The Otranto Barrage was an Allied naval blockade of the Strait of Otranto between Brindisi in Italy and Corfu on the Greek side of the Adriatic Sea in the First World War. The blockade was intended to prevent the Austro-Hungarian Navy from escaping into the Mediterranean and threatening Allied operations there. The blockade was effective in preventing surface ships from escaping the Adriatic, but it had little or no effect on the submarines based at Cattaro.
The Adriatic is 72 km (39 nmi ; 45 mi ) wide at the Otranto Straits. [1] The blockade consisted mainly of a fleet of drifters, most of them British, and usually armed with a 6-pounder gun and depth charges. [2] In 1915 when the blockade was begun, two divisions of 20 would be on patrol at a time, equipped with steel indicator nets intended to trap submarines or at least alert the surface vessels to their presence. A third division would be at Brindisi. [3] The drifters were supported by destroyers and aircraft. However, the demands of the Gallipoli Campaign and other naval operations left the Otranto Barrage with insufficient resources to deter the U-boats, and only the Austro-Hungarian U-6 [4] was caught by the indicator nets during the course of the war. It was later considered that the straits had simply been too wide to be netted, mined or patrolled effectively. [2]
The ease with which German and Austrian submarines continued out of the Austro-Hungarian ports in spite of the barrage (and the success they had in disrupting shipping in the whole of the Mediterranean) strongly embarrassed the Allies, the system being called "a large sieve through which U-boats could pass with impunity". [2] In 1917–1918, reinforcements from the Australian and American navies brought the blockading force up to 35 destroyers, 52 drifters and more than 100 other vessels.[ citation needed ] Nevertheless, submarines continued to slip through until the end of the war; the introduction of the convoy system and better coordination amongst the Allies only helped to cut the losses they were causing. [2]
The Austrians mounted nighttime raids against the barrage, five in 1915, nine in 1916 and ten in 1917. After a raid by four Huszár-class destroyers in December 1916, a conference in London concluded that the drifters were insufficiently defended. The barrage was placed under the command of a British officer, Commodore Algernon Walker-Heneage-Vivian, who was able to call upon all Allied ships not in use elsewhere. [3] His second-in-command was another British officer, Commander Charles Edward Turle. The largest raid was carried out on the night of 14/15 May 1917 by the cruisers SMS Novara, Helgoland, and Saida supported by the destroyers SMS Csepel and Balaton and Austro-Hungarian U-boats U-4 and U-27, along with German U-boat UC-25 (operating as Austro-Hungarian U-boat U-89). The fleet, commanded by Commodore Miklós Horthy, sank 14 drifters out of 47 on duty, and damaged a further three seriously. [2]
Skipper Joseph Watt was later awarded the Victoria Cross for defending his drifter Gowanlea under heavy attack from Novara. The British light cruisers HMS Dartmouth and Bristol—together with Italian and French destroyers, under command of Italian Rear Admiral Alfredo Acton—steamed from Brindisi to engage the Austrians, resulting in the Battle of the Otranto Straits. The British damaged Saida and disabled Novara, severely injuring Horthy. However, the British cruisers broke off the engagement when the Italian flag officer received notice of heavy Austrian forces coming out of Cattaro. Saida towed Novara back to port. Dartmouth was damaged by UC-25 as it returned to Brindisi. The night before, the same U-boat had laid a minefield at the mouth of Brindisi harbour; the French destroyer Boutefeu struck one of these mines exiting the harbour the very same day and exploded, sinking with all hands.
In June 1918, Horthy—by now commander-in-chief of the Austro-Hungarian Navy—decided to launch an attack on the barrage employing the four Tegetthoff-class battleships based at Pola, the most modern in the fleet. While en route down the Adriatic, the battleship SMS Szent István was torpedoed and sunk by an Italian torpedo boat at dawn on 10 June, resulting in the attack being cancelled.
Naval warfare in the Mediterranean during World War I took place between the naval forces of the Entente and the Central Powers in the Mediterranean Sea between 1914 and 1918.
The First Battle of Durazzo was a naval battle of World War I. It was fought off Durazzo, Albania at the end of December 1915 and involved the navies of Austria-Hungary, the United Kingdom, Italy, and France.
The Adriatic Campaign of World War I was a naval campaign fought between the Central Powers and the Mediterranean squadrons of Great Britain, France, the Kingdom of Italy, Australia, and the United States.
SMS Novara was a Novara-class scout cruiser of the Austro-Hungarian Navy which served during World War I. Built by the Danubius shipyard between December 1912 and January 1915, Novara was the third and final member of her class to enter service, some six months after the start of the war. She was armed with a battery of nine 10-centimeter (3.9 in) guns and had a top speed of 27 knots.
