T3 was a sea-going torpedo boat that was operated by the Royal Yugoslav Navy between 1921 and 1941. Originally 78 T, a of the Austro-Hungarian Navy built in 1914, she was armed with two guns, four torpedo tubes, and could carry 10–12 naval mines. She saw active service during World War I, performing convoy, escort and minesweeping 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 78. She 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, she was allocated to the Navy of the Kingdom of Serbs, Croats and Slovenes, which later became the Royal Yugoslav Navy, and was renamed T3. At the time, she and the seven other 250t-class boats were the only modern sea-going vessels of the fledgling maritime force. During the interwar period, T3 and the rest of the navy were involved in training exercises and cruises to friendly ports, but activity was limited by reduced naval budgets. The ship was captured by the Italians during the Axis invasion of Yugoslavia in April 1941. After her main armament was modernised and her crew increased to 62, she served with the Royal Italian Navy under her Yugoslav designation, although she was only used for coastal and second-line tasks. Following the Italian capitulation in September 1943, she was captured by Germany and, after being fitted with additional anti-aircraft guns, served with the German Navy or the Navy of the Independent State of Croatia as TA48. In German/Croatian service her crew of 52 consisted entirely of Croatian officers and enlisted men. She was sunk by Allied aircraft in February 1945 while in the port of Trieste, where she had been built.

Background In 1910, the Austro-Hungarian 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 on expectations 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 (now Kotor) 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 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 crew consisted of three officers and thirty-eight 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. 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, and had a large ventilation cowl under the bridge and another smaller one aft of the funnel. Due to an inadequate budget, 78 T and the rest of the 250t class were essentially large 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, which had to be progressively solved once they were in service.

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. 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 fifth of its class to be built, 78 T was laid down on 22 October 1913, launched on 4 March 1914, and completed on 23 August 1914. Later that year, one machine gun was added for anti-aircraft work.

Career

World War I 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 in order 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.

On 24 May 1915, 78 T and seven other 250t-class boats were involved in the shelling of various Italian shore-based targets known as the Bombardment of Ancona, with 78 T involved in the shelling of Porto Corsini near Ravenna. In the latter action, an Italian shore battery returned fire, hitting the scout cruiser and damaging one of the other 250t-class boats. On the night of 18/19 June, 78 T was part of a flotillaconsisting of two scout cruisers, three destroyers and five 250t-class boatsproviding distant cover for a bombardment of Rimini and Pesaro when they encountered and sank the Italian steamer Grazia near San Benedetto del Tronto. On 23 July, 78 T and 77 T joined the scout cruiser in bombarding Ortona as part of a 1st Torpedo Flotilla shore bombardment and landing operation on the central Adriatic coast of Italy which also targeted San Campomarino and Termoli and involved cutting the telegraph cable on the island of Tremiti. On 17 August, the 1st Torpedo Flotilla shelled the island chain of Pelagosa in the middle of the Adriatic, and 78 T was part of a force 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. 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. This force was tasked to maintain 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 78 T and four other 250t-class boats were sent south with the scout cruiser in order 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 6 February 1916, Helgoland, 78 T and five other 250t-class boats were sent to intercept the British light cruiser and Italian which had attacked Wildfang while she was escorting a seaplane raid. Instead of meeting the pair that had forced Wildfang to retreat, the Austro-Hungarian force encountered the British light cruiser and French which had since relieved themnorth of Durazzo in Albania. The torpedo boats manoeuvred into two groups of three for the attack, but in one of the groups two leading boats collided, with one sustaining damage, forcing that group to retreat to the port of Budva in Austro-Hungarian-occupied Montenegro, and the other group pressed their attack unsuccessfully. The entire Austro-Hungarian force then returned to the Bocche, having lost an opportunity to interdict significant convoy traffic further south between Albania and Italy. On 24 February, 78 T was part of an Austro-Hungarian forceconsisting of a scout cruiser, four destroyers and five 250t-class boatssent to disrupt the Allied evacuation of Durazzo, but encountered no Allied ships. In 1917, 78 Ts forward 66 mm gun was placed on an anti-aircraft mount. On 11 May 1917, the British submarine stalked 78 T off Pola, firing two torpedoes at her. The British captain had kept his submarine's periscope extended too far and for too long, and the tell-tale "feather" had alerted the crew of 78 T, allowing her crew to avoid the incoming torpedoes. 78 T, 93 F and 96 F, accompanied by the Huszár-class destroyer , unsuccessfully pursued the British submarine. On 21 May, the suffix of all Austro-Hungarian torpedo boats was removed, and thereafter they were referred to only by the numeral. On 23 September, 77 and 78 were laying a minefield off Grado in the northern Adriatic when they had a brief encounter with an Italian MAS boat. While laying mines on routes between Venice and Ancona on 19 November, 78, along with four other 250t-class boats, was intercepted by four Italian destroyers but were able to escape damage. On 28 November, a number of 250t-class boats were involved in two shore bombardment missions. In the second mission, 78 joined seven other 250t-class boats and six destroyers for the bombardment of Porto Corsini, Marotta and Cesenatico. The bombardment damaged the railway tracks between Senigallia and Rimini and destroyed one locomotive and several wagons, but when the flotilla moved to attack two small steamers, an Italian armoured train arrived and engaged them with its guns, and they broke off. On the return voyage to Pola, the ships were apparently pursued by Italian warships, but the scout cruiser sailed to provide support, and the Italians withdrew.