Archaeologists have found the stays of a mysterious vessel that could possibly be one among Norway’s oldest shipwrecks, throughout an effort to find tons of unexploded ammunition dumped on the underside of a lake close to Oslo.
Sonar pictures present the hull of the 33-foot-long (10 meters) picket ship at a depth of about 1,350 ft (410 m) beneath the floor of Lake Mjøsa, about 60 miles (100 kilometers) north of the Norwegian capital.
What is understood of the ship’s development suggests it was constructed as much as 700 years in the past, quickly after the transition from Viking ships — which had been nearly the identical at each ends — to medieval designs with a particular bow and stern, Øyvind Ødegård (opens in new tab), a maritime archaeologist on the Norwegian College of Science and Know-how (NTNU), advised Stay Science.
“We solely have the acoustic [sonar] pictures of the wreck,” he stated. “But it surely seems from the information that there’s the define of one thing that probably could possibly be a stern — and if that is the case, then that does not actually seem till the 1300s.”
To date, dangerous climate and poor visibility have prevented researchers from investigating the wreck web site with digicam gear, and it now appears to be like like that will not be attainable till situations enhance subsequent yr, Ødegård stated.
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The sonar pictures clearly present the distinctive body of a “clinker-built” ship, a standard Norse boatbuilding methodology through which the planks of the hull overlap, making the hull lighter. Through the medieval interval, that methodology was outdated by easily joined planks on stronger “carvel-built” ships, a Mediterranean innovation.
Ødegård is a part of a challenge led by the Norwegian Defence Analysis Institution (FFI) in collaboration with NTNU to find and map a whole lot of tons of surplus ammunition dumped in Lake Mjøsa from the Nineteen Forties till the Seventies.
The lake has additionally been an important commerce route between affluent communities since a minimum of the Viking Age (the eighth to eleventh centuries), and Ødegård stated he was drawn by the potential for discovering cultural objects within the depths.
“Discovering the wreck was nearly a byproduct of the unique mission to map dumped munitions,” he stated. “I anticipated to search out some issues — that is why I used to be taking part within the challenge.”
Lake Mjøsa covers greater than 140 sq. miles (360 sq. km); of that space, solely about 15 sq. miles (40 sq. km) have been mapped, utilizing the FFI’s Hugin autonomous underwater automobile (AUV).
The AUV is supplied with sonar — sound navigation and ranging — which makes use of the reflections of sound pulses to make detailed acoustic pictures of the environment, even in nearly lightless environments, such because the depths of the lake.
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A number of acoustic pictures from the AUV have been used to make a three-dimensional mannequin of the wreck.
Ødegård advised that the vessel would have had a single mast with a sq. sail — very like a Viking ship — however that it appears to have sported a central rudder, quite than the normal Viking rudder on the proper facet of the hull.
Ships of the identical dimension and construct had been in all probability widespread on Lake Mjøsa within the medieval interval, though the researchers will not be capable to decide the vessel’s function till they will discover it with cameras. “If we’re fortunate, there could possibly be some cargo on board,” Ødegård famous.
Additionally unknown is how a lot of the hull protrudes above the deep layers of sediment on the lake flooring, that are partially invisible to the AUV’s sonar gear, he stated.
There could also be even older wrecks to search out within the lake. “If we’re going to discover a Viking shipwreck in Norway, then Mjøsa might be the place with probably the most potential for such a discover,” Ødegård advised Science Norway (opens in new tab).