Types of Naval Ships

Because a battleship and a destroyer are not the same thing.

NATO has a variety of different codes it uses to designate ship types (not the same as ship classes), so we'll use them.

If you want to know how things got this way, see the History of Naval Warfare. To see the kinds of firepower used on the high seas, examine Naval Weapons.

A couple of notes first.

Navies Love Nuclear Power
If an N is in the type designation, that means that the vessel is nuclear-powered. This is not the same as nuclear-capable, the latter meaning that it can carry nuclear weapons.

Nuclear powered ships or submarines are very useful things for a navy to have. Simply put, they don't need to be refuelled during a sortie and are only limited by the endurance of their crew and other supplies. This allows the vessel to go more or less anywhere in the ocean and if they're a submarine stay submerged for weeks if not months on end.

All submarines in the US Navy are nuclear powered, as are all currently-active carriers; USS Kitty Hawk was the last conventionally powered carrier in service with the USN, and was decommissioned on May 12, 2009. The crazy amount of energy generated by a carrier's two reactors (eight in the case of USS Enterprise) make them some of the fastest ships in the fleet, despite their bulk--nuclear-powered ships are the largest naval ships in the world.

There are two drawbacks - expense and radioactivity, although the latter is far less of a problem than it was. In fact, you actually get less radiation exposure on a tour on a US submarine than you would on the shore, as cosmic rays are absorbed by water.

One further drawback of nuclear submarines is that although their range is functionally infinite, they cannot shut down their nuclear reactors without losing all systems entirely until they start the reactor up again, which may be impossible without towing the sub back to port (emergency batteries only last so long). So the reactor system, including cooling pumps and other machinery, runs all the time. This makes nuclear submarines much noisier than diesel-electrics, by the ultra-sensitive standards of modern submarine warfare. They are incapable of true "silent running".

"G" is for Guided Missile
Most ship designations were created before the 1950's and 60's. Ships then were separated by size and role. Then, the guided missile was invented. The difference in range and combat power between a ship armed with conventional guns and one armed with guided missiles was such that navies around the world added "G"s into their designations so that they were still accurately divided. Therefore, a DDG is a destroyer with Guided Missiles. Likewise CG, CGN, FFG, SSG, SSGN, etc. Most vessels today have some form of guided missile on, usually anti-air, often anti-ship too. Anti-submarine missiles (i.e. launch a fair distance to drop a torpedo in the water) also exist, such as the American ASROC and Soviet/Russian "Silex", and the (now-retired) Australian Ikara and French Malafon. Some (e.g. Ikara) are flown under remote control to the vicinity of the target; others (Malafon, early ASROC) are pitched into the air on a ballistic trajectory.

Anti-ship missiles come in two basic types:
 * Sea skimmers, designed to fly very low, such as the US Harpoon and French Exocet. Generally subsonic and of a range under 100 nautical miles.
 * Fly extremely high, then go into a very fast terminal dive, such as the Kh-22/AS-4 "Kitchen". Generally supersonic and with long-range.

Most destroyer and frigate level vessels carry four to eight anti-ship missiles in deck-mounted canisters (in Western navies, typically but not invariably Exocet or Harpoon).

To actually get the "G" you must have an area defence SAM with a range of more than 10 nautical miles, i.e the capability to defend other vessels. Older frigates and destroyers like the Spruance-class destroyers and Leander-class frigates, never got a G.

However, this system is at times inconsistent, with the SSGN designation going to submarines whose only air defence is likely to be a couple of dudes with hand-held SAMs standing on the conning tower or just the crew taking pot shots with rifles (or, y'know, going under the water). In the context of submarines and only submarines, the G indicates surface-to-surface guided missiles like the US Tomahawk.

Flagships
In naval parlance, a "flagship" is the lead ship of a group of vessels. It is so called as it is the ship used by the commanding officer of a particular group of vessels, traditionally flying a distinctive flag. It's a temporary designation- a "flag officer" (usually an admiral) can move his or her flag as he or she sees fit. Flag officers usually choose larger ships so that there's room aboard for him/herself and the acompanying staff, which can be considerable.

Some ships may have a separate flag bridge. The regular captain still runs his or her vessel and does not have to take orders from the Admiral regarding their own ship. For example, the Admiral can tell the captain where to go, but the Captain will decide how he gets there. This will often have extra communications and data-handling facilities in order for the admiral to be able to manage the battle adequately. Depending on the class and size (and sometimes the age) of ship, these may be integral or added on afterwards at the expense of something else (e.g. some of the guns, in ex WW-2 cruisers that no longer needed as many and/or which were being converted to missile armament).

Tend to be carriers, cruisers or destroyers, but specialized command vessels exist too. As expected, the United States Navy is the most active user of these, having an entire (two-ship) class of vessels, the Blue Ridge class, to serve exclusively as command ships; the ships are currently assigned to the Sixth Fleet (based in Italy, as part of USEURCOM) and the Seventh Fleet (based in Japan, as part of USPACOM).

Capital Ships
The key vessels of any navy--the ones expected to do the majority of the fighting and the ones on whom victory or defeat hinges. Depending on the time period, these may be: In the case of the Royal Navy, these are their three (soon to be two) carriers, two LPD, one LPH and nine DDG. The US Navy's 11 nuclear carriers and numerous LHAs and LHDs would count here, and depending on how precisely you define a capital ship, its guided missile cruisers and destroyers.
 * 3rd Rate (74 Guns) or better Man 'O War (80 to 100 guns was 2nd Rate, 100+ guns was 1st Rate) during the Age of Sail
 * Battlecruisers and Battleships, between about 1860 and 1945
 * Aircraft Carriers, from about 1920 onward
 * In smaller modern navies, Cruisers or Destroyers

Size Creep
Simply put, warships classes have a tendency to grow over time. An example illustrates this best: the first destroyer to be called by that name was the Destructor, a Spanish ship (whose name means "destroyer" in Spanish) launched in 1887, which displaced 380 tons, was 192 feet long, 25 feet wide, and carried a crew of 60. On the other hand, the US Arleigh Burke Flight IIA class, considered a formidable type of modern guided missile destroyer, displaces 9200 tons, is 509 feet long, 59 feet wide, and has a crew of about 270.

In general--and this has happened with nearly every class of ship that exists--as engineers create more, newer and better equipment, they try to cram as much into the current design as possible, until they just run out of space. When it comes time to design a new class, they make it bigger to fit all the new stuff. Then they fill that hull to capacity, and then repeat the process.

A notable exception to this can be seen in cruisers; they actually got somewhat smaller starting in the late 1950s, as armor disappeared from their design. The exception reversed itself in the 1980s, and cruisers started getting bigger again...right at the time destroyers had caught up to them in size. Now there is little if any difference between destroyers and cruisers, in size or in role.

All this goes to say is that a ship's role is more important than its size for determining type, and that you have to be very careful when comparing ships from different ages, as a modern destroyer may well outmass some early battleships!

Designation issues
Certain classes have been dubbed frigates when they're closer to destroyers or something like that, often for budgetary reasons or to sound less militaristic. Other reasons include the fact that ship designations simply change over time due to various reasons, particularly the introduction of new technology or designs, hence why we no longer have Ships of the Line or Monitors. Indeed, the word "Frigate" comes from an older English word meaning boat.


 * The British Invincible-class STOVL carriers were dubbed "through-deck cruisers" to get them through the Treasury and had a space-consuming Sea Dart SAM system added to be more convincing, later removed.
 * Soviet/Russian carriers were dubbed "aviation cruisers" by Moscow in order to bypass restrictions on aircraft carriers passing the Crimea. Legal shenanigans aside, however, it was a close reflection of their actual armament.
 * Japan's new Hyūga class "helicopter destroyers" look suspiciously like helicopter carriers. Which can generally also operate V/STOL jets. Like the F-35B. Which Japan plans to buy. Japan's constitution prohibits an offensive military; aircraft carriers of any kind are almost always interpreted as being forbidden by this (given Japan's history with aircraft carriers, there is a reason for this). The JMSDF insists that it will only use the "destroyers" for helicopters, though no good explanation is given for why they need a long flight deck...
 * The US went without a class of "cruisers" under the old US naming scheme. This was changed when the US public and Congress began to perceive a "Cruiser Gap" vs. the USSR--that is, on paper, the USSR had many more cruisers than the US, as the only ships the US called cruisers were old "gun cruisers" (CA, CL) left over from WWII and the few nuclear-powered cruisers that it had (CGN). To eliminate the "gap", the US re-categorized its ships, with many ships from the Belknap and Leahy classes designated DDL, or destroyer leader, redesignated as CG, cruiser guided missile.
 * One also has to deal with non-English speaking navies, especially the Soviet/Russian one, who use a different set of names.
 * The US Zumwalt class "destroyers", currently under construction, could easily be re-designated as cruisers. It seems to be the reverse of the "Cruiser Gap" nonsense: buying a bunch of destroyers sounds less expensive than buying the same number of cruisers. So for the benefit of Congress in an era of reduced naval budgets, the Zumwalts are "destroyers".

Pre-Steam Ship Types
The majority of this article is devoted to the types of ships that are used today or were used within the last century. Some of these ships share names with, but are separate from, older ship types from the Age of Sail or earlier. Sometimes called "Men 'O War". Although they further break down into sub-types based on their particular rigging style, here is a list of warships that you might find when tall ships ruled the waves:


 * Armed Merchantman: Before steam, big guns, and armor, almost any ship would do as a warship if it could either carry guns or carry lots of extra men. Although they generally couldn't stand up to purpose-built warships, they made a suitable substitute for defending against pirates, going pirating, and as a little extra firepower when you were short on real fighting ships. Once armor and big guns became important, these gradually went away as it takes a very different design for a ship to effectively mount modern weapons vice transport cargo efficently.
 * Frigates: Smaller ships meant for long-range, independent cruising, scouting for a large fleet, commerce raiding, and one-on-one actions versus enemy frigates. Their lone-wolf nature leads many of the most exciting sailing stories to take place aboard these. Their role was eventually replaced by cruisers, and then submarines and aircraft.
 * Ships-of-the-Line: Large sailing ships meant for one purpose: direct, close-range combat with the enemy fleet in the "line of battle". Slow and heavily armed, they were eventually replaced by Battleships.
 * Galleys: Warships that were mainly human-powered, with rows of "sweeps" (oars) that gave them superior maneuverability compared to sailing ships and bursts of speed for short distances, but not much long-range capability. They also had to be light enough for rowers, and so didn't usually carry heavy weapons. The oldest type of warship, they continued to be used into the 1700s in a coastal defense role. Many were designed solely for boarding or ramming.

So let's begin.

Auxiliary Ships (AA)
The backbone of any naval fleet. These carries extra supplies- food, fuel, ammo etc. They can also be used for intelligence or command stuff too. They will be found with small defence capabilities, but will need protection from other ships. Many of these ships are designed to be able to refuel, rearm, and resupply other ships at sea, in order to extend the time they can spend out of port. When the practice, called "Underway Replenishment," was invented in the 1920's and 30's, it was practically a secret weapon for the US, who had much less of a dependence on foreign ports and much longer endurance than everyone else. The weapon came to life in the Pacific by 1944, with the US being able to operate its fleet anywhere it chose for as long as it felt like.

There are large numbers of sub-types. For example, the following is still not a complete list:
 * AKV- Cargo ship and aircraft ferry.
 * APB- self-propelled barracks ship.
 * AGF- Miscellaneous research ship.
 * AFS- Combat Stores Ship; carries ammo and various other supplies
 * AO- Oiler; carries fuel and other liquids.
 * AOE- Fast Combat Support Ship; a large ship that carries fuel, ammo, and supplies. The "E" must stand for "everything".
 * AH- Hospital Ship. Exactly What It Says on the Tin.
 * AD- Destroyer tender, carries supplies, repair parts, and support facilities for destroyers. Now obsolete, they were common back when destroyers were much smaller and had shorter endurance.
 * AS- Submarine tender. Likewise.
 * AGI- intelligence gathering vessels, basically spy ships disguised as trawlers. Having one of these hanging around your carrier group in a war is not a good idea, as they could guide in bombers and/or missiles.
 * LCC- Command Ship. Originally meant for the commander of an amphibious assault (hence the LC for "landing craft"), as it was expected a naval commander would travel by carrier or battleship. The US Navy now uses these to command entire theaters.

Examples;
 * Chiwawa class oiler (AO)- five used by US in World War Two. Two remain in private service today.
 * Berlin class replenishment ship (Germany)- two built, two planned.
 * Project 160 "Altay" class- old Soviet/Russian oilers, but still around.

Aircraft Carriers (CV, CVN)
Nothing quite beats an aircraft carrier for a) coolness and b) power projection. If a hostile carrier shows up on your coast, you are in trouble - especially a US one, as their air groups are larger and more powerful than most nations' air forces.

