“I have been diving all my life and have examined hundreds of wrecks, but I have never seen anything like this. The ships stood as if they had just been abandoned.” The words of the director of Denmark’s Sea War Museum Jutland express his amazement at discovering three shipwrecks that have remained upright and exceptionally well-preserved – even by Baltic standards – for more than 300 years.
Gert Normann Andersen led the October expedition on which the wrecks were located and filmed from an ROV at depths of around 150m. Two are cargo vessels from the Netherlands, while the third and largest armed ship is thought to be a Scandinavian vessel, all likely to be from the 17th/18th century.
‘It was fantastic to see the wrecks appear on the screen when we sent an underwater robot with a camera down to the seabed,” said Andersen. “The wrecks stood almost as they did the day they sank hundreds of years ago.”
Making the discovery especially gratifying was that the expedition was feeding into Project ENDURE, a investigation into the degradation of materials under water. The Baltic Sea is reckoned, with North America’s Great Lakes, to offer the greatest protection for submerged timbers, but the team could hardly have found a better illustration of its preservation qualities.
The Thyboron-based Sea War Museum Jutland was working with Danish subsea-services provider JD-Contractor, which provided the offshore vessel Sima and ROVs with advanced technology. Part of the 27-strong team was Prof David Gregory, a specialist in underwater materials degradation with the National Museum of Denmark. He had just received a 20 million kroner (approx £2.4m) European Research Council grant to start work on the five-year Project ENDURE.
“In the North Sea, all wrecks are broken down in record time,” said Andersen. “All the woodwork is eaten by pileworms, and wave action and heavy fishing-gear take care of the rest.” In the Baltic timber-eating worms are unable to survive in water that is acidic and low in oxygen at depth, and there is no deep-sea fishing industry to damage shipwrecks.
Swedish photogrammetry experts Ingemar Lundgren and Fredrik Skorg of Ocean Discovery have been using the thousands of photographs and footage taken at the site to create 3D virtual images of the wrecks. “Photogrammetry is expensive at these water depths, because the method requires both expensive equipment, experts and a large ship, but it is undoubtedly the best method we have today for investigating and documenting wrecks at great depths,” said Andersen.
Marine archaeologist Dr Christian Lemée is producing a report on the age and origin of the shipwrecks. The analysis will be assisted by the lifting on the last day of the expedition of a ship’s knee (curved or L-shaped timber used for bracing) that had been found lying loose on the seabed. It is being conserved for detailed examination.