The Battle of the Strait of Otranto of 1917 was the result of an Austro-Hungarian raid on the Otranto Barrage, an Allied naval blockade of the Strait of Otranto. The battle took place on 15 May 1917, and was the largest surface action in the Adriatic Sea during World War I. The Otranto Barrage was a fixed barrier, composed of lightly armed drifters with anti-submarine nets coupled with minefields and supported by Allied naval patrols.
The Bombardment of Ancona was a naval engagement of the Adriatic Campaign of World War I between the navies of Italy and Austria-Hungary. Forces of the Imperial and Royal Navy attacked and bombarded military and civilian targets all across Ancona in central Italy and several other nearby islands and communities in response to Italy's declaration of war on Austria-Hungary.
SMS Helgoland was a Novara-class scout cruiser built for the Austro-Hungarian Navy right before World War I. Helgoland participated in several raids on the ships defending the Strait of Otranto, including the Battle of the Strait of Otranto in May 1917. She was transferred to Italy in 1920 in accordance with the peace treaties ending World War I and renamed Brindisi. After modifications, the ship was assigned to the squadron responsible for the Eastern Mediterranean until 1924. She spent the next five years based in Libya and Italy before Brindisi was disarmed and turned into a depot ship in 1929. The ship was stricken from the Navy List in 1937 and later broken up.
Nino Bixio was a protected cruiser built by the Italian Regia Marina in the early 1910s. She was the lead ship of the Nino Bixio class, which were built as scouts for the main Italian fleet. She was equipped with a main battery of six 120-millimeter (4.7 in) guns and had a top speed in excess of 26 knots, but her engines proved to be troublesome in service. Nino Bixio saw service during World War I and briefly engaged the Austro-Hungarian cruiser SMS Helgoland in 1915. Her career was cut short in the post-war period due to severe cuts to the Italian naval budget, coupled with her unreliable engines. Nino Bixio was stricken from the naval register in March 1929 and sold for scrap.
Marsala was a protected cruiser built by the Italian Regia Marina in the 1910s. She was the second and final member of the Nino Bixio class, which were built as scouts for the main Italian fleet. She was equipped with a main battery of six 120-millimeter (4.7 in) guns and had a top speed in excess of 26 knots, but her engines proved to be troublesome in service. Marsala spent World War I based at Brindisi; she was involved in the Battle of the Otranto Straits in May 1917, where she briefly engaged Austro-Hungarian cruisers. Marsala's career was cut short in November 1927 when she was stricken from the naval register and sold for scrap, the result of her unreliable engines and drastic cuts to the naval budget.
SMS Saida was a Novara-class scout cruiser built for the Austro-Hungarian Navy in the early 1910s. The ship was armed with a main battery of nine 10 cm (3.9 in) guns, and six twin 53.3 cm (21.0 in) torpedo tubes were added in 1917. She was built by the Cantiere Navale Triestino shipyard from 1911 to 1914, entering service days after the outbreak of World War I. She spent the war as a flotilla leader, conducting raids and patrols in the narrow waters of the Adriatic Sea.
The 250t class were high-seas torpedo boats built for the Austro-Hungarian Navy between 1913 and 1916. A total of 27 boats were built by three shipbuilding companies, with the letter after the boat number indicating the manufacturer. There were small variations between manufacturers, mainly in the steam turbines used, and whether they had one or two funnels. The eight boats of the T-group, designated 74 T – 81 T, were built by Stabilimento Tecnico Triestino, located at Trieste. The sixteen boats of the F-group, 82 F – 97 F, were built by Ganz-Danubius at their shipyards at Fiume and Porto Re. The three M-group boats, 98 M – 100 M, were manufactured by Cantiere Navale Triestino at Monfalcone.
Bisson was the name ship of her class of destroyers built for the French Navy during the 1910s, entering service in 1913. She served in the Mediterranean Sea during the First World War, sinking the Austro-Hungarian submarine U-3 on 6 July 1915 and took part in the Battle of Durazzo in December 1915 and the Battle of the Strait of Otranto in May 1917. She was stricken in 1933 and scrapped in 1939.
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 66 mm (2.6 in) guns and four 450 mm (17.7 in) 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. Present 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 Szent István during the action that resulted in the sinking of that ship by Italian torpedo boats in June 1918.
T4 was a seagoing torpedo boat operated by the Royal Yugoslav Navy between 1921 and 1932. Originally 79 T, a 250t-class torpedo boat of the Austro-Hungarian Navy built in 1914, she was armed with two 66 mm (2.6 in) guns, four 450 mm (17.7 in) 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. In 1917 the suffixes of all Austro-Hungarian torpedo boats were removed, and thereafter she was referred to as 79. Present in the Bocche de Cattaro during the short-lived mutiny by Austro-Hungarian sailors in early February 1918, her crew remained loyal. She was part of the escort force for the Austro-Hungarian dreadnought Szent István during the action that resulted in the sinking of that ship by Italian torpedo boats in June 1918.
