Promoted to engineer in 1774, he designed the 74-gun, comprising and . He then worked on several 12-pounder frigates. During the War of American Independence, Navy minister Sartine, his successor Castries, and engineer Borda requested standard plans to standardise the production of 18-pounder frigates (equivalent to the British fifth-rate), 74-gun ships of the line (equivalent to the British third-rate), 80-gun two-deckers (without equivalent: similar to a third-rate, but longer than a second-rate and with comparable firepower), and 118-gun three-deckers (equivalent to the British first-rate). Sané won three successive competitions: