SS Vaderland was an ocean liner launched in July 1900 for the Red Star Line service between Antwerp and New York. During her passenger career, the ship initially sailed under British registry, but was re-registered in Antwerp in 1903. Vaderland was a sister ship to Zeeland and a near sister ship to Kroonland and Finland.

After the beginning of the First World War, Vaderland was re-registered in Liverpool and converted to a troopship, ferrying troops of the Canadian Expeditionary Force from Halifax to Liverpool. While under the operation of White Star–Dominion in 1915, she was renamed Southland to avoid the German-sounding Vaterland.

In September 1915, Southland was torpedoed in the Aegean Sea by German submarine UB-14 with the loss of 40 men. The ship was beached, repaired, and returned to service in August 1916. While in service between the United Kingdom and Canada on 4 June 1917, Southland was torpedoed a second time, this time by U-70; she was sunk off the coast of Ireland with the loss of four lives.

In July 1899, the Red Star Line announced plans for the construction of four large steamers. Two ships, Vaderland and Zeeland at John Brown & Company of Clydebank in Scotland, and two others, Kroonland and Finland, were to be built at William Cramp & Sons in Philadelphia. Owned by American Line and managed by International Navigation Co. Ltd. London, she was 11,899 gross register tons, and after modification provided accommodation for 342 first-class, 194 second-class, and 626 third-class passengers.

Launched on 12 July 1900, Vaderland began her maiden voyage on 8 December 1900 when she left Antwerp for Southampton and New York City. She was chartered to the American Line and made three -Southampton – Cherbourg – New York round-trip voyages between 11 December 1901 and 8 April 1902. On 16 May 1903 she commenced Antwerp – New York service under the Belgian flag, starting her last on 25 December 1914. During this service, she collided with the 43-gross register tonnage American schooner John A. Allen off Georges Bank between the North Atlantic Ocean and the Gulf of Maine on 22 July 1906; John A. Allen was lost, but all seven people aboard her survived. On 19 January 1907 she collided with the British steamer Naworth Castle in the English Channel off the Goodwin Sands; Naworth Castle sank. Forty-two members of the 1912 United States Olympic Team returned from Stockholm, Sweden, to New York City aboard Vaderland on 31 July 1912.

On 22 September 1914 Vaderland commenced Liverpool – New York sailings under the British flag and in December 1914 was chartered to White Star–Dominion for three Liverpool - Halifax - Portland sailings. In 1915 she was requisitioned as a troopship. In 1915 she was renamed Southland as the Dutch word vaderland was considered too similar to the German Vaterland.

Southland was later used in the Mediterranean to carry troops of the 6th Essex regiment and two companies of l/7th Essex, transported from Devonport to Gallipoli from 4 July 1915 to 11 August 1915, and later from Alexandria, the Australian 21st Battalion with some troops from the Australian 23rd Battalion, General Legge and staff and 2nd Division Signals Company. During its sail from Egypt to Gallipoli on the 2 September 1915 at 9:45am it was torpedoed at right forward by the German submarine UB-14 30 nautical miles (56 km) from Lemnos in the Aegean Sea. The ship did not sink immediately, and was eventually beached on Lemnos, and all but 40 of 1,400 men were able to leave in lifeboats and were picked up by other transports and HT Neuralia, although mostly by HMS Ben-my-Chree by about midday though some troops spent up to 4 hours in the water. During the subsequent rescue operations Ben-my-Chree took on board 649 troops and 121 crew from 21 boats and rafts and provided medical attention as required until all were transferred to the troopship SS Transylvania in Mudros harbour. Southland eventually limped back to Mudros assisted by HMS Racoon and was repaired.

The sinking was reported as