An American Nimitz-class CVN and a British Invincible-class CVH, illustrating the difference in size.

NAVAL UNITS

Naval combat scores are given in the form AAW/ASuW/ASW (Special). The first number is that unit's antiaircraft score, the second is that unit's anti-ship score, and the third is that unit's anti-sub score. The (Special) is for stuff like shore bombardment and special bonuses or abilities.

SS: Diesel-Electric Attack Submarine
Cost: 2/1
Combat: 0/1/2
Production: Shipyards Level 1

These are basically similar to the German U-Boats of World War II. With Diesel or other conventional engines for running on the surface and battery-powered electric motors for underwater, these subs are mostly used for commerce raiding or defending one's own coast. Although noisy when running the Diesels to recharge the batteries, the electric motors are actually quieter underwater than nuclear subs, but with a sacrifice in submerged endurance. You need to have at least "Light Ships only" to build SS submarines.

SSK: Advanced Conventional Attack Sub
Cost: 3/1
Combat: 0/3/2
Production: Shipyards Level 1, AIP Technology

Only found in a few navies, these are highly advanced submarines with either diesel-electric or advanced air-independent propulsion systems, anechoic tile, and sophisticated sonars. As effective against subs as nuclear attack boats, since they have longer underwater endurance and are quieter than ordinary SS subs. You must have "Air-Independent Propulsion" technology and at least Level 1 Shipyards to build these subs. (Note: Only the real-world sub classes "Upholder" (UK), "Kilo" (USSR), and "214" (Germany/Italy) qualify for this classification).

SSN: Nuclear-powered attack sub
Cost: 4/2
Combat: 0/3/2
Production: Shipyards Level 2, Nuclear Program Level 1.

The best way to kill a sub is with another sub, and the best sub to do that with is a nuclear-powered attack sub. These vessels are true submarines, and they only need to come up to the surface to restock the food pantry every few months. More expensive than a diesel-electric sub, but worth it. NOTE: US Navy subs that are really SSN but which have VLS tubes for Tomahawk cruise missiles are considered SSGN, but US, British, and other subs that can fire missiles only through torpedo tubes count as SSN.

SSNCD: Nuclear-powered attack sub
Cost: 5/2
Combat: 0/4/4 (invisible to SOSUS Nets, +1 Bonus in hunting SSBN's)
Production: Shipyards Level 2, Nuclear Program Level 1, M-Drive Technology.

These are standard nuclear-powered attack submarines that use the "Caterpillar" drive system to become almost silent. This makes them much harder to detect, and thus much more effective, although it also makes them more expensive. This drive system allows them to pass through SOSUS nets without detection, and gives them a bonus when hunting SSBN's.

SSKCD: Advanced Conventional Attack Sub with M-Drive
Cost: 4/1
Combat: 0/4/4 (invisible to SOSUS Nets, +1 Bonus in hunting SSBN's)
Production: Shipyards Level 2, AIP Technology, M-Drive Technology

The marriage of the "Caterpillar" drive system to the advanced Air-Independent Propulsion System can create a submarine that is an exceptional weapon. Quieter even than an SSNCD underwater, and with long underwater endurance, these subs are a cheaper alternative to SSNCD's.

SSG: Diesel-powered Cruise Missile Sub
Cost: 3/2
Combat: 0/3/1 (1 point shore bombardment)
Production: Shipyards Level 1, Aircraft Factory level 1

The most powerful sub for attacking surface ships is a submarine armed with cruise missiles. Able to sneak to within firing range of a convoy, cruise missile subs can launch sea-skimming anti-ship missiles from beyond enemy sonar and weapon range and devastate their targets without fear of reprisal. These subs also usually carry several cruise missiles with nuclear warheads for attacking targets on land. These basic SSG's usually are fairly noisy underwater, and often have to surface to fire their limited number of missiles.

SSGN: Nuclear-powered Cruise Missile Sub
Cost: 5/2
Combat: 0/4/2 (1 point shore bombardment)
Production: Shipyards Level 1, Aircraft Factory level 1, Nuclear Program Level 1

The addition of nuclear power to the SSG makes a larger sub that can carry more missiles, and which can hide underwater longer. In the Russian fleet, these are considered capital ships, and for good reason. The "Oscar II" class submarines carry the offensive missile bunch of a BC and are much harder to find and destroy.

