Naval warfare in the Mediterranean during World War I

There was sporadic naval warfare in the Mediterranean during World War I between the Central Powers' navies of Austria-Hungary, Germany and the Ottoman Empire and the Allied navies of Italy, France, Greece, Japan, America and the British Empire.

Austro-Hungarian Imperial and Royal Navy
Austria-Hungary was a medium-sized naval power in 1914. With a fairly short coastline (from Trieste in present day Italy to Cattaro in modern Montenegro) and no colonies, Austria-Hungary was much more of a land power than a sea power.

Indeed, the Austro-Hungarian Navy included four powerful s and a number of submarines. In addition, the Germans managed to send some U-boats to the Mediterranean which operated from Austrian naval bases, initially under the Austrian navy flag, later under the German navy flag.

Italian Regia Marina (Royal Navy)
The Kingdom of Italy during World War I had six dreadnought battleships (ITALIAN BATTLESHIP Dante Alighieri as a prototype, ITALIAN BATTLESHIP Giulio Cesare, ITALIAN BATTLESHIP Conte di Cavour and ITALIAN BATTLESHIP Leonardo da Vinci of the, ITALIAN BATTLESHIP Andrea Doria and ITALIAN BATTLESHIP Caio Duilio of the ).



During the war, the Italian Royal Navy spent her major efforts in the Adriatic Sea, fighting the Austro-Hungarian Navy. The resulting so-called Adriatic Campaign of World War I consisted mainly of Austro-Hungarian coastal bombardments of Italy's Adriatic coast, wider-ranging German/Hungarian submarine warfare into the Adriatic and the Mediterranean, and Italian use of new weapons (mainly MAS and human torpedoes) that were successful in the sinking of two Austrian battleships.

For most of the war the Italian and Austro-Hungarian navies each kept a relatively passive watch over their counterparts. The Italian fleet lost the pre-dreadnought battleship ITALIAN BATTLESHIP Benedetto Brin at Brindisi (27 September 1915) and the dreadnought ITALIAN BATTLESHIP Leonardo da Vinci at Taranto (2 August 1916) due to magazine explosion (although some historians argue of Austrian sabotage). In the last part of the war, the Regia Marina developed new naval weapons: the MAS boats that sank the Austro-Hungarian battleship SMS Szent István in the Adriatic Sea on 10 June 1918, and an early type of human torpedo (Mignatta) that entered the harbour of Pula and sank the Austro-Hungarian flagship SMS Viribus Unitis on 1 November 1918.

Campaigns
In the Mediterranean Sea, the war began with most of the large, but elderly French fleet deployed on escort duty to protect convoys across the Mediterranean from the smaller, but newer Austrian fleet and cover against possible Italian entry into the war on Austria's side. Several British ships were also sent to Malta to reinforce the British Mediterranean Fleet. Germany also had a small Mediterranean fleet (based at the Austrian naval base of Pola in current day Croatia) and at the commencement of hostilities, the powerful battlecruiser SMS Goeben and the light cruiser SMS Breslau, were patrolling the western Mediterranean. The German Mediterranean fleet did not find the French convoys, so proceeded to bombard the French cities of Bizerte and Bône in modern-day Tunisia. Pursued by superior French and British forces, the Goeben and Breslau reached Turkey, where they were nominally transferred to the Ottoman Navy when the Ottoman Empire entered the war on the Central Powers side, and fought many battles against the Russian Black Sea Fleet until Russia's surrender in 1917.

After the Kingdom of Italy entered the war on the Allied side in 1915, the strategy of the Allies was to blockade the Adriatic and monitor the movements of the Austrian fleet. In general, this strategy was successful but the Germans and the Austrians were able to send submarines out into the Mediterranean where they did some damage. Total Allied warship losses to Austrian and German submarines were: two 2nd-line battleships, two armored cruisers, five destroyers, and two submarines (in addition to many damaged navy ships and sunk freighters). The primary sea bases for the Austrian and German fleet in the Adriatic were Pola (in Istria) and Cattaro (in southern Dalmatia).

On the Allied side, their navies were able to sail relatively freely throughout the Mediterranean by keeping the Central Powers' surface units bottled up in either the Adriatic or at Constantinople. This freedom of movement was tremendously important for the Allies, as they were not only able to keep open their supply routes (to Egypt for example), but to also evacuate the Serbian Army from capture and even launch (and supply) amphibious invasions at Gallipoli in 1915 and Salonika in 1916.

