Fleet Composition
There's been quite a bit of discussion on the forum lately about how to build effective fleets given what each nation starts with. With that in mind comes this post, which will list each ship type that appears in the game and how each nation used or planned to use them. There will also be examples of fleet types that were used during the war at the end of the post.
Battleship
These are the big guns, the pride of every navy. For the most part all battleships built prior to 1935 were designed to take out other battleships.
I'll make a note in here about the so-called "super heavy battleship" unit in the game. From a historical perspective, there was no such thing. There were treaty battleships and non-treaty battleships, and the only non-treaty battleships that were designed and construction started after 1939 were the Japanese Yamato-class, Soviet Sovetsky Soyuz-class, American North Carolina-, South Dakota-, Iowa-, and Montana-class battleships, the British Vanguard-class, and the German H-class battleships. Of the non-treaty ships, the Yamatos and Montana are what the game considers to be "super heavy battleships", but the Sovetsky Soyuz (in-game lvl4 BB) and H-class (in-game lvl4 BB) were the same physical size, if not larger, than the Montana and Yamato. The UK's Vanguard-class, Italian Littorio-class, and American Iowa-class, also lvl4 BBs in the game, wouldn't even come close to the size of the other 4 classes, being roughly 20,000 tons smaller than the Sovetsky Soyuz, which was the smallest of the big non-treaty ships.
So, with that said, the SH.BB unit shouldn't be in the game. Rather, the Montana and Yamatos should be lvl5 BBs (1940-level) to represent the fact that they are "the next level", with Japan having higher than normal starting techs in the '38 scenario to build its Yamato-class 2 years "early" (aka it researched ahead).
UK, France, USSR, Italy, Japan, Spain: All five countries built their battleships with the goal of having them fight other battleships. Spain lost both of its battleships during its civil war and the USSR never finished its new generation. French battleships built after 1930 are the first of the "fast battleships", but their intended usage remained the same.
USA: While their older battleships were built with the same purpose as the previous 6 nations, their newer ones were built as "fast battleships". US fast battleships were designed to operate alongside carriers as carrier escorts in order to counter Japanese cruisers, which were fast enough to potentially reach carriers before planes could react and strong enough to withstand light cruiser fire. Later on US battleships evolved into expensive AA platforms, capable of repelling most air attacks.
Germany: The Bismarck and Tirpitz were designed for dual roles; that of a convoy raider paired with a screen (the M-class light cruisers and the Spähkreuzer-class heavy destroyers were intended to be screens for convoy raiders) and to operate as part of a balanced fleet in the battleship's traditional role. Due to Germany's severe lack of sea-worthy escort ships, neither ship was able to perform roles outside of convoy raiding. The H-class ships that were to come after the Bismarck and Tirpitz would've been used in the traditional sense had they been completed.
Battlecruiser
Most battlecruisers were built either during WW1 when naval theory suggested they had a viable role in fleet engagements, or during the late 30's in order to comply with tonnage limitations.
UK, USSR, Japan: These countries had built or planned to build BCs to perform the same roles as normal battleships.
Germany: Germany's battlecruisers were designed to act as long-range commerce raiders, capable of out-running larger ships and out-gunning anything smaller. As a result their guns were noticeably smaller than a normal ship-of-the-line, as they weren't intended to fight other capital ships. The Scharnhorst and Gneisenau were classified as BCs by the UK, while every other navy called them battleships. The UK changed their designation of these ships to battleships after the war.
France, Netherlands, USA: These nations built their battlecruisers to hunt down cruisers. They were lightly armored and fast, as they had to be able to catch up to their targets and didn't require heavy armor due to the small guns cruisers carried. They didn't require large caliber guns either, as they were not meant to be used against other capital ships; in this regard they were very similar to Germany's battlecruisers, although they had a different purpose. The American Alaska-class heavy cruisers are an example of a mis-classification. They should've been classed as battlecruisers since everything about the Alaska fits the battlecruiser definition.
Carrier & Light Carrier
Both ship types had similar roles, so I'll combine their entries here. Escort carriers are not covered in this entry. Basically, there were two schools of thought when it came to fleet carrier usage.
UK, France, Germany, Italy, Spain, USSR: These countries used or planned to use carriers to provide air support for their battleships. The CAGs would primarily be used as scouts and to prevent land-based aircraft from approaching the fleet. The UK attack on Taranto caused the UK to shift its carrier doctrine to the Japanese and US one, as well as the battleship losses in the South China Sea against Japanese aircraft.
Japan, USA: Both countries, despite still having a focus on battleships, early on realized the value carriers would have in the Pacific, where their ability to field a wide variety of aircraft in even the most remote location would be a huge strategic asset. The UK later changed its naval doctrine to have a heavier carrier focus, after the successful Taranto raid and witnessing first-hand the effectiveness of Japanese carriers in the Pacific and Indian Oceans against the Royal Navy.
