Well the Centurion is a 60 gunner, not a 50, but is very near the size of later 50 gunners like the HMS Leopard, only the Leopard carries fewer guns of heavier caliber (except for the lower deck which is still 24 pounders.) But I think Kriswood is right in that when the Centurion was built she wouldve been considered fairly large for a two decker, I hadn't taken that into account. There were 70 gunners then I think, but I'm pretty sure 64s, 74s, and certainly 2 decker 80 gun ships hadnt been invented yet, or were only experimental. The Bellona was one of the first english built 74s, and she was launched in 1760, 28 years after the Centurion. However, after the invention of the 74 the Centurion wouldve been considered a bit small, and would have been considered too small and lightly armed for the line of battle by Nelsonic times, and possibly even by the American revolution. ships of her size were certainly still built by then, despite this (Mainly by the British, Dutch, and Spanish) for the British they were often flagships on distant stations, and there was usually one or two British 50s or 64s in the carrbiean as late as the war of 1812.