The Sinking of Viribus Unitis

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The last great victim of the World War I in the Adriatic sea was the admiral ship of the former Austro-Hungarian monarchy, battleship Viribus Unitis (lat. "With united forces" - motto of the emperor Franz Joseph I.). She sank without battle, in the middle of Pula harbour, with Croatian flag on her mast, not Austro-Hungarian! Her tragic story certainly deserves attention.

SMS Viribus Unitis on trials, August/September 1912

The main characteristic of the World War One in the Adriatic was the fact that the main opposing forces, Austro – Hungary and Italy, almost constantly kept their fleets in naval bases, avoiding larger military operations. Austro – Hungary attempted one such operation in June 1918, and it ended in disaster – the sinking of SMS Szent István. After that, Austro – Hungarian leadership was even more determined to keep their fleet in bases, and, thereby, prevent further losses. Italians were also not prepared to put their ships in danger, but they were trying to create an alternative method of inflicting losses on the Austro – Hungarian side. The most desirable targets were, of course, Austro – Hungarian capital ships – SMS Viribus Unitis, Tegetthoff and Prinz Eugen. But attacking them seemed impossible – they were being kept anchored in Pula harbour, protected by a complicated set of obstacles at the harbour entrance and numerous fortifications on the shore. Still, in early 1918, Italian Lieutenant Raffaele Paolucci, a naval surgeon, realised that it would be possible to attack the ships in Pula by swimming through the obstacles into the harbour while carrying explosives.

A map of Croatia, showing the location of Pula

In May 1918 Paolucci notified the Italian Army about his plans. Although it was not clear whether the mission would actually take place, it was, nevertheless, decided that he would begin the necessary training.
In July Paolucci met Major Raffaele Rossetti, who had modified a German unexploded torpedo so that it could carry two persons, as well as explosives. With this modified torpedo, Rossetti and Paolucci were able to ride under water at a speed of some 3 km/h. The torpedo was propelled by two propellers which were driven by compressed air. Adequately equipped and supported by the Italian Army, the two diversionists spent three months planning their mission and training the usage of their small vessel in the gulf of Venice.

Raffaele Rossetti                           Raffaele Paolucci

In the autumn of 1918, Austro-Hungary was unstoppably falling apart. On the 6th of October 1918, National Council of Slovenians, Croats and Serbs (SCS) was founded in Zagreb (in Croatian: Narodno Vijece Slovenaca, Hrvata i Srba - SHS). The Serbs in the Council were representing the Serbs from Croatia, not Serbia. Up to that moment, Croatia was a part of Austro-Hungary. On the October 29th the Council severed all political and diplomatic connections between Croatia and Austria, and between Croatia and Hungary. After that, Croatia, Slovenia and Bosnia became united in the State of SCS (Drzava SHS). Emperor Charles I. (Karl I.) gave the entire Austro-Hungarian war and merchant fleet, with all harbours, arsenals and shore fortifications to the Council of SCS. On the October 31st in Pula harbour for the last time the emperor's hymn was played. While the red and white Austro-Hungarian flags were being lowered on the masts of the ships in harbour, the hymn Gott erhalte unseren Kaiser sounded posthumous.

Pula harbour with Tegetthoff class battleships

The stiff and icy rear admiral Miklos Horthy de Nagybanya turned over the war fleet to the representatives of the National Council of SCS from Zagreb. After being given to the National Council, the fleet had become the property of the State of SCS, but it is certainly correct to say that it became Croatian because almost entire coastline and all islands of former Austro - Hungary belonged (and still belong) to Croatia; also, the vast majority of sailors in the fleet were Croats. After the fleet was handed over, thousands of Croats in harbour began to sing the Croatian hymn - Lijepa nasa. While the Croats were singing, Hungarians, Slovenians, Austrians and many others were rushing home, because it was held that the war was over. As the hymn was played, Croatian flags were raised on the masts of the ships.

SMS Viribus Unitis in Pula harbour
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The man who, around 5 PM on the October 31st 1918, took over the entire fleet, was the commander of Viribus Unitis, Janko Vukovich de Podkapelski. He was a remarkably capable and respected soldier and sailor, from Jezerane in Lika (mountainous part of Croatia). The National Council of SCS promoted him to rear admiral, and sent notes to the governments of France, United Kingdom, Italy, United States of America and Russia, in which it said that the State of SCS was not in war with any of the mentioned countries and that the Council had taken over the entire Austro-Hungarian fleet.

