Naval Classification - Part III - Modern Ship Classes

The third in a three part series describing naval ships.  This covers the modern era of ships.

In the 'Modern Era' as I'm defining it, I'm including ships defined more by their role and function than their size, number of guns, or crew.  Many ships had initial roles they performed for hundreds of years, but now it is the role which defines the ship and not the ship performing the role.  Confusing?

Consider the term "Cruiser".  Cruiser was a naval role where a ship of some size would roam around by itself and engage enemy merchants or ships.  The ships would simply "cruise" until they spotted an enemy and then would either engage them, or run.  The size of the ship could be anything from a Fourth Rate to First Rate ship-of-the-line.  Modern cruisers are ships which were initially designed to fulfill the "cruiser" role, and thus came to be known as cruisers.  However, in war time operations of WWII, the role of the ships now known as cruiser changed, but the ships still retain their name.

The easiest way I believe to explain the classification of modern era ships is to start with the largest surface ships and work downwards in role.

Battleship
The goal of the battleship was to build a huge armored ship and pack on big guns.  Battleships were thickly armored from bow-to-stern, keel-to-castle.  A basic definition of battle ship is a ship capable of engaging any other non-battleship vessel with a better than even odd of survival.  Battleships were significantly larger than cruisers.  At the start of WWII, every nation in the world considered the Battleship the apex of power and all fleets were centered around a core of Battleships.

Battleships suffered from an unusual confluence of events.  As the guns grew powerful enough to propel explosive shells farther than the ship could see, something was needed to let the ships aim farther than they could see.  The invention of radar seemed to fit the bill.  Using radar, battleships could engange enemies with a reasonable possibility of successful hits.  Unfortunately, radar also sounded the death knell of the battleship as radar multiplied the power of aircraft, shifting the balance of power to the Aircraft Carrier.


Cruiser

Coming in multiple sizes and types, cruisers are defined as being heavily armed and lightly armored.  Lightly armored is a relative term, as most cruisers could engage destroyers with relative ease.  Essentially, cruisers contain the firepower of a battleship without the heavy armor protection.  Cruisers have the capability of working alone without support, but are often part of a larger fleet.

Destroyer

Destroyers, some navies call them frigates, came in many different types.  The main role of a true destroyer is the ability to engage any other ship, though often luck is required.  Against battleships and cruisers, destroyers attack with torpedoes.  Aircraft and other destroyers are countered with rapid fire guns.  The threat of submarines are countered by depth charges.  Destroyers do not act independently, however.  they always work with some other large formation of ships: either a fleet or a convoy.

Destroyers serve the role of scout and protector.  They are cheap enough to be 'expendable' compared to the larger ships, but are large enough to pose a threat to anything.  Destroyers are the work horse of any navy, performing whatever role is required.  More destroyer exist in navies than any other type of ship, mainly because their power-to-cost ratio is better than any other ship. 

Aircraft Carrier

Aircraft Carriers came into their own in WWII, and possibly by accident.  Every navy in the world viewed the battleship as the pinnacle of naval power.  With the destruction of the American pacific battleship fleet at Pearl Harbor, the United States was left with only carriers.  Six months later 3 American Carriers and 25 support ships drove off a Japanese invasion force of 6 carriers, 7 battleships, and 56 support ships.  Furthermore, no surface ships ever fired on each other during this battle.  From that point onward, the Aircraft Carrier came to dominate naval strategy.

By themselves, aircraft carriers are a poor warship incapable of adequately defending itself.  Their armament is defensive in nature, mostly consisting of small caliber rapid-fire guns to shoot incoming aircraft.  Their offensive power comes in the aircraft they carry.  Even in WWII, aircraft were capable of carrying weaponry which could sink any other naval ship and project power onto land. 

Missile Ships

Many types of ships now exist with the prefix 'Missile' before their class.  The main armament of these ships is self guided explosive missiles.  With the power of missiles, even a single missile could disable a carrier, or potentially sink it with some luck.  Missile ships still require protection from aircraft and submarine based threats, but mainly their power is focused entirely offensively in their missile.

