HMS Centurion was a 60-gun fourth rate ship of the line of the Royal Navy, built at Portsmouth Dockyard by Joseph Allin the younger and launched on 6 January 1732. At the time of Centurion's construction, the 1719 Establishment dictated the dimensions of almost every ship being built. Owing to concerns over the relative sizes of British ships compared to their continental rivals, Centurion was ordered to be built 1 ft (0.3 m) wider across the beam than the Establishment prescribed. HMS Rippon was similarly built to non-Establishment dimensions at the same time.
Model of the Centurion, made in 1748
Centurion capturing the Covadonga
Centurion at the Battle of Beauport, 31 July 1759. The scene as witnessed by Captain Hervey Smith, Wolfe's aide de camp.
The Anson Ward at Greenwich Hospital
John Harrison was an English carpenter and clockmaker who invented the marine chronometer, a long-sought-after device for solving the problem of calculating longitude while at sea.
Thomas King's 1767 portrait of John Harrison, located at the Science and Society Picture Library, London
Henry Sully's clock (Fig.1) with escapement (Fig.2) and shipboard gimbaled suspension mechanism (Fig.7).
Harrison's first sea clock, the H1
Harrison's second sea clock, the H2