Navies Love Nuclear PowerIf 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, have enough electricity to generate their own oxygen from seawater, 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. The appearance of the first US nuclear submarine, USS Nautilus, made most techniques for anti-submarine warfare developed during the Second World War useless, since those relied on the submarine coming to surface to recharge its batteries. 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) allow them to steam at full speed around the world indefinitely. USS Enterprise could out-accelerate all of her non-nuclear escorts despite her bulk thanks to her eight reactors. They're also very fast despite being among the largest ships in the world. There are a couple of drawbacks to using nuclear reactors for power. One of course, is the radioactivity, although this is actually far less of a problem than it was in the past.note Nuclear-powered vessels are also rather complicated and expensive to maintain, a problem which is only exacerbated over time through exposure to a corrosive environment. One major operational 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".note
"G" is for Guided MissileMost 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 three 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.
- Fly at medium to high altitudes at extremely high speeds and dive down upon the target, such as the P-800 Oniks and PJ-10 Brahmos. Supersonic/hypersonic, with a pretty short range, but with tremendous destructive power.
- One more that could be the beginning of an entirely new type - the Chinese DF-21D, a ballistic missile capable of destroying ships. The future of this approach remains to be seen.
FlagshipsIn 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 accompanying 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 ShipsThe 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:
- 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 navies, Cruisers
- Now replaced by Destroyers; only three navies still operate vessels under a cruiser designation, though the distinction between the two types has blurred to the point of complete irrelevance (see size creep and designation issues below). In fact, the ships commonly called destroyers now are cruisers in all but name.
Size CreepSimply put, any given category of warship tends to increase in size and displacement over time. Take destroyers, for example: when the Spanish Destructor was launched in 1887, it had a hull 192 feet long and a beam 25 feet wide, displaced around 380 tons, and a complement of 60 men. Compare this to one of the United States' current Arleigh Burke class destroyers, the largest of which have a hull 509 feet long and a beam 66 feet wide, a displacement of around 10,000 tons, and a crew consisting of 23 officers and 300 enlisted men (and women). Similar figures can be seen with aircraft carriers and frigates, both of which have seen their displacements increase several times since their respective designs were first conceived. On the other hand, size of cruisers began to (temporarily) shrink shortly after World War II, as increasingly powerful anti-ship missiles were seen as rendering heavy armour and big guns obsolete. The result has been that there is no longer any actual difference between a destroyer and a cruiser. Indeed, the last cruisers commissioned by the US Navy were literally built on an identical hull to the destroyers built at the same time. The reason why modern warships are so much larger has a lot to do with the fact that they are designed to be more effective at multitasking. Whereas the 19th century Destructor was originally designed as a fleet escort for the specific purpose of destroying torpedo boats, a modern multirole destroyer of the Arleigh Burke class can attack all manner of surface, underwater, and aerial targets at the same time. Such a design philosophy is made possible by technological factors such as miniaturization and computer networks, both of which allow the integration of multiple weapons systems inside a single hull or for a smaller vessel to take on the functions of a larger one. Additionally, improvements in engine and hull design has lead to larger warships being built without the engineering limitations of their forebears.
Designation issuesCertain 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, as noted above, may have to do with advances in technology rendering one class of vessel obsolete while pushing new ones to the forefront. This happened in the 19th century with ships-of-the-line and frigates: although the former carried several times more guns than the latter, a combination of rifled guns firing explosive shells, steam power, and iron cladding allowed the construction of frigates more powerful and manoeuvrable than a ship-of-the-line.
- 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 built in, later removed (among other things, this enabled them to carry more aircraft).
- Soviet/Russian carriers were dubbed "aviation cruisers" by Moscow in order to bypass restrictions on aircraft carriers passing the Bosporus. Legal shenanigans aside, however, it was a close reflection of their actual armament.
- Soviet carriers were rather useless in Black Sea anyway — it is entirely covered by the modern coast-based aircrafts, so they were only built there, as largest docks in USSR were in Ukraine. Their peculiar armament mix is mainly explained not by the need to transit the Straits, but by the then-current Soviet naval doctrinenote and political opposition within the Government, including party ideologues who stated that carriers are the weapons of aggression and thus come against the tenets of Marxism.
- 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...
- These "helicopter destroyers" lack a ski-ramp, so any V/STOL jets would be severely limited in terms of fuel and armament (they could land pretty easily, though). Also, their aircraft elevators are placed in the center of the deck rather than at the edges, which makes moving aircraft around a little easier at the risk of getting the elevators stuck and leaving a hole in the deck. Long flight deck or not, they're going to be pretty useless for fixed-wing aircraft. A Phalanx CIWS turret has also been installed at the front of the flight deck, in a position that would impede the operation of fixed-wing aircraft. Also, while helicopters don't need much room to land and take off, anyone who's had to wrangle a helicopter onto a pitching destroyer's cramped helipad can tell you it's much easier when you have more room.
- The JMSDF has begun construction of a pair of even larger "helicopter destroyers", the names of which have not yet been revealed. The new "destroyers" will be over 800 feet long and weigh in at over 27,000 tons, making them larger than many of Japan's World War II aircraft carriers. Unlike the Hyūga class, the CIWS mountings are all on sponsons off the sides of the flight deck, meaning there is no obstacle to the operation of fixed-wing aircraft. One of the elevators is also positioned on the deck edge, just aft of the island, instead of the middle of the flight deck. While the design still lacks a ski jump ramp, with a deck so long it would be very possible to operate V/STOL jets with reasonable efficiency anyway. There is also speculation that Japan intends to employ an anti-submarine version of the V-22 Osprey tilt-rotor aircraft, which could also explain the need for such a gigantic ship instead of just building another pair of Hyūgas.
- Recent aggressive moves by Russia and China have made the Japanese... antsy.
