Rating system of the Royal Navy

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The rating system of the Royal Navy and its predecessors was used by the

The first movement towards a rating system may be seen in the 15th century and the first half of the 16th century, when the largest

• Royal Ships - the largest ships in the previous "great ships" grouping, mounting 42–55 guns and carrying at least 400 men;^[3]
• Great Ships - the rest of the ships in the previous "great ships" grouping, mounting 38–40 guns;
• Middling ships
  mounting 30–32 guns; and
• Small ships mounting fewer than 30 guns

A 1612 list referred to four groups: royal, middling, small and pinnaces; but defined them by tonnage instead of by guns, starting from 800 to 1200 tons for the ships royal, down to below 250 tons for the pinnaces.^{[2]: 128 [q 2]}

By the early years of King

The earliest rating was based not on the number of guns, but on the established complement (number of men). In 1626, a table drawn up by Charles I used the term rates for the first time in a classification scheme connected with the Navy. The table specified the amount of monthly wages a seaman or officer would earn, in an ordered scheme of six rates, from "first-rate" to "sixth-rate", with each rate divided into two classes, with differing numbers of men assigned to each class. No specific connection with the size of the ship or number of armaments aboard was given in this 1626 table, and as far as is known, this was related exclusively to seaman pay grades.[2]^{: 128 [q 3]}

This classification scheme was substantially altered in late 1653 as the complements of individual ships were raised. From about 1660 the classification moved from one based on the number of men to one based on the number of carriage guns a ship carried.^[1]

The smaller two deckers originally blurred the distinction between a fourth rate and a fifth rate. At the low end of the fourth rate one might find the two-decker 50-gun ships from about 1756. The high end of the fifth rate would include two-deckers of 40- or 44-guns (from 1690) or even the demi-batterie 32-gun and 36-gun ships of the 1690–1730 period. The fifth rates at the start of the 18th century were generally "demi-batterie" ships, carrying a few heavy guns on their lower deck (which often used the rest of the lower deck for row ports) and a full battery of lesser guns on the upper deck. However, these were gradually phased out, as the low freeboard (i.e., the height of the lower deck gunport sills above the waterline) meant that in rough weather it was often impossible to open the lower deck gunports.[4]

Sixth-rate ships were generally useful as convoy escorts, for blockade duties and the carrying of dispatches; their small size made them less suited for the general cruising tasks the fifth-rate frigates did so well. Essentially there were two groups of sixth rates. The larger category comprised the sixth-rate frigates of 28 guns, carrying a main battery of twenty-four 9-pounder guns, as well as four smaller guns on their superstructures. The second comprised the "post ships" of between 20 and 24 guns. These were too small to be formally counted as frigates (although colloquially often grouped with them), but still required a post-captain (i.e. an officer holding the substantive rank of captain) as their commander.^[4]

The rating system did not handle vessels smaller than the sixth rate. The remainder were simply "unrated". The larger of the unrated vessels were generally all called sloops, but that nomenclature is quite confusing for unrated vessels, especially when dealing with the finer points of "ship-sloop", "brig-sloop", "sloop-of-war" (which really just meant the same in naval parlance as "sloop") or even "corvette" (the last a French term that the British Navy did not use until the 1840s). Technically the category of "sloop-of-war" included any unrated combatant vessel—in theory, the term even extended to bomb vessels and fire ships. During the Napoleonic Wars, the Royal Navy increased the number of sloops in service by some 400% as it found that it needed vast numbers of these small vessels for escorting convoys (as in any war, the introduction of convoys created a huge need for escort vessels), combating privateers, and themselves taking prizes.^[4]

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.

Introduced in the late 1770s, the carronade was a short-barreled and relatively short-range gun, half the weight of equivalent long guns, and 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,

When carronades formed a ship's principal armament, they were included in the count of guns. For instance, HMS Bonne Citoyenne was a 20-gun corvette of the French Navy that was captured and recommissioned in the Royal Navy as a sloop and post ship. 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 must distinguish between the established armament of a vessel (which rarely altered) and the actual guns carried, which might change quite frequently for a variety of reasons: guns might be lost overboard during a storm, be jettisoned to speed the ship during a chase, or explode in service and become useless; they might also be stowed in the hold to allow the carriage of troops, or, for a small vessel such as HMS Ballahoo, to lower the centre of gravity and thus improve stability in bad weather. Some guns would also be removed from ships during peacetime service, to reduce the stress on the ships' structure, creating a distinction between a ship's wartime complement of guns (the figure normally quoted) and her lower peacetime complement.

^* The smaller fourth-rates, primarily the 50-gun ships, were, from 1756 on, no longer classified as ships of the line. Since not big enough to stand in the line of battle, were often called frigates, though not classed as frigates by the Royal Navy. They were generally classified, like all smaller warships used primarily in the role of escort and patrol, as "cruisers", a term that covered everything from the smaller two-deckers down to the small gun-brigs and cutters.

