A 3rd rate ship, as defined by the British rating system, was a ship of the line which mounted between 64-80 guns. Usually, this would mean two gun decks. Despite their relative size and power compared to larger 1st and 2nd rates, it was considered that 3rd rates maintained an effective, perhaps even superior balance between sailing ability, firepower and cost.
For a number of nations, 3rd rates were the most popular ship size. Cheaper to operate and easier to sail without the sacrifice of offensive capability, the only ships a 3rd rate could not single-handedly engage were larger three-decked ships. A large number of 3rd rates were built and employed on a variety of missions.
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