- 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 DLG, or destroyer leader, redesignated as CG, cruiser guided missile. Destroyer leaders that were deemed too small to designate as cruisers were instead redesignated as simply guided missile destroyers (DDG). At the same time, destroyer escorts (DE) were redesignated as frigates (FF), in keeping with the designation commonly used in other navies for small escort ships. Though this caused a bit of confusion at the time, because previously the US Navy had considered destroyer leader (DL or DLG, meaning a large destroyer intended as a flagship of a destroyer flotilla) to be a term interchangeable with frigate.
- 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 (in an absurd case of size creep, the Zumwalts are larger than every light cruiser the US Navy has ever built, and most of the heavy cruisers as well). 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". This proved to be relatively ineffective, Congress ended up cutting the production from 10 ships to just 3.
Pre-Steam Ship TypesThe 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 efficiently.
- The concept made a brief comeback steam-era in the each of the World Wars; a key German strategy each time was attempting to choke off supplies from Britain, which as an island can only be supplied by sea. As a stopgap measure many merchant ships were given guns for self-defense, and at the same time Germany armed (and disguised) its own merchant ships in order to sneak up on unsuspecting British ships and sink them before they had a chance to call for help.
- Frigates: Smaller ships meant for long-range, independent cruising, scouting for a large fleet, commerce raiding, and one-on-one actions versus enemy frigates. A defining characteristic of frigates was that the most if not all of their armament was mounted on a single gun deck, whereas ships-of-the-line had multiple gun decks. 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.
- As a sidenote, the original United States Navy consisted of six 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.
- Over time, frigates crew in size to be comparable in length (though rarely in height) to contemporary ships-of-the-line, with fewer guns but superior speed and manoeuvrability. The battlecruisers of their day, to an extent, but since armor didn't exist in ship design of the time it was firepower that they traded to for their speed.
- 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, whose type name is a shortened version of the original phrase "line-of-battle ship". (Another modern inheritance of that phrase, used only to describe civilian ships now that the line of battle is itself obsolete, is the word "liner".) To maximize firepower, ships-of-the-line had two or even three decks of guns, though massive three-deckers proved to be rather impractical since maintaining stability required the third gun deck to be very close to the waterline and thus the gun ports had to be locked closed in all but the calmest seas.
- While the name battleship derived from "line-of-battle ship", their design lineage actually traces more to frigates, specifically the early ironclad "armoured frigates". Since the weight of iron armor made the multiple gun decks of ships-of-the-line impossible, it was frigates that became the first oceangoing armoured ships. Though the weight of the armor also made it difficult to achieve the speed that was the frigate's trademark, so armoured frigates could really be seen as something of a frigate/ship-of-the-line hybrid with armour plate stacked on top.
- 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, or if they did, they carried only a few, typically in a chase armament. 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. The term "galleon" derives from galleys, even though it came to generically describe large sailing ships with no oars at all.
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.
- AE- Ammunition ship.
- AFS- Combat Stores Ship; carries ammo and various other supplies.
- AKE- Dry Cargo/Ammunition ship; designed to do the job of both AEs and AFSs
- AO- Oiler; carries fuel and other liquids. These replaced Colliers, which carried coal back when ships used that for fuel.
- AOE- Fast Combat Support Ship; a large ship that carries fuel, ammo, and supplies. The "E" must stand for "everything". Additionally, they're called "fast" because they are designed to keep up with dedicated warships like an aircraft carrier and its escorts.
- 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.
- Chiwawa class oiler (AO)- five used by US in World War II. 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.
- Sacremento class fast combat support ship (AOE) - four used by the US Navy until 2005, they were the first supply ships to be able to keep pace with a carrier battle group. To achieve superior speed to other auxiliaries, the steam turbines originally intended for the unbuild 5th and 6th Iowa class battleships were employed.
- Their successors, the Supply class AOEs, are powered by gas turbine (jet) engines for the same reason.
- US Henry J. Kaiser class AOs
- US Lewis and Clark class AKEs
Aircraft Carriers (CV, CVL, CVE, CVA, CVAN, CVN) noteNothing 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 jump" 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, aside from landing on the water and being hoisted aboard, something that not all aircraft were good at.
- 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 significantly 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 certainly couldn't land on a carrier.
- In addition to the various weight and space limitations of landing and launching from a carrier, there is the problem of corrosion. The ocean is of course made of salt water, which has very nasty corrosive effects on iron and steel (ever wonder why sailors spend so much time swabbing the decks and repainting the ship?). Maritime aircraft often have to be specially designed and equipped to be particularly corrosion resistant, an issue that land-based aircraft need not worry about.
- Carriers that fly the Russian ensign, which in a blatant but generally accepted attempt to get around the aforementioned rule forbidding carriers from going through the Bosporus have formidable armament in their own right.
- British Invincible-class carriers bore an integral Sea Dart SAM system for most of their careers (which was in fact included in the design specifically so the Royal Navy could get away with claiming they weren't really carriers, as Parliament wasn't authorizing carriers at the time) 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. In fact, until 1942 or so, many American carriers carried batteries of anti-ship guns, later removed because they took up space and proved unnecessary (in practice, much of this space would be taken by Anti-Air guns instead).
- 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 (on account of the LCU boats being replaced by the much faster and longer-ranged LCAC hovercraft).
- STOVL carriers- smaller carriers, usually carrying Harriers (so far, the only worthwhile STOVL fighter-bombers) or helicopters due to having a shorter length. A cheaper alternative, owned by a few nations such as Spain, Italy and Thailand. The US still has 9 of them; and they're building more, though in the case of the US these are amphibious assault craft for which carrying STOVL aircraft is a secondary role. Most non-US STOVL carriers use a "ski jump" ramp allowing their aircraft to take off with larger payloads, a system that the US Navy stubbornly refuses to implement on its LHA and LHD type ships despite its proven superiority in STOVL aircraft operation.