SSGNCD Nuclear-powered Cruise Missile Sub with M-Drive
Cost: 6/2
Combat: 0/6/4 (1 point shore bombardment)
Production: Shipyards Level 1, Aircraft Factory level 1, M-Drive Technology

The addition of nuclear power to the SSG makes a larger sub that can carry more missiles, and which can hide underwater longer. In the Russian fleet, these are considered capital ships, and for good reason. The "Oscar II" class submarines carry the offensive missile bunch of a BC and are much harder to find and destroy.

SSGK: AIP-Powered Cruise Missile Sub
Cost: 5/2
Combat: 0/4/4 (1 point shore bombardment)
Production: Shipyards Level 1, Aircraft Factory level 1, AIP Technology

Giving an SSG a better power plant and newer technology creates a more deadly weapons platform. Able to sneak in even closer to a surface fleet, and able to fire their missiles while submerged, these ships are an extremely effective blockade weapon. These do not exist in real life, but there is little reason why they couldn't be built.

SSB: Diesel-powered Ballistic Missile Sub
Cost: 4/2
Combat: 0/1/1 (but can nuke any target in same hemisphere as the sub)
Production: Shipyards Level 1, Aircraft Factory level 1, plus either Nuclear Program Level 2 OR the conversion of 3 nuclear warheads

An early, extremely basic design, these subs carry only 3 SLBM missiles with a single warhead each. Only one of these subs is left in the world, and it is in the Chinese Navy. This sub, however, can still hide in the vastness of the open ocean and serve as an effective deterrent to potential aggressors, since losing one's three biggest cities can make any conquest a bitter victory.

SSBN: Nuclear-powered Ballistic Missile Sub
Cost: 6/2
Combat: 0/2/2 (but can nuke any target in same hemisphere as the sub)
Production: Shipyards Level 2, Aircraft Factory level 1, Nuclear Program Level 2

The ultimate in nuclear deterrence isn't the stealth bomber, it's a ballistic missile sub. These "boomers" can usually launch between 12 and 24 nuclear-tipped missiles, some with up to ten MIRV warheads each! These subs are also some of the quietest in the sea, and are difficult to locate. In your Starting Position, one of the figures is the number of missiles each sub can launch. New-build SSBN's have 18 missiles each, unless you are given the technology and blueprints by a nation whose SSBN's can fire more.

SSBNCD: Nuclear-powered Ballistic Missile Sub with M-Drive
Cost: 7/2
Combat: 0/2/3 (but can nuke any target in same hemisphere as the sub)
Production: Shipyards Level 2, Aircraft Factory level 1, Nuclear Program Level 2, M-Drive Technology

As seen in the movie "The Hunt for Red October", this is a nearly silent submarine armed with nuclear-tipped ballistic missiles. These subs are essentially immune from detection from all enemy forces, except those equipped with BGL sensors. If you have one of these, any attack on your motherland can be countered by someone not having a country anymore.

FF: Anti-Submarine Warfare (ASW) Frigate
Cost: 2/1
Combat: 1/1/1
Production: Shipyards Level 1

Small, cheap, but lightly armed, these ships are mainly used for convoy escort duty as a protection against submarines. The most numerous ships in most navies.

FFG: Guided Missile Frigate
Cost: 3/1
Combat: 2/1/1
Production: Shipyards Level 1, Aircraft Factory Level 1.

These ships are combined anti-sub and Anti-Air Warfare (AAW) escorts. They are basically ASW frigates with better radars and some sort of medium or long-ranged anti-aircraft missile system, defined as having at least one missile with a range greater than 10 miles.

DD: Destroyer (ASW)
Cost: 3/2
Combat: 1/2/2 (1 point in shore bombardment)
Production: Shipyards Level 1, Aircraft Factory Level 1.

These are larger and more capable versions of ASW frigates. They also usually have some sort of anti-ship weapons system, such as Harpoon missiles or 5-inch guns. More advanced navies have DD's that also include a short-ranged point-defense missile system for protection against incoming aircraft and anti-ship missiles.

