Vengeur-class ship of the line

The Vengeur-class ships of the line were a class of forty 74-gun third rates, designed for the Royal Navy as a joint effort between the two Surveyors of the Navy at the time (Sir William Rule and Henry Peake). The Vengeur Class, sometimes referred to as the Surveyors' class of third rates, amongst other names, was the most numerous class of ships of the line ever built for the Royal Navy - forty ships being completed to this design. Due to some dubious practices, primarily in the commercial dockyards used for construction, this class of ships earned itself the nickname of 'Forty Thieves.'

Between 1826 and 1832, ten of these ships were cut down by one deck (raséed) to produce 50-gun "frigates". These were the Barham, Dublin, Alfred, Cornwall, America, Conquestador, Rodney (renamed Greenwich), Vindictive, Eagle and Gloucester. Planned similar conversions of the Clarence (renamed Centurion) and Cressy around this time were cancelled, but the Warspite was additionally converted along the same lines in 1837–1840.

Around 1845 four of these ships were converted into 'blockships', the then-current term for floating batteries, equipped with a steam/screw propulsion system and re-armed with 60 guns. In this guise some of them saw action during the Crimean War. The four were the Blenheim, Ajax, La Hogue and Edinburgh. About ten years later, a further batch of five ships was similarly converted - this included the Russell, Cornwallis and Pembroke of this class (as well as the Hawke and Hastings of other designs).