- Full-length carriers- can carry larger aircraft, such as the F/A-18 and Su-33. Only six nations have one currently (US, Russia, France, Brazil, China, India), with one more (UK) due to join that club in this decade. Or rather, re-join, with their largest ever naval vessels. And only one country has 10 of them - The US.
- Within this category there are two major variants. The original type (still used by the US, France and Brazil) is CATOBAR, which uses a steam (or in the upcoming Gerald R. Ford class, electromagnetic) catapult to launch aircraft and arrestor wires to catch them by a tailhook when landing. The more recent variation is a hybrid of STOVL and CATOBAR called STOBAR (used by Russia, China and India, though the latter two plan to build CATOBAR carriers eventually, and will be used by the UK when their new carriers are completed), in which aircraft take off via a ski jump without catapult assistance, but land using arrestor wires. CATOBAR allows for higher takeoff weight and expends less fuel during takeoff, but STOBAR is simpler and cheaper, while still offering greater flexibility than STOVL carriers.
- 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 Battlecruisers already under construction when the treaty limit hit. So what do do with a bunch of half-finished Battlecruiser 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 fixed-wing heavier-than-air craft, essentially airplanes instead of blimps or balloons. There were, in WW1 and immediately after, plans for ships that carried or streamed one or the other for gunfire spotting. CV is "Carrier, heaVier than air".
- The "V" may also be from the French word for "to fly" - Volare. Suffice to say there's a wide array of possible origins for the V, and pinning just one down is difficult because the decision-making process was undertaken by men who are now dead, and didn't leave very good notes on why they did what they did.
- Official reasoning is rather different. "V" is the letter used to designate a USN/USMC squadron as being composed of fixed-wing heavier-than-air craft, essentially airplanes instead of blimps or balloons. There were, in WW1 and immediately after, plans for ships that carried or streamed one or the other for gunfire spotting. CV is "Carrier, heaVier than air".
- Amphibious Assault Ships: Typically classified as various types of landing ships, these are too small to carry out full-out air operations (their deckspace usually dedicated to helicopters and a few V/STOL planes). They usually operate under the umbrella of a dedicated CV.
- "Helicopter Destroyers", "Through-Deck Cruisers", "Aviation Cruisers", etc. Reasons vary from differences in naval doctrine to political considerations. Oftentimes these ships may not have the proper equipment or deck/hangar space to fill the role of a CV to begin with (such as the Japanese Hyuga class helicopter destroyers).
- And sometimes you end up with weird cases such as USS Wolverine and USS Sable, possibly the only paddle-wheel freshwater aircraft carriers in naval history. Both ships were officially classified as Miscellaneous Auxiliaries rather than Aircraft Carriers, and used to train Naval Aviators in carrier operations on Lake Michigan during World War II, due to a critical shortage of CVs needed in combat. Neither ship possessed a hangar deck, and both ships were too small and slow to launch and recover planes in calm winds.
Battleships (BB)The Big Boys. First of all, to forestall any confusion generated by poor use of terminology ("battleship" is often incorrectly used as a synonym for "warship"), there are no battleships on active duty in any navy today, after the U.S. Navy retired the Iowa-class in 2005. 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. Interestingly, apart the submarines, those weapons themselves are nowadays obsolete and modern shipboard radar and computer guided anti-aircraft weaponry is very effective, which is the main reason why the U.S. kept the four Iowa-class battleships in active service until the 21st century. They last fired their 16 inch (406 mm) guns in anger in Operation Desert Storm in 1991. At the time of their retirement they were equipped also with long range Tomahawk 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, then You Are Already Dead. Aside from actual ship-to-ship combat, battleships were very effective at providing fire support for amphibious operations and destroying shore positions; in WWII, U.S. battleships fought more Japanese coastal forts than Japanese ships. A seaborne artillery barrage is also more frightening than aerial assault, as it cannot be predicted by any means, adding the psychological effect. 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". Historically, battleships are generally divided into two types: pre-Dreadnought battleships and Dreadnoughts.note This division is caused by the huge difference in design doctrine and employed technology between the two types, with the British HMS Dreadnought combining several new design concepts and technological advances into a single design that rendered every previous battleship obsolete in one fell swoop, including all of the Royal Navy's preexisting battleships. Examples:
- USS Texas, the first battleship to serve in the U.S. Navy, entering service in 1892. Though revolutionary for the American navy, she was not actually the first battleship in the Americas, being built in response to the Brazilian Navy's purchase of the Riachuelo, which was believed capable of laying waste to the entire U.S. Navy in open combat. The Texas and her quasi-sister ship the Mainenote were both designed around battleships then in vogue with the European navies, but both were considered obsolete before entering servicenote The Maine was lost in an ultimately unexplained explosionnote in Havana Bay, and the Texas served in the Battle of Santiago De Cuba during the Spanish-American War, helping to destroy the Spanish Atlantic Fleet as they tried to make a run for the sea.
- The Mikasa, flagship of Tōgō Heihachirō during the Russo-Japanese War, mounted a mixed battery of guns, including four 12 inch guns in two turrets, and a mix of 3 inch and 6 inch guns in broadside arrangements. She is most famous for leading the Japanese fleet at the Battle of Tsushima Strait, where the Russian Second Pacific Squadron was intercepted and mostly destroyed in their attempt to reinforce Vladivostok (their original goal was to reinforce Port Arthur, but the harbor fell before they could complete their voyage from the Baltic Sea on the other side of the world). The Mikasa was preserved as a museum ship in 1922, and has been permanently moored at Yokosuka ever since. It is now the only remaining pre-dreadnought battleship in the world.
- HMS Dreadnought (completed 1906, scrapped 1921) from the United Kingdom, which changed the design of all succeeding battleships. Battleship design up to that point had consisted typically of two turrets (one fore and one aft) for the four main guns, and slightly smaller turrets for slightly smaller secondary guns along the sides of the superstructure. This proved to be rather inefficient in that the secondary guns didn't really weigh enough less to justify their reduced power, and it also made aiming the guns more difficult. At the time the only way to effectively aim naval guns was to estimate the correct angle and then view the splash of the shells that missed to adjust for the next shot. Problem was, nobody could distinguish between the splashes of a 12-inch shell and a 10-inch shell at long range. Dreadnought dispensed with these problems by simply having only 12-inch guns, ten of them, a then-unprecedented amount of firepower.