Only certain aircraft can take off or land on an aircraft carrier. Choppers and some fighters are fine (with modern aircraft, carrier-friendly models have to be designed to be carrier-friendly from the outset), but a B-52 is a no-no. This is because carriers are still small compared with air bases. Even carrier operations are fraught with problems.
 * Taking off, you will either have to take off vertically, go up a ski-ramp (most non-US carriers) or be catapulted off the end (the US approach). The last approach means that a pilot is exposed to very high acceleration and the plane has to be built for being pulled by its nose gear as well as pushed by its engines. The advantage of a full-length carrier, however is that you can launch and recover larger, heavier aircraft carrying more and/or heavier weapons. Note before the invention of jet aircraft this was not a problem; propeller-driven aircraft before the 1950s were light enough to achieve flying lift in the short space of a carrier's deck. (Early catapults did help, however, in launching fully-loaded aircraft, or when the aircraft were launched sideways off the hangar deck...)
 * Landing, you have to find the carrier (not an easy proposition in the dark) and land on it (again, not easy considering factors like wind speed and the carrier's own movement). With an arrestor wire as in US carriers, this requires actually getting in the right place to snag the wire (with an arresting hook that your plane must have), which then slows you down very quickly indeed. The whole process has been described as a "controlled crash" and also "landing on a postage stamp" and "having sex during a car accident". Then try doing it damaged. Before the invention of aircraft that could land vertically, this was the only way to get a plane aboard a ship at sea.
 * A notable exception to the "no large bombers" trend occured during the 1942 Doolittle Raid. A bunch of B-25 medium bombers were launched from an aircraft carrier to bomb Tokyo. A B-25 is of course much, much smaller than a B-52, but they were certainly never meant to take off from a carrier, and had to be significanly stripped down to be light enough to take off in the required space. The pilots also took off knowing, at best, this would be a one-way trip to China: the planes certianly couldn't land on a carrier.
 * During the 1960s, the CIA flew U-2 spyplanes off of carriers. And landed back aboard
 * And occasionally, as stunts, the U.S. Navy has flown much larger aircraft off its carriers - NASA's QSRA research transport for one, and even a C-130 Hercules...!

Carriers don't carry much in the way of their own personal weaponry, however. They need other ships to protect them from attack, and also rely on their own aircraft. Exceptions include carriers that fly the Russian ensign, which in a quirk or Russian design philosophy have formidable weaponry in their own right. British Invincible-class carriers bore an integral Sea Dart SAM system for most of their careers until it was removed to make way for more fighters, and some US carriers in their early days carried the same long-range Terrier missile system as their cruiser escorts. The US LHAs were also originally designed with multiple 5" gun mounts so that they could be their own naval surface fire support platforms (freeing up an escort for other duties), but they were later removed when doctrine no longer called for the ships to come close enough to shore for them to be practical.

There are two basic types of carriers:
 * STOVL carriers- smaller carriers, usually carrying Harriers or helicopters due to having a shorter length. A cheaper alternative, owned by a few nations such as Spain, Italy and Thailand.
 * Full-length carriers- can carry larger aircraft, such as the F/A-18 and Su-33. Only four nations have one currently (US, Russia, France, Brazil), with three more (UK, India, China) due to join that club in this decade. In the UK's case, re-join, with their largest ever naval vessels.

If you are confused by the designation "CV" for carriers, you aren't alone. The explanation is found in the interesting but tangled history of international relations and naval bureaucracy:
 * The first US Aircraft carriers were built in the 1920's. In 1923 the Great Powers of the world at the time got together and, trying to avoid a repeat of the kind of massive naval arms race that took place prior to WWI between Britain and Germany, created the Washington Naval Treaty. This document set limits on all sorts of ship types--though mainly battleships and cruisers--by how much they weighed in tons, this being a rough way of measuring their firepower and armor. Each country was allowed a certain tonnage of each class that they could build, and an overall tonnage limit. The results were predictable: everyone started looking for loopholes. In the case of the US, there were a whole bunch of cruisers already under construction when the treaty limit hit. So what do do with a bunch of half-finished cruiser hulls? Convert them into a ship class that wasn't limited as harshly by the treaty! In this case, the brand-new, experimental aircraft carrier. Now, when they did this, they ran into a problem: US Cruisers had the designation "CA" for "Cruiser, Armored" (maybe they liked the 2-letter designations). They wanted to call them "Cruiser, Aviation" but that would also leave you with "CA". So they decided to designate them "CV", for "Cruiser, aViation". Then that designation spread around the world once the US rose to dominate the naval scene following WWII.
 * Official reasoning is rather different. "V" is the letter used to designate a USN/USMC squadron as being composed of heavier-than-air craft, essentially airplanes instead of blimps or balloons. There were, in WW 1 and immediately after, plans for ships that carried or streamed one or the other for gunfire spotting. CV is "Carrier, heaVier than air".

Battleships (BB)
First of all, to forestall any confusion generated by poor use of terminology, there are no battleships on active duty in any navy today. Until World War Two, these were the largest, most powerful warships in use. They carried the biggest guns, ranging from 9 inches (technically, 240 millimeters) to 18 inches (again, technically, 460 millimeters, or 18.1 inches...) in diameter and capable of throwing projectiles weighing a ton or more up to 35 miles and carrying thick armor plate. During WWII, these were rendered obsolete by aircraft and submarine weapons, and later by guided missiles.

They are, it must be said far, far better looking and more characterful than the efficient but soulless aircraft carriers which perhaps explains their enduring appeal to enthusiasts. Or perhaps it's just more visceral. When one looks at an aircraft carrier, one sees little more than a giant flat top: the ship itself is not imposing, and indeed it is the smaller planes that it launches that do all the work, with the ship itself perhaps not even within visual range. On the other hand, there's no mistaking the silhouette of the battleship and what that silhouette means: many, many, MANY BFGs, and if you're close enough to tell they're pointed at you--You Are Already Dead.

The term is a contraction from the earlier "line-of-battle ship", meaning the ships heavy and powerful enough to serve in the line of battle during the era of Wooden Ships and Iron Men. At the time, 'line-of-battle ship' was more commonly abbreviated as 'Ship of the Line'.