Janko Vukovich de Podkapelski

In the evening of October 31st, Paolucci and Rossetti boarded the torpedo boat MAS 95 and headed for Pula. They arrived to a location a few miles away from harbour entrance, and it was here where they put on waterproof rubber suits and left MAS 95. Rossetti thought that the whole operation would last only five hours, and he told the crew of MAS 95 to rendezvous with him and Paolucci on the same location at 03:00. They mounted their modified torpedo, submerged it until only their heads remained above the water surface, and, at 22:13, started the motor and headed towards the harbour entrance. In the meantime, the Croatian crews were celebrating on their brightly lit ships (cease-fire was signed!), completely unaware of what was about to happen.

The crew of Viribus Unitis.
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At 22:30 Paolucci and Rosseti reached the first barricades at the harbour entrance. These were 3 metres long floating metal cylinders, connected by thick steel cables. Furthermore, the area was observed by former Austro – Hungarian, now Croatian guards, who used several searchlights. Unable to submerge and ride under it, the Italians decided to push their vessel over the barricade. This proved to be dangerous, as this action resulted in a lot of noise. Fortunately for them, nobody heard the noise. A former Austro – Hungarian submarine passed quietly by them in the opposite direction, with only its conning tower above the water. Undetected, Paolucci and Rossetti continued riding towards the harbour.

A map of Pula harbour, showing how the Italians approached the Viribus Unitis

After spending a short period of time riding the torpedo, they approached the seawall that was protecting Pula's anchorage. Paolucci got off the torpedo and swam along the wall searching for a way around it. Instead, he found a gate – made of heavy pieces of wood and with protective metal spikes. As Paolucci swam back towards Rossetti, the tide had turned, forcing him to swim against the current, and it started raining. Faced with numerous difficulties they hadn't expected, the two diversionists started wondering whether they should abort the mission. Still, they decided to continue. Again they hoisted their vessel and pushed it over the gate. This time the noise was masked by the rain and hail that started to fall.

The hull of Viribus Unitis in STT shipyard just before launching
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It was now 01:00 November 1st 1918. With the seawall behind them, the Italian diversionists continued riding towards the anchored warships that were now clearly visible. However, they found additional obstacles on their way – anti-submarine nets with attached mines. It took two hours for them to find a way through. It was 03:00 - they were vastly behind schedule, by that moment they should have been back on MAS 95; instead, they haven't even came near their target. They continued riding down the row of warships, towards the place where they expected to find Viribus Unitis. It has to be mentioned here, that the Italian diversionist were not acting on their own. There were several Italian agents in Pula harbour at that moment, and they helped Rossetti and Paolucci to pass through the barricades undetected.

The launching of Viribus Unitis in STT shipyard on June 24th 1911
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When they finally reached Viribus Unitis, it was 04:45. It was dawn; faint light started to appear on the horizon. Suddenly, when they were just next to Viribus Unitis, one of the intake valves on their torpedo opened and their vessel started sinking. Rossetti soon fixed the problem. Soon after that, Rossetti took one of two Mignatta (Leech) limpet mines (200 kg / 400 pd of TNT) that their torpedo was carrying and attached it to the hull of Viribus Unitis. He set the mine to explode at 06:30.

A stern view of the Viribus Unitis

Around 05:00, as they were riding away from Viribus Unitis, the Italians were spotted by the guards on the ship. Rossetti and Paolucci tried to reach the shore, but a boat launched from Viribus Unitis was rapidly approaching them. Realising that they are about to be captured, the Italians sank their torpedo. Soon after that they were pulled out of the water by the crew of Viribus Unitis. When they were brought aboard, Rossetti told admiral Vukovich that his ship would soon be blown up and that he should save the crew. He did not say where the mine was nor when it was due to explode. When admiral Vukovich, who carefully and calmly listened to Rossetti, realised what would soon happen, he told the crew to quickly abandon ship. In the horror, alarm, confusion, while hundreds of sailors were running and bumping into each other deep inside the ship and on the superstructure, Rossetti and Paolucci asked Vukovich whether they could save themselves. Vukovich agreed and the Italians climbed on the ship's railing and jumped overboard.

The crew of Viribus Unitis in front of 305 mm guns
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However, once in the water, they were captured by a group of angry sailors who took them back aboard the ship. There they were surrounded by sailors who demanded to know where the mine was and who, if nothing else, wished the Italians to die on the ship that would soon be blown up. Seeing what was going on, admiral Vukovich approached the angry sailors. Rossetti and Paolucci told Vukovich that they demand the status of prisoners of war. Admiral Vukovich ordered the crew not to harm the Italians. It was 06:20.

The crew of Viribus Unitis
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Ten minutes passed very quickly. The sailors were still very angry and were threatening Rossetti and Paolucci. Admiral Vukovich was trying to calm the sailors and to restore order. It was now 06:30. But there was no explosion. Now Rossetti and Paolucci became afraid. They thought that the mine malfunctioned and that their mission had failed. Also, they thought that they would not be able to avoid imprisonment and a trial. Their whole effort seemed futile. The feeling of satisfaction was replaced by a feeling of disappointment. Now time seemed to pass much more slowly. Most of the crew of Viribus Unitis were in lifeboats, rowing around the ship, uncertain whether to return to the ship or not. Minutes passed slowly. The Italians were already overcome by apathy. Then, at the moment when they almost gave up hope, a distant and rather quiet roar was heard and everybody aboard the ship felt a shudder. Immediately after that a huge column of water rose into the air at the ship's right side of bow and then, as the column collapsed, water stared falling on the foredeck in what resembled a waterfall. Mignatta exploded at 06:44.

SMS Viribus Unitis in La Valetta harbour on Malta in May 1914 with HMS Inflexible in the foreground
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The members of the crew that were still aboard started leaving the ship in disarray, mostly jumping overboard. In this confusion, Rossetti and Paolucci again asked admiral Vukovich whether they could leave the ship. Vukovich agreed, shook their hands and shouted to one of the lifeboats near the ship to pick up the Italians after they leave the ship. Once aboard this boat, Rossetti and Paolucci watched the doomed ship sink. They were taken to the Tegetthoff as prisoners. From there they were transferred to a hospital ship to recover.

Ploce harbour, June 30th 1914; SMS Viribus Unitis, in mourning colours, along the yacht Dalmat, just before the coffins with the bodies of Franz Ferdinand and his wife are transferred to Viribus Unitis. Central 150 mm fire control tower in the foreground.
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Poor underwater protection was one of the characteristics of Tegetthoff class dreadnoughts, but even so, these ships had coal bunkers designed in such a way that they acted as additional underwater armour. However, the coal bunkers of Viribus Unitis were empty, so the explosion was not alleviated. The damage to the starboard part of the bow was too extensive and neither the ship's watertight compartments nor the pumps could compensate the enormous intake of water. Viribus Unitis started slowly listing to its starboard side. The rate of sinking increased rapidly. At 07:00, November 1st 1918, the 21, 000 ton admiral battleship Viribus Unitis, with Croatian flag on her mast, capsized and sank quickly with around 300 members of her crew and with admiral Vukovich, before the eyes of the terrified people of Pula. Janko Vukovich de Podkapelski, who was the commander of the Croatian fleet for only 12 hours, was last seen at the final moments of the ship's agony, standing peacefully on the stern, waiting for death to come.

The officers of Viribus Unitis
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Four days after the sinking, the Italian troops entered Pula (France and United Kingdom allowed Italy to occupy large parts of Croatian coast, as a reward for entering the war on their side). Italian divers located the wreckage, cut it with explosives, and raised several parts. The main mast could still be seen in the late 1950-ies, at a depth of some 15 metres, but after that it vanished. It was the very same mast on which on that fateful November morning Croatian flag was hung. There are still some parts of the ship left on the bottom. They have not been recovered as they do not cause any problems to other vessels using the harbour. It is interesting to point out that the known footage of sinking of the Szent István and of the Viribus Unitis was taken from the same ship - the Tegetthoff, which was present on both tragic occasions.
The question whether the Italians knew about the note sent to them before the attack, has never been answered. Volunteer diversionists, Raffaele Rossetti and Raffaele Paolucci were freed by the Italian army on November 5th. They returned to Italy as national heroes and received golden medals, as well as 1.300.000 lire each.

The sinking of the Viribus Unitis as viewed from the Tegetthoff

Spectacular events are usually later added some untrue facts, in order to change the meaning of the event. This, unfortunately, happened to the story of the sinking of Viribus Unitis. Namely, thanks to the Serbian lobby that is often spreading lies about Croatia, it is often mentioned that the crews of the ships in Pula on October 31st 1918, after removing Austro-Hungarian flags, placed paper bands with the word 'Yugoslavia' in their position, because the fleet had become Yugoslavian (meaning Serbian)! However, the name Yugoslavia appeared in 1929 - 11 years after the sinking. Up to then the state was called The Kingdom of SCS, as the Serbs named it after forcing the State of SCS (Slovenia, Croatia and Bosnia) to unite with Serbia. To clarify, the Slavic part of Austro - Hungary ceased existing on October 29th; the State of SCS (Croatia, Slovenia and Bosnia) existed from October 29th till December 1st 1918; the Kingdom of SCS (the State of SCS + Serbia, Macedonia and Montenegro) existed from December 1st 1918 till January 6th 1929; the Kingdom of Yugoslavia existed from January 6th 1929 till April 17th 1941. It is, therefore, perfectly obvious that the fleet that was handed over to the National Council on October 31st did certainly not become Yugoslavian.

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