- 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. Only being able to manage four 12-inch guns, the remaining turrets were fitted with 12 10-inch guns. Had Japan settled for 10-inch guns in all turrets, the term for battleships with a single-caliber main armament might've ended up being "Satsumas".
- The USS South Carolina was designed before the Dreadnought and the Satsuma, and had a far more efficient gun layout, being the first battleship to have all of its turrets mounted on the centerline and the first to use superfiring turrets (that is, one turret mounted to fire directly above another). This meant that despite being smaller than the Dreadnought, the South Carolina was just as well-armored and had the same 8-gun broadside. But construction was slow, and she wasn't even laid down until two weeks after the Dreadnought entered service.
- However, both the Satsuma and the South Carolina lacked the other, less famous innovation of the Dreadnought: the use of steam turbines instead of triple-expansion steam engines, which made it faster by about 3-4 knots. This was actually the more enduring innovation, as the concept of an all big gun armament couldn't be completely adhered to given that a battleship often had to defend itself against smaller ships. HMS Dreadnought herself ultimately was completed with a secondary armament of 27 3-inch guns to fend off the dreaded torpedo boats, and by the time of World War II battleships were invariably equipped with secondary guns designed primarily for anti-aircraft use.
- 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.
- The Iowa-class (completed 1944, after various retirements and re-commissioning of the class, were finally retired "for good" 1998-1999) from the United States, probably the best overall design of battleships built. You can still see all four of the class as museum ships; USS Missouri is at Pearl Harbor (her home port during World War II, which ended on her deck), while USS New Jersey is in the Delaware River in Camden, New Jersey (right across from Philadelphia, where she was built). USS Iowa is on display in the Port of Los Angeles at San Pedro, and USS Wisconsin is part of the Nauticus Museum Complex in Norfolk Virgina.
- Following their 1980's refit, they also held the distinction of being some of the most heavily armed warships in history, with nine 16" guns, twelve 5" guns, 32 Tomahawk land attack missiles, 16 Harpoon anti-ship missiles, and four 20mm Phalanx CIWS guns. Ironically, while this made them ridiculously powerful surface combatants, the removal of all of the old machine guns pretty much made them irrelevant for air defense, which was one of their primary jobs in World War II. Not that those machine guns would have helped much against the aircraft the enemy would have been using in the 1980s, however. There were proposals for much more extensive refits that would also include anti-aircraft missiles and the Aegis combat system, or even replacing the rear turret with a flight deck for Harrier jets, but these were deemed too expensive.
- The Yamato-class from Japan (completed 1941/1942, sunk 1944/1945) were the largest battleships ever constructed, weighing in at over 65,000 tons and thus 20,000 tons larger than the Iowa-class. They were armed with nine enormous 18.1" guns, a secondary armament of twelve (later reduced to six) 6.1" guns,note a tertiary armament of twelve (later increased to twenty-four) 5" guns, and eventually one hundred sixty-two 25mm anti-aircraft cannons. They also had an excellent armor scheme with the thickest belt armor and thickest turret faces of any battleship ever built - although they had a serious defect in the way their torpedo protection was designed and Japanese armor was not the best quality. In practice, though, they epitomized Awesome, but Impractical and accomplished little other than soaking up large numbers of bombs and torpedoes before sinking. The second ship of the class, Musashi, was sunk without ever firing a shot against an enemy warship.note Yamato had slightly more luck, contributing to the sinking of two destroyers and one escort carrier in the Battle off Samar, but still ended up retreating when her commander lost his nerve due to the dogged fighting of the enemy fleet-even though Yamato herself outweighed all of the enemy ships combined.
- Battleships can be incredibly durable, being able to take literally dozens of shell, bomb and torpedo hits before succumbing. The reason is that they are designed to fight opponents similar than themselves, and some of their speed margin is sacrificed for protection.
Cruisers (CA, CB, CL, CG, CGN, CBGN*)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 (pre-Dreadnought) battleships. By the time of WWI, the main types were the "armoured cruiser,"note , and the generally smaller but faster "protected cruisers."note By WWI, most navies were already beginning to replace the protected cruiser with the "light armoured cruiser" (soon shortened to just "light cruiser"), which is exactly what it sounds like. Less commonly, there were also "unprotected cruisers" with no armour whatsoever, which amounted to really big destroyers with cruiser-sized guns. After the WWI, treaty restrictions divided cruisers between "light" and "heavy" types, with the late-war HMS Hawkins being the template for treaty definitions of the latter type. The designations were not based on size, but on armament. While from a design standpoint there were substantial differences between a pre-war armoured cruiser and a post-war heavy cruiser, and even moreso between a protected cruiser and a light cruiser,note they generally served similar roles. Heavy cruisers (CA; the designation deriving from the earlier "armoured cruiser", from a time when not all cruisers were armored) had a main armament of 8 inch (203 mm) guns or (on rare occasions- such as in the case of the unique Alaska class "large cruisers") larger, while light cruisers (CL) had smaller guns, almost always 6 to 6.1 inch (152 to 155 mm) main guns but sometimes in the 5.5 inch (140 mm) range. By treaty defiintion, 8 inch guns were actually the maximum for a heavy cruiser, with guns larger than 6.1 inch automatically being considered "heavy." Heavy cruisers with guns smaller than 8 inch were either pre-treaty holdovers, ie the British Hawkins class with 7.5 inch (191 mm) guns, or ships from smaller navies that weren't bound by the Washington and London Naval Treaties.note Likewise, cruisers with guns larger than 8 inch were either post-treaty ships or built by non-treaty nations. 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,note and had identical armor to their heavy cruiser counterparts. The US and Britain also produced specialized anti-aircraft cruisers (CLAA), with very large numbers of 4.7 inch (120 mm), 5 inch (127 mm) or 5.25 inch (133 mm) dual-purpose guns as their main armament. These ships were effectively giant destroyers but with (barely) cruiser-level armor, making them an early example of the eventual overlap of the cruiser and destroyer roles. To say nothing of overlap between cruiser and destroyer design, as the CLAA basically amounted to an oversized destroyer with a little bit of armor added. 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. Examples:
- The best-known today and the most numerous is the US Ticonderoga class, a Guided Missile Cruiser. The original Aegis ships, they set the standards for modern air defense by which all other cruisers and destroyers are judged. Starting with the sixth ship, they are armed with a pair of 64-cell vertical launch tubes for their missiles (primarily from the "Standard" family of anti-aircraft missiles, but Tomahawk cruise missiles and VL-ASROC anti-submarine missiles can be mixed in as well). The first five had old-style twin-arm missile launchers that could only fire Standard-MR and ASROC, and as a result were retired early. They were built on a slightly modified version of the Spruance class destroyers' hull (side-by-side comparison here◊), but with a completely new superstructure containing the Aegis system's SPY-1 phased-array radar (consisting of four distinctive flat-panel octagonal arrays, each covering one 90-degree angle around the ship) and its fire control system. One example, the USS Vincennes, infamously shot down an Iranian passenger jet during the Iran–Iraq War, having mistaken it for Iranian Air Force fighter.
