IT WAS A QUIET NIGHT on 9 June, 1918, when the two Austria-Hungarian sister-battleships SMS Szent Istvan and Tegettoff left the port of Pula (now in Croatia) and set course for Dubrovnik.
Neither vessel was felt to have much to fear from the Italian Navy, because they were accompanied by a destroyer and six torpedo-boats.
The Szent Istvan, named after the first Christian king of Hungary, St Stephen, was still a new ship of 20,000 tons, and to that date had fired her gigantic 30cm guns only in practice. The plan was for both ships to rendezvous with others in the fleet and attack the Allied sea blockade near Brindisi in southern Italy.
The captain and his officers were conducting a final preparatory meeting in the admiral’s cabin on the rear deck. The captain was issuing instructions as the watch-keepers got ready.
The look-outs had nothing to report, and none of the 1000-plus crewmen could suspect that all hell was about to break.
Meanwhile it had been barely nightfall when Italian Navy corvette captain Luigi Rizzo gave the command to return to base. The crew of the torpedo-boats MAS15 and MAS21 had experienced rough weather but little action, and were keen to enter port.
As it was a clear night, they suddenly noticed smoke-plumes on the distant horizon. It could only be an enemy vessel.
Rizzo ordered his Captains Gori and Aonzo to sail straight for the plumes. It was a long way, but both torpedo-boats succeeded in breaking through the cordon of escorting vessels, and went on the attack against the Austria-Hungarian battleships.
Once in range, Rizzo decided to let MAS21 push the attack against the Tegettoff, but her torpedoes missed their target. At the same time MAS15 set course towards the Szent Istvan and fired two torpedoes. Both hit the battleship in the hull, near the boilers. The rear boiler-rooms immediately started to flood, and the ship listed by 10° to starboard.
The Szent Istvan’s captain responded by ordering the heavy guns to be turned to port to counter the list, but more and more water was pouring into the boiler-rooms, resulting in a power loss, and loss of pumping capacity too.
At 6.05 in the morning, the Szent Istvan capsized and sank, close to the island of Premuda. Her demise was filmed by an officer on the Tegettoff, and this is the only film ever made of the sinking of a warship during WW1. Eighty-nine crew lost their lives.
The Szent Istvan was discovered by the Yugoslavian Navy in the 1970s, and is now a protected wreck that can be dived only with special permission.
It took my Croatian friend Drazen Goricki a long time to get all the required permissions, but eventually the Ministry of Culture and the underwater archaeology department agreed to a group diving the wreck, the first time in many years that this had been allowed.

OUR EXPEDITION TEAM consisted of divers from five countries, but members of a special police diving unit and of the Croatian Navy would join us.
Our home port was the police unit’s base in Mali Losinj. We would be using its fast boat to go out to the wreck 20 miles away, and we could also get trimix and prepare our rebreathers there.
This expedition was to be assisted by underwater archaeologist and experienced trimix diver Igor Miholjek of Croatia's conservation institute, responsible for the retrieval and conservation of artefacts.
We also intended to take as many film and photo images as possible.
The dive-plan was discussed and the team divided. My buddy was Austrian diver Phillipe Alfarei.
It's not often that you get the opportunity to dive a wreck normally closed off to divers, so I had wanted to prepare well, and put my equipment and camera through comprehensive tests.
However, shortly before the dive I tested my camera and found that the flash was not working. I decided that I would have to take pictures using my video-light instead.

ON THE DESCENT, it became apparent that the visibility would be no more than 6m. The downline was connected to one of the two large propellers, and just beside them the rudders were clearly visible.
We took some pictures, descended further towards the bottom and found a fairly large opening that would allow us to swim beneath the wreck.
We found several leather shoes among the debris on the seabed, and some 15m ahead could make out the 30cm cannon, their huge barrels reflecting the size of this enormous wreck.
However we were at 66m now, and time flies at that depth. We swam back to the downline to start our ascent and a long decompression.
On succeeding dives Drazen Goricki found a passage to the admiral’s cabin. Here several beautiful bronze lights with cut glass were retrieved for conservation.
The ship’s telephone, with which orders were issued from the bridge, was found during one of the penetrations deep into the wreck. At 66m such dives had their risks, especially in an inverted wreck.
Close to the admiral’s cabin was his bathroom, the tub clearly recognisable. Silver cutlery and porcelain was retrieved from the various cabins, and on one of my dives I discovered one of the large searchlights that had been mounted on the mast, partially hidden in the sand.
Closer to the bow was the ammunition room, also filmed and photographed.
Throughout the expedition the weather stayed exceptionally fine, with little wind. We carried out more than 70 dives, and in the ensuing months all the artefacts recovered will be conserved and catalogued – and will eventually be displayed in a museum.

SMS SVENT ISTVAN 

BUILT: 1914 Ganz & Co Danubius shipyard, Fiume (now Rijeka)
WEIGHT: 20,000 tons
LENGTH: 152m  
BEAM: 28m
COMPLEMENT: 1094
PROPELLERS: Two
SPEED: 20 knots
GUNS: Four 30cm, twelve 15cm, twelve 7cm and three 66mm AA
TORPEDOES: Four 533mm