DDG: Guided Missile Destroyer
Cost: 4/2
Combat: 3/2/2 (1 point in shore bombardment)
Production: Shipyards Level 1, Aircraft Factory Level 1.

These are destroyers that are mainly designed as anti-aircraft escorts for convoys or larger ships like Carriers. In most navies, these are the biggest and most powerful ships. However, most DDG's also have good ASW weapons and sensors like towed-array sonar and ASROC rocket-boosted torpedoes. These are the largest and most powerful ships that nations with only Level 1 shipyards can build.

DDGA: Guided Missile Destroyer
Cost: 5/2
Combat: 5/3/2 (2 point in shore bombardment)
Production: Shipyards Level 1, AEGIS technology, Aircraft Factory Level 1.

A DDG with a lightweight version of the AEGIS system, these are the most cost-effective air defense ships in the game. These only exist in the American and Japanese navies at the beginning, although the Southern Europeans have the technology to build them as well.

CL: Light Gun Cruiser
Cost: 5/2 (2/1 to upgrade to CG or CGH)
Combat: 2/3/0 (3 points in shore bombardment)
Production: Shipyards Level 2, Tank Factory Level 1.

These WWII-era gun cruisers are now only found in the Peruvian navy. Old, manpower-intensive, and with outdated radar and no sonar, these ships are kept mainly for the fact that their armament of 6-inch guns is a powerful weapon for shore bombardment or against a foe who lacks modern missiles. Also, the fact that they were built in the days when ships still used heavy armor plate means they stand up well to smaller modern sea-skimming missiles. They can be upgraded to become Missile Cruisers or Helicopter Cruisers by a nation that has a level 2 shipyard.

CG: Guided Missile Cruiser
Cost: 6/2
Combat: 4/4/3 (2 points in shore bombardment)
Production: Shipyards Level 2, Aircraft Factory Level 1.

These ships are all primarily used as anti-aircraft escorts for aircraft carriers. These ships are only found in the Italian, French, American, and Russian fleets, and only the Americans and Russians have more than one or two of them.

CGA: AEGIS Guided Missile Cruiser
Cost: 7/2
Combat: 6/5/4 (3 points in shore bombardment)
Production: Shipyards Level 2, Aircraft Factory Level 1, AEGIS Technology.

Only found in the American Navy, these ships are some of the most powerful ever built. Carrying up to 122 long-range SAM's, these ships also carry their own helicopters, have sophisticated radars and sonars, have 5-inch guns, and can even carry land-attack cruise missiles and anti-ship missiles as well.

CHG: Helicopter Missile Cruiser
Cost: 7/3
Combat: 4/4/3 (2 Points in Bombardment)
Production: Shipyards Level 2, Aircraft Factory Level 1.
Aircraft: 10 (VSTOL/Helicopters only)
Production: Shipyards Level 2, Aircraft Factory Level 2

These are cruisers with a large helicopter deck aft for carrying extra ASW helicopters. They can, in theory, also carry attack helicopters or NV fighters, but if they are used in this role, they lose 1 point of ASW power.

BC: Nuclear-powered Battlecruiser
Cost: 8/3
Combat: 5/5/4 (3 points in shore bombardment)
Production: Shipyards Level 3, Nuclear Program Level 1, Aircraft Factory Level 1

Halfway between a cruiser and a battleship, these ships are only found in Russia's navy. With a very heavy missile armament, but no large guns, these are essentially powerful anti-aircraft and anti-ship escorts for carriers, but they are also capable of forming the center of a Surface Action Group.

BCA: Nuclear-powered AEGIS Battlecruiser
Cost: 9/3
Combat: 7/6/5 (4 points in shore bombardment)
Production: Shipyards Level 3, Nuclear Program Level 1, Aircraft Factory Level 1, AEGIS Technology

These may not exist yet in the real world, but a similar design is currently under consideration by the US Navy. With a larger hull than a cruiser, these ships would carry an obscene number of VLS cells for launching SAM missiles and land-attack cruise missiles.