- The Russian Slava class. The lead vessel is now called Moskva (Moscow) and took some minor damage during the Russian-Georgian war of 2008. Notable for having its long-range anti-ship missiles mounted in very prominent above-deck launchers along the sides of its superstructure. This doesn't do its radar cross section any favors, but it certainly looks intimidating.
- The American Atlanta class, anti-aircraft light cruisers fielded during WW2 with a total of 16 5-inch guns. Capable of putting out prodigious amounts of anti-aircraft fire, although ineffective versus other, heavier warships. With one exception: the Atlanta class were the only American cruisers in World War II that still carried torpedoes, which proved useful in early night battles, before the wide-scale use of radar allowed cruisers to use their guns at maximum range even in poor visibility.
- The British "Town" class from World War II. 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,note of which Mikhail Kutuzov is now a museum ship in Novorossiysk. Despite being hopelessly obsolete in the Cold War era, they were a major part of fueling the above-mentioned "cruiser gap" nonsense.
- The Greek museum ship Georgios Averof, often mistaken (even in Greece) for a pre-dreadnought battleship, is actually the last remaining armored cruiser in the world. She was the Greek flagship in both World Wars, surviving because the crew disobeyed orders to scuttle her and instead fled to Alexandria when the Nazis overran Greece.
Battlecruisers (CC, CBGN*)A term for very large cruisers with battleship-like armament. The original term proposed for the first battlecruisers was "Dreadnought armoured cruiser" (the idea being that they would be to armoured cruisers what the Dreadnought was to battleships), but this was considered cumbersome (and turned out to be inaccurate, as unlike pre-Dreadnought battleships the armoured cruisers continued to be built) so it was shortened to battlecruiser. The new name would contribute to the very unfortunate tendency to treat battlecruisers as if they were suitable stand-ins for true battleships. Only one type today gets labelled this, not entirely accurately - the Russian Project 1144 Orlan/"Kirov" (the original name of the first one) class.note 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 II was 28 knots; anything slower than that was a pre-Treaty holdover). By the time World War II 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 size creep on battleships meant also the increase on battleship waterline lengths and hence increase on their hull speeds (the longer the waterline of the vessel, the greater its attainable hull speed): also, larger hulls enabled them to carry larger machinery inside. 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 (under slightly different restrictions from the Treaty of Versailles, but with the same 10,000 ton limit) 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 by claiming a 10,000 ton displacement. These really just heavy cruisers with unusually large guns, and were eventually redesignated as such by Germany. Japan conceptualized the B-65 cruiser. The United States, once the treaty expired, built and fielded the Alaska class,note which were largely to counter the Japanese B-65 design that never actually got built. 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. Unfortunately, the Second World War showed that improvements in battlecruiser armor weren't good enough - both HMS Hood and the Kirishima were battlecruisers with much-improved armor protection, but even that was not enough to save them when facing modern battleships in combat - the Bismarck and the USS Washington respectively. Of course, having such an incredibly awesome name, battlecruisers appear disproportionately often in fiction. They're rarely actually seaborne, though.
Destroyers (DD, DDG, DDR, DL, DLG)The largest ship type in many navies today or the backbone of larger navies, destroyers are (usually) 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. With those early destroyers, it was found that the simplest design for destroying torpedo boats was, essentially, a giant torpedo boat. Starting with WW1, torpedo boats were eclipsed as a threat by submarines,note and so during both world wars, destroyers mostly were used to hunt submarines, defend convoys, and (starting in WW2) provide radar and anti-aircraft coverage for larger ships.note 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. If you wanted to re-categorize ships, you could probably compress modern cruisers, destroyers, and frigates into one class called "escorts" and be done with it. 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 note , although the American ships can also launch large numbers of Tomahawk land-attack 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. With 62 in service and at least 13 more in construction or planned (plus the Japanese and Korean derivatives for another 9 ships), the Arleigh Burkes are the most numerous destroyer class since the WW2-era Fletchers.
- 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 (and, later on, the possibility of using railguns and lasers). 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.note 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. Ironically, the namesake of the class was an admiral who championed the idea of the Navy using a large number of smaller, less expensive 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. With 31 built, they were the largest destroyer class of the Cold War era. They were also the largest destroyers of that era in terms of tonnage, being similar in size to a pre-WW2 light cruiser. Their hull design was even reused for the Ticonderoga class cruisers.
- The air defense variant, the four-ship Kidd class, was designed for the fledgling Iranian navy (under the preliminary name of Kouroush class), but a year after construction started the Iranian Revolution happened and they instead became part of the US Navy. They tended to get deployed to the Middle East a lot, because one of the modifications made to the design was heavily improved air conditioning. They've since been transferred to Taiwan, being renamed yet again as the Kee Lung class.
- The American Fletcher class, built for World War II, and the most numerous class of destroyer built. (175 total for the US Navy) Many were sold to other countries, and the last one in service was decommissioned from the Mexican Navy in 2001.
- The Allen M. Sumner class (58 ships), Robert H. Smith class (12 ships, a minelaying subclass of the Sumner) and Gearing class (98 ships) destroyers were all closely related, with only slight changes in the hull design but a superior armament with much more efficient layout (replacing the Flechers' 5 5-inch guns in single turrets with 6 guns in twin turrets). Due to their improved layout and slightly larger hulls, some of these remained in US service into the late 1970s to early 1980s, with the torpedo tubes being replaced by an ASROC launcher and the rear turret with a hanger for an armed drone helicopter in the 1950s.
- The Russian Udaloy class destroyers are a good example of a destroyer mainly designed to hunt submarines. Roughly the Soviet equivalent of the Spruance class. While their
- The improved Udaloy II type was intended to combine the Udaloys' anti-submarine capability with the Sovremmeny class's anti-ship missiles, but only one was built before the collapse of the Soviet Union and the accompanying collapse in military funding.
- 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. Despite being very similar in size and introduced around the same time, they're not closely related in design to the Udaloy class and in an example of pointless inefficiency do not use the same hull design. Roughly equivalent to the Kidd class, but a lot more numerous.
- 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.note 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.
- The ancestors of the modern destroyer were the Japanese Fubuki class (also known as "Special Type destroyers, as they were such a huge leap in capability over what came before them), which were the best destroyers of the late 1920s and pretty much sent the destroyer along its evolutionary path to being the formidable, all-purpose vessel that is today. Very fast, well armed and packing a devastating set of torpedoes, the Fubukis did their job in WWII, even if they were starting to get old.
- The Akizuki class were the next major step, being twice the size of the Fubukis and nearly 50% larger even than their American contemporaries like the Fletcher classes, and despite predating the existence of missiles they were the first specialized anti-aircraft destroyers.
Frigates (FF, FFG, DE)Frigates are generally smaller than destroyers (though the distinction is becoming less and less relevant as size creep sets in), 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 (DE)", 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 already 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 smaller warship from the Age of Sail; see above in "Pre-steam ship types" for a description of those. 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 (their anti-submarine weaponry is primarily their helicopters), and have been exported widely. They are used by, among others, Spain, Taiwan, Turkey, Greece, Egypt, Bahrain, Poland and Australia, with some of these navies using ex-US ships and others having had Perry class frigates built specifically for them back when the design was new. 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. They're also notable in that, despite being designed with almost no room for upgrading, they had additional weapons and sensors stacked on them anyway and thus are somewhat topheavy. Spain and Taiwan saw this coming and their Santa Maria and Cheng Kung classes are slightly modified versions with a wider hull to compensate for added weight.
- 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". They utilize the excellent "Sea Wolf" anti-aircraft missile for self-defense; while its range is far too short to be much use in protecting other ships, it's so accurate that it can even shoot a target as small as a 4.5" artillery shell out of the air.
- 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.
- Russian project 11356 frigates, an evolution of the venerable proj. 1135 Krivak class, now fielded by India as Talwar class and by Russia itself as Admiral Grigorovich class. Based on a tried and true hull design, they feature an entirely new armament (including the supersonic Brahmos/Onyx ASM), sensor and electronic packages, and the redesigned, more stealthy superstructure, which makes them pretty formidable combatants.
- Another Russian frigate, a proj. 22350 Admiral Gorshkov, is intended to be the replacement of the Krivaks, and the latest in the gee-whiz category, with everything in the ship being state-of-the-art. Which, unfortunately, is responsible for the lead ship still not being commissioned despite standing virtually completed for a couple of years now, while all the kinks and delays in her machinery are being ironed out. At ~5 kt displacement the ship is essentially a small destroyer, and should become one of the most powerful frigates in the world when finally commissioned. However, after the delays first surfaced, the Russian Navy ordered six Grigoroviches as a stop-gap, so they might even outpace Gorshkov in the pipeline.
Corvettes (FFL)Smaller versions of frigates, primarily designed for coastal duties- many are now close to frigate size though. Small, manoeuverable 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. Even though given their 45 knot top speed is exceptionally fast for any type of warship, sharing the name of a sports car really would've been appropriate.
- In early 2015, the US Navy actually decided to re-designate these ships as frigates and plans to arm them heavily enough to qualify. It helps they're already close to the same size as the average frigate.
- 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 an integral helicopter (with a hangar etc., not just a helipad) in just 2.5 kilotons of displacement. And as usual with the Russian ships, it is armed heavier that the many frigatesnote — which led to the habitability of the crew suffering as a result. They miss the Saar 5 armament density, though, but only because they're more then a full kiloton heavier.
- The Israeli Sa'ar 5 class corvettes, like their Sa'ar 4.5 missile boats (see below) stretch the limit of how heavily armed a ship of their size can be. The carry 8 Harpoon anti-ship missiles, 64 Barak anti-aircraft missiles, a Phalanx CIWS, 6 anti-submarine torpedo tubes and a Panther anti-submarine helicopter. They used to also carry 8 smaller Gabriel anti-ship missiles, but these were removed due to the ships being (unsurprisingly) top-heavy. Even with that alteration, they still squeeze armament similar to a full-sized frigate into a package of only 1200 tons, and at 33 knots top speed they're faster than most full-sized frigates to boot.
