Italian fleet begins operations in the Adriatic

The British chronology of the war records under 25 May 1915 that the Italian fleet began operations in the Adriatic. Italy declared war on Austria-Hungary on 23 May, and the state of war took effect from 24 May. The first clashes at sea therefore broke out as early as the night of 23–24 May, and it was not the Italians but the Austrians who struck first and hardest. On 25 May Italian sailors occupied the post at Porto Buso, which had been shelled the day before, and communiqués from Rome announced the fleet’s first successes.

Two fleets on one sea

In May 1915 the Italian navy, the Regia Marina, had several modern dreadnoughts, older battleships, armoured cruisers, about sixty destroyers and nearly twenty submarines. Since August 1914 the main forces had been stationed at Taranto as the Armata Navale under the Duke of the Abruzzi, Luigi Amedeo of Savoy, the well-known traveller and polar explorer. The lighter ships were concentrated at Brindisi, while a destroyer flotilla based at Venice was to support the army advancing eastwards.

Italy’s Adriatic coast was flat, almost without good harbours and exposed to attack. The eastern, Austrian shore was indented, full of islands and sheltered bays in which the enemy’s bases lay hidden: Pola, Sebenico and the Bay of Kotor. The chief of staff of the Italian navy, Admiral Paolo Thaon di Revel, wanted to save the heavy ships for a decisive battle and to fight day to day with destroyers, submarines and mines. The Austro-Hungarian fleet commander, Admiral Anton Haus, likewise had no intention of risking his battleships in an open engagement with the superior forces of the Italians and their allies. Instead he decided to strike quickly, before the enemy could organise himself.

The Austrian blow of 24 May

During the night of 23–24 May almost the entire Austro-Hungarian fleet, including three dreadnoughts and several older battleships, sailed from Pola, divided into groups with separate targets on the Italian coast. At dawn the main force, led by Admiral Haus aboard the battleship Habsburg, shelled Ancona for about an hour. Shells hit the shipyard, the military hospital, the prison, an orphanage and houses, and also damaged the cathedral of San Ciriaco. A torpedo sank a German steamer lying in the harbour. According to Italian figures, more than 60 people, soldiers and civilians, were killed in Ancona alone.

Other ships shelled Senigallia, Rimini, Potenza Picena, Porto Corsini, Vieste, Manfredonia and Barletta. The targets were above all the bridges, stations and trains on the coastal railway by which the Italians were moving troops north, as well as signal and wireless stations. Seaplanes dropped bombs on Venice. In the south the Austro-Hungarian cruiser Helgoland with destroyers clashed with the Italian destroyer Turbine, which had attacked the enemy to cover another vessel. Turbine was shot to pieces and sank. Between ten and fifteen sailors were killed, depending on the source, and about thirty, led by her commander, were taken prisoner. The Italian cruisers Libia and Città di Siracusa engaged the Austrians, but the faster enemy ships drew away. Before noon all the Austro-Hungarian vessels were back in their bases, with slight losses of their own: a few killed and damage to a couple of ships.

Porto Buso

The Italians responded the same day at the northern end of the Adriatic, where the fleet was to cover the right flank of the army crossing the border. At about 2 a.m. on 24 May the destroyer Zeffiro, under Commander Arturo Ciano, slipped unnoticed into the lagoon at Porto Buso, a border post of the Austrian customs guard and army near Grado. The fire of her guns smashed the barracks, the jetty and several motor boats. Some of the garrison were killed trying to escape, and the post commander hoisted a white flag. Zeffiro brought 48 prisoners back to Venice. It was the Italian navy’s first offensive action of this war. On 25 May a detachment of Italian sailors landed at Porto Buso and took over the post, and in the following days the Austrians also withdrew from Grado itself. In the south, on the same 24 May, an Italian detachment landed on the islet of Pelagosa in the middle of the Adriatic, but found nobody there and sailed away after a few hours.

The first days showed what the war in the Adriatic would look like. The battle fleets rarely left harbour, and the fighting was done by destroyers, torpedo boats, submarines and aircraft. As early as 26 May Italy proclaimed a blockade of the enemy’s coasts, and at the end of the month a British battleship squadron joined the Duke of the Abruzzi’s fleet. The Allies’ superiority, however, did not translate into command of the sea. In the summer of 1915 the Italians lost two armoured cruisers, Amalfi and Giuseppe Garibaldi, to submarine torpedoes.