Divers plunged into the waters of Dundee’s City Quay as the project to dry dock the HMS Unicorn took an “important step” on Monday.
The hull of the historic ship was checked by divers and sections measured to allow flotation bags to help keep the frigate steady in the water.
A crane was used to assist the divers into the water.
Footage of a diver in the water is above this article
The main objective was to assess the condition of the nearby gate for the East Graving Dock as plans are made to drain water there to allow Unicorn to be dry docked.
The dock itself was also given a once over by divers, checking how much debris lies underwater, to plan for the drainage.
A report is being prepared based on the findings but an early assessment suggests the dock is clear and the volunteers plan to move on to the next stage.
If the gate does need repair work that could delay the whole project and increase the funds needed.
It is hoped the nearby North Carr Lightship can join the Unicorn in dry dock, if space and conditions allow it.
The Unicorn was last dry docked in 1972 but only for a handful of days for it be checked and cleaned before returning to its current home.
Volunteers with the Unicorn Preservation Society say keeping the ship in water will only hasten her decay.
Finlay Raffle, HMS Unicorn Preservation Society engagement officer, said: “This has been an early but important step in the long-term future of the ship.
“The main goal is to get it dry docked permanently. It is almost 200 hundred years old.
“We are waiting on some cash from the Tay Cities Deal before moving forward as well.”
Even if the gate is watertight, it will still be a number of years before the project is complete as the volunteers raise more funds, Mr Raffle added.
They hope when it is in dry dock, it can help bring tourists and businesses to the City Quay waterfront area.
Joe McKee, member of Tamara, which works to preserve the North Carr Lightship, has worked on ships all over the world.
He said: “The project will need considerable funds, but with these ships once they are gone, they are gone.
“I think it is critical to preserve these things.”
The Unicorn museum re-opened late last week after months of closure because of coronavirus.