Escort Carrier
These ships were small, slow carriers that were meant to hunt submarines. At most they held around 20 aircraft, which is less than the size of a CAG (50 planes). Only the US, UK, and Japan fielded these ships and there was no variation in their usage between those nations.
Heavy Cruiser
This ship class wasn't defined until 1932. Heavy cruisers built prior to 1932 are called "treaty cruisers", as they were designed to meet the main gun and tonnage limitations of the Washington Naval Treaty. The definition of a CA as defined in the London Naval Treaty is "a ship up to 10,000 tons armed with guns larger than 155mm". In contrast, CLs were defined as "a ship up to 10,000 tons armed with guns smaller than 155mm." Due to the limits on the number of CAs each treaty signatory could field, most CAs in the game were built prior to 1932. The vast majority of heavy cruisers carried 6" or 8" guns.
UK, Japan, US, France, Spain, Italy, USSR: These nations' CAs were designed to act as escorts for capital ships, to escort merchant shipping, and to lead patrol groups. The US later used them as mobile AA batteries.
Denmark, Norway, Sweden, Finland, Netherlands: These nations' CAs weren't actually heavy cruisers, but rather Coastal Battleships. Their specs mean they are best modeled as slow CAs with heavy armor. All of these ships were meant to operate and defend the nations' coastlines alongside destroyers, hence their name.
Germany: Due to the limitations imposed on it from the Treaty of Versailles, Germany could not field large capital ships, and thus had to be creative given the tonnage limitations it had to meet. The result was the Panzerschiffe (armored ship), a cruiser carrying 11" guns and heavy armor. These ships were considered a major threat to Allied shipping, so much so that they sparked a naval arms race between France, Italy, the USSR, Spain (attempted to join), and the UK in response to the French Dunkerque-class BC, which was designed to counter the Panzerschiffe. All German heavy cruisers were designed and used as commerce raiders, which is a role for the ship type unique to Germany.
Light Cruiser
These ships formed the backbone of every major navy. While Battleships and Carriers were the most valuable and prized, and destroyers were the workhorses, light cruisers were the escort ship of choice for all the world's navies. They were significantly cheaper than heavy cruisers and more durable than destroyers, yet were capable of fulfilling both ships' roles competently.
UK, France, Netherlands, USA, Italy, Japan, Spain, USSR: All of these navies used cruisers to lead destroyer groups, protect merchant shipping, perform screening and scouting roles for capital ships, hunt submarines and auxiliary commerce raiders, and perform anti-air defense roles. The US put an additional focus on AA guns for its cruisers at the expense of their surface fighting capability. Italy's cruisers were regarded as "fast but flimsy" by the Allies.
China: China's CLs were meant to be used as coastal defense ships, used to intercept Japanese landing parties and sink destroyer scouts. The bulk of the Chinese fleet was scuttled in the Yangtze River in order to slow Japan's advance during the initial stage of the 2nd Sino-Japanese War.
Germany: The 6 Weimar Republic CLs were meant to be used as commerce raiders, while the M-class ships were meant to be used as scouts for larger commerce raiders. A special type of heavy destroyer would've performed the traditional CL role.
Destroyer
There were three basic uses for destroyers: act as large torpedo boats that could quickly close in on a large ship and sink it with torpedoes before being sunk itself, hunt and chase down submarines, and perform screening actions for larger ships.
Destroyer Leaders were typically slightly larger destroyers with a larger bridge and more communications equipment than a normal destroyer. Aside from that they were essentially the exact same ship as the ones they were leading.
Germany, Poland: Germany designed a special type of destroyer called the Spähkreuzer (scout cruiser), which would've performed all duties a light cruiser would perform as part of a larger fleet. The other German destroyer classes and Polish destroyers acted as large torpedo boats for coastal patrols.
Japan: Japan lacked the experience with submarine warfare that the other naval powers had, and as such grossly underestimated the importance of anti-sub warfare destroyers. A large number of Japanese destroyers were sunk by American submarines, for example, and it wasn't until the final stages of the war that Japan started to mass-produce destroyers for convoy-escort duties. The super-carrier Shinano was sunk by an American submarine, due to inadequate destroyer screens.
Everyone else: Everyone else used destroyers for all three roles mentioned above, with the US and UK in particular using them heavily as convoy escorts and submarine hunters. Typically, sub hunters were deployed with escort carriers.
Submarine
There were several different types of submarines that saw service in WW2. Aside from the type everyone thinks of (sneak up on ships and launch torpedoes), there were several other types. Some submarines were designed as transports, either for special forces or as normal supply ships (Italy and the USSR had several of the latter type). Others relied on a large main gun for offense rather than torpedoes (common amongst pre-1932 British and French subs), and the Japanese experimented with submarine carriers and super-small "midget" submarines that operated from a mother ship.
