For more than a century, the remains of one of the most famous ships of the Austro-Hungarian Navy, SMS Viribus Unitis, have rested on the seabed of Pula Harbour. The battleship was sunk on 1 November 1918. Today, its wreck represents an important part of Pula’s maritime heritage and a valuable underwater archaeological site bearing witness to the final days of the Austro-Hungarian Monarchy.
Built in Trieste and commissioned in 1912, the 152-metre-long battleship was the first of four Tegetthoff-class dreadnoughts. It was among the most advanced warships of its time, armed with twelve 305 mm guns. As the flagship of the Austro-Hungarian fleet, it played a particularly important role in the Monarchy’s navy, whose main naval base was located in Pula.
The ship’s fate was sealed during the dramatic final days of the First World War. On 31 October 1918, following the collapse of the Austro-Hungarian Monarchy, the battleship was handed over to the newly formed State of Slovenes, Croats and Serbs, with Janko Vuković-Podkapelski assuming command of the fleet. The very next morning, on 1 November, while Viribus Unitis lay at anchor in Pula Harbour, Italian naval commandos Raffaele Rossetti and Raffaele Paolucci attached an explosive device to its hull. The resulting explosion caused the ship to sink, claiming the lives of several crew members, including its commander, Vuković-Podkapelski.
To gain a better understanding of what remains of the ship today and to document its current condition, a series of dives was carried out at the wreck site as part of the VU-3D project.
The aim of the research is to record the present condition of the ship’s remains and the traces of its sinking on the seabed. The collected data will be used to create a detailed digital 3D model, followed by a physical model produced using 3D printing technology.
Two main recording techniques are being used during the dives: underwater photogrammetry, which combines numerous photographs to create a three-dimensional representation, and side-scan sonar, which uses sound waves to map shapes and structures on the seabed. Together, these methods make it possible to document the ship’s remains and gain a clearer understanding of their present-day distribution without disturbing the archaeological site.
This approach is particularly important because the site does not contain a fully preserved shipwreck, but rather the remains of a vessel that has been exposed to various influences and changes over the past century. Digital documentation therefore provides a valuable record of its current condition, which can support future research, conservation efforts and the interpretation of the site.
The diving team included Holger Buss from Germany, a specialist in underwater imaging and the creation of 3D models of shipwrecks, and Christian Harzhauser from Vienna, who also specialises in underwater imaging and wreck documentation. Both have previously worked on the digital documentation of sunken vessels, including the well-known wreck of the passenger steamship Baron Gautsch.
Professional archaeological supervision was provided by Krunoslav Zubčić of the Croatian Conservation Institute. The dives also involved Marko Srečec from The Old Diver diving centre and Mario Ribica from Aquarium Pula.
The project is being carried out with the support of Marina Polesana, whom we thank for their cooperation and assistance in organising the fieldwork.
The collected data and resulting 3D models will provide a more detailed insight into the condition of the remains of SMS Viribus Unitis and create new opportunities to present its history to the public. In this way, modern technology contributes to the research and preservation of Pula’s maritime heritage, in a city whose history is closely intertwined with the development of the Austro-Hungarian Navy.