Examples:
 * The Dreadnought (completed 1906, scrapped 1921) from the United Kingdom, which changed the design of all succeeding battleships.
 * In fact, other nations (e.g. the United States) were working on the same concept at the same time, and she has been called 'a ship whose time had come' (DK Brown, "Warrior to Dreadnought"). But being first has kudos, and going from laying of keel to a ship which could steam, if not quite yet fight, in a year and a day shocked the world, and is a capital-ship building record that has never been beaten.
 * Japan very nearly beat Dreadnought by several months with Satsuma, but couldn't afford enough high-quality guns to outfit every turret.
 * The Iowa (completed 1944, after various retirements and re-commissioning of the class, were finally retired "for good" 1998-1999) class from the United States, probably the best overall design of battleships built.
 * The Yamato class from Japan (completed 1941/1942, sunk 1944/1945) the largest battleships ever constructed. The star of Uchuu Senkan Yamato.

Cruisers (CA, CL, CG, CGN)
Cruisers were originally used for independent action, of a long-range nature, which was the original use of the term, as it was more a role. Today, cruisers are the largest types of ships below a carrier and the heaviest ships designed for surface-to-surface warfare.

The first cruisers appeared in the 1870's and quickly diversified into a baffling profusion of types, ranging from small scout cruisers to huge armoured cruisers which were as big as battleships. After the WWI, treaty restrictions divided cruisers between "light" and "heavy" types. The designations were not based on size, but on armament. Heavy cruisers (CA; the designation deriving from the earlier "armored cruiser", from a time when not all cruisers were armored) had a main armament of 8 inch (203 mm) guns or (on rare occasions) larger, while light cruisers (CL) had smaller guns, almost always 6 to 6.1 inch (152 to 155 mm) main guns. Since the types were defined solely by gun size (and notably not by number of guns), the US, Britain and Japan all dodged treaty restrictions on the number of heavy cruisers by building "light" cruisers that carried so many smaller guns that they were every bit the equal of a heavy cruiser in firepower, and had identical armor to their heavy cruiser counterparts.

Gun armed cruisers slowly disappeared after WWII and today they are mainly armed with missiles and used as escorts for carriers, in the air defence role. The Aegis system, fitted on a number of types of cruisers and destroyers, is the USA's primary carrier protection system- an automated SAM system, for destroying anti-ship missiles. It allows for co-operative engagement- one ship can control the missiles of the others, and of other ships in the fleet whose missiles are compatible, reducing the number of radars that an anti-radar missile can home in on. Designed during the Cold War, it was not combat-proven until the Gulf War of 1991.

Only three nations today, the US, Russia and Peru, have actual cruisers in operational service (France has a hybrid helicopter-carrier/cruiser it uses as a training ship in peacetime). These are all guided missile cruisers (CG), carrying anti-ship and/or land-attack missiles, except for Peru's Almirante Grau, which is primarily a gun cruiser and the last one in service in the world- the former Dutch vessel was laid down in 1939 and not commissioned until 1953 because of the Second World War.

The best-known today and the most numerous is the US Ticonderoga class, a Missile Cruiser. Others include:
 * The Russian "Slava" class. The lead vessel is now called Moskva and took some minor damage during the Russian-Georgian war of 2008.
 * The American Atlanta class, light cruisers fielded during WW 2 with a total of 16 5-inch guns. Capable of putting out prodigious amounts of anti-aircraft fire, although ineffective versus other, heavier warships.
 * The British "Town" class from World War Two. One of these, HMS Belfast is a museum ship in London.
 * Soviet Sverdlov class cruisers are the last conventional gun cruisers class in the world, of which Mikhail Kutuzov is now a museum ship in Novorossiysk.

There are things called or formerly "helicopter cruisers", "aviation cruisers" or "through-deck" cruisers which are basically other terms for aircraft carriers when you want to get them through the Dardanelles (an international treaty bans aircraft carriers, defining them as ships solely designed to launch aircraft- so the Soviets added a lot of missiles on) or your own country's Treasury.

Battlecruisers (BC)
A term for very large cruisers, only one type today gets labelled this, not entirely accurately - the Russian Project 1144 Orlan/"Kirov" (the original name of the first one) class. A nuclear-powered cruiser with a very impressive armament (only aircraft carriers have more, those being contained in their air wings), it is really just a very big cruiser. Then again, to some extent so were the original battlecruisers.

Battlecruisers had a bit of a heyday leading up to World War One. As their name suggests, they were meant to be a combination of battleship and an armoured cruiser: as fast and armored as a cruiser, but carrying the guns of a battleship; in other words, the naval equivalent of the Glass Cannon. They were (as described at the time) meant to outgun what they couldn't outrun, and outrun what they couldn't outgun; at the time, battleships had top speeds in the 20-knot range, whereas cruisers and battlecruisers could reach 28 knots at the minimum. While good in theory, when it came to actual combat several problems rapidly appeared, primarily being that admirals tended to use them alongside their battleships due to their armament, they often didn't have enough armour to survive an encounter with their opposite numbers, which accounted for all of the capital ship losses for both sides at the Battle of Jutland. In response, designers began piling on better armour, resulting in a ship that was basically a battleship, whilst battleships simultaneously got faster and faster (the generally accepted minimum top speed of a battleship by World War Two was 28 knots). By the time World War Two rolled around the two types had basically merged into the "fast battleship", and the last British battlecruiser design (cancelled by the Washington Treaty) only earned the name because the corresponding battleship intended to go with it was even more heavily armed and armoured.

The idea continued to persist though, on virtually all sides. The Washington Naval Treaty of 1922 limited the size and types of ship allowed in each navy; cruisers in particular were explicitly limited in size and armament, with a maximum of 8" guns and displacing 10,000 tons. Each side knew that if war broke out, they would need some type of ship to counter all these cruisers, and thus developed "cruiser killer" contingency designs for that event. Germany began building "Pocket Battleships," cruisers with 11" guns mounted and which displaced 12,000 tons, which they managed to pass of on paper as treaty-limited. Japan conceptualized the B-65 cruiser. The United States, once the treaty expired, built and fielded the Alaska class. And so on and so forth. But by this time, battleships had already become almost as fast as battlecruisers (in the case of the Iowa, just as fast), and carriers could reach and sink cruisers long before a battlecruiser could get within range. So, just like battleships, battlecruisers spent the war escorting aircraft carriers and performing shore bombardment.

Of course, having such an incredibly awesome name, battlecruisers appear disproportionately often in fiction. They're rarely actually seaborne, though.