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 famous Higgins Boat was a wooden landing craft manufactured by the thousands for the US and its allies during WWII and afterwards. A vivid depiction of their use in combat can be found in Saving Private Ryan and numerous other works that depict that era.
- The US LCU (Landing Craft, Utility)
- The US LCAC (Landing Craft, Air Cushion) is a unique take on the concept, which replaced the LCU. 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. Their great advantage lies in the fact that they're essentially small aircraft: it's nearly impossible to run one aground, short of intentionally driving into large rocks, cliffs, trees, or structures. This means they can put amphibious forces ashore in places previously thought impossible to reach, summed up in the US amphibious community adage "No beach out of reach!" LCACs are also much faster than the average landing craft, with the trade-off of larger size (can't fit as many in an Amphib) and reduced carrying capacity relative to their size.
- Various amphibious armored vehicles can be used as landing craft if needed and conveniently double as ground transportation for troops once ashore. They have the advantage of being somewhat better armed and armored than most landing craft but the drawback of being very slow while "swimming" and requiring a particularly calm beach with a gentle slope to safely land on. Examples include the US AAV-7 and LAV-25, and the Russian BRDM and BTR series vehicles.
Amphibious Assault Ships (LS, LH, LP)Amphibs or "Gators"note 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). Originally the designation LHA meant that the ship used only helicopters to deploy troops to shore, and LHD denoted that the ship also had a well deck for launching and recovering landing craft. However, then the US Marine Corps complained loudly enough that the navy decided to put well decks in their LHAs anyway, so there is really no operational 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. During the Cold War, it was envisioned that they could be employed as an equivalent to World War II escort carriers (CVE) in the event of a major naval war.
- The US LPD and LSD classes, for the smaller variety. (designation: Landing ship, Platform, Dock and Landing Ship, Dock) The main difference between the two is that an LPD usually has a hangar bay for sheltering and maintaining helicopters, thereby making it a useful helicopter landing Platform.
- 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". Though this originated among LST crewmen during World War II, in fact LSTs had higher survival rates than most other ship types.
- The Spanish Juan Carlos I, a modified version of the American Wasp class LHD, but intended to be an aircraft carrier first and an amphibious assault ship second. The primary alterations from the American design are the incorporation of a "ski jump" on the flight deck and provision to convert the light vehicles bay into an expansion of the aircraft hanger as needed.
- A pair of additional ships of this design are under construction for Australia, as the Canberra class.
- The Italian Cavour. Like the Juan Carlos I, it's operated as a light aircraft carrier first and an amphibious ship (in this case, an LPH (Landing Platform Helicopter) second. It has a ski jump with an unusually shallow angle, which cut construction costs but also reduced the advantage of the ski jump.
- The South Korean Dokdo class (similar to an LHD), one of the smallest amphibious assault ships.
- The Soviet Ivan Rogov class is a hybrid LPD/LST, and at 14,000 tons they're the largest ships capable of beaching themselves to offload vehicles.
- Like destroyers, the Japanese (Army in this case) pioneered the ship type with Shinshu Maru, way back in 1934.
MinelayersExactly What It Says on the Tin. A ship whose main function is to lay naval mines to sea. Especially popular by navies whose coast is shallow, has large archipelago or long coastline. Naval mines can be a real menace at close straits, harbours and shallow seas, and a single mine can sink a large ship. A minelayer is usually a good seagoing vessel with flush deck, with mine rails, shafts and/or scuttles attached. A passenger ferry or a ro-ro merchantman can easily converted in a minelayer by just bolting the mine rails on the car deck and embarking the mines inside, and then lowering the stern gate where the mines are to be laid. In the past, destroyer-minelayer hybrids were also used, but this would now be considered a waste of a destroyer.
- Examples: Finnish Navy Hämeenmaa class minelayers
Minesweepers (MCM)Also 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, maneuvering thrusters or pods which allow them to travel in any direction and turn on a dime, and diving facilities, which allow them to successfully 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 tactic used 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 (PC stands for Patrol ship, Coastal). 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; at most they're designed to withstand small arms fire. Examples:
- The US Cyclone class PCs.
- The Australian Armidale Class PCs.
Gunboats (PG)A small but fast craft, armed either by a BFG or a light but extremely rapid-firing cannon. These boats are favoured by navies whose coastline allows fast hide-and-seek tactics, and they are extremely popular on riverine warfare. This type of warship gave the name for Gunboat Diplomacy. Largest Gunboats are classed as Corvettes, while smallest are classed as Patrol Boats. Examples:
- The USN Assault Support Patrol Boats (ASPB).
Torpedo Boats (PT)Small boats armed with torpedoes. Mostly used in World War II, they're largely obsolete now due to anti-ship missiles. Which naturally led to missile boats (see below) being designed to replace them. 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 MacArthur and his family and staff 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. This act of daring earned every member of the squadron a silver star and its CO, Lieutenant Commander (later Vice Admiral) John D. Bulkeley the Medal of Honor. Regardless of what you think of MacArthur, this was an impressive feat of tactics and seamanship that also served as a morale booster and an endless source of Allied propaganda during the war.
- PT-109 became famous during and after World War II, despite being cut in half in a collision with the Japanese Fubuki-class destroyer Amagiri, 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.
Missile Boats (PTM)Eggshells with hammers. The 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. India put them to good use in its 1971 war with Pakistan. The US had some, but have now retired them as not cost-effective. The missile boats do have their drawbacks, though. 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). Due to their small size they are not very seaworthy, they have poor accommodation facilities, poor range and poor seagoing properties. They can easily be destroyed from air. And there are morale problems, especially if manned by conscripts: the sailors know they are expendable. However, they are on their own if the country deploying them has dense archipelago or broken coastline behind which to hide and where to strike.
- 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 Osa II class, in Finnish Navy the Tuima ("Fury") class, was generally hated by the Navy conscripts who had to serve onboard. They bore nicknames like Tuska ("Agony") class and Moskvich (after a poor quality Soviet car). The working and living conditions onboard could at best be described as Spartan (by the deck crew) and at worst hellish (by the engine crew).
