A wooden foremast from HMS Victory featuring a hole punched into it by a cannonball during the Battle of Trafalgar is set to go on display.
Lord Nelson's flagship, which featured in the 1805 battle, is undergoing a 13-year revamp at Portsmouth Historic Dockyard.
The previously unseen piece will be exhibited in the HMS Victory gallery which reopens on 17 May.
The gallery will tell the story of one of Royal Navy's most famous warships.
A life mask of Vice Admiral Horatio Nelson, that was taken in Naples in 1798 and later used to produce a marble sculpture of him by Anne Seymour Damer, is also set to be among the key exhibits.
The ship currently has a dual role as the flagship of the First Sea Lord - the professional head of the Royal Navy - and as a living museum to the Georgian Navy.
Organisers said that construction and conservation will be major themes among the displays which will compare ship-building skills 200 years ago and the painstaking work which is still undertaken today.
Andrew Baines, executive director of operations for the National Museum of the Royal Navy (NMRN) and lead curator on the new gallery, said: "Visitors love HMS Victory and they never tire of her story.
"Even those who think they know all about the ship will discover something new."