First and second rates supplied concentrated power, but most of the fleet consisted of more economical third rates. A 74 offered enough firepower and durability for the line without consuming the resources of the largest flagships. That balance let a navy build the numbers required to fight across several theatres. A modern analogy places a Type 45 fitted with the Mark 41 VLS cells for which space was reserved in the third-rate role, while an Arleigh Burke sits closer to the first-rate end. The comparison concerns capability, cost, and fleet numbers; it does not transfer the age-of-sail rating system literally to modern warships.
Notable Point · 56:50-59:28
Why 74-gun third rates carried the fleet
The British order of battle illustrates why third rates balanced firepower, cost, and fleet numbers better than the largest ships.