- The Norwegians have the Skjold class, which are both the fastest warships in the world (a whopping 60+ knots, the exact speed is classified) and the first operational stealth warships. They are designated as "corvettes" by Norway despite their being only slightly larger than an "Osa", on the premise that they're too seaworthy to be called mere "boats". The armament of 8 anti-ship missiles (in concealed launchers) and a 76mm gun are quite typical of a missile boat, though. These replaced the Hauk class, which were a rather more ordinary design.
- 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 76mm gun). At least 30 were planned, but only 6 were builtnote and they never really did anything before being retired. Being a good 15 knots faster than the already speedy "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 Barak anti-aircraft missiles (or 6 Gabriel anti-ship missiles), and two gun turret positions that can each mount either a 3-inch gun, a 25mm autocannon or a Phalanx CIWS. And there used to be a version of these ships that included a helipad and hanger,note despite both versions weighing under 500 tons. This has the effect of making ships that are classified as "missile boats" almost as well armed as your average frigate. They make up for it by having as speed of "only" 34 knots, a bit faster than most frigates but mediocre for a missile boat.
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.
BoghammarThe maritime equivalent of a technical. An improvised fighting vessel, usually manufactured by attaching a machine gun, anti-aircraft cannon or recoilless rifle on a speedboat. Usually favoured by third world countries, irregulars, especially in chaotic or underdeveloped countries, and by pirates. The name derives from Swedish speedboat manufacturer Boghammar Marin AB, who manufactured the first armed speedboats for the Iranian Navy.
SubmarinesSubmarines 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". At least in US and British parlance.) 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. During their heyday in the first half of the 20th century, submarines were a constant source of Paranoia Fuel, due to their ability to attack without warning (on more than one occasion, capital ships were sunk in their home harbors by daring submarine commanders). During the Spanish Civil War, submarine warfare by unknown partiesnote resulted in the Nyon Conference, where strict rules were established concerning submarines operating unescorted in the Mediterranean, with portions of the sea patrolled by British, French, Germans, and Italians to prevent submarine attacks note 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 II 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.note 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 (SS, SSK)These are your U-Boats of World War II, 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. Under the right conditions, they can be even more dangerous than a theoretically more powerful nuclear submarine, because of the lack of noise. 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 is a good example of the Russian sort. Relatively small and very quiet, they find a notable export success, especially in Asia, and are now bought by the such disparate countries as India, China, and Vietnam.
- Their successor, Lada class, intended to compete with the new German designs, is, however, beset by a teething problems and isn't expected to enter service (except for a single experimental boat) for a few more years.
- 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...note
- 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.
- The Collins and Gotland class both have an unusual "X" configuration tail planes (instead of the typical "+" configuration of two rudders and two dive planes, all four planes serve as both rudders and dive planes), which improves maneuverability and also makes it possible to "land" the submarine on the ocean floor without risking damage to the planes.
Nuclear Attack Submarines (SSN)Faster than diesel-electric submarines (and even most surface ships!), Nuclear attack subs have two further advantages: First, they can stay at sea for longer at a time. By making their own oxygen from seawater and scrubbing the carbon dioxide from the air with filters, a nuclear attack submarine can stay at sea and submerged for months on end, until the foodstuffs on board run out. Second, unlike diesel-electric boats, they do not need to periodically surface to charge the battery by running the diesels (known as snorkelling-the sub literally sticks a snorkel out of the water to suck in air for the engines). This makes them much harder to detect by ships and aircraft. 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 (the most obvious difference is that the Virgina class have half as many torpedoes...which merely means reverting to the number carried by the Los Angeles class) and much less expensive (though in reality the Virginias turned out to be only slightly cheaper due to inflation).
- 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" (even though the "Akula" class is a new hull design rather than just an incremental improvement of the "Victor III"). Confusing.
- The Soviet Union used to have the "Alfa" class (called the Lyra by the Russians, after the constellation). It was incredibly advanced for its time, featuring a welded Titanium hull, allowing to enormous dive depths, a lead-bismuth cooled reactor of immense power, and the degree of automation unprecedented to this day — for all its novel features it was crewed by just thirty men. On the other hand it lacked in stealth (though it's difficult to be stealthy running 44 knots underwater, on cruise speeds it was no worse than the other Soviet subs of the time) and it was so expensive that only a small series was built.note Frequently featured as a "bad" submarine in Tom Clancy works.
- Modern Russian Project 885 Yasen class is an answer to the US' Seawolf, and is similarly ruinously expensive — in fact, even more expensive than their boomer counterparts, which are much larger — and many analysts expect a Virginia-like "economy" class to surface after an initial series will be built, as the Akula class boats are getting old.
Guided Missile Submarines (SSGN)During World War II, 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 specialty 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 (using the early boats of the class which were incompatible with the newer Trident II missile), designed for conventional attacks on land or sea targets using numerous Tomahawk cruise missiles. This unfortunately does lead to the odd situation of having two classes of Ohio submarines in existence at the same time; the SSGNs and the rest of the SSBNs from the class they were converted from.
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. They also carry torpedoes; these are usually - but not invariably - conventional-tipped, and mostly for self-defense. 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.
- USS Alabama, featured in Crimson Tide, is a real member of the US Ohio Class.
- The mainstay of the Soviet/Russian boomer fleet are the boats of the project 667BDR/BDRM, AKA Kalmar/Defin class, called Delta III/IV by NATO. Deltas III, the oldest of them, are in the process of replacement by...
- The project 955 Borey boats, designed to carry the problem-saddled Bulava SLBM, although by this time everything seems mostly settled. These are easily distinguished by the unusual reverse slope of their conning towers' face, and the virtual lack of the characteristic "hump" of the older Soviet boomers, because the solid-fueled Bulava is much more compact than their hydrazine fueled missiles.