The Austro-Hungarian U-boat fleet was created in the decade prior to the First World War. They were built to a variety of designs, many under licence from Germany. They served throughout the war against Italian, French and British shipping in the Mediterranean Sea with some success, losing eight of the twenty eight boats in service in return. They were reinforced by the Imperial German Navy’s Pola Flotilla, mainly comprising coastal U-boats transported by rail from Germany's northern shipyards to the Austrian ports on the Adriatic Sea. Following the end of the war in 1918, all Austrian submarines were surrendered to the Entente powers, who disposed of them individually. As both Austria and Hungary became landlocked in the aftermath of the war, no Austrian or Hungarian submarines have been commissioned since.
Dubrovnik was a flotilla leader built for the Royal Yugoslav Navy by Yarrow Shipbuilders in Glasgow in 1930 and 1931. She was one of the largest destroyers of her time. Resembling contemporary British designs, Dubrovnik was a fast ship with a main armament of four Czechoslovak-built Škoda 140 mm (5.5 in) guns in single mounts. She was intended to be the first of three flotilla leaders built for Yugoslavia, but was the only one completed. During her service with the Royal Yugoslav Navy, Dubrovnik undertook several peacetime cruises through the Mediterranean, the Turkish Straits and the Black Sea. In October 1934, she conveyed King Alexander to France for a state visit, and carried his body back to Yugoslavia following his assassination in Marseille.
SM U-3 or U-III was the lead boat of the U-3 class of submarines or U-boats built for and operated by the Austro-Hungarian Navy before and during the First World War. The submarine was built as part of a plan to evaluate foreign submarine designs, and was built by Germaniawerft of Kiel, Germany.
SM U-4 or U-IV was a U-3-class submarine or U-boat built for and operated by the Austro-Hungarian Navy before and during the First World War. The submarine was built as part of a plan to evaluate foreign submarine designs, and was the second of two boats of the class built by Germaniawerft of Kiel, Germany.
The U-5 class was a class of three submarines or U-boats that were operated by the Austro-Hungarian Navy before and during World War I. The class was a part of the Austro-Hungarian Navy's efforts to competitively evaluate three foreign submarine designs.
The U-10 class was a class of five submarines or U-boats of the Austro-Hungarian Navy during World War I. The class was similar to the German Type UB I submarine of the German Imperial Navy ; the first two boats delivered to Austria-Hungary had previously been commissioned in the German Navy.
SM U-5 or U-V was the lead boat of the U-5 class of submarines or U-boats built for and operated by the Austro-Hungarian Navy before and during the First World War. The submarine was built as part of a plan to evaluate foreign submarine designs, and was the first of three boats of the class built by Whitehead & Co. of Fiume after a design by Irishman John Philip Holland.
SM U-6 or U-VI was a U-5-class submarine or U-boat built for and operated by the Austro-Hungarian Navy before and during the First World War. The submarine was built as part of a plan to evaluate foreign submarine designs, and was the second of three boats of the class built by Whitehead & Co. of Fiume after a design by Irishman John Philip Holland.
The U-20 class was a class of four submarines or U-boats built for and operated by the Austro-Hungarian Navy during World War I. The class is sometimes referred to as the Havmanden class because it was based upon the design of the Royal Danish Navy's 1911 Havmanden-class submarines, three of which were built in Fiume.
SM U-20 or U-XX was the lead boat of the U-20 class of submarines or U-boats built for and operated by the Austro-Hungarian Navy during the First World War. The design for U-20 was based on that of the submarines of the Royal Danish Navy's Havmanden class, and was largely obsolete by the beginning of the war.
SM U-21 or U-XXI was a U-20-class submarine or U-boat built for and operated by the Austro-Hungarian Navy during the First World War. The design for U-21 was based on submarines of the Royal Danish Navy's Havmanden class, and was largely obsolete by the beginning of the war.
SM U-22 or U-XXII was a U-20-class submarine or U-boat built for and operated by the Austro-Hungarian Navy during the First World War. The design for U-22 was based on submarines of the Royal Danish Navy's Havmanden class, and was largely obsolete by the beginning of the war.
SM U-23 or U-XXIII was a U-20-class submarine or U-boat built for and operated by the Austro-Hungarian Navy during the First World War. The design for U-23 was based on that of the submarines of the Royal Danish Navy's Havmanden class, and was largely obsolete by the beginning of the war.
The U-27 class was a class of eight submarines or U-boats built for and operated by the Austro-Hungarian Navy during World War I. The class was based upon the German Type UB II design of the German Imperial Navy and was constructed under license in Austria-Hungary.
The U-43 class was a class of two coastal submarines or U-boats operated by the Austro-Hungarian Navy during World War I. The two submarines that comprised the class were Type UB II submarines of the Imperial German Navy, making the two classes identical. From the beginning of World War I, Austria-Hungary had been working to increase the size of its U-boat fleet, so the Imperial German Navy, which was finding it difficult to obtain trained submarine crews, sold two of its UB II boats, UB-43 and UB-47, to its ally in June 1917.
The Schichau class consisted of 22 torpedo boats built for the Austro-Hungarian Navy between 1885 and 1891. The class was one of the first torpedo boat classes built for the Austro-Hungarian Navy, and they were initially powered by steam from a single locomotive boiler. The entire class was reconstructed between 1900 and 1910, when they received two Yarrow boilers and a second funnel.
HMS TB 81, originally named Swift, was a torpedo boat that served with the British Royal Navy. She was built in 1884–1885 by the shipbuilder J Samuel White as a private venture, and was purchased for the Royal Navy in 1885, and was one of the largest torpedo boats of her time. She remained in service into the First World War, when she was employed as a patrol boat, finally being sold for scrap in 1921.
The Cobra class was a class of four torpedo boats built by the British shipbuilder Yarrow for the Austro-Hungarian Navy in the late 1890s. All four ships served through the First World War and were scrapped in 1919.
SMS Viper was a torpedo boat of the Austro-Hungarian Navy. Viper was built by the British shipbuilder Yarrow between 1895 and 1896 and formed the basis for the following Cobra-class torpedo boats. She was renamed Torpedoboot 17 in 1910 and served through the First World War as a patrol boat and minesweeper. She was scrapped in 1920.
SMS Natter was a torpedo boat of the Austro-Hungarian Navy. Natter was built by the German shipbuilder Schichau-Werke between 1895 and 1896. She was renamed Torpedoboot 18 in 1910 and used for local coast defence during the First World War. She was scrapped in 1920.
