This designation became especially common because it included the 74-gun ship, which eventually came to be the most popular size of large ship for navies of several different nations. It was an easier ship to handle than a first or second rate ship, but still possessed enough firepower to potentially destroy any single opponent. It was also cheaper to operate.
Although the rating system was only used by the Royal Navy, British authors might still use "third-rate" to speak of a French 74. By the end of the 18th century, the rating system had mostly fallen out of common use, ships of the line usually being characterized directly by their number of guns, the numbers even being used as the name of the type, as in "a squadron of three 74s".