BB: Battleship
Cost: 9/4, or 3/2 to upgrade from mothballs
Combat: 3/5/0 (5 points in shore bombardment)
Production: Shipyards Level 3

Expensive and obsolete, these are no longer found, although the Denim fleet has two of them in mothballs, one in Bremerton, Washington, and the other in Hawaii. With a heavy gun armament of 9 16-inch guns and an equally heavy Tomahawk cruise missile armament, these are the most powerful ships for attacking land targets in the world.

BBGA: Battleship with Guided Missiles
Cost: 10/4, or 3/3 to upgrade from BB
Combat: 5/8/0 (6 points in shore bombardment)
Production: Shipyards Level 3, Aircraft Factory Level 1, AEGIS Technology

A long-dead proposal to upgrade the US Iowa-class battleships, this would have been a ship with the guns of a battleship and a heavy armament of surface-to-air missiles. Add in the AEGIS radars and VLS launch cells for increased missile firepower, and you have the ULTIMATE surface warship.

CVH: VTOL Carrier
Cost: 7/3
Combat: 1/0/0
Aircraft: 20 (VSTOL/Helicopters only)
Production: Shipyards Level 2

The most affordable way to provide air cover for your fleet, these carriers are small (around 15000 tons) and can only operate helicopters and aircraft like the Harrier or Yak-141 that can take off and land Vertically. Normally used mainly for ASW work and convoy escort, they are not designed for major fleet actions. Although any carriers you have at the start of the game will probably have enough planes to fill them up, any new ones you build will have to have new planes or else they are pretty useless. You may carry the helos for an Airmoble Cavalry division if you do not put any other aircraft on their decks, and put the troops for that division on an accompanying PHIB.

CVL: Light Carrier
Cost: 8/4
Combat: 1/0/0
Aircraft: 40 (Any carrier-capable planes)
Production: Shipyards Level 3

These are small carriers that are capable of carrying and launching fixed-wing aircraft. Found only in a few navies, these are in practice usually used with Harriers. Capable of fleet battles against any foe that doesn't have full supercarriers.

CVA: Attack Carrier
Cost: 9/5
Combat: 2/0/0 (Russia/E. Europe only: 2/3/1)
Aircraft: 60 (Any carrier-capable planes)
Production: Shipyards Level 3, Aircraft Factory Level 1.

One step short of a supercarrier, these ships are found in only 3 navies (France, Russia, and E. Europe), and each of these has at most 1. These classes of ships have heavier defensive missile armaments than American carriers, and thus have a better anti-air rating. The ex-Soviet "Kuzentsov" class also has a vertical-launch missile system that carries the offensive punch of a Battlecruiser.

CVN: Nuclear-powered Supercarrier
Cost: 10/6
Combat: 1/0/0
Aircraft: 90 (Any carrier-capable planes)
Production: Shipyards Level 3, Nuclear program Level 1.

With more planes than some small countries and an unlimited cruising range at top speed, these are the most powerful and flexible seaborne weapons systems ever devised. The only things they fear are saturation missile attacks with nuclear warheads, and nuclear torpedoes. At around 90,000 tons, they are also the biggest warships ever built.

CVX: Stealth Carrier
Cost: 12/6
Combat: 3/2/1 (Invisible to Patrol Planes...but the fleet around them probably isn't)
Aircraft: 80 (Any carrier-capable planes)
Production: Shipyards Level 3, Stealth Technology, CVX Technology, AEGIS Technology, Aircraft Factory Level 1.

Under design by the US Navy, but not yet built, these carriers make use of Stealth Technology to minimize their radar signature, and also carry their own defensive armament in the form of a block of VLS cells for AEGIS missiles. Although these are about the same size as a CVN, changes in basic shape needed for stealth slightly reduce their aircraft capacity.

CVB: Battle Carrier
Cost: 13/7
Combat: 6/6/2
Aircraft: 120 (Any carrier-capable planes)
Production: Shipyards Level 3, AEGIS Technology, Aircraft Factory Level 1, Nuclear Program Level 1, CVB Technology.

