The  sixth rates were a series of six ships built to his 1805 design. Perhaps his smallest vessels were the two Placentia-class sloops of 42 tons burthen, which he designed for coastal patrol duties off Newfoundland.
The sixth fleet comprised a group of ships constructed based on his 1805 design. His smallest vessels were probably the two Placentia-class sloops with a capacity of 42 tons, designed to patrol the coast off Newfoundland.