Maritime archaeologists believe they have solved the mystery of a shipwreck that has lain off the Dorset coast for more than 120 years.

The sunken ship, known as the Pin Wreck, was first discovered off the coast of St Albans Head in 1990.

It gained its name because of the hundreds of metal bolts which lay around it.

The wreck, which is about 24m long, is constructed of wood with yellow metal sheathings and lies at a depth of about 27m.

The capstan of the Pin Wreck
The capstan of the Pin Wreck (Bournemouth University/PA)

A team from Bournemouth University (BU) has now identified the ship as an Admiralty mooring lighter, which was built in 1866 and is thought to have been used in the salvage operation of HMS Eurydice off the Isle of Wight in 1878.

Mooring lighters were towed vessels containing mechanical devices for moving heavy loads and were used for laying moorings and in salvage work.

Objects previously recovered from the wreck included a ceramic fragment attached to a large pulley block marked “Portsmouth Dockyard” which led the team to examine the records from the historic Hampshire port.

A university spokesman said: “Research in the national archives uncovered plans of two identical lighters from Portsmouth dockyard, named YC 5 and YC8.

The gearing wheel beneath the capstan of the Pin Wreck
The gearing wheel beneath the capstan of the Pin Wreck (Bournemouth University/PA)

“These were the only vessels whose precise details matched that of the wreck, but there was no record of their loss.

“They then found a crucial piece of the puzzle in a copy of the Shipping Gazette from September 11th 1903.

“This reported the sinking of a mooring lighter off St Albans Head in rough weather whilst on tow from Portsmouth to Portland.

“Thirty men had to transfer from the lighter to its tug before it sank.”

The spokesman said the team had since confirmed the wreck as being that of YC8, adding: “The BU team have now applied for the wreck to be designated as a protected site.”

The bow of the Pin Wreck
The bow of the Pin Wreck (Bournemouth University/PA)

Dave Parham, professor of maritime archaeology at BU, who led the investigation, said: “This is a rare example of a type of service vessel which was essential for maintaining the operations of Britain’s ports in the nineteenth century, so it is vital that we preserve it.

“Its identity has remained a mystery for three decades but what we observed on our dive meant we could find the clues that could reveal the secrets of the wreck and understand how it ended up on the seabed.”

He added: “The materials the vessel is made from suggest a high-quality build, possibly linked to a royal dockyard.

“The fact it appears to have been lost in service and was carrying substantial haulage equipment means it could offer valuable insight into the role these craft played in our maritime history.”