Destroyers (DD, DDG)
The largest ship type in many navies today or the backbone of larger navies, destroyers are smaller than cruisers, but (usually) larger than frigates. Some navies, such as the UK's Royal Navy, call warships "destroyers" if they are mainly designed to defend against air attacks, and "frigates" if they are mainly designed to fight against other ships and hunt and kill submarines. Thus, the Royal Navy's Type 42 destroyers are actually smaller than their Type 22 frigates and the Type 45s may well be smaller than the next RN frigates. Other navies divide destroyers and frigates by size rather than role, so they may have both sub-hunting and air-defense destroyers.

Destroyers were so named because they were originally "torpedo-boat destroyers", a class invented by the British in the late 1800's and early 1900's to protect battleships against small, fast, maneuverable torpedo boats. Especially with the advent of the all-big-gun "Dreadnought"-class battleships, the big ships' guns were too big, too long-ranged, and too slow-firing to adequately defend against small, fast-moving targets at close range, so destroyers were invented to fill that need. Starting with WW 1, torpedo boats were eclipsed as a threat by submarines, and so during both world wars, destroyers mostly were used to hunt submarines, defend convoys, and (starting in WW 2) provide radar and anti-aircraft coverage for larger ships. It could be argued that the role of Destroyers never changed, the only question being what any given set of Destroyers was designed to destroy, be it torpedo boats, submarines, enemy aircraft, or, with modern destroyers, enemy ships, plus all the above categories. The advent of radar and guided missiles certainly gave modern ship designers much more flexibility and precision in how to apply their firepower.

Will generally have at least one helicopter on board for sub hunting, search and rescue, and general utility.

Examples:
 * The American Arleigh Burke class of destroyers use a similar AEGIS system to the Ticonderoga class cruisers, and are practically small cruisers. Japan operates the very similar Kongou and Atago classes as their most powerful warship type. South Korea operates the King Sejong the Great class, a slightly enlarged version with 25% more missile capacity and other less significant improvements. All are mainly designed to provide air defense with guided missiles, although the American ships can also launch large numbers of Tomahawk cruise missiles. The Japanese versions could do so as well, except that Tomahawks (even the anti-ship version) are deemed to be prohibited "offensive" weapons and thus the JMSDF doesn't have any. The Korean ships instead use the domestically-designed Hyunmoo-3C cruise missiles (which are similar in capability but look like giant versions of the Harpoon antiship missile). Both can engage surface warships and do surface bombardment, as well.
 * The American Zumwalt class of destroyers, currently under construction, will take the ultimate prize in size creep. They are 5000 tons heavier than the Ticonderoga class cruisers, the only cruisers left in US service, and will be armed with a pair of advanced 155mm (6.1-inch) guns, the largest (though only by one inch) to be mounted on any ship in decades. If the Washington and London Naval Treaties of the 20s and 30s were still in effect, it would have been a legal requirement to designate the Zumwalt class as cruisers, and if so designated would be either the 2nd or 3rd largest cruisers ever deployed by the US Navy (depending on whether the oddball Alaska class are considered cruisers or battlecruisers). They will also incorporate extensive stealth technology, rendering them perhaps the ugliest (or coolest, most futuristic looking) warships since the days of the first ironclads. As a result of all this, they are also incredibly expensive, and the US Navy's order for them was progressively cut down from 32 to two as cost overruns kept piling up; the Navy has since changed its mind, increasing its order again--to three ships.
 * The proposed new Russian class is also in the 12-14 kt range, and with its 2×2 152 mm cannons would certainly outgun the Zumwalts. It also could be a first nuclear "destroyer" in the world, if the nuclear powerplant will be approved for it.
 * The American Spruance class used to provide ASW for carrier battle groups.
 * The Russian "Udaloy" class destroyers are a good example of a destroyer mainly designed to hunt submarines.
 * The Russian "Sovremmeny" class destroyers are a good example of a destroyer mainly designed to fight other ships (with long-range anti-ship missiles) and provide air defense. China also operates a few.
 * The Russian "Kashin Mod" class destroyers were used during the Cold War as "Tattletales", intended to closely follow US carrier battle groups and report back on their activities. In the event of war, they were to turn and run away, while firing backwards-facing missiles in a last-ditch attempt to sink the carrier. Everyone involved freely admitted that this was likely a futile suicide mission if war ever broke out. So, of course, just before the Cold War ended, one was sold to Poland to become the flagship of the Polish Navy. Renamed Warszawa, it was in service until 2003. The Russian Navy still operates one ship of this class, and the Indian Navy has five of the similar Rajput class (nicknamed "Kashin II" in the West), which have their missiles pointed forward.
 * The British Type 42 or Sheffield class (all named after British towns) are designed to provide anti-aircraft missile protection for British aircraft carriers. They are fairly small for destroyers (at least by modern standards), and are also operated by Argentina. Amusingly, they fought on both sides of the Falklands War.
 * The newest British destroyer class is the Type 45 or Daring class, also meant for air defence, with stealth features and a lot of weapons that it can carry, but will be left off unless needed. A planned twelve examples will now be six. You may now castigate the Ministry of Defence.
 * Perhaps one of the most defining of all Destroyer classes was the WWII Tribal Class. Originally designed as Light Cruisers but instead the designs were changed to create a class of Destroyers that serves the Royal and Commonwealth navies with great distinction in all naval theaters of World War II. Suffering heavy losses in the line of duty only 1 now remains, the HMCS Haida.

Frigates (FF, FFG)
Frigates are generally smaller than destroyers, and are almost always designed primarily to hunt submarines. Many of them lack guided missiles, even in fairly modern navies. "Frigates" in the modern sense is a term that only dates to the 1940s, when it was reintroduced by the Royal Navy for sub-hunting vessels. The original "Guided Missile Frigates" were later re-classified as cruisers, but the term stuck. Before that, the modern frigate role was called "Destroyer Escort", as in, a smaller ship that accompanies destroyers on missions to hunt down submarines, or forms the outer ring of defense for a convoy. If you've ever wondered why the (non-missile) frigates of the US Navy had such large hull numbers, it's because the numbering carried over from the destroyer escorts, which redesignated as frigates (in line with what virtually ever other navy was calling them by then) in 1975. Frigates are usually the smallest type of warship able to carry helicopters. Not to be confused with the original use of the term "Frigate", which was a small warship from the Age of Sail, designed for independent scouting and patrol missions, rather than to fight from within the Line of Battle. As a sidenote, the original United States Navy consisted of six (old-style) frigates that (in the right situation) were the terror of the seas for their quality construction and experienced (as seamen--not so much as warriors) crews. Of course, they never had to face the full brunt of the Royal Navy.

