Yugoslav torpedo boat T5

The Yugoslav torpedo boat T5 was a sea-going torpedo boat that was operated by the Royal Yugoslav Navy between 1921 and 1941. Originally built as 87 F, a 250t-class torpedo boat built for the Austro-Hungarian Navy in 1914–15, she was armed with two 66 mm guns and four 450 mm torpedo tubes, and could carry 10–12 naval mines. She saw active service during World War I, performing convoy, escort and minesweeping tasks, and anti-submarine operations. Following Austria-Hungary's defeat in 1918, 87 F was allocated to the Navy of the Kingdom of Serbs, Croats and Slovenes, which became the Royal Yugoslav Navy, and was renamed T5.

During the German-led Axis invasion of Yugoslavia in April 1941, the vessel was captured by the Italians and served with the Royal Italian Navy under her Yugoslav designation, conducting coastal and second-line escort duties in the Adriatic. Following the Italian capitulation in September 1943, she was returned to the Royal Yugoslav Navy-in-exile and served as T5. At the end of the war she was transferred to the new Yugoslav Navy and served as Cer until she was broken up in 1962.

Background
In 1910, the Austria-Hungary Naval Technical Committee initiated the design and development of a 275 LT coastal torpedo boat, specifying that it should be capable of sustaining 30 kn for 10 hours. This specification was based an expectation that the Strait of Otranto, where the Adriatic Sea meets the Ionian Sea, would be blockaded by hostile forces during a future conflict. In such circumstances, there would be a need for a torpedo boat that could sail from the Austro-Hungarian Navy (kaiserliche und königliche Kriegsmarine) base at the Bay of Kotor (Bocche di Cattaro) to the Strait during the night, locate and attack blockading ships and return to port before morning. Steam turbine power was selected for propulsion, as diesels with the necessary power were not available, and the Austro-Hungarian Navy did not have the practical experience to run turbo-electric boats. Stabilimento Tecnico Triestino (STT) of Trieste was selected for the contract to build the first eight vessels, designated the T-group. Another tender was requested for four more boats, but when Ganz & Danubius reduced their price by ten percent, a total of sixteen boats were ordered from them, designated the F-group. The F-group designation signified the location of Ganz & Danubius' main shipyard at Fiume.

Description and construction
The 250t-class F-group boats had a waterline length of 58.5 m, a beam of 5.8 m, and a normal draught of 1.5 m. While their designed displacement was 266 t, they displaced about 330 t fully loaded. The crew consisted of 38–41 officers and enlisted men. The boats were powered by two AEG-Curtiss steam turbines driving two propellers, using steam generated by two Yarrow water-tube boilers, one of which burned fuel oil and the other coal. The turbine was rated at 5000 shp with a maximum output of 6000 shp and designed to propel the boats to a top speed of 28 kn. They carried 20 t of coal and 34 t of fuel oil, which gave them a range of 1200 nmi at 16 kn. The F-group had two funnels rather than the single funnel of the T-group. Despite the specifications of the contract being very close to the requirements for the coastal torpedo boat, the Ganz & Danubius boats were classified as sea-going. The 250t-class were the first small Austro-Hungarian Navy boats to use turbines, and this contributed to ongoing problems with them.

The boats were armed with two Škoda 66 mm L/30 guns, and four 450 mm torpedo tubes. They could also carry 10–12 naval mines. 87 F was laid down on 5 March 1914, launched on 20 March 1915 and completed on 25 October of that year.

