HNLMS O 13

O 13 was a O 12-class submarine of the Royal Netherlands Navy that saw service during World War II. She was built by the Koninklijke Maatschappij De Schelde of Vlissingen. She was one of many Dutch ships doing convoy duty during the Spanish Civil War. At the time of the German invasion of the Netherlands, O 13 was on patrol off the Dutch coast and was attacked by German planes on multiple occasions. After fleeing to England, the sub was lost during a patrol on the North Sea.

Before World War II
O 13 ran into a fishing boat, the HD 7, from Den Helder in the Schulpengat on September 26, 1933, sinking the HD 7. With sister ship the O 15, the O 13 attended the Brussels International Exposition in 1935. Later that year the O 13, with O 12, O 15, Hertog Hendrik, Van Ghent, Kortenaer en Z 5, sailed the North Sea, stopping in Gothenburg and Oslo. In 1937 the O 13 did convoy duty in the Strait of Gibraltar during the Spanish Civil War, along with the Hertog Hendrik, Johan Maurits van Nassau, Nautilus, Java and the O 15.

During World War II
During the German attack on the Netherlands in 1940 O 13 patrolled along the Dutch coast and was attacked multiple times by German aircraft. On May 10, 1940, she sailed to England escorted by the minesweeper Jan van Gelder and arrived in Portsmouth the next day. During the evacuation of Dunkirk and Bordeaux O 13 was on patrol in the English Channel. After the Fall of France O 13 was transferred to the 9th Submarine Flotilla based in Dundee, Scotland, together with the other Dutch submarines O 20, O 21, O 23, and O 24. O 13 sailed on her first patrol from Dundee on 12 June 1940 and disappeared. The submarine was presumed lost on 22 June 1940.

Since there are no German records about the O 13 having been sunk it is assumed that the sub ran on a mine, a distinct possibility since O 13 was patrolling in an area known to have been mined, possibly the same minefield where the Polish submarine Orzeł was lost. One other possibility is that the O 13 was rammed by the Polish submarine Wilk, which reported running into an unidentified submarine during the time span in which the O 13 was lost.

Monument and memory
In September 2009, Dundee International Submarine Memorial was dedicated to the memory of the 296 sailors and commandos who served on submarines operating from there and who did not return, among them the crews of the O 13 and the O 22. O 22 was located near Norway in 1993. O 13 is referred to as "still on patrol", as it is the last Dutch submarine still to be found, of the seven submarines the Royal Dutch Navy lost in World War II. In September 2012, the Royal Netherlands Navy announced they would renew the search with new, advanced equipment.