To many, ship-of-the-line, third rater and frigate are just words on a page describing a sail powered warship.   They are different types of ships with different capabilities.  Before 1577 when Samuel Pepys, a member of Parliament and Secretary to the Board of Admiralty, put pen to paper and actually thought out a rational rating system for ships, there was no standard.

Henry VIII started the process when his navy consisted of 58 ships he grouped into four classes – ships, galleasses (a galley with masts for sails), pinnaces (small ships with masts) and row barges. Over the next hundred years, ships were put into four categories – Royal Ships (42- 55 guns), Great Ships (38 – 40 guns), Middling Ships (30 – 32 guns) and Small Ships (under 30 guns).

As ships grew larger, carried more guns, needed a bigger crew and by definition were more costly to build and operate. In 1677, Samuel Pepys was the Secretary of the Admiralty and responsible for providing estimates and budgets to give to Parliament so it could fund the Royal Navy.

Pepys wanted to accurately forecast the long term operating costs of a warship. His solution was to rate ships by two measurements – the number of guns and the weight or tonnage of the ship. From there, he could size its crew. One that was known, Pepys could forecast pay and allowances as well as consumables such as food, clothing, and other supplies.

His rating system was officially modified six times, the last of which was in 1817. During the Napoleonic Wars, the Royal Navy had seven categories.

‘First Raters’ were at the top of the pyramid with 100+ cannon on three decks, a crew of 850 – 875 men and weighing 2,500 tons. A ‘second rater’ was manned with 700 – 750 men, carried 90 – 98 guns and weighed 2,200 tons.

Third rate ships had 64 – 80 cannon on two decks and needed a crew of between 500 – 650 men to sail the 1,750 ton ship. ‘Fourth raters’ had 50 – 60 guns on two decks, a crew of 320 – 430 and weighed about 1,000 tons. First through fourth rate ships were considered “ships-of-the-line.”

Frigates began with ‘fifth raters’ a.k.a. “great frigates. Manned with a crew of between 200 and 300, they were armed with 32 to 44 guns on one or two decks and displaced 700 – 1,450 tons. The famous American frigates –Chesapeake, Congress, Constitution, Constellation, President and United States would be considered fifth raters under the British system.

‘Sixth raters’ had between 20 – 28 guns, weighed between 340 and 550 tons and carried 140 – 200 officers and men. Sloops-of-war, brigs, cutters, schooners et al were considered non-rated ships no matter how many guns they carried.

The Royal Navy built more fourth and fifth rate frigates than any other type other than 16 – 18 gun sloops-of-war. Frigates were the heart and soul of the Royal Navy and from their quarterdecks, young captains like Nelson, Pellew and Cockburn began to write their chapters in Naval history.