Warships were once classified with a rate between 1 and 6.
For the last 100 – 130 years of the Age of Sail nearly all the navies of the world adopted a ratings system for their ships. It was first introduced by the British First Lord of the Admiralty, Admiral Lord Anson during 1751 – 1756, however modern historians sometimes give a rating to ships before that date for ease of classification.
The first three rates covered ships of the line, which were those considered powerful enough to join the battle line in a major engagement. Fourth-raters were already becoming obsolete as ships of the line when the system was begun; they were useful in shallower waters, and were considered a capital ship by some of the smaller navies. (The fledging USA commissioned large frigates of 44 or more guns for its first navy.)
Rates four and five were typically given to frigates and other support vessels, and a sixth rating was only given to a vessel commanded by a post-captain – those under commanders and lower were considered sloops and did not receive a rating.
The following lists the rates as at 1800. Later the lower gun limits were raised for most classifications to reflect the generally larger ship sizes.
- 1st…..Over 2000 tons – 100-130 guns on 3 decks – 850-900 crew.
- 2nd….1650-1950 tons – 84-90 guns on 2 or 3 decks -750-850 crew.
- 3rd….1200-1600 tons – 64-80 guns on 2 decks – 520-750 crew.
- 4th….700-1000 tons – 44-60 guns on 1 or 2 decks – 380-500 crew.
- 5th….650-730 tons – 32-40 guns – 200-300 crew.
- 6th….400-630 tons - 20-28 guns – 150-200 crew.
A rating also refers to a naval seaman whose rank is known as a rate.
Reference: "The Oxford Companion to Ships and the Sea."