Naval Classification - Part II - Surface Ships

Surface ships
As previously discussed, surface ships developed into their role as a "Ship-of-the-Line".  Some small shore-based ships did exist, but after the discovery of the New World the need to control the sea became paramount.  The "Ship-of-the-Line" was any ship placed in a line of battle and was sea worthy.  However, over time there came certain standard ways to classify ships, mostly by the number of guns a ship carried.

This article will describe the different ways used to classify surface ships and the difficulty with each system.

By Number of Guns
The problem here was a ship carrying 42 5-inch canons would be rated the same as a ship carrying 42 4-inch canons.  Both would be "42s", but one had larger bore canon and, conceivably, different effective ranges.  The beauty of this system is it makes it very quantitative, there is no "subjectivity", the difference is just ignored.


By Size of Crew

This process seems simple, the bigger ship needs bigger crews.  Lets measure ships by the size of the crew they carry.  Another "quantitative" method, it doesn't tell much about the ship's effectiveness.  Consider two ships with the canons above.  The two ships may have different crew sizes to man their canons.  The 42 5-inchers may need 6 men per canon, while the 4-inchers require 5 men per canon.  The difference here comes to 42 men, with the 5-incher ship being "bigger".

By Length of Ship

The length of a ship used to give an accurate accounting of its serviceability in combat.  The longer ships, were more likely to survive, and carried more guns.  However, with the introduction of guns stacked in decks, the concept of Length as a credible ranking system fell out of favor.  Using the example above, the 42 5-incher could have guns on three decks, roughly 10 guns per deck.  The 4-incher may only have 2 decks, making it roughly 20 per deck.  Theoretically, the 4-incher would have to be longer than the 5-incher, making the 4-incher the "bigger" ship.

By Tonnage
The only method to continue from days of yore into modern parlance, is to measure on tonnage.  The idea behind this is the larger will displace more.  A reasonable method, it works fairly well as a larger ship usually equates to more guns, bigger crews, and larger size.   This fails to take into account the material which makes up the ship.

Rating/Rangs

The English and French eventually developed a ranking system for their ships.  In England, ships were assigned to one of three "ratings".  The French did something similar, but divided them into 5 different Rangs.  Later, the English had to revise their rating system and added a total of 6 ratings to the ship

A ship was assigned its rating based on both the number of guns and the size of its crew.  As technology improved, the "ratings" were increased in size.  Thus, a 16th century Third Rate ship was significantly smaller than a Third Rate ship of the 18th century.

The chart below summarizes, roughly, what I've learned about the size of the "rated" Ships-of-the-line:

British Rating System

Rating	Crew	Guns	Tonnage
First Rate	750+	100+	2000+
Second rate	600-750	90-98	1500-2200
Third Rate	200-300	60-90
Fourth Rate		46-60
Fifth Rate	215-194	30-45
Sixth Rate	150-240	20-24

Sources

Winfield, Rif, British Warships in the Age of Sail: 1603-1714 Barnsley (2009) ISBN 978-1-84832-040-6 British Warships in the Age of Sail: 1714-1792 Barnsley (2007) ISBN 978-1-84415-700-6

British Warships in the Age of Sail: 1793-1817, (2nd edition) Barnsley (2008). ISBN 978-1-84415-717-4  

Only those in the First through Fourth Rates were considered a Ship-of-the-Line.  The last two rates were usually smaller ships designated for coastal or small operational duties.

First Rate

Huge ships with over a hundred guns on three decks.  Despite their size, they were cumbersome to maneuver.  Due to the expense in building them, only a few were present in a fleet at a time.  They were the most feared ships of the seas, but were easily outrun by smaller ships.

Second Rate

Second Rate ships were slightly smaller than their First Rate counterparts.  However, they were cheaper to build and operate.  With so few First Rate ships available, a Second Rate ship was used to fill as the command vessel. 

Third Rate

Third Rate vessels were the smallest ship-of-the-line through the 17th century.  After that, the English decided the smaller Third Rate vessels could not be expected to fight alone, and a new classification was developed.  Third-Rate vessels are arguably the best of the ship-of-the-line.  Although outgunned, they were nimbler, faster, and easier to handle than the larger ships.  This meant Third Rate ships were often able to decide when an encounter took place against their larger brethren.

Fourth Rate
Fourth Rate ships were an introduction in the 18th century.  Many of the smaller Third Rate ships carried insufficient firepower and speed.  Operational differences between the ships eventually led the Fourth Rate class to be created.  They were used as supporting fire ships when in line of battle, but rarely operated by themselves.

Fifth and Sixth Rate

This ships bear a similar role, coastal defense.  They were not considered a ship-of-the-line, but still carried sufficient firepower to ward of marauders and patrol.  Fifth Rate ships also bore the duty of engaging merchant ships.  Sixth Rate ships were phased out of service by the early 1800s.  They were very small ships and deemed insufficient for good operational use.

Ships of both these classes were often termed "Frigate".

American Frigate
The American Frigates were 36/38 gun or 44/50 gun ships.  However, their design and building material essentially elevated them above the standard.  They were faster than other ships of their size and very nimble.  Made of Southern Live Oak, these ships had incredible hull strength and many times shots which would penetrate another ship would either bounce off or embed itself in the wood without penetrating.  The American Frigates were technically Fourth Rate or Fifth Rate ships by the British Standard, but they outclassed other ships of similar size to the point the British navy ordered their similar sized ships to not engage them one-on-one.

Issues with the Rating System
The Rating System worked up until technology changed.  As the ironclad warships came into existence, the number of guns decreased even as tonnage increased.  The decrease in number of guns lead to increased gun size, eventually leading to explosive shells which could tear a wooden ship apart.  Steam power made all of this possible, increasing mobility (or at least, the ability to go in a given direction against the wind), although speed decreased.

The Rating system continued to be in use through the 18th century.  However, eventually it was replaced by a different system: one based on roles.