In 1910, the Austria-Hungary Naval Technical Committee initiated the design and development of a coastal torpedo boat, specifying that it should be capable of sustaining 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 base at the 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 of Triest was selected for the contract to build eight vessels, ahead of one other tenderer. The T-group designation signified that they were built at Trieste.
Description and construction
The 250t-class T-group boats had a waterline length of, a beam of, and a normal draught of. While their designed displacement was, they displaced about fully loaded. The crew consisted of 39 officers and enlisted men. The boats were powered by two Parsonssteam 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 with a maximum output of and were designed to propel the boats to a top speed of. They carried of coal and of fuel oil, which gave them a range of at. The T-group had one funnel rather than the two funnels of the later groups of the class. Due to inadequate funding, 77 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. They 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 Škoda 7 cm guns| L/30 guns, and three 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 fourth of its class to be completed, 77 T was laid down on 24 August 1913, launched on 30 January 1914 and completed on 11 August 1914. Later that year, one machine gun was added.
Career
World War I
At the outbreak of World War I, 77 T was part of the 1st Torpedo Group of the 3rd Torpedo Craft Division of the Austro-Hungarian 1st Torpedo Craft Flotilla. During the war, 77 T was used for convoy, patrol, escort and minesweeping tasks, anti-submarine operations, and shore bombardment missions. On 24 May 1915, 77 T and seven other 250t-class boats participated in the Bombardment of Ancona, which involved shelling of various Italian shore-based targets, with 77 T involved in the operation against Ancona itself. 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 77 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 and, accompanied by 77 T and two other 250t-class boats, raided the Otranto Barrage, an Alliednaval 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 23 September 1917, 77 T and another 250t-class boat were laying a minefield off Grado in the northern Adriatic when they had a brief encounter with a Royal Italian NavyMAS motor torpedo boat. By 1918, the Allies had strengthened their ongoing blockade on the Strait of Otranto, as foreseen by the Austro-Hungarian Navy. As a result, it was becoming more difficult for the German and Austro-Hungarian U-boats to get through the strait and into the Mediterranean Sea. In response to these blockades, the new commander of the Austro-Hungarian Navy, KonteradmiralMiklós Horthy, decided to launch an attack on the Allied defenders with battleships, scout cruisers, and destroyers. During the night of 8 June, Horthy left the naval base of Pola in the upper Adriatic with the dreadnought battleships and. At about 23:00 on 9 June 1918, after some difficulties getting the harbour defence barrage opened, the dreadnoughts and, escorted by one destroyer and six torpedo boats, including 77 T, also departed Pola and set course for Slano, north of Ragusa, to rendezvous with Horthy in preparation for a coordinated attack on the Otranto Barrage. About 03:15 on 10 June, while returning from an uneventful patrol off the Dalmatian coast, two Italian MAS boats, MAS 15 and MAS 21, spotted the smoke from the Austrian ships. Both boats successfully penetrated the escort screen and split to engage the dreadnoughts individually. MAS 21 attacked Tegetthoff, but her torpedoes missed. Under the command of Luigi Rizzo, MAS 15 fired two torpedoes at 03:25, both of which hit Szent István. Both boats evaded pursuit. The torpedo hits on Szent István were abreast her boiler rooms, which flooded, knocking out power to the pumps. Szent Istváncapsized less than three hours after being torpedoed.
Interwar period
77 T survived the war intact. In 1920, under the terms of the previous year's Treaty of Saint-Germain-en-Laye by which rump Austria officially ended World War I, she was allocated to the Kingdom of Serbs, Croats and Slovenes. Along with three other 250t-class T-group boats, 76 T,78 T and 79 T, and four 250t-class F-group boats, she served with the Royal Yugoslav Navy. Taken over in March 1921, in KJRM service, 77 T was renamed T2. When the navy was formed, 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 tenderHvar and the submarines and, 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 T2 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 1939, T2 was scrapped.
