Calculations of the two studies don't match
Meanwhile, Jaan Metsaveer, a shipbuilding engineer and emeritus professor at Tallinn University of Technology (TalTech), who also sat on the JAIC, said that official calculations show that the MS Estonia had a reserve buoyancy (the volume of a ship above the waterline, which can be made watertight, thus increasing the vessel's buoyancy – ed.) of 4,500 tonnes.
This covers two meters above the waterline, which can carry an additional weight of 4,500 tonnes. Thus, 4,500 tonnes of water flowing under the car deck was enough to sink the whole ship in any location.
However, it is also possible for a part of the ship to lose reserve buoyancy, for example, the stern sections. The result is that the stern sinks significantly deeper and the bow rises higher, so that 4,500 tonnes is above the water-line.
Margus Kurm says he does not agree with this estimation. "Swedish marine scientists have concluded with their calculations, simulations and model tests (done by Swedish state agency Vinnova) that the ship would not have sunk until its entire superstructure, and 83 percent of the hull, is filled with water. This means that 11,000 tonnes of water had to flow under the car deck, not the 4,500 tonnes referenced. "
Vinnova conducted the tests in 2008, by which time software used in simulations was better than that available in 1995.
"Don't these kinds of disagreements between scientists prove the need to gather as much evidence as possible, including investigating the wreck on the seabed?" Kurm asks.
Professor Mihkel Kõrgesaar agrees that the calculations made in 2008 are more likely to be accurate. At the same time, he said that in the same way, later calculations say that the ship ought to have stayed afloat, but as it didn't no one really knows how it actually came to sink.