Examples:
 * The American Oliver Hazard Perry class frigates, while designed mainly to hunt subs, do carry an impressive anti-aircraft missile system for their size, and have been exported widely. They are used by, among others, Spain, Taiwan, Turkey, Greece, Egypt, Bahrain, and Australia. Some of those ships were built in their operating country to slightly modified design, others sold off after the US Navy decided they didn't need them any more. Ironically, the anti-aircraft missiles have now been removed from the US examples, due to the company making the missiles no longer offering tech support for them, and the newer versions of the missile being physically incompatible with the Perry class's older launchers.
 * British Type 23 or Duke (they are named after English dukes) class frigates are actually larger than Type 42 destroyers, designed mainly to hunt subs, and featured in the James Bond movie "Tomorrow Never Dies".
 * The French-designed Lafayette are "stealth frigates" with hulls and superstructure designed to minimize their radar cross-section. They are used by France, Singapore, and Taiwan.

Corvettes (FFL)
Smaller versions of frigates, primarily designed for coastal duties- many are now close to frigate size though. Small, manoeuvrable and generally lightly-armed. Often found in navies of countries bordering smaller seas. Some smaller navies bordering major oceans will use them for heavier duty however, and typically modify them accordingly.

Examples:
 * The new US Littoral Combat Ship (LCS) will be similar to a corvette; however, the U.S. Navy has stubbornly refused to use the "corvette" designation for any of its ships, even before a certain sports car came around.
 * The Swedish Visby "stealth corvettes".
 * The Russian Project 1234 Ovod (Gadfly) "Nanuchka" class.
 * The new Russian "Stereguschiy" class is unusual in that it manages to squeeze a helicopter in just 2.5 kilotons of displacement.

Landing Craft (LC)
Landing craft are smaller ships of limited endurance designed to take troops from a ship and put them on the shore. They are generally deployed from transports or Amphibious Assault Ships (see below) and are not capable of independent operations. Most are simply boats with a shallow draft and a ramp in front for troops and (depending on the size) larger vehicles like trucks or tanks.

Examples:
 * The US LCU (Landing Craft, Utility)
 * The US LCAC (Landing Craft, Air Cushion) is a unique take on the concept. It is a hovercraft which is capable of actually flying a few feet above the waves and can actually drive up on shore to provide vehicles with a more stable foundation for unloading. It is also much faster than the average landing craft, with the tradeoff of larger size (can't fit as many in an Amphib) and reduced carrying capacity.

Amphibious Assault Ships (LS, LH, LP)
Amphibs or "Gators" as they are referred to in the US Navy, are a sort of cross between aircraft carriers and troop transports. They are designed to take large groups of ground troops and their equipment and transport them long distances, then deploy them to shore using landing craft or helicopters. Most Amphibs have a stern gate and "well deck" in the aft portion which they can flood, allowing landing craft to float in and out of the ship quickly. They also usually have a flight deck large enough to accommodate transport helos. Some, like US LHA's and LHD's, have flight decks and hangar bays which are large enough that they can transport their own helicopters and offensive aircraft. Like carriers, they usually have little defensive armament of their own and need to be protected. In navies without aircraft carriers, this is frequently the largest ship class around. In standard US practice, these ships do not operate alone, but instead are the lead ship of the landing force component of a larger fleet, often operating together (e.g.: an LHD, and LPD, and an LSD all together with the ground troops and aircraft distributed between them.)

Examples:
 * The US LHA and LHD class ships, for the larger variety. (designation: Landing ship, Helicopter, Assault and Landing ship, Helicopter, Dock). There is very little difference between the two. Both have a secondary role as VTOL aircraft carriers, though their standard aircraft load is much smaller (20-30 vs. 70-80) and is optimized for close air support of ground troops.
 * The US LPD and LSD classes, for the smaller variety. (designation: Landing ship, Platform, Dock and Landing Ship, Dock)
 * The US LST class ships, now retired in US service but still used by other navies, are basically giant, oceangoing landing craft; they can actually cross the high seas and then deposit large numbers of troops, tanks, artillery, and other vehicles directly onto shore. (designation: Landing Ship, Tank)
 * Naval jokes hold that "LST" actually stands for "large slow target".
 * The Spanish Juan Carlos I class (similar to an LHA).
 * The Italian Cavour.
 * The South Korean Dokdo class (similar to an LHD), one of the smallest amphibious assault ships.
 * The Soviet Ivan Rogov class.

Minesweepers (MCM)
Exactly What It Says on the Tin. Although, as the old navy joke goes, "Any ship can be a minesweeper once", these are ships expressly designed for locating and neutralizing naval mines and explosives. They are usually small, slow, and virtually defenseless. However, they are designed with nifty things like non-magnetic (wooden or fiberglass) hulls, manuevering thrusters or pods which allow them to travel in any direction and turn on a dime, and diving facilities, which allow them to sucessfully get near and disarm mines without detonating them. Many modern minesweepers now have Unmanned Underwater Vehicles (UUV's) to aid in locating and neutralizing mines from a safe distance. "MCM" stands for Mine CounterMeasures ship.


 * US Avenger MCMs.
 * German Seehund MCMs.
 * A common tactic during World War I and World War II for making a path through a minefield when minesweepers were either unavailable or impractical (enemy fire would get them before they could clear the mines) were to take an older merchant vessel and fill it with wood, cork, cardboard, or other bouyant materials and then drive it through the minefield at full speed. This tactic was risky for the unlucky crew chosen to pilot the ship, as the whole point was to detonate as many mines as possible with their own ship. Even with the extra flotation and damage absorption, any ship will eventually be rendered non-seaworthy and sink given enough mine hits.

Patrol Boats (PC)
Also known as FAC (Fast Attack Craft) and FIAC (Fast Inshore Attack Craft), these are fairly small vessels, some not much larger than big speedboats, used for coastal operations. You'd find these tackling smugglers or terrorists in a film. They're designed for speed and manoeuvrability, not range. They can, however, be used in large numbers to overwhelm larger ships; for example, the Iranians have been known to train to use such "swarm attacks", and the "Tamil Tigers", a Sri Lankan rebel group, successfully used them in combat. Expect to see very high casualty rates even in successful swarm attacks, though. Boats this small don't carry much (if any) armor.

Examples:
 * The US Cyclone class PCs.

Torpedo Boats (PT)
Small boats armed with torpedoes. Mostly used in World War Two, they're largely obsolete now due to anti-ship missiles.