^* The larger fifth-rates were generally two-decked ships of 40 or 44 guns, and thus not "frigates", although the 40-gun frigates built during the Napoleonic War also fell into this category.

^* The smaller sixth-rates were often popularly called frigates, though not classed as "frigates" by the Admiralty officially. Only the larger sixth-rates (those mounting 28 carriage guns or more) were technically frigates.

^* The ton in this instance is the burthen tonnage (bm). From c.1650 the burthen of a vessel was calculated using the formula ${\displaystyle {\frac {k\times b\times {\frac {1}{2}}b}{94}}}$, where ${\displaystyle k}$ was the length, in feet, from the stem to the sternpost, and ${\displaystyle b}$ the maximum breadth of the vessel. It was a rough measurement of cargo-carrying capacity by volume, not displacement. Therefore, one should not change a measurement in "tons burthen" into a displacement in "tons" or "tonnes".

^* Vessels of less than ten guns were commanded by lieutenants, while those with upwards of ten guns were commanded by commanders.

In February 1817 the rating system changed.^[5] The recommendation from the Board of Admiralty to the Prince Regent was dated 25 November 1816, but the Order in Council establishing the new ratings was issued in February 1817. From February 1817 all carronades were included in the established number of guns. Until that date, carronades only "counted" if they were in place of long guns; when the carronades replaced "long" guns (e.g. on the upper deck of a sloop or post ship, thus providing its main battery), such carronades were counted.

There was a further major change in the rating system in 1856. From that date, the first rate comprised all ships carrying 110 guns and upwards, or the complement of which consisted of 1,000 men or more. The second rate included one of HM's royal yachts, and otherwise comprised all ships carrying under 110 guns but more than 80 guns, or the complements of which were under 1,000 but not less than 800 men.

The third rate included all the rest of HM's royal yachts and "all such vessels as may bear the flag of pendant of any Admiral Superintendent or Captain Superintendent of one of HM's Dockyards", and otherwise comprised all ships carrying at most 80 guns but not less than 60 guns, or the complements of which were under 800 but not less than 600 men. The fourth rate comprised all frigate-built ships of which the complement was not more than 600 and not less than 410 men.

The fifth rate comprised all ships of which the complement was not more than 400 and not less than 300 men. The sixth rate consisted of all other ships bearing a captain. Of unrated vessels, the category of sloops comprised all vessels commanded by commanders. Next followed all other ships commanded by lieutenants, and having complements of not less than 60 men. Finally were "smaller vessels, not classed as above, with such smaller complements as the Lords Commissioners of the Admiralty may from time to time direct".

Rating was not the only system of classification used. Through the

Vessels were sometimes classified according to the substantive rank of her commanding officer. For instance, when the commanding officer of a gun-brig or even a cutter was a lieutenant with the status of master-and-commander, the custom was to recategorise the vessel as a sloop. For instance, when Pitt Burnaby Greene, the commanding officer of Bonne Citoyenne in 1811, received his promotion to post-captain, the Navy reclassed the sloop as a post ship.

Although the rating system described was only used by the Royal Navy, other major navies used similar means of grading their warships. For example, the French Navy used a system of five rates ("rangs") which had a similar purpose. British authors might still use "first rate" when referring to the largest ships of other nations or "third rate" to speak of a French seventy-four. By the end of the 18th century, the rating system had mostly fallen out of common use, although technically it remained in existence for nearly another century, ships of the line usually being characterized directly by their nominal number of guns, the numbers even being used as the name of the type, as in "a squadron of three seventy-fours".

As of 1905, ships of the United States Navy were by law divided into classes called rates. Vessels of the first rate had a displacement tonnage in excess of 8000 tons; second rate, from 4000 to 8000 tons; third rate, from 1000 to 4000 tons; and fourth rate, of less than 1000 tons. Converted merchant vessels that were armed and equipped as cruisers were of the second rate if over 6000 tons, and of the third rate if over 1000 and less than 6000 tons. Auxiliary vessels such as colliers, supply vessels, repair ships, etc., if over 4000 tons, were of the third rate.^[6]

Auxiliary vessels of less than 4000 tons—except tugs, sailing ships, and receiving ships which were not rated—were of the fourth rate. Torpedo-boat destroyers, torpedo boats, and similar vessels were not rated. Captains commanded ships of the first rate. Captains or commanders commanded ships of the second rate. Commanders or lieutenant-commanders commanded ships of the third rate. Lieutenant-commanders or lieutenants commanded ships of the fourth rate. Lieutenant-commanders, lieutenants, ensigns, or warrant officers might command unrated vessels, depending on the size of the vessel.^[7]

The term first-rate has passed into general usage, as an adjective used to mean something of the best or highest quality available. Second-rate and third-rate are also used as adjectives to mean that something is of inferior quality.