The Novara class was a class of three scout cruisers built for the Austro-Hungarian Navy. Named for the Battle of Novara, the class comprised SMS Saida, SMS Helgoland, and SMS Novara. Construction started on the ships shortly before World War I; Saida and Helgoland were both laid down in 1911, Novara followed in 1912. Two of the three warships were built in the Ganz-Danubius shipyard in Fiume; Saida was built in the Cantiere Navale Triestino shipyard in Monfalcone. The Novara-class ships hold the distinction for being the last cruisers constructed by the Austro-Hungarian Navy.
SMS Admiral Spaun was a scout cruiser built for the Austro-Hungarian Navy. Named for Admiral and Marinekommandant Hermann von Spaun, Admiral Spaun was constructed shortly before World War I. Laid down at the Pola Navy Yard in May 1908, the cruiser was launched in October 1909. Admiral Spaun was commissioned into the Navy just over a year later, in November 1910. The first ship of the Austro-Hungarian Navy to be constructed with steam turbines, her design later influenced the construction of the Novara-class cruisers.
SMS Orjen was one of six Tátra-class destroyers built for the kaiserliche und königliche Kriegsmarine shortly before the First World War. Completed in 1914, she helped to sink an Italian destroyer during the action off Vieste in May 1915 after Italy declared war on Austria-Hungary. Two months later the ship participated in an unsuccessful attempt to recapture a small island in the central Adriatic Sea from the Italians. In November and early December Orjen was one of the ships conducting raids off the Albanian coast to interdict the supply lines between Italy and Albania, although she did not participate in the First Battle of Durazzo in late December. Orjen participated in several raids on the Otranto Barrage in 1916–1917 with limited success. She was transferred to Italy in 1920 in accordance with the peace treaties ending the war and renamed Pola. She mostly served as a training ship or in Italian North Africa when she was not in reserve from 1924 to 1928. Renamed Zenson in 1931, the ship was scrapped in 1937.
SMS Csepel was one of six Tátra-class destroyers built for the kaiserliche und königliche Kriegsmarine shortly before the First World War. Completed in 1913, she helped to sink an Italian destroyer during the action off Vieste in May 1915 after Italy declared war on Austria-Hungary. Two months later the ship participated in an unsuccessful attempt to recapture a small island in the central Adriatic Sea from the Italians. In November and early December Csepel was one of the ships conducting raids off the Albanian coast to interdict the supply lines between Italy and Albania. She was hit one time during the First Battle of Durazzo in late December. Her stern was blown off by a French submarine in early 1916 and her repairs were not completed until early 1917.
SMS Balaton was one of six Tátra-class destroyers built for the kaiserliche und königliche Kriegsmarine shortly before the First World War. Completed in 1913, she did not participate in the attacks on the Italian mainland after Italy declared war on Austria-Hungary in May 1915. Two months later the ship bombarded a small island in the Central Adriatic Sea during an unsuccessful attempt to recapture it from the Italians. In November and early December Balaton was one of the ships conducting raids off the Albanian coast to interdict the supply lines between Italy and Albania. She played a minor role in the 1st Battle of Durazzo in late December. Balaton participated in several unsuccessful raids on the Otranto Barrage in 1917, although she sank an ammunition ship during the Battle of the Strait of Otranto. She was transferred to Italy in 1920 in accordance with the peace treaties ending the war and renamed Zenson. The Regia Marina used her for spare parts; she was discarded in 1923 and subsequently scrapped.
SMS Tátra was the lead ship of her class of six destroyers built for the kaiserliche und königliche Kriegsmarine shortly before the First World War. Completed in 1913, she helped to sink an Italian destroyer during the action off Vieste in May 1915 after Italy declared war on Austria-Hungary. Two months later the ship participated in an unsuccessful attempt to recapture a small island in the Central Adriatic Sea from the Italians. In November and early December Tátra was one of the ships conducting raids off the Albanian coast to interdict the supply lines between Italy and Albania. During the early stages of the 1st Battle of Durazzo in late December, the ship was tasked to tow her one of her sister ships that had been crippled by a mine. She was forced to abandon her sister when the Austro-Hungarians were spotted by a strong force of Allied ships and had to evade their pursuit. Tátra participated in several unsuccessful raids on the Otranto Barrage in 1917. She was transferred to Italy in 1920 in accordance with the peace treaties ending the war and renamed Fasana. The Regia Marina used her for spare parts; she was discarded in 1923 and subsequently scrapped.
