The Merlin class was a class of twenty-one sloops of wooden construction built for the Royal Navy between 1743 and 1746. They were all built by contract with commercial builders to a common design prepared by Jacob Acworth, the Surveyor of the Navy; however, there were small differences between individual vessels, with a platform deck being constructed in the hold in Swallow (i), Merlin, Raven and Swallow (ii), whereas the other seventeen had no platform deck and thus their depth in hold was thus nearly twice as much.