T2 was a seagoing torpedo boat operated by the Royal Yugoslav Navy between 1923 and 1939. Originally 77 T, a 250t-class torpedo boat of the Austro-Hungarian Navy built in 1914, she was armed with two guns and four torpedo tubes, and could carry 10–12 naval mines. She saw active service during World War I, performing convoy, patrol, escort, minesweeping and minelaying tasks, anti-submarine operations, and shore bombardment missions. In 1917, the suffixes of all Austro-Hungarian torpedo boats were removed, and thereafter she was referred to as 77. The vessel was in the Bocche di Cattaro during the short-lived mutiny by Austro-Hungarian sailors in early February 1918; members of her crew raised the red flag but undertook no other mutinous actions. 77 was part of the escort force for the Austro-Hungarian dreadnought during the action that resulted in the sinking of that ship by Italian torpedo boats in June 1918.
Following Austria-Hungary's defeat in 1918, 77 was allocated to the Navy of the Kingdom of Serbs, Croats and Slovenes, which later became the Royal Yugoslav Navy, and was renamed T2 and had her armament upgraded. At the time, she and seven other 250t-class boats were the only modern sea-going vessels of the fledgling maritime force. During the interwar period, the navy was involved in training exercises and cruises to friendly ports, but activity was limited by reduced naval budgets. Worn out after twenty-five years of service, T2 was stricken from the naval register and scrapped in 1939.
Background 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. At the same time, the committee issued design parameters for a high seas or fleet torpedo boat of , top speed of 30 kn and endurance of . This design would have been a larger and better-armed vessel than the existing Austro-Hungarian s. The specification for the high seas torpedo boat was based on 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 (the Bocche or Bay of Kotor) 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. Despite having developed these ideas, the Austro-Hungarian Navy then asked shipyards to submit proposals for a boat with a maximum speed of . Stabilimento Tecnico Triestino (STT) of Triest was selected for the contract to build eight vessels, the T group, ahead of one other tenderer. The T-group designation signified that they were built at Triest.
Description and construction The , T-group boats had short raised forecastles and an open bridge, and were fast and agile, well designed for service in the Adriatic. They had a waterline length of , a beam of , and a normal draught of . While their designed displacement was , they displaced about fully loaded. 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. There were two boiler rooms, one behind the other. The turbines were rated at and designed to propel the boats to a top speed of , although a maximum speed of could be achieved. 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. 79 T and the rest of the 250t class were classified as high seas torpedo boats by the Austro-Hungarian Navy, despite being smaller than the original concept for a coastal torpedo boat. The naval historian Zvonimir Freivogel states that this type of situation was common due to the parsimony of the Austro-Hungarian Navy. They were the first small Austro-Hungarian Navy boats to use turbines, and this contributed to ongoing problems with them, which had to be progressively solved once they were in service. The crew consisted of three officers and thirty-eight enlisted men. The vessel carried one yawl as a ship's boat.
The boats were originally to be armed with three Škoda L/30 guns, and three torpedo tubes, but this was changed to two guns and four torpedo tubes before the first boat was completed, to standardise the armament with the F group to follow. A searchlight was mounted above the bridge. The torpedo tubes were mounted in pairs, with one pair mounted between the forecastle and bridge, and the other on a section of raised superstructure above the aft machinery room. 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 and commissioned on 11 August 1914. Prior to her commissioning, one Schwarzlose M.7/12 machine gun was included in the armament of all boats of the class for anti-aircraft work. Four mounting points were installed so that the machine gun could be mounted in the most effective position depending on the expected direction of attack. Until October 1915, the boat was painted black, but from that point it was painted a light blue-grey.
Career World War I At the outbreak of World War I on 28 July 1914, 77 T was part of the 1st Torpedo Group of the 3rd Torpedo Craft Division of the Austro-Hungarian 1st Torpedo Craft Flotilla, which was led by the scout cruiser commanded by Linienschiffskapitän (Captain) Heinrich Seitz, and supported by the mother ship . The original concept of operation for the 250t-class boats was that they would sail in a flotilla at the rear of a cruising battle formation, and were to intervene in fighting only if the battleships around which the formation was established were disabled, or to attack damaged enemy battleships. When a torpedo attack was ordered, it was to be led by a scout cruiser, supported by two destroyers to repel any enemy torpedo boats. A group of four to six torpedo boats would deliver the attack under the direction of the flotilla commander.