Regardless of the nation that fielded them, all combat submarines were mainly used as convoy raiders, with one notable exception: Japan. Japan's submarines and crews were designed and trained to hunt warships rather than merchant ships. This was due to Japan's defensive doctrine of Decisive Battle, where small torpedo-armed ships would lure the USN toward the Home Islands and perform guerrilla actions while Japan's battleships would destroy the weakened USN. See Japan's entry for more details on Japan's small warship doctrine. Due to Japan's serious lack of ASW capabilities, American subs were extremely effective at sinking Japanese warships, despite not being trained for such a role.
Historical Fleets
I'm going to make an important distinction here between large fleets and squadrons. Most large fleets didn't fight as a single unit, but were composed of smaller squadrons. The fleets I'm going to list will actually be squadrons, because the game encourages smaller fleets rather than large ones. This list is a work-in-progress and also won't be all-inclusive, and only focus on a few examples. I won't list every historical fleet composition that existed, but will try to have several examples of the same type of mission.
German Plan Z Battle-Group
This is the main offensive squadron composition Germany planned to use once Plan Z was completed. These squadrons were to operate together and destroy the RN, and there would've been a total of 4 squadrons.
2 BB, 1 CV, 5 or 6 Spähkreuzers (5 in-game heavy destroyers; this model doesn't exist in vanilla)
Japanese Indian Ocean Raid (1942) Squadrons
1 group consisted of the light carrier Ryujo and 6 light cruisers; sunk 25 merchant ships over 10 days.
1 group consisted of two heavy cruisers and a destroyer; sunk 5 merchant ships over a period of 4 days.
1 group of 5 submarines sunk 5 merchant ships in 10 days.
Last group consisted of 5 carriers, 4 battleships, and 18 destroyers; this group used aircraft to attack Sri Lanka (Ceylon).
Japanese Indian Ocean Raid (1944) Squadron
3 CAs
Royal Navy Eastern Fleet, 1942
Force A: 1 BB, 2 CV, 2 CA, 2 CL, 6 DD (individual ships, would be 1 or 2 units in-game)
Force B: 2 BC, 1 CV, 3 CL, 7 DD
Red Navy
Not broken up into squadrons because the individual fleets operated together for most operations and were the size of a squadron for the larger navies. Only the Baltic Fleet was large enough to split up into squadrons.
* Soviet Black Sea Fleet: 1 BB, 5 cruisers (3 in-game CA, 2 in-game CL), 3 DD leaders, 15 DDs, and 44 submarines
* Soviet Baltic Fleet: divided into 6 groups
** Baltic Fleet Battleship Group: 4 BBs
** 1st Destroyer Group: 1 CL, 5 destroyers
** 2nd Destroyer Group: 4 destroyers
** 3rd Destroyer Group: 7 destroyers
** 1st Submarine Group: 23 submarines (2 or 3 in-game units)
** 1st Submarine Group: 19 submarines (2 in-game units)
* Soviet Pacific Fleet: 2 CLs, 1 DD leader, 10 DDs (2 in-game units), 78 submarines (about 8 in-game units)
* Soviet White Sea Fleet: 8 DDs (2 in-game units), 15 SSs (about 2 in-game units)
First Battle of Sirte, Italy
The "Close Escort" group consisted of destroyers whose job was to directly protect the convoy ships. The "Close Covering Force" was to follow behind the convoy to act as a decoy while the "Distant Covering Force" was to support the "Close Covering Force" in the event of a major battle.
Close Escort: 6 DDs (2 units in-game)
Close Covering Force: 1 BB, 3 CL, 3 DD (1 unit)
Distant Covering Force: 3 BB, 2 CA, 10 DD (2 or 3 units)
First Battle of Sirte, UK
The RN had 3 groups in the area, one convoy escort and 2 sub hunter/convoy raider groups based out of Malta, Force B and Force K.
Convoy Escort: 3 CL, 8 DD (2 units)
Force K: 2 CL, 2 DD (1 in-game unit)
Force B: 1 CL, 2 DD (1 in-game unit)
Battle of Midway, USA
Task Force 17: 1 CV, 2 CA, 6 DD (2 units)
Task Force 16: 2 CV, 5 CA, 1 CL, 9 DD (3 units)
Battle of Midway, Japan
First Fleet
*Main Force: 3 BB, 3 CVL, 1 CL, 9 DD (2 or 3 in-game units)
*Carrier Assault Force: 4 CV, 2 BB, 2 CA, 1 CL, 12 DD (3 or 4 in-game units)
Second Fleet
*Main Force: 2 BC, 4 CA, 1 CVL, 1 CL, 8 DD (2 in-game units)
*Occupation Force: 1 CVL, 1 CL, 11 DD (3 or 4 in-game units), 2 TP (enough to carry 5,000 troops)
*Support Force: 4 CA, 2 DD (1 in-game unit)
*Advance Force: 1 CL, 10 SS (1 or 2 in-game units)
work-in-progress