During their heyday they filled a niche role somewhere between destroyers, aircraft and submarines. Like submarines, their heavy torpedoes gave them the ability to do serious damage to very large ships, even battleships--PT boats had more firepower per ton than any other vessel. Like destroyers, their small size, maneuverability, and high speed gave them the ability to defend a fleet adequately against close-range threats. Like aircraft, their relative cheapness meant they could be employed en masse.

However, they also shared the disadvantages of the types and some unique to themselves: Their onboard supplies were even more limited than a submarine's or a destroyer's, limiting their range and staying power in a battle. They couldn't move as fast as aircraft and made easier targets for other ships and planes. The emphasis on speed and firepower left no room for armor.

Eventually, their role became a compromise: they were used as the commandos and raiders of the naval world. Hit and run attacks, night attacks under smokescreen, infiltration and exfiltration of special forces, evacuation of VIPs from hostile areas, and scouting were all missions under their purview.

Two particular incidents made them famous:
 * A flotilla of 6 PT boats was used to evacuate General Douglas McArthur from the Philippines during the opening days of WWII, successfully evading most of the Imperial Japanese Navy over 600 nautical miles of ocean and safely delivering the general to Australia, an act of daring which earned every member of the squadron a silver star and its commander the Medal of Honor.
 * PT-109 became famous during and after World War II, despite being cut in half in a collision with a Japanese destroyer, mainly due to the fact that her commander at the time was John F Kennedy. The story of his survival and how he saved what was left of his crew made him into a war hero and may have contributed to his election as president.

They're also well known in Italy due the extensive use made by the Italian Navy (calling them MAS, Motobarca Armata SVAN, standing for 'armed motorboat SVAN' (SVAN was the original manufacturer)) in World War I, where they got their Crowning Moment of Awesome when a couple MAS torpedoed and sank the Austrian flagship after a random encounter.

PT boats became obsolete after the war mainly because other vehicles and weapons became more effective at their jobs. Their role has been taken up by submarines and missile boats. However, the way they were used and small, easy-to-identify-with crew makes them excellent fodder for dramatic fiction, so they tend to show up more often than other ships like destroyers and cruisers which did more important but more boring work.

One exception to their general obsolescence: Some countries, such as Iran, have begun to bring back the concept using semi-submersible boats, guided torpedoes, and swarm tactics as a counter to more expensive large ships. These would work best using surprise, waiting partially submerged for a larger ship to come by, then surfacing, firing their torpedoes, and running away.

Missile Boats (PTM)
Missile Boats are the logical successor to Torpedo Boats, substituting the slow, short-ranged torpedoes of WWII for the fast, long-ranged missiles of today. They are subject to many of the same shortcomings as torpedo boats but in some cases the increased long-range striking power makes up for it. Like their predecessors, they typically pack a lot of firepower into a very small, fragile package.

During The Cold War the Soviet Union particularly liked the idea of lots of small, fast ships that could engage in hit-and-run attacks on other vessels... or hit-and-sink attacks, as the Soviets considered them expendable and realized they would have to be employed in large groups to account for the fact they'll take many losses before they reach launch range. After all, as the boss said, Quantity has a quality all it's own. They armed them with surface-to-surface anti-ship missiles, usually the P-15/SS-N-2 "Styx". The US, which believed in fewer but more powerful and survivable large ships lagged behind in developing these until much later, when the dominant power of anti-ship missiles was more established.

Some other countries (particularly Israel, after an Egyptian missile boat sank a destroyer of theirs in the Six Day War of 1967) took up the idea and the USSR exported the type. The US had some, but have now retired them as not cost-effective. Actual combat showings have suggested they are not effective in a modern environment, primarily due to their small size and large antiship missiles taking up a lot of space and displacement keeping them from mounting a meaningful defense against aircraft and helicopters (that is, unless you're Israeli and your missile boats literally start breaking records for armament per size).


 * The Soviet/Russian Project 205 Tsunami/"Osa" class is a particularly good example. The NATO designation means "wasp" in Russian- a good name for small, annoying boats with a nasty sting.
 * The Norwegians had the Hauk class.
 * The US Navy had the Pegasus class. They were very fast hydrofoil missile boats with an impressively heavy armament for their size (8 Harpoon missiles, double the firepower of an "Osa", and a rapid-fire 3 inch gun). At least 30 were planned, but only 6 were built and they never really did anything before being retired. Being a good 15 knots faster than the "Osa" class and armed with longer-range missiles, they probably would've had much better chance of survival in combat.
 * The Israeli standard missile boat, the Sa'ar 4.5 probably pushes the boundaries of what can be considered reasonable armament for missile boats. each ship carries 8 Harpoon missiles, and between 16 and 32 anti-aircraft missiles, and there used to be a version of these ships that included a helipad. this has the effect of making ships that are classified as "missile boats" about as well armed as your average frigate.

"Missile boat" is also another name for an SSBN, so be careful there.

Rigid (Hull) Inflatable Boats (RIB, RHIB)
Basically, small speedboats with a light rigid hull for structure and inflatable pontoons for buoyancy. Often mounted with a light to medium machine gun. Sort of parasite boats, many naval vessels carry a number of these for boarding operations, inport security, search and rescue, and other general purpose jobs. RIBs are the latest iteration of this kind of vessel; in the past, using different designs they have been known as Gigs, Barges, Cutters, Yachts, Runabouts, and simply Boats.

Submarines
Submarines are boats that can travel underwater, and fight there. Or, as the navy joke goes, they're boats for which the number of sinkings equals the number of surfacings. (Also, they are always "boats", never "ships".)

Submarines are designed, basically, to be silent hunters. The earlier submarines were essentially submersibles, spending most of their time on the surface and diving only when attacking or attempting to escape.

The possibility of a submarine, armed with torpedoes, being in your area of operations, can tie up a couple of ships at least (The Falklands War for example). However, modern submarines can also carry anti-ship and land-attack missiles. The deck guns of World War Two are no longer present, as they increase underwater noise and are less powerful than modern torpedoes anyway. Any anti-air capacity is basically a hand-held SAM launcher carried in a waterproof box.

Submarines are sometimes found operating on their own, but any US carrier group brings a couple along for protection.

There are four basic types.

Diesel-Electric submarines (SSK)
These are your U-Boats of World War Two, suitably updated with longer underwater endurance times, better sensors, homing torpedoes, and faster speeds. They run on diesel engines when on the surface and batteries (big ones) underneath.

