutters to undergo repairs to her hull in 1960. It was discovered that her insides had
corroded and were hidden by insulation and furniture and her C
strake had several leaks; attempts to use
welding arcs to fix the latter ended up "burning through the basic plate" and resulted in
Diones entire strake needing to be replaced. As a result of the experience with
Dione, a routine was established to inspect the hulls of the remainder of the cutters.
Dione remained in Freeport until 1963, when she was set to be decommissioned.
Dione left Freeport on 2 February.
Dione was sold as a
supply ship on 24 February 1964. == Commercial service ==