Popular war literature and much science fiction is peppered with terms like battlecruiser, frigates, destroyer, and other warships. What is often lacking is the technical definitions of these types of vessel and how to determine if that Yentazi ship is a battlecruiser or a battleship. Included are the US Navy designations for each type of ship.
These are generally the most massive ships operated by a fleet, second only the realm of the super-aircraft carriers. A battleship’s primary weapons are cannons, and in a futuristic space setting, this would certainly include lasers, particle cannons, as well as traditional projectile cannons and even gauss/rail guns. While clad in massive amounts of armor and bearing massive guns, the main clout of the Battleship is it’s sheer size. Deployment of battleships is as likely to involve national level politics as well as military deployments. A nervous ally can be bolstered by the deployment of an allied Battleship to one of their contested regions, while a saber-rattling opponent can be forced to show their hand for a bluff by close deployment of a battleship. While less strategically valuable than a carrier, which can command a larger volumn of space, no one EVER wants to go toe to toe with a battleship.
The principle weakness of the Battleship is the sacrifice of speed in favor of massive firepower and impressive armor. The battlecruiser is a compromise between the Cruiser genre of ships and the larger battleships. A battlecruiser will sacrifice either firepower or armor protection to gain the same speed as a normal cruiser. Those that keep the firepower for the sake of armor tend to be called Gun Cruiser, those that sacrifice firepower for speed and keep their armor are pocket battleships. Gun toting battlecruisers serve as extra muscle to be used in fleet on fleet engagements, while the pocket battleship is deployed to hunt the merchant marine and shipping vessels of enemy powers.
Cruisers are medium sized ships that are intended to operate in small numbers, alone, or in support of a primary strike force. Smaller and less expensive to build and operate than battleships, the role of the cruiser is as varigated as the name. In the current day, the supremacy of guided missles, aircraft and submarines have greatly limited the value of the gun toting cruiser and as such the US fields very few of these ships.
CL - The Light Cruiser is determined as a warship with an armored hull and less than battleship/heavy cruiser sized guns. Light cruisers can range from oversized destroyers to normal cruisers with less than expected firepower. Tonnage is rarely considered in the classification of light versus heavy in cruiser types.
CB - the Large Cruiser is a rare class that mounts the forward firepower of a battlecruiser but has the side and rear firepower of a normal cruiser and cruiser type armor. Large Cruisers and Battlecruisers are very difficult to tell apart, though the later tend to be much more common.
Possibly the most famous Heavy cruiser is the Constitution class of Heavy cruisers from Star Trek, the Original series.
CA - The Heavy Cruiser mounts medium bore guns, as compared to the heavy/big bore guns deployed by battleships and battlecruisers. In comparison, Light cruisers carry light or small bore capital guns. Deployed much like Battleships, Heavy cruisers are cheaper, more common, and require less resources to maintain.
CG - The Missle Cruiser supplants it’s big guns with an arsenal of guided missles fire from tubes buried in the deck, or from rotating missle turrets. While a few big guns are retained, these are superfluous to the guided long and medium range missles carried by the ship.
The role of the Destroyer is to serve as a scout and picket ship for the larger and slower ships of a fleet. They scout coastal regions for areas of opportunity to attack, eliminate coastal defense ships such as torpedo boats and other light ships and generally are the first to engage enemy ships in combat. Destroyers are fast, agile, and carry only moderate armor and relatively light weaponry.
The most famous fictional destroyers are the Imperial and Victory Class Star Destroyers from the Star Wars universe. However, by the weapons layout and disposition of these ships, the Victory is more of a Heavy cruiser or a Battlecruiser, while the larger Imperial is very much in heart and steel a Battleship.
The ships are generally smaller than Light Cruisers and Destroyers and are generally not used in fleet combat. However, frigates remain deployed constantly in peace or wartime. These ships are small and fast enough to run down fast light cargo ships, serve as harasser and skirmisher ships and perform courier duty as the need arises.
Even smaller than the frigate, the Corvette is used as a agile coastal water fighter that is also capable of long distance travel. In terms of futuristic warships, the Corvette would be the smallest warship possessing a FTL drive, while smaller ships would be in system patrol craft and monitor type warships. Corvettes are operated by smaller powers unable to afford large numbers of destroyers.
These craft, torpedo boats, gun monitors and the like are short range craft limited to close to shore engagements. In a futuristic setting, these are the warships that are not able to move faster than light and are limited to whatever planet or starsystem they are in. These ships tend to be small, fast, and maneuverable, and their crews are fighting on their own turf and are more knowledgeable of the region than invading forces.
Following the end of WWII, the dominance of airpower and the mobile Aircraft Carrier overshadowed the big gun era of warships from the previous century. The prominence of the Carrier depends on the power of small aerospace fighters and attack craft compared to the vulnerability of said gun based warships. If fighters are able to battle and defeat these gun toting behemoths, the carrier will have a prominent place in a fleet. If the gun toting cruisers and battleships can repulse fighters with little to no damage, the presence of carriers will be non-existant. In the Star Trek milieu, fighters are nearly worthless when confronting the shielded vessels of the Federation and other powers, so cruisers are the norm and carriers are non-existant. While in the Star Wars universe, the fighter is capable of causing severe damage to gun based ships, so carriers are available in a variety of shapes and forms as well as most any warship carrying a contingent of fighters as defense.
Virtual cities in their own right, supercarriers support an entire wing of aircraft or space fighters, generally 100 or evne more depending on the overall size and disposition of fighter formations. These mammoth vessels command an area of space far excedding the range of mundane guns, and with their stows of fighters are able to destroy many targets at great range. While vulnerable to close range attack, carriers are armed and armored, but this is secondary to their role as a fighter craft platform.
The Escort Carrier
Smaller, faster and only carrying a single group (30-40 fighter craft, Escorts are used to ‘escort’ convoys and defend smaller areas than are needed for a larger super carrier. Many crews describe their ships as Combustible, Vulnerable, and Expendable, a reference to the ship hull code of CVE.
The Light Carrier
Even smaller in tonnage than the CVE, the Light Carrier is a conversion manufactured onto a non-carrier design. Most light carriers are built off of modified cruiser hulls and carry the same fighter complement of a CVE in more confined space.