Archaeological divers from Denmark’s Viking Ship Museum have revealed the discovery off Copenhagen of what they are calling the world’s largest cog, a type of mediaeval merchant vessel.
Described as among the most advanced designs of its time, the dimensions of the ship and the construction techniques employed provide new insights into northern European shipbuilding techniques and trade, say the experts. Exceptionally well-preserved, it is reckoned to have been built around 1410.
The ship was found at a depth of about 13m half-buried in sand and silt in the Oresund, the strait between Denmark and Sweden that connects the Baltic Sea to the Kattegat and provides access to the North Sea.
The vessel has been named Svaelget 2 after the channel in which it was discovered, during surveys of seabed intended for reclamation and the creation of a new district called Lynetteholm.
The starboard side of the ship from keel to gunwale had been preserved by the sediment to an extent not seen before in a cog wreck, with the divers even uncovering traces of the rigging.
The stern castle provides the first archaeological proof of the existence of such cog structures – timber-built platforms that would have sheltered the crew but which had only ever been seen before in illustrations from the time.
Brick galley
Another major surprise was the discovery of a galley built of some 200 bricks and 15 tiles. This would have enabled the crew to cook over an open fire.
In the same area the archaeologists found bronze cooking pots, ceramic bowls and remains of fish and meat, along with tableware, painted wooden bowls, shoes, combs and rosary beads. Barrel staves and skewers for cooking fish were also found.
Measuring 28m long, with a 9m beam and a height of 6m, Svaelget 2 is estimated to have had a massive load capacity of more than 300 tonnes. No cargo or ballast was found but, with the hold left uncovered, barrels of salt or bales of cloth were likely to have floated away during the sinking.
“The find is a milestone for maritime archaeology,” said excavation leader Otto Uldum, describing the discovery as that of a “super ship”.
“It is the largest cog we know of, and it gives us a unique opportunity to understand both the construction and life on board the biggest trading ships of the Middle Ages,” he said.
“The cog revolutionised trade in Northern Europe. It made it possible to transport goods on a scale never seen before. A ship with such a large cargo capacity is part of a structured system where merchants knew there was a market for the goods they carried.
“Svælget 2 is a tangible example of how trade developed during the Middle Ages. Shipbuilders went as big as possible to transport bulky cargo – salt, timber, bricks or basic food items.”
Even when fully laden, cogs could be managed by a small crew and were therefore inexpensive to run. A vessel of the size of Svælget 2 could manage long voyages, such as that from what is now the Netherlands through the Oresund to various Baltic trading towns.
Timber analysis
Timber analysis shows that the wood used to build the ship came from what is now Poland and the Netherlands, with Pomeranian oak used for the planks and Dutch wood forming the frames. “The ship was built in the Netherlands, where the expertise to construct these very large cogs was found,” says Uldum.
“It is extraordinary to have so many parts of the rigging. We have never seen this before, and it gives us a real opportunity to say something entirely new about how cogs were equipped for sailing.”
Of the stern castle he said: “We now have 20 times as much material to work with. It is not comfort in a modern sense, but it is a big step forward compared to Viking Age ships, which had only open decks in all kinds of weather.”
And he added that a brick galley had never been seen before in a medieval ship found in Danish waters. “It speaks of remarkable comfort and organisation on board. Now sailors could have hot meals similar to those on land, instead of the dried and cold food that previously dominated life at sea.”
All components and artefacts recovered are being conserved at Denmark’s National Museum in Brede. The excavation has been financed by By & Havn, Copenhagen City & Port Development, and is featured in DRTV documentary series Mystery of the Deep. The Viking Ship Museum is in Roskilde, and the work of its maritime archaeologists has been featured before on Divernet.
