DenmarkWreck of the world's largest cog found

Morten Strauch

 · 11.01.2026

The wreck of the cog was found in the fairway off Copenhagen
Photo: By & Havn
During the construction of the new Lynetteholm peninsula in Copenhagen, the wreck of the largest known cog to date was discovered at the end of 2025. Due to its extraordinary dimensions, the medieval merchant ship provides new insights into boatbuilding technology and the Hanseatic League's maritime trading network.

The wreck bears the name "Svælget 2" - named after the place where it was found in the Svælget fairway off Copenhagen. At 28 metres long, 9 metres wide and with a load capacity of around 300 tonnes, the cog surpasses all previous finds and impressively underlines the efficient boatbuilding skills of the Hanseatic period. The ship is dated to around 1410 and was built in Holland using timber, some of which came from what is now Poland.

The cog was an efficient type of ship that could be sailed by a relatively small crew, even with a heavy load. The large cogs were built, among other things, to make the dangerous journey from Holland around Skagen, on to the Öresund and the trading towns of the Baltic Sea. "Svælget 2" is a direct reference to the extensive trading structures that connected Northern Europe in the 15th century:

"A ship with such a large cargo capacity is part of a structured system in which the merchants knew that there was a market for the cargo they were transporting. Svælget 2' is a vivid example of how trade developed during the Middle Ages," emphasises Otto Uldum, underwater archaeologist and excavation manager of the project.

The site where the "Svælget 2" was found off the Danish capitalPhoto: By & HavnThe site where the "Svælget 2" was found off the Danish capital

"This is a clear indication that everyday goods were traded here. They were built as large as was technically possible in order to transport goods that took up a lot of space. These could have included salt, wood, bricks or foodstuffs. The cog fundamentally changed trade in northern Europe: it made it possible to transport goods in unprecedented quantities," adds Uldum.

Bronze pots, ceramic bowls, painted wooden bowls, shoes, combs and rosary beads were also uncovered between the large frames and the remains of a fort. These finds on the wreck also provide an insight into the lives of the people on board - how they lived, worked and practised their faith.

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