World War I
During World War I, 87 F was used for convoy, escort and minesweeping tasks, anti-submarine operations, and shore bombardment missions. She also conducted patrols and supported seaplane raids against the Italian coast. Due to inadequate funding, 87 F and the rest of the 250t class were essentially coastal vessels, despite the original intention that they would be used for "high seas" operations. On 3 February 1916, 87 F and two other 250t-class boats were involved in a shore bombardment operation against Ortona and San Vito Chietino, led by the armoured cruiser SMS Sankt Georg. Three days later, the scout cruiser SMS Helgoland (1912), 87 F and five other 250t-class boats were intercepted by the British light cruiser HMS Weymouth (1910) and French destroyer FRENCH DESTROYER Bouclier north of Durazzo in Albania, during which the only damage was caused by a collision between two of the other 250t-class boats. On 9 July, the light cruiser SMS Novara led a force which included 87 F and two s in a raid on the Otranto Barrage, the Allied naval blockade of the Strait of Otranto, which resulted in the sinking of two drifters. On 4 November, three Italian destroyers and three torpedo boats were involved in a brief encounter in the northern Adriatic with two Austro-Hungarian destroyers accompanied by 87 F and two other 250t-class boats. The following day, the same three torpedo boats conducted a shore bombardment of Sant'Elpidio a Mare.

In 1917, one of her 66 mm guns was placed on an anti-aircraft mount. On 28 November 1917, a number of 250t-class boats were involved in two shore bombardment missions. In the second mission, 87 F joined seven other 250t-class boats and six destroyers for the bombardment of Porto Corsini, Marotta and Cesenatico. On 10 June 1918, 87 Fand five other 250t-class boats were part of the escort force that failed to protect the Austro-Hungarian dreadnought SMS Szent István from the Italian MAS boats that sank her. In October 1918, 87 F was at Durazzo in Albania when the port was bombarded by a multinational Allied naval force. She escaped with minor damage, in what was the last major action involving the Austro-Hungarian Navy.

Interwar period
87 F survived the war intact. In 1920, under the terms of the previous year's Treaty of Saint-Germain-en-Laye, she was allocated to the Kingdom of Serbs, Croats and Slovenes (KSCS, later Yugoslavia). Along with three other 250t-class F-group boats, 93 F, 96 F and 97 F, and four 250t-class T-group boats, she served with the Royal Yugoslav Navy (Kraljevska Jugoslovenska Ratna Mornarica, KJRM; Кpaљeвcкa Југословенска Pатна Морнарица). Transferred in March 1921, in KJRM service, 87 F was renamed T5. In 1925, exercises were conducted off the Dalmatian coast, involving the majority of the navy. In May–June 1929, six of the eight 250t-class torpedo boats accompanied the light cruiser Dalmacija, the submarine tender Hvar and the submarines YUGOSLAV SUBMARINE Hrabri and YUGOSLAV SUBMARINE Nebojša, on a cruise to Malta, the Greek island of Corfu in the Ionian Sea, and Bizerte in the French protectorate of Tunisia. It is not clear if T5 was one of the torpedo boats involved. The ships and crews made a very good impression while visiting Malta. In 1932, the British naval attaché reported that Yugoslav ships engaged in few exercises, manoeuvres or gunnery training due to reduced budgets.

World War II and post-war service
In April 1941, Yugoslavia entered World War II when it was invaded by the German-led Axis powers. At the time of the invasion, T5 was assigned to the 3rd Torpedo Division located at Šibenik, which included her three former F-group sisters. On 8 April, the four boats of the 3rd Torpedo Division, along with other vessels, were tasked to support an attack on the Italian enclave of Zadar on the Dalmatia coast. They were subjected to three Italian air attacks and, after the last one, sailed from the area of Zaton into Lake Prokljan, where they remained until 11 April. On 12 April, the 3rd Torpedo Division arrived at Milna on the island of Brač, and refused to follow orders to sail to the Bay of Kotor. All four former F-group boats were then captured by the Italians.

T5 was then operated by the Italians under her Yugoslav designation, conducting coastal and second-line escort duties in the Adriatic. Her guns were replaced by two 76 mm L/40 anti-aircraft guns, but no other significant alterations was made to her. After the Italians capitulated in September 1943, she was returned to the KJRM-in-exile in December of that year. T5 was commissioned by the Yugoslav Navy after the war, and renamed Cer. She was fitted with two 40 mm guns on single mounts and one 20 mm gun, and her torpedo tubes were also removed. She served until 1962, when she was broken up.