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. 

Naval Classification - Part I

A confusing topic at times involves the differences between sizes of ships.  This article will review various ship classifications and their uses through history.  Given the length of the topic, it is broken into multiple articles.

The Ram
Pre-canon ships involved two ways to attack: either boarding or ramming.  Powered by human muscles, the ram ship has served as the primary naval warship for thousands of years.  However, ramming was as dangerous for the ramming vessel as for the rammed vessel.

Fire Ship
Fire ships were an accepted battle tactic during the days of wooden ships.  Creating a fire ship basically involves turning a ship into a barge of combustible materials and igniting it.  The ship is then steered into an opposing ship.   Succeeding with a fire ship requires some luck and, more importantly, a trapped foe.  Ships in open water would be difficult to hit, so most fire ship attacks occurred when the foe was stuck in a bay, harbor, or enclosed area.  A later variation of the fire ship involves filling a ship with explosive material, get the ship close to the target, and explode it.

Torpedo Boats
The objective of torpedo boats is to deliver torpedoes to enemy ships.  Torpedoes have differed over time.  Original torpedoes consisted of explosives attached to a long pole.  Thus, torpedo boats were required to get close and plant explosives on the enemy ship, usually under the cover of night.  Another use was for a torpedo boat to "plant" the torpedoes in the water.  These type of torpedoes would become "mines" later in history.

When the self-propelled torpedo, or "fish torpedo", came into use, the role changed again.  World War II introduced a small, light, fast craft capable of high speed "hit-and-run" attacks.  The primary tactics of torpedo boats is to swarm larger enemy ships and, through sheer numbers, attempt to destroy more expensive craft.

Submarines
The first submersible vessel used in military operations, Turtle, involved a small ship with a screw on the front of it.  The concept of the attack was to approach unnoticed and plant explosives onto the enemy ship, HMS Eagle.  Although creative, the attempt (and all subsequent attempts) were unsuccessful.

The first significant use of submarines would wait until WWI.  From that time onwards, submarines became the main threat to naval merchant vessels.  WWI and WWII submarines traveled on the surface of the ship, powered by diesel engines.  These same engines powered batteries, which became the  power source once submerged.  Submarines are low to the water and difficult to spot.  However, Diesel engines required Submarines to surface regularly and recharge the batteries.  During this time they were vulnerable to air and surface attack.

The advent of nuclear power changed submarines forever.  Finally, submarines could run submerged for months at a time.  Unlike their predecessors, however, the role of the nuclear submarines changed again.  Instead of attacking naval shipping, nuclear subs (or "boomers") carry nuclear ICBMs.  The role of hunting submarines fell to destroyers and aircraft.  However, the reintroduction of the 'attack sub', a sub designed to hunt other submarines and ships, returns the submarine to its original concept.

Surface Ships
Surface ships come in many different types.  The main idea for all surface ships is to carry large bore guns long distances and pound the enemy...at least until the advent of aircraft.  Classifying surface ships becomes tricky because the classification system used differs from country to country, and technological advances made some "big ships" into "smaller ships".  The easiest way is to identify them by "Role"

Ship-of-the-Line
Technically, a Ship-of-the-Line was any large ship with many guns and heavy, thick skin.  The "ship" part is easy to understand, but the term "line" comes from the battle tactic of having ships in a column and going into battle.  Moving in column makes sense in many ways.  It is easier to keep track of all ships, every ship needs to keep track of, at most, two ships: the one in front of it and the one behind it.  It reduces the possibility of collision with friendly ships, a danger when vessels were self-propelled.  The possibility of friendly fire was removed.  Lastly, if any ship but the last had to be abandoned, a ship further down the line could pick up survivors.

However, many of the "destroyers" and "frigates" were also a Ship-of-the-Line.  But over time Ship-Of-The-Line came to mean the biggest ships with the most firepower, although the American Frigate tends to disrupt this image.

Next week we will discuss the different classifications of Surface ships.