Ship cemetery Baltic Sea: Why are there so many shipwrecks here?

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A shipwreck from the 17th century was discovered in Lübeck – a sensation for the Hanseatic city. But on the bottom of the Baltic Sea lie tens of thousands of well-preserved wrecks. Why are they doing so well there?

Divers in Lübeck have a around 400-year-old wreck of a 17th-century Hanseatic ship discovered. It should now be recovered

In the Lübecker Trave last year, a routine measurement at a depth of eleven meters  an almost 400-year-old sunken ship from the Hanseatic era with more than 150 barrels on board was discovered. For the Hanseatic city of Lübeck, it is a sensational find and an important testimony to its own history. It should now be salvaged. But discoveries of wrecks in the Baltic Sea are initially not uncommon, says underwater archaeologist Florian Huber. 

“According to estimates, between 10,000 and 100,000 shipwrecks lie on the bottom of the Baltic Sea in quiet peace on the seabed. What makes the find near Lübeck unique: the location in the western Baltic Sea and the fact that the ship came from the end of the heyday of the Hanseatic city, which was active in maritime trade, in the 17th century. “We don't know that many ships from that time,” Huber explains.

Model of a historical cargo ship of the “Fleute” type. This is what the wreck found in Lübeck is said to have looked like

“The Baltic Sea is a huge, ice-cold museum”

From a scientific point of view, such a find is “particularly exciting, because you can learn from it how ships were built back then, what technology is behind it,” explains Huber, who has been exploring the world's oceans since 1992. The approximately 150 barrels that were discovered on the Lübeck ship are also important evidence of the past. “We learn about the cargo that was traded back then”. 

But why do wrecks and other long-sunken treasures in the Baltic Sea hold up so well? There are several reasons for this. Large parts of the North European inland sea are low in oxygen, cold, dark and have low salinity.

Florian underwater archaeologist Huber has been a certified research diver since 2002 and today trains hobby and sport divers, among other things

“The Baltic Sea is like a huge, ice-cold museum – like a refrigerator that simply preserves everything that falls in there,” says Huber. Often not only the wood is preserved, but also the charges. “Leather and textile remains are often found.” You can often still find the goods – “sometimes the cod is still in the barrels. You can find bones. Everything organic is simply very, very well preserved under water,” says Huber. Traces of quicklime were also discovered in the barrels of the Lübeck wreck, an important building material that was traded in the Hanseatic period.

“Wine bottles, champagne bottles and also beer bottles have actually been found in the Baltic Sea. They were Of course not that old, but I would say 100 years, 200 years. They were still edible. The champagne was auctioned and sold for tens of thousands.”

The shipworm is the biggest enemy of wood wrecks

But don't just conserve the cold and darkness of the sea: One of the most popular holiday destinations for Germans is not at all popular with some creatures. This is particularly beneficial for the wood wrecks slumbering on the bottom of the Baltic Sea. Their biggest enemy, the shipworm Teredo navalis, doesn't feel at home here. He likes oxygen-rich salt water. The further east you go in the Baltic Sea, the more fresh water collects there. “At the Gulf of Bothnia around Finland and Sweden there is almost fresh water, so there is only very little salt left and accordingly the shipworm can no longer survive there .”

That's why there are usually very well-preserved wrecks there. “Some of the wrecks in the Baltic Sea are two, three, four or five hundred years old – and they are still standing upright the masts. This is unique in the world.”

The first dive to the Lübeck wreck took place in November 2021 . Here you can see: Traces of the shipworm on the wreck parts

This also explains why the parts of the ship found in Lübeck look a bit “eaten up”. Lübeck is located in the western part of the Baltic Sea. In pictures published by the city of Lübeck of the find, clear traces of the shipworm can be seen in the wood. “In addition to shipworm, wrecks are also threatened by climate change, fishing trawlers and looting,” adds Huber. 

Another reason for concern: In a press release from the Hansastadt on the sensational find, it is said that the wreck is endangered by sea currents in addition to the shipworm. The find must be protected and preserved because it is classified as a “unique and outstanding find for the history and archeology of the western Baltic Sea”. 

The conservation of wrecks is difficult

One of the mammoth tasks that the Hanseatic city of Lübeck will now have to deal with when it recovers the wreck will be the preservation of the wreckage. Huber points out that everything that comes out of the water cannot simply be dried somewhere and then put in a museum.

Wood in particular continues to work. After a centuries-long slumber at the bottom of the sea, it is saturated with water. That has to be brought out slowly. The water “must be replaced with a liquid plastic to keep the wood cells from collapsing. The process is laborious and expensive.”

One of the most spectacular finds in the Baltic Sea to date: the Swedish warship “Vasa” from the 17th century

Other salvaged ships, such as the English Mary Rose or the Bremen Cog. In 1961 Sweden brought the warship Vasa, which had sunk in the 17th century, out of the Baltic Sea and built a museum especially for it. The wreck had to be impregnated with polyethylene glycol for 17 years to prevent the wood from shrinking or cracking as it dried.

“You always have to think carefully about whether you can afford it and whether you want to.”< /p>

Important cultural heritage for Lübeck

In any case, the Hanseatic city of Lübeck is certain that the wreck from the Trave must be brought to the surface: “It should be salvaged and conserved as quickly as possible so that it can then be preserved as a to preserve part of the history of the Hanseatic League and to preserve its entire authenticity for the future”.

#DailyDrone: Lübeck