Navies retained 64s beside more powerful 74s because the smaller third rates still had useful advantages. A 64 did not have to surrender automatically when facing a 74 and could maneuver better in some circumstances. Shallower operating requirements suited inshore waters and distant stations where supporting a larger ship was harder. The type offered a viable, less expensive complement to the fleet's larger backbone ships.
Notable Point · 1:22:01-1:23:22
64s, specialization, and fleet size
The closing historical argument explains why 64-gun ships remained useful beside 74s through maneuverability, shallow-water access, distant service, and lower cost.