Medieval ship found in Norway’s largest lake

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At the bottom of Mjøsa, Norway’s largest lake, a shipwreck from hundreds of years ago rests in near-perfect condition, frozen in time.

The ship, with its unique stern post and overlapping planks, reveals a moment in the lake’s maritime history and is estimated to have dated from between the 1300s and 1800s.

Researchers discovered the wreck while conducting the Mission Mjøsa project, which aims to map the 140 square miles (363 square kilometers) of seabed using high-resolution sonar technology.

The Norwegian Defense Research Institution led the mission two years after conducting several inspections of areas of the lake where large quantities of munitions had been dumped using remotely operated vehicles (ROV). The lake is a source of drinking water for about 100,000 people in Norway, according to the Norwegian University of Science and Technology, so the munitions posed a health risk. The shipwreck was discovered when surveying the lake.

The Mission Mjøsa project aims to use sonar to map the bottom of the lake to find dangerous dumped munitions.

“My expectation was that mapping dumped munitions might also uncover shipwrecks – that turned out to be the case,” said Øyvind Ødegård, senior researcher in marine archeology at the Norwegian University of Science and Technology and the mission’s lead investigator. “It was just that the statistical probability of finding well-preserved shipwrecks was considered quite high.”

The recently uncovered shipwreck sits at a depth of approximately 411 meters (1,350 feet) and was captured in sonar imagery, a system that uses pulses of sound to detect and measure the area beneath the water’s surface. The images showed that the ship was 10 meters long.

The freshwater environment and lack of wave activity at this depth had kept the ship in pristine condition, save for the corrosion of a few iron nails at each end of the ship. For Ødegård, the wear of the metal is a clear indication that the wreck has been resting at the bottom of the lake for quite some time, as it would take hundreds of years for corrosion to occur. Eventually, the ship could lose its structure if all the nails crumble, he said.

At the stern of the ship there is evidence of a central rudder, a steering feature that typically did not appear until the late 13th century. Combining these two features, archaeologists have been able to estimate ships’ range no earlier than 1300 and no later than 1850.

The ship appears to have been built using a Norse technique in which the planks of the body overlap each other. This method was used during the Viking Age to make ships lighter and stronger and is known as clinker construction.

Since the shipwreck was found in the middle of the lake, Ødegård believed that the ship had sunk in bad weather. It’s very likely the ship used square sails, he added, which proved difficult for sailors to navigate when caught in extremely windy conditions.

The oldest ship discovered in Norwegian waters so far is the Sørum logboat, found in the Bingen Booms on the Glomma River, which dates to 170 BC. is dated. The almost 2,200-year-old shipwreck was relatively well preserved for its age of thousands of years.

“Wooden shipwrecks can be preserved very well in freshwater because they lack the organisms that normally eat wood found in the ocean, for example,” Ødegård said. “I suppose if we want to find intact Iron Age or medieval craft in Norway then Lake Mjøsa is the place to be as it is big enough to have its own distinct maritime history with lots of seafaring and trade .”

During the Viking Age the lake served as a major trade route, although according to Ødegård there are notable gaps in what is known before and during this period. “No matter how old, each find will help us to better understand how the shipbuilding tradition developed in an inland lake compared to the Nordic countries.”

To map the bottom of the lake, the research team used a state-of-the-art autonomous underwater vehicle called Hugin, made by Norwegian technology company Kongsberg Maritime. This is the first time such equipment has been used in a freshwater environment, according to Ødegård, and it has not been used much in archaeology. He called Hugin’s research proposal for the occasion a “rare tidbit”.

The autonomous underwater vehicle called Hugin (pictured) is used for the first time in a freshwater environment to survey the bottom of Lake Mjøsa in Norway.

On the final day of exploration, researchers had sent down an ROV to take pictures of the wreck, but had to abort the mission due to bad weather. Ødegård would like to come back next year to try again.

Meanwhile, researchers continue to map the bottom of the lake. To date they have only mapped 15 square miles (39 square kilometers) and have many more planned. Ødegård said he expected more shipwrecks to be discovered.

“We were able to find ships from the early days of human activity in the area. They could be there and in good condition,” said Ødegård. “You can’t rule anything out.”

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