THEY call her the Yorkshire Mary Rose and, like her Portsmouth counterpart, the treasures she took with her to a watery grave tell a fascinating story of the past.

The General Carleton – the subject of a new book – was a 390-ton merchantman, built in Whitby in 1777, probably in the same shipyard that produced Captain Cook’s famous Endeavour.

She plied her trade in the Baltic, but also played a role in the American War of Independence, evacuating troops and supplies from Savannah and Charleston.

But in 1785 she was back in the Baltic and in late September she foundered in a storm and sank off the coast of Poland.

Many of the crew died, including the captain, but at least three survived.

However, when she went down she was carrying barrels of pine tar which split, spilling the contents over many items which would normally have quickly rotted away.

And in a series of marine excavations during the Nineties, divers were able to recover almost 800 artefacts, much of it clothing, revealing details of life, on board and ashore, for the merchant seamen of the time.

While a lot has been written over the years of life in the warships of the period, far less has been published regarding the many merchantmen that crisscrossed the oceans.

But now retired Essex teacher Stephen Baines has redressed the balance in his book The Yorkshire Mary Rose, the ship General Carleton of Whitby.

Among the articles found when the ship was excavated by the Polish Maritime Museum were numerous jackets, breeches, stockings and hats.

Together they make what academic Professor Lawrence Babits has called “the finest collection of well-dated 18th-Century common male’s clothing ever found”.

And as Mr Baines points out: “The fact that a large number of the excavated artefacts would probably have been made in or near Whitby is also of enormous importance to the understanding of the history of that town and its hinterland.”

For some of the items even carry carefully carved or embroidered initials, enabling them to be identified, with near certainty, as belonging to various crew members of the tragic voyage more than 200 years ago.

■ The Yorkshire Mary Rose, the ship General Carleton of Whitby by Stephen Baines, Blackthorn Press, ISBN 978 1 906259 20 4, £14.95. Paperback.

Available from bookshops or at blackthornpress.com