A previously undocumented German wreck has been discovered in Scapa Flow.
The vessel is believed to be a pinnace - a small boat which would have acted as a supply boat for larger ships.
It is likely to have gone down with its parent ship when the German High Seas Fleet was scuttled in 1919, following the end of World War One.
A team from Orkney diving boat MV Valkyrie came across the wreck after an unexpected object was picked up on sonar equipment.
Diver Simon Brown expected to find a lump of anti-torpedo boom net.
Instead he discovered a German vessel which has lain undiscovered for almost 100 years.
Skipper Hazel Weaver told BBC Radio Scotland: "There's lots of piles of steel boom netting dumped after the First World War and the Second World War in Scapa Flow and we assumed it was a pile of that."
She said Mr Brown offered to investigate the discovery and he was in the water for about an hour.
"He took a lot of photos and came back up very, very excited," she added.
Ms Weaver said they had not come across similar vessels previously, so they consulted Kevin Heath of local diving services firm Sula Diving.
"He identified it as a motor pinnace, or diesel pinnace, from the German High Seas Fleet," she said.
"It's a remarkable discovery, especially to find such a wreck even with all the brass works still in tact."
More than 50 German ships sunk to the bottom of Scapa Flow on 19 June 1919.
Most were removed from the water after the war but local people say seven remain on the sea bed.
Ms Weaver said there are still a lot of artefacts to be discovered below the surface of the water and experts are using sonar to survey the area.
"More are being found all the time," she said. "Other operators in Scapa Flow are also looking for these smaller items because they represent a slice of history that is more or less being forgotten now."