 Agamemnon was ordered from the commercial shipbuilder Henry Adams at his Bucklers Hard shipyard on the Beaulieu River on 5 February 1777 , to be built to the lines of the Ardent class , as designed by Sir Thomas Slade . Her keel was laid down in May . She was constructed using timber sourced from the surrounding New Forest . The total cost of her construction was £ 38 @,@ 303 15s 4d . She was commissioned on 28 March 1781 under Captain Benjamin Caldwell — a full 13 days before her launch on 10 April . 