During the war, 77 T was used for convoy, patrol, escort and minesweeping tasks, anti-submarine operations, and shore bombardment missions. 77 T was transferred to Sebenico on 16 August. In early September, intelligence was received by the Austro-Hungarian command that an Italian volunteer corps were planning to land on the Dalmatian or Istrian coast, and the 1st Torpedo Flotilla was involved in fruitless patrolling off Sebenico and Zara between 19 and 24 September. According to the naval historian Zvonimir Freivogel, this was disinformation that allegedly originated with the French and was intended to keep the Austro-Hungarian fleet engaged while the French conducted operations in the southern Adriatic undisturbed. On the evening of 3 November, the 1st Torpedo Flotilla left Sebenico to make a night torpedo attack on the French fleet, which had begun its seventh raid on the Adriatic on 31 October. By the time they reached the threatened areas, the French had withdrawn as they were running low on coal. On 6 November, 77 T conducted a patrol off the Dalmatian island of Lastovo, and returned to the main fleet base at Pola in the upper Adriatic on 23 December.
On 10 May 1915, during the lead-up to the Italian declaration of war on Austria-Hungary, 77 T swept the approaches to the Italian port of Ancona for mines. On the afternoon of 23 May, and almost the entire Austro-Hungarian fleet left Pola soon after to deliver an immediate response against Italian cities and towns along the Adriatic coast, aiming to interdict land and sea transport between southern Italy and the northern regions of that country which were expected to be a theatre of land operations. The fleet split into six groups with a range of targets up and down the coast. On 24 May 1915, 77 T and seven other 250t-class boats participated in the Bombardment of Ancona, which involved shelling Italian shore-based targets, 77 T being involved in the operation against Ancona itself. 77 T laid defensive mines off the Dalmatian port of Split on 6 June. On the night of 18/19 June, separate Austro-Hungarian naval task groups attacked both Venice and Rimini, with distant cover provided by a group led by Saida and the scout cruiser and consisting of three destroyers and five 250t-class boats, one of which was 77 T. Near San Benedetto del Tronto, this group intercepted and sank the Italian steamer Grazia. Immediately after this operation, 77 T underwent a refit at Pola. On 23 July, 77 T and another 250t-class boat participated in another shore bombardment mission led by Helgoland against Ortona on the central Adriatic coast of Italy. 77 T was involved in an attack on the island chain of Pelagosa in the middle of the Adriatic on 28 July. On 17 August, the 1st Torpedo Flotilla again shelled Pelagosa, and 77 T was part of a force led by Saida tasked to protect the southern approaches to the islands from enemy submarines. The success of this bombardment, which destroyed the only source of drinking water, caused the Italians to abandon Pelagosa. 77 T again bombarded Pelagosa on 9 September. During September she conducted patrols between the islands of Lastovo, Pelagosa, and Biševo and the Italian port of Bari.
In late November 1915, the Austro-Hungarian fleet deployed a force from Pola to Cattaro in the southern Adriatic; this group included six of the eight T-group torpedo boats. This force was tasked with maintaining a permanent patrol of the Albanian coastline and interdict any troop transports crossing from Italy. After an attack on Durazzo in Albania in which two Austro-Hungarian destroyers were sunk after straying out of a cleared lane through a minefield, on 30 December 77 T and four other 250t-class boats were sent south with the scout cruiser to strengthen morale and try to prevent the transfer of the captured crew of one of the destroyers to Italy. No Italian ships were encountered, and the group returned to the Bocche the following day.
On 17 January 1916, 77 T salvaged a damaged Austro-Hungarian seaplane near the Montenegrin coastal town of Petrovac and towed it to the Bocche. On 22 February, 77 T and two other 250t-class boats, accompanied by a , laid a minefield outside the Montenegrin port of Antivari. With Austro-Hungarian forces closing on Durazzo from the land, the Allies began to evacuate by sea, and Austro-Hungarian naval forces were sent to attempt to interdict. On 24 February, Helgoland, four destroyers, 77 T and five other 250t-class boats were sent to intercept four Italian destroyers covering the evacuation, but were unable to locate them. Between 11 March and 2 May 77 T underwent a further refit at Pola, and on 4 May was transferred to the Bocche. On the night of 31 May – 1 June, the s and , accompanied by 77 T and two other 250t-class boats, raided the Otranto Barrage, an Allied naval blockade of the Strait of Otranto. Orjen sank the British drifter Beneficent, but once the alarm had been raised, the Austro-Hungarian force withdrew. 77 T laid mines off Cape Rodoninorth of Durazzoon 29 June, and returned to Pola in July. On the night of 23/24 September, 77 T and three other 250t boats laid mines off the Po River estuary near Venice. On 12 October, 77 T was attacked by enemy aircraft about west of the Pinida lighthouse on the eastern coast of Istria.