In Britain's Royal Navy during the classic age of fighting sail, a fifth-rate was the penultimate class of warships in a hierarchal system of six "ratings" based on size and firepower. Rating The rating system in the British (originally English) Royal Navy as originally devised had just four Rates, but early in the reign of Charles I the Fourth rate was divided into new classifications of Fourth, Fifth and Sixth Rates. While a Fourth Rate was defined as a ship of the line, Fifth and the smaller… (More on Fifth-rate)