Yugoslav torpedo boat T4

The Yugoslav torpedo boat T4 was a seagoing torpedo boat that was operated by the Royal Yugoslav Navy between 1921 and 1932. Originally built as 79 T, a 250t-class torpedo boat built for the Austro-Hungarian Navy in 1913–1914, 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, patrol, escort and minesweeping tasks, anti-submarine operations and shore bombardment missions. Following Austria-Hungary's defeat, 79 T was allocated to the Navy of the Kingdom of Serbs, Croats and Slovenes, which became the Royal Yugoslav Navy, and was renamed T4. In 1932, she ran aground on the Dalmatian coast and became a total loss.

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 darkness, 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 Triest was selected for the contract to build eight vessels, ahead of one other tenderer. The T-group designation signified the builder, STT.

Description and construction
The 250t-class T-group boats had a waterline length of 58.2 m, a beam of 5.7 m, and a normal draught of 1.5 m. While their designed displacement was 262 t, they displaced about 320 t fully loaded. The crew consisted of 39 officers and enlisted men. The boats were powered by two Parsons 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 turbines were 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 18 t of coal and 24 t of fuel oil, which gave them a range of 980 nmi at 16 kn. The T-group had one funnel rather than the two funnels of the later groups of the class. Despite the specifications of the contract being very close to the requirements for the coastal torpedo boat, the STT boats were classified as seagoing. The 250t-class, T-group were the first small Austro-Hungarian Navy boats to use turbines, and this contributed to ongoing problems with them.

The boats were originally to be armed with three Škoda 66 mm L/30 guns, and three 450 mm torpedo tubes, but this was changed to two guns and four torpedo tubes before the first boat was completed, in order to standardise the armament with the following F-group. They could also carry 10–12 naval mines.

The sixth of its class to be completed, 79 T was laid down on 1 December 1913, launched on 30 April 1914 and completed on 30 September 1914. In 1914, one 8 mm machine gun was added.

World War I
During World War I, 79 T was used for convoy, patrol, escort and minesweeping tasks, anti-submarine operations, and shore bombardment missions. Due to inadequate funding, 79 T 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 24 May 1915, 79 T and seven other 250t-class boats participated in the the Bombardment of Ancona, which involved shelling of various Italian shore-based targets, with 79 T involved in the shelling of Porto Corsini near Ravenna. During that action, an Italian 4.7 in shore battery returned fire, hitting the light cruiser SMS Novara and damaging one of the other 250t-class boats. In late November 1915, the Austro-Hungarian fleet deployed a force from its main fleet base at Pola to Cattaro in the southern Adriatic; this force included six of the eight T-group torpedo boats, so it is possible that one of these was 79 T. This force was tasked to maintain a permanent patrol of the Albanian coastline and interdict any troop transports crossing from Italy. On the night of 31 May – 1 June 1916, the s SMS Orjen and SMS Balaton, accompanied by 79 T and two other 250t-class boats, raided the Otranto Barrage, an Allied naval blockade of the Strait of Otranto. Orjen sank one drifter, but once the alarm had been raised, the Austro-Hungarian force withdrew.

In 1917, one of her 66 mm guns was placed on an anti-aircraft mount. On 28 November, a number of 250t-class boats were involved in two shore bombardment missions. In the first mission, 79 T and two other 250t-class boats supported the bombardment of Senigallia by three destroyers, before they were joined by five more 250t-class boats and another three destroyers for the bombardment of Porto Corsini, Marotta and Cesenatico. On 10 June 1918, 79 T and another five 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.

Interwar period
79 T 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 T-group boats, 76 T, 77 T and 78 T, and four 250t-class F-group boats, she served with the Royal Yugoslav Navy (Kraljevska Jugoslovenska Ratna Mornarica, KJRM; Кpaљeвcкa Југословенска Pатна Морнарица). Taken over in March 1921, in KJRM service, 79 T was renamed T4. At the outset, she and the other seven 250t-class boats were the only modern sea-going vessels in the KJRM. In 1925, exercises were conducted off the Dalmatian coast, involving the majority of the navy. In May and 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 T4 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. In 1932, T4 ran aground on the Dalmatian coast and became a total loss.