While last year investigators of the Estonian Safety Investigation Bureau thought that damage to the starboard hull of MS Estonia runs for 22 meters, it has now been revealed that it measures over 40 meters in length. More oil is also leaking from the wreck.
The Estonian Safety Investigation Bureau (OJK) and the Swedish Accident Investigation Authority (SHK) carried out a photogrammetric study of the hull of sunken passenger ferry MS Estonia between June 7-16.
OJK head, Captain Rene Arikas, said that hull deformation is far more extensive than the crew found last year.
"If preliminary studies last year suggested the tear on the starboard side was four meters high and 22 meters long, we have now learned it measures at least six meters in height and runs along for 40 meters, longer even," Arikas told ERR.
"The hull is deformed there, with holes, cracks, crumpling and the outside plating of the ship being pressed inward. Because the damage continues under the hull, we cannot see its full extent, but it is visible along ca 40 meters."
Investigators found the damage near the top of the 155-meter ferry's sixth deck, while, this time, deformation was also observed on deck seven. For example, there is damage to the boat davits.
The damage on the starboard stern side runs along the entire stern deck from deck six to decks seven and eight.
There are no surprises on the bow side. The bow ramp is still lying on the seafloor in the same position, partially resting on the hull.
Arikas said that photogrammetry provides a very detailed 3D image of the wreck. "We can see both major deformation and injuries just a few millimeters across very clearly that we were previously unable to detect using sonar."
The crew also discovered that oil leaks have become more extensive since last year. "The camera showed tiny oil bubbles rising to the surface." The investigators also discovered a new leak in the hull.
The wreck lies in Finland's economic zone and is the country's responsibility. Arikas said that representatives of the Finnish border guard came on board for two days to study the team's work and the information collected.
"To decide whether to try and localize the leak or prepare for major spills. Looking at the extensive damage we have found, we cannot rule out the leak becoming much worse," the captain suggested.
The international crew of around 40 used a remotely operated underwater vehicle (ROV) to take some 25,000 images of the MS Estonia hull. "We had to photograph the wreck from every angle so it could be studied at all, said Kees Leverenz, the crew's photogrammetry specialist. This allows the position, dimensions and shape of objects to be measured.
Rene Arikas said that the team should have the preliminary results of the photogrammetry study by the last week of June.
The investigators also carried out marine surveys, such as a hydroacoustic study of the seafloor, and will be moving on to ferromagnetic studies next to map the location, mass and shape of metal objects – the bow from where it detached up to its sinking. The latter will require a new public procurement.
"We will complete our 3D photogrammetric model inside two or three months, and we will have an image of the wreck with accurate colors, geometry and resolution," Arikas said.
"The plan is to create a theoretical twin of MS Estonia based on the data collected to be used for various simulations and modeling," Arikas suggested.
"In summary, the goal is to compare what we can see on the seafloor today to what the digital twin can tell us through simulation. Whether the sinking of the ship and the damage sustained along the way in our model coincide with what we see on the seabed."
"Visibility is worse on the car deck, and there is debris. We need to find a different technological solution for mapping out the car deck," the expedition lead said.
He added that studying the car deck is crucial as it needs to be determined how cargo was secured, as well as the location of the tethering points and where they broke, in addition to the state of the car deck doors.
SHK held a public tender for the expedition and signed a contract with Swedish company Ocean Discover AB. The team used the Dutch offshore supply vessel Vos Sweet that was used to laser scan the MS Estonia wreck.
The final results and conclusions of the expedition should be published around next spring.
Estlink passenger ferry MS Estonia sank on the way from Tallinn to Stockholm on September 28, 1994, with 852 people out of 989 on board losing their lives in the shipwreck.
The Discovery Network, on September 28, 2002, aired a documentary that showed previously unknown damage to the ferry's hull – a four-meter-wide hole in the starboard section.
Editor: Marcus Turovski