In some respects, they're more useful than nuclear-powered subs. Since they're smaller, they can operate better in shallow waters. They are also quieter, since they don't have a reactor running.

However, they are slower, have shorter ranges and are generally not capable of spending weeks below periscope depth. If a moderate-to-large sized opposing surface or air force manages to ever find them, they have little-to-no chance of escape.

The US, UK and France have stopped using these in a combat role. Russia and China retain a fair number, finding them useful for their more limited needs (neither navy often ventures far from their shores), while smaller submarine-using navies (not all that many can afford sub fleets) have no choice but to use these.

Interestingly, Israel's Dolphin class submarines, despite being diesel-electric, are theoretically capable of carrying nuclear-armed missiles and thus giving Israel a regional second-strike capability. Given Israel's fear that Iran will get nuclear weapons in the near future, it's fairly likely that the IDF is preparing for that possibility (if it hasn't already thought of that and carried it out...).

A Pakistani diesel Submarine, PNS Hangor, made the first submarine kill of a surface ship since WWII in its country's unpleasantness with India in 1971. It is also one of only two successful attacks by submarines since 1945. You've probably heard of the other one.

Sub-divided into patrol submarines and other coastal-defence based ones.


 * The Australian Collins class, after a lot of teething problems and controversy, is now considered to be the best of these today.
 * The Russian "Kilo" class, exported to a few countries, including China, is a good example of the Russian sort. Tends to get overblown in its capabilities by some commentators.
 * Germany still produces quite a few good U-boats for a number of nations. The aforementioned Israeli Dolphin class were actually built in Germany, based on Howaldtswerke-Deutsche Werke's (HDW) 209 class subs. The first two (Dolphin and Leviathan) were donated by Germany in general and HDW's parent company ThyssenKrupp in particular as compensation for, well, you know...
 * The Swedish Gotland class submarines are notable exceptions to the normal diesel-electric rule of limited submergence duration, being able to supposedly stay submerged for weeks, although their performance while relying on their Air Independent Propulsion (AIP) system is only 5 knots.

Nuclear Attack Submarines (SSN)
Faster than diesel-electric submarines (and even some surface ships!), Nuclear attack subs have two further advantages: they can stay at sea for longer at a time, being only limited by the foodstuffs on board and they do not need to periodically surface to ventilate the diesel fumes (known as snorkelling).

However, "fast-attack boats", as the US Navy terms them, are ruinously expensive to build and maintain, and only the US, Russia/USSR, Britain, France, China and India operate these boats. Brazil is developing some with French help.

In wartime, the role of an SSN is twofold - to defend friendly ship from attacks by enemy submarines, and to find and sink enemy "Boomers" (see below). Due to their inherently stealthy nature, they are also frequently used for intelligence and covert operations. Delivery of special operations forces has become a major mission for nuclear subs since the end of the Cold War.

During the Cold War (and presumably still today), attack subs from both sides would attempt to trail the opposition's missile submarines, ready to sink them if the need arose.


 * The US Navy's fast-attack fleet is mainly composed of the Los Angeles Class, though some have been retired in favour of the newer Virginia class. The later ones of the former and all the latter have 12 vertical launch tubes for Tomahawk cruise missiles, but can carry them internally too.
 * There are also three Seawolf class subs in the US inventory; these are said to be the fastest and most powerful attack submarines ever built. It was originally intended to build several dozen of these, but with the end of the Cold War it turned out they were "too powerful": there was no longer a massive Soviet sub threat, and the Virginia class is only marginally less capable and much less expensive.
 * The Royal Navy's Trafalgar Class is said to have the most advanced sonar in the world. The older Swiftsure-class will soon be replaced by the Astute-class.
 * The main Soviet/Russian fast-attack sub is the "Akula" class. Well, NATO call it the Akula (Shark). The Soviet navy gave that name to the missile submarines that NATO called the "Typhoon" class, calling this the Shchuka-B, as it was an improvement of the Shchuka, NATO name "Victor III". Confusing.

Guided Missile Submarines (SSGN)
During World War Two, German U-Boats would attack allied convoys on the surface, in large formations known as "Wolf Packs", firing torpedoes and their deck guns to sink the vulnerable freighters.

With the advent of guided missiles, a single SSGN-type submarine could now do this on its own, hiding below the water and launching volleys of cruise missiles at merchant vessels in convoy. Alternatively, they could lay off the enemy coast undetected and fire missiles at enemy airbases, railway bridges and other strategic structures.

During the Cold War, this was a speciality of the Soviet Navy, who operated the "Echo", "Charlie", "Oscar I" and "Oscar II" classes, which would use some of them attempt to prevent the U.S. resupplying its armies in Europe during wartime or to attack carrier battle groups threatening the Soviet homeland. There were also diesel-powered versions, like the amusingly Western-named "Whiskey Long Bin" and the "Juliett".

Since then, the US Navy has converted some of its fleet of Ohio Class missile submarines to SSGN configuration, designed for conventional attacks on land or sea targets using numerous Tomahawk cruise missiles.

Ballistic Missile Submarines (SSBN)
What people tend to mean when they talk about "nuclear submarines", although some of the early Soviet ones were diesel powered. These large submarines, known as "Boomers" (or "Bombers" in the Royal Navy) for obvious reasons, carry a complement of nuclear-tipped ballistic missiles, each missile usually carrying Multiple Independent Reentry Vehicles (MIRV), giving them the frightening ability to nuke several dozen targets in one go.

The purpose of the SSBN is simple - to hide until such time as it is ordered to launch its missiles. It is, after all, rather easier to hide a submarine at sea which can keep moving than a large, static installation on land. Silence is golden. In the event your country is nuked, they will be ready to launch retaliation later (the British have a procedure where a Prime Minister can order a launch from beyond the grave by use of pre-written letters in a safe on the vessel)

Five nations operate Boomers - the US, Russia, Britain, France and China again - and the US and Russian/Soviet fleet have provided fertile ground for fiction, thanks to the dramatic potential inherent in a small, enclosed environment with the capacity for initiating worldwide destruction.


 * The Red October was a fictional (enlarged) member of the Soviet Akula/"Typhoon" class. Six of these very distinctive looking and very large submarines (the biggest ever built) were built, with one remaining in Russian service as a test platform. Russia also operates "Delta III" and "Delta IV" class boomers, as well as having the new Borey class entering service.
 * The USS Alabama, featured in Crimson Tide, is a real member of the US Ohio Class.