Question: What is the ship that sank in the Baltic sea and is in the novel Salt to the Sea?

Context paragraphs:
The I.V. Stalin White Sea – Baltic Sea Canal: The I.V. Stalin White Sea – Baltic Sea Canal (Russian: Беломорско - Балтийский канал имени Сталина: История строительства, 1931 - 1934 гг.  (Stalin’s White Sea - Baltic Kanal: History of Construction 1931 - 1934)) is a 1934 Soviet historical volume detailing the construction of the White Sea-Baltic Sea Canal and the labor used to construct it.  The volume was edited and compiled by Maxim Gorky and contributed to by various other Soviet writers.  In 1935, the work was translated from Russian into English and subsequently published in England as "The White Sea Canal" and in the United States as "Belomor: An Account of the Construction of the Great Canal Between the White Sea and the Baltic Sea".  The original version of the work consists of thirty-five chapters covering both the history of the canal’s construction and personal narratives of the inmates who lived and worked in the labor camps.  Together, these accounts were intended to show the power and ability of the state in reforming landscape and people according to its goals.

MV Fu Shan Hai: MV "Fu Shan Hai" (Chinese: 富山海) was a Chinese bulk carrier which on 31 May 2003 was involved in a collision with the Polish container ship "Gdynia" north-west of the Danish island of Bornholm in the Baltic Sea.  Later the same day "Fu Shan Hai" sank in 69 m of water.  At that moment, she was the biggest ship to be sunk in the Baltic Sea.

Salt to the Sea: Salt to the Sea is a 2016 historical fiction young adult novel by Ruta Sepetys.  It tells the story of four individuals in World War II who make their way to the ill-fated MV "Wilhelm Gustloff".  The story also touches on the disappearance of The Amber Room, a work of art stolen by the Nazis that has never been recovered.

Estonia: Estonia ( ; Estonian: "Eesti" ), officially the Republic of Estonia (Estonian: "Eesti Vabariik" ), is a country in the Baltic region of Northern and Eastern Europe.  It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia (343 km), and to the east by Lake Peipus and Russia (338.6 km).  Across the Baltic Sea lies Sweden in the west and Finland in the north.  The territory of Estonia consists of a mainland and 2,222 islands in the Baltic Sea, covering 45339 km2 of land and water, and is influenced by a humid continental climate.  Ethnic Estonians are a Finnic people, sharing close cultural ties with their northern neighbour, Finland, and the official language, Estonian, is a Finno-Ugric language closely related to Finnish and the Sami languages, and distantly to Hungarian.

MV Wilhelm Gustloff: MV "Wilhelm Gustloff" was a German military transport ship which was sunk on 30 January 1945 by  in the Baltic Sea while evacuating German civilians, Nazi officials and military personnel from Gdynia (Gotenhafen) as the Red Army advanced.  By one estimate, 9,400 people died, which makes it the largest loss of life in a single ship sinking in history.

Ports of the Baltic Sea: There are over 200 ports in the Baltic Sea.  When only those ports that handle minimum of 50,000 tonnes of cargo annually, and where at least part of this cargo is international, are taken into account the number of ports reaches approximately 190.  In 2008, the total amount of cargo handled in the Baltic Sea ports amounted to 822.4 million tonnes, which is 0.4 per cent less than in 2007.  Primorsk, Saint Petersburg and Muuga were the biggest ports in the Baltic Sea in 2008.  Together the three top ports handled over one fifth of total cargo volumes in the Baltic Sea in 2008.

Baltic Sea Parliamentary Conference: The Baltic Sea Parliamentary Conference (BSPC) was established in 1991 as a forum for political dialogue between parliamentarians from the Baltic Sea Region.  BSPC aims at raising awareness and opinion on issues of current political interest and relevance for the Baltic Sea Region.  It promotes and drives various initiatives and efforts to support a sustainable environmental, social and economic development of the Baltic Sea Region.  It strives at enhancing the visibility of the Baltic Sea Region and its issues in a wider European context.

List of islands in the Baltic Sea: This is a list of islands in the Baltic Sea.  The Baltic Sea proper is bordered to the north by the Bothnian Sea and, further north, the Gulf of Bothnia, neither being part of the Baltic Sea proper.  The eastern basins the Gulf of Finland and the Gulf of Riga are likewise not considered part of the Baltic Sea proper.  Whether islands situated in, or on the borders to, these basins (Åland Islands, Hailuoto and Kotlin) shall be included in the list is therefore a matter of definition.

Baltic Sea campaigns (1939–45): The Baltic Sea Campaigns were conducted by Axis and Allied naval forces in the Baltic Sea, its coastal regions, and the Gulf of Finland during World War II.  After early fighting between Polish and German forces, the main combatants were Germany and Finland, opposed by the Soviet Union.  Sweden's navy and merchant fleet played important roles, and the British Royal Navy planned Operation Catherine for the control of the Baltic Sea and its exit choke point into the North Sea.  While operations included surface and sub-surface combat, aerial combat, amphibious landings, and support of large-scale ground fighting, the most significant feature of Baltic Sea operations was the scale and size of mine warfare, particularly in the Gulf of Finland.  The warring parties laid over 60,000 naval mines and anti-sweep obstacles, making the shallow Gulf of Finland one of the most densely mined waters in the world.

List of companies of Estonia: Estonia is a country in the Baltic region of Northern Europe.  It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia (343 km), and to the east by Lake Peipus and Russia (338.6 km).  Across the Baltic Sea lies Sweden in the west and Finland in the north.  The territory of Estonia consists of a mainland and 2,222 islands and islets in the Baltic Sea, covering 45339 km2 of land, and is influenced by a humid continental climate.

Supporting paragraphs: Salt to the Sea MV Wilhelm Gustloff
Answer: MV "Wilhelm Gustloff