Rating System of The Royal Navy - The Number of Guns and The Rate

The Number of Guns and The Rate

The rated number of guns often differed from the number a vessel actually carried. The guns that determined a ship's rating were the carriage-mounted cannon, long-barreled, muzzle-loading guns that moved on 'trucks' — wooden wheels. The count did not include smaller (and basically anti-personnel) weapons such as swivel-mounted guns ("swivels"), which fired half-pound projectiles, or small arms.

For instance, HMS Cynthia was rated for 18 guns but during construction her rating was reduced to 16 guns (6-pounders), and she also carried 14 half-pound swivels.

Vessels might also carry other guns that did not contribute to the rating. Examples of such weapons would include mortars, howitzers or boat guns, the boat guns being small guns intended for mounting on the bow of a vessel's boats to provide fire support during landings, cutting out expeditions, and the like. From 1778, however, the most important exception was the carronade.

The late 1770s saw the introduction of the carronade, which was a short-barreled and relatively short-range gun, half the weight of equivalent long guns, and which was generally mounted on a slide rather than on trucks. The new carronades were generally housed on a vessel's upperworks—quarterdeck and forecastle—some as additions to its existing ordnance and some as replacements. When the carronades replaced or were in lieu of carriage-mounted cannon they generally counted in arriving at the rating, but not all were, and so may or may not have been included in the count of guns, though rated vessels might carry up to twelve 18-, 24- or 32-pounder carronades.

For instance, HMS Armada was rated as a third rate of 74 guns. She carried twenty-eight 32-pounder guns on her gundeck, twenty-eight 18-pounder guns on her upperdeck, four 12-pounder guns and ten 32-pounder carronades on her quarterdeck, two 12-pounder guns and two 32-pounder carronades on her forecastle, and six 18-pounder carronades on her poop deck. In all, this 74-gun vessel carried 80 cannon: 62 guns and 18 carronades.

When carronades became part (or in some cases all) of a ship's main armament, they had to be included in the count of guns.

For instance, Bonne Citoyenne was a 20-gun corvette of the French Navy that the British captured and recommissioned in the Royal navy as the 20-gun sloop and post ship HMS Bonne Citoyenne. She carried two 9-pounder cannon and eighteen 32-pounder carronades.

By the Napoleonic Wars there was no exact correlation between formal gun rating and the actual number of cannons any individual vessel might carry. One therefore needs to distinguish between the established armament of a vessel (which rarely altered) and the actual guns carried, which might happen quite frequently for a variety of reasons; guns might be lost overboard during a storm, or "burst" in service and thus useless, or jettisoned to speed the ship during a chase, or indeed removed down into the hold in order to use the ship (temporarily) as a troop transport, or for a small vessel, such as the schooner HMS Ballahoo, to lower the center of gravity and thus improve stability in bad weather. Also some of the guns were removed from a ship during peacetime service, to reduce the stress on the ship's structure, which is why there was actually a distinction between the wartime complement of guns (and men) and the lower peacetime complement—the figure normally quoted for any vessel is the highest (wartime) establishment).