maintenance work, the Holigost began to succumb to leaks and timber decay.
In 1423 a 'dyver' named Davy Owen, probably a Welshman, was employed to dive under the ship to stop up cracks, perhaps, the earliest-known instance in England of a diver being used in ship repair.
Future scientific research on the ship could reveal much about late medieval ship design and construction, both in England and Spain. The wreck might also improve current understanding of life aboard ship, ship-handling and naval warfare in the 15th century.
Given the care with which the ship was laid up, the site itself might also preserve information about contemporary dock-building and docking practices. Historic England experts use a range of research methods, including sonar, remote sensing including aerial imaging using drones, and dendrochronology.
The remains of the largest of the four ships, the Grace Dieu, were identified in the river Hamble in the 1930s and have been protected since 1974.
Dr Friel first spotted the wreck site on an English Heritage aerial photograph of the Bursledon stretch of the river Hamble when he worked in the former Archaeological Research Centre (ARC) at the National Maritime Museum, Greenwich.
He made the connection with documentary evidence that Henry V's Holigost had been laid up there. Subsequent probing of the site by ARC revealed the presence of a solid object under the mud of the river Hamble in Hampshire, but no further work was undertaken.
Dr Friel has included the air photo in his new book, Henry V's Navy and brought the site to the attention of Historic England. Historic England has moved to protect the ship and will soon begin further research.
The Holigost
Tonnage (burden): 760 tons
No of masts: 1
Crew size: 99-199
Origin: originally the Santa Clara [Saint Claire - of Assisi, an Italian Saint and early follower of Saint Francis of Assisi], a ship belonging to the Queen of Spain; captured late 1413/early 1414 by one of William Soper's ships [Soper was one of Henry V's key admin men]; rebuilt 1414-15 as the Holigost
Disposal: docked at Burseldon (Hamble) in 1426; last mentioned in records 1447-52
Summary: only ever used in war operations; participated in Earl of Dorset's expedition to the Seine (1416), the battles of 1416 (off Harfleur) and 1417 (in the Bay of the Seine) (the ship was damaged in both), and the Earl of Devon's seakeeping voyage of 1420. Varying tonnage figures due to the addition of upperworks for specific expeditions.