USCGC Bittersweet (WLB 389) was a C or Iris-class 180-foot buoy tender

Buoy tender

A buoy tender is a type of vessel used to maintain and replace navigational buoys. The name is also used for someone who works on such a vessel and maintains buoys....

 of the United States Coast Guard

United States Coast Guard

The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...

.

Built by the Zenith Dredge Company of Duluth, Minnesota

Duluth, Minnesota

Duluth is a port city in the U.S. state of Minnesota and is the county seat of Saint Louis County. The fourth largest city in Minnesota, Duluth had a total population of 86,265 in the 2010 census. Duluth is also the second largest city that is located on Lake Superior after Thunder Bay, Ontario,...

, the ship was laid down on 16 September 1943, and launched on 11 November 1943. Commissioned on 11 May 1944, Bittersweet was assigned to the 17th Coast Guard District, and sailed for Alaska

Alaska

Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 via the St. Lawrence River, the Panama Canal

Panama Canal

The Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...

 and San Francisco, arriving on 19 November 1944.

Based at Kodiak

Kodiak, Alaska

Kodiak is one of 7 communities and the main city on Kodiak Island, Kodiak Island Borough, in the U.S. state of Alaska. All commercial transportation between the entire island and the outside world goes through this city either via ferryboat or airline...

, her primary mission was the performance of general aids to navigation

Navigational aid

A navigational aid is any sort of marker which aids the traveler in navigation; the term is most commonly used to refer to nautical or aviation travel...

 (ATON) duties, but she also carried out numerous search and rescue operations, fought fires, delivered medical supplies, and enforced fishing laws.

At the end of the war in September 1945, in addition continuing her ATON duties, Bittersweet was now charged with the performance of law enforcement duties. Kodiak remained the ship's homeport until 30 June 1964 when it changed to Ketchikan

Ketchikan, Alaska

Ketchikan is a city in Ketchikan Gateway Borough, Alaska, United States, the southeasternmost sizable city in that state. With an estimated population of 7,368 in 2010 within the city limits, it is the fifth most populous city in the state....

. She remained there until mid-1976 when the ship underwent major renovations at the Coast Guard Yard

United States Coast Guard Yard

The United States Coast Guard Yard or just Coast Guard Yard is a United States Coast Guard operated shipyard located on Curtis Bay in northern Anne Arundel County, Maryland, just south of the Baltimore city limits. It is the coast guard's sole shipbuilding and major repair facility, and part of the...

 at Curtis Bay, Maryland.

Bittersweet was then stationed at Woods Hole, Massachusetts

Woods Hole, Massachusetts

Woods Hole is a census-designated place in the town of Falmouth in Barnstable County, Massachusetts, United States. It lies at the extreme southwest corner of Cape Cod, near Martha's Vineyard and the Elizabeth Islands...

 and used for ATON and icebreaking. In addition she took part in oil spill cleanup operations and also participated in the International Ice Patrol

International Ice Patrol

The International Ice Patrol is an organization with the purpose of monitoring the presence of icebergs in the Atlantic and Arctic Oceans and reporting their movements for safety purposes. It is operated by United States Coast Guard but is funded by the 13 nations interested in trans-Atlantic...

, collecting hydrographic and drift buoy data off the Grand Banks

Grand Banks

The Grand Banks of Newfoundland are a group of underwater plateaus southeast of Newfoundland on the North American continental shelf. These areas are relatively shallow, ranging from in depth. The cold Labrador Current mixes with the warm waters of the Gulf Stream here.The mixing of these waters...

 using a mobile laboratory.

Bittersweet was decommissioned on 18 August 1997, and given to Estonia. Renamed Valvas, the ship serves in the Estonian Border Guard.