In 1915, the major fleet action was the Allied attempt to knock the Ottoman Empire out of the war by an attack on Constantinople. The Allies needed to pass the Dardanelles strait in order to supply Russia. The Battle of Gallipoli lasted for most of the year but was unsuccessful. An initial naval assault was deterred by mines and coastal fortresses, and the subsequent land assault was also defeated, but with heavy casualties on both sides.

After Gallipoli, the only significant naval battle occurred on May 15, 1917 when three Austrian cruisers under Captain Miklós Horthy staged a series of pin-prick raids on Italian and British transports near Valona, Albania who were evacuating the Serbian Army from being overrun. The raid was a partial success but the raiders were nearly destroyed by a shell hit which knocked out an engine on the Austrian cruiser SMS Novara. With heavier Allied forces closing in, the Austrians were routed back to Pola. The Austrians then decided to raid patrol boats guarding the Otranto Straits between Italy, Corfu and Albania. For further details see the battle of the Otranto Barrage.

On August 2, 1916, the Italian dreadnought ITALIAN BATTLESHIP Leonardo da Vinci exploded at Taranto, killing 249 of its crew. Reminiscent of the USS Maine (ACR-1), the event was widely reported in the Italian press, which immediately blamed Austrian or German saboteurs, something the Central Powers did nothing to disavow. The cause of the explosion has never been verified. It had considerable effect as a propaganda tool for both sides.

In December 1917, Luigi Rizzo with his MAS sank the Austro-Hungarian pre-dreadnought battleship SMS Wien, that was at anchor inside the defences of Trieste harbour.

Italian sinkings of two Austrian battleships
In 1918, two of the Austrian dreadnoughts were sunk.

One sank during a war-battle near the island of Premuda in Dalmatia. This was the SMS Szent István, which was sunk during another sortie (June 10) against the Allied blockade by fast moving Italian motor torpedo boats of Luigi Rizzo.

The second, the SMS Viribus Unitis, was sunk by a new weapon created and used by engineer and naval officer Raffaele Rossetti: the human torpedo called "Mignatta". At the end of the war there was a mutiny in the Austrian Navy and Horthy was ordered to surrender the entire Austrian fleet to the National Council of Slovenes, Croats and Serbs. Rossetti did not know of this decision and did his well planned attack the same day. So, another Austro-Hungarian dreadnought sank. The explosion went off under the ship on November 1 (just after the Austro-Hungarian government collapsed) and the Slav National Council made no efforts to restore the hulk, since Italy occupied the region only a few days later.

Secondary campaigns and interventions
Allied fleets also played a role in coercing the Greek government to join the Allies and later supply the campaigns in Palestine and Macedonia. Although Germany was able to gain control of the Black Sea and part of the Russian fleet after the collapse of the Russian Empire, they were never able to break out into the Aegean. The German–Turkish fleet tried in 1918, but hit a minefield; the Breslau was sunk and the Goeben almost followed that fate, but the captain was able to run the ship aground and beach it before capsizing. The Goeben was not repaired until after the war.

Allied fleets occupied Constantinople briefly after the Armistice of Mudros, until the new Turkish Republic under Mustafa Kemal took back control of the city in 1923.

Allied ships did continue to intervene in Russia after the war ended, bringing expeditionary forces and supplies via the Mediterranean to the White armies in southern Russia.

Japan, an ally of Great Britain, sent a total of 14 destroyers to the Mediterranean starting in April 1917. The Japanese ships were very effective in patrol and anti-submarine activity. The Austro-Hungarian navy lost nine submarines during the war: five sunk by the Italian navy (SMU U-10 (Austria-Hungary), SMU U-13 (Austria-Hungary), SMU U-16 (Austria-Hungary), SMU U-20 (Austria-Hungary), SMU U-23 (Austria-Hungary)), one by Italian and French units (SMU U-30 (Austria-Hungary)), one by British units (SMU U-3 (Austria-Hungary)), none by the Japanese navy, which converserly suffered 68 dead and heavy damage on the destroyer JAPANESE DESTROYER Sakaki, torpedoed by Austrian submarine SMU U-27 (Austria-Hungary).