These are immense carriers of around 150,000 tons. They have never been built, but were once proposed by the US Navy but rejected due to cost. If you want to rule the seas, however, this is one heck of a way to do it.

PHIB: Amphibious Invasion Fleet
Cost: 5/2 for one fleet.
Combat: 1/0/0
Aircraft: 10 (VSTOL/Helicopter Only)
Production: Shipyards Level 2

Amphibious warfare fleets are actually groups of several specialized ships, from simple freighters to Tank Landing Ships (LST's) and huge Assault ships (LHD's) that are basically small aircraft carriers that double as landing craft motherships. Each PHIB group can transport 1 Marine Division and land it on the beach, as well as one Divsion of reinforcements (up to and including Armored Divisions) that land on the following turn. In peacetime, these can also be used to ferry ground units to distant parts of your empire or to defend an ally on the other side of the world.

PT: Torpedo Boats
Cost: 1/1 for one flotilla of 5 ships
Combat: 0/1/1 (+1 Ambush Bonus against ships)
Production: No Production Restrictions.

PG: Gunboats
Cost: 1/1 for one flotilla of 5 ships
Combat: 0/1/0 (1 point bombardment)
Production: No Production Restrictions.

PTM: Missile Patrol Boats
Cost: 1/1 for one flotilla of 5 ships
Combat: 1/1/0 (+2 Ambush Bonus against ships)
Production: Aircraft Factory Level 1, no shipyard restrictions.

All of these FAC are small fast attack craft armed with weapons from torpedoes and depth charges to light cannon to long-range anti-ship missiles. Small and short on defenses, they are dead meat in a stand-up fight, but if they can successfully be used to ambush enemy ships and launch a surprise attack, they can be very deadly. They are also useful for patrols along your coast or among island groups to watch for foreign vessels probing your defenses, and for coastal defense against amphibious invasions, and the gunboats can get in close to shore and up rivers to attack shore positions at point-blank range.

You may defend your coast with minefields or coast defense batteries, and you may build and deploy nets of sonar sensors on the seafloor to detect submarines.

MINE-S: Naval Minefields
Cost: 2/1 per 200 miles of coast.
Combat: Add 5% to combat score of other units.
Production: No Production Restrictions.

These are floating contact mines and sophisticated seafloor mines that launch homing torpedoes. These are deployed along your coast and in choke points like straits to keep enemy fleets away from your shores. They cost 2/1 per 200 miles of coast to lay. Coastal minefields may cause economic or political penalties if used excessively, since mines can come loose from their moorings and hit civilian merchant ships or your own vessels. They eliminate the attack bonus of Marines landed from PHIB units. They also add 5% to your defensive combat strength in battles to defend that part of the coast against amphibious assault, or in battles to defend those choke points. They can be laid in thicker bands to a maximum of 20% bonus. They cost 1/1 to clear. They cannot be moved. If foreign vessels try to move through those choke points, there is a chance (depending on how evil the Moderator wants to be) that one or more ships may be sunk or damaged, and this could be an embarrassing international incident.

SHD: Coast Defense Batteries
Cost: 1/1 per unit.
Combat: 0/30Combat Score.
Production: Aircraft Factory Level 1

These are large artillery pieces in fortified positions and fixed batteries of anti-ship missiles. They can be deployed to defend harbors or likely invasion beaches. They defend against amphibious assaults and forced passage of choke points with an anti-ship score of 3. They cannot be moved. They do not confer any social, political, or economic penalties. They can be dismantled for free.

SOSUS Sonar nets:
Cost: 3/2per 500 square miles.
Combat: Add 10% to ASW combat score of other friendly units.

These are networks of sonar sensors deployed on the seabed. They cost 3/1 per 500 square miles, usually in a line 100 miles long and 5 miles deep. They can detect passing submarines and surface ships, but in an era of RORSATS and radar planes, they mainly look for subs. You have a 50% chance of seeing any other player's subs or ships that pass through this area. You must define the area to be scanned, and they cannot be moved. They can be dismantled for free by simply turning them off. They do not confer any social or political penalties, and they add 10% to your ASW scores of all units in all battles in this area. They cannot be deployed in thicker belts to enhance this bonus.