TALLINN - Rene Arikas, the director of the Estonian Safety Investigation Bureau and head of the survey of the MS Estonia shipwreck, said that it has become clear in the course of additional surveys conducted this year that the damage to the vessel's starboard side is much greater than previously known.
He added that MS Estonia's bow ramp will also be brought to the surface in the course of further surveys.
Arikas recalled that the objective of preliminary assessment is to identify the possible causes of previously unknown damage. "There are preliminary studies at sea as well as the main surveys we have started, and interviews with the survivors are about to begin. A tender is also underway to find a partner to create MS Estonia's digital twin for us to perform various experiments and modeling with," Arikas said at a press briefing on Wednesday.
Preliminary surveys were conducted last summer in cooperation with the Swedes. There was also a probe constantly in the water to measure currents. "We found that the mobility of the tidal currents is relatively small, practically marginal," Arikas said.
According to him, turbidity of the sea water was also detected at a depth of 76 meters and deeper, and it was revealed that the turbidity was constantly changing, even hourly. It was important to plan the work.
A bathymetric model of the seabed and the wreck was also completed, on the basis of which a printout was made. A digital 3D model of MS Estonia using various drawings of the ship was also created. "This is the most accurate model of the vessel before the disaster," Arikas said. "A model of the vessel is needed, among other things, when we start conducting interviews with the survivors."
Main surveys were launched in May of this year and continue in June, using a vessel which, by its nature, was ideally suited for detailed studies.
The purpose of acoustic profiling was to study the seabed in the immediate vicinity of the wreck. It turned out that there is an outcrop of basement rock near the wreck, and there is both a softer and harder layer of clay around the wreck. When the underwater robot touched the outcrop of the basement rock that was under the wreck near the damage, it was a hard rock from which the robot's grip bounced back.
During the photogrammetric survey, 40,000-45,000 pictures were taken of the wreck, which means that the accuracy of the picture is at least 10 millimeters, but in places that required higher accuracy, the picture accuracy was even one millimeter. With the help of the pictures, a 3D image of the wreck was immediately created, which gave the opportunity to decide whether the image of the wreck was sufficient or whether it is necessary to photograph some places again already during the work.
Regarding the damage to the vessel's starboard side, while last year's surveys showed that its length is at least 22 meters and its height is four meters, then this year's surveys show that the damage to the starboard side is at least 40 meters long and at least six meters high. The extent of the damage is so large that it was possible to enter the car deck with a small drone. "We will most likely want to re-measure this damage in the course of further studies," Arikas said.
While last year it was established that the stern corner of the sixth deck had been damaged, this year it became clear that the internal structures and ceiling of the sixth deck were also damaged and damage also extends to the seventh and eighth decks. The boat deck on the seventh deck also has large deformations, with no lifeboats or rafts in place. The davits of many lifeboats had also been broken.
It was possible to enter the car deck to a depth of 15 meters, because, if the team had proceeded, there would have been a high risk of losing the underwater robot due to floating objects. However, it became clear that it is necessary to return to the car deck using a different technology -- one that is able to capture a 360-degree image. Nor can it be ruled out that it is necessary to also go to the car deck with divers.
According to Arikas, the area of interest on the car deck is the fastening materials, that is how well the goods were fastened and whether the fastenings are intact. "We want to identify the vehicles as much as possible, the number plates of some vehicles are visible. We want to clarify the position of cargo on the ship, as well as the condition of the various doors of the vessel, whether they are closed or open. We will also have access to the starboard side damage from the inside," he added.
According to Arikas, the survey data gathered so far is currently being processed and a model of both the wreck and the seabed is being created, which could be completed by the end of August or the beginning of September. It is also planned to print out the bow and ramp section of MS Estonia in order to test as accurately as possible how the ramp and visor have moved. The bow visor shall also be printed separately in the state it was in when it was brought out from the bottom of the sea in order to carry out a practical test for the buoyancy of the visor.
It is also planned to take metal samples from the damage to find out the reasons for its occurrence. Some of the ship's windows will also be brought up to determine their resistance to pressure. The vessel's bow ramp will also be brought to the surface for further investigation.