Why is a fleet of two aircraft carriers, two torpedo cruisers, one battleship and one destroyer an impossible fleet?


Near the end of episode 5 of Kantai Collection, Kaga said that a fleet of two
aircraft carriers ([
_Kaga_](http://en.wikipedia.org/wiki/Japanese_aircraft_carrier_Kaga) and
[_Zuikaku_](http://en.wikipedia.org/wiki/Japanese_aircraft_carrier_Zuikaku)),
two torpedo cruisers ([
_Kitakami_](http://en.wikipedia.org/wiki/Japanese_cruiser_Kitakami) and
[_Ooi_](http://en.wikipedia.org/wiki/Japanese_cruiser_%C5%8Ci)), one
battleship ([
_Kongo_](http://en.wikipedia.org/wiki/Japanese_battleship_Kong%C5%8D)) and one
destroyer ([
_Fubuki_](http://en.wikipedia.org/wiki/Japanese_destroyer_Fubuki_%281927%29))
was originally an impossible fleet, so they go along with assigning Fubuki - a
destroyer - to be the flagship of the fleet.

Why is such a fleet an impossible one in the first place?




If you're willing to impose a certain level of realism on the show, then such
a fleet would indeed be absurd by WWII-era naval warfare standards.

In WWII, the biggest source of firepower for a navy was large ships, primarily
battleships and aircraft carriers. Such ships required a huge amount of
resources to operate - _Kaga_ , _Zuikaku_ , and _Kongou_ each had well over a
thousand personnel on-board. They could be used effectively in a variety of
situations, from naval combat, to blockades, to bombarding enemy troops
anywhere near water.

But, such large ships had a fatal weakness, which had been known since the
19th century: torpedoes. A battleship could easily sink weak enemy boats from
a long distance away. For example, _Kongou_ 's [356 mm
guns](http://en.wikipedia.org/wiki/Vickers_14_inch/45_naval_gun) had a maximum
range of 35 km (the effective range was somewhat lower, but still quite far).
However, if the enemy forces had a large number of [small
boats](http://en.wikipedia.org/wiki/Torpedo_boat), each armed with torpedoes,
it would be difficult for the battleship to take down all of these with its
relatively slow weaponry. Certainly, it could hit some of them, but with
enough numbers it wouldn't be able to take them all down effectively. Aircraft
carriers fare a bit better in this respect, but they too had to worry about
any sort of armored torpedo-carrying vessel or submarine, and enemy fire could
prevent aircraft from launching or landing, which would basically cripple
their offensive capabilities.

With enough ships, the enemy forces could easily advance to within the
effective range of torpedo fire (which depended on the model of torpedo, but
was around 4-8 km for [one common
torpedo](http://en.wikipedia.org/wiki/Mark_14_torpedo) used by the U.S. Navy).
It would not take long to deal heavy damage to the large ship, possibly even
sinking it. Small enemy vessels (such as cruisers) could also quickly approach
to get in range of their own guns, at which point the main advantage of
battleships and aircraft carriers (long range) is lost. If this seems like a
poor strategy, keep in mind that torpedo boats could be very small (at some
points even converted merchant/fishing vessels were used for this purpose),
and operated by only a few people, yet a small number of them would pose a
serious threat to much larger battleships and aircraft carriers. Thus, the big
ships need some way to deal with smaller ships approaching them too quickly
for the large ship to deal with.

This is the reason destroyers were invented. Destroyers were relatively
heavily armored (given their small size), highly mobile small ships which were
primarily used for short-range tactical combat and to escort larger ships.
While torpedo-boats and other swarms of small ships could out-maneuver large
ships with enough numbers, they weren't a threat if you could intercept them
before they got in firing range and take them out. A destroyer like _Fubuki_
would generally only be used in combat against other naval forces. Their
[medium-caliber
guns](http://en.wikipedia.org/wiki/12.7_cm/50_Type_3_naval_gun) could still
easily outrange (maximum range of over 18 km) torpedoes, and would be a threat
to approaching cruisers as well. A destroyer only required around 200
personnel, and more than just destroying enemy torpedo boats, they were
generally pretty versatile: they could be used for holding tactical positions,
reconnaissance, torpedoing enemy ships, attacking enemy submarines
(essentially just underwater torpedo boats), and anti-air attacks, depending
on the needs of the mission and the available equipment. Even in the worst
case scenerio that the destroyer sinks, this still buys time for the (much
more important) large ships to escape, fight back, or wait for reinforcements.

Generally, any larger ship during WWII would be escorted by at least one
destroyer. Especially important ships might get more than one destroyer
escort. So, for a fleet of 2 aircraft carriers, one battleship, and 2 light
cruisers ( _Kitakami_ and _Ooi_ are described as torpedo cruisers, but this is
just a type of light cruiser armed primarily with torpedoes), we'd expect at
least 5 or so destroyers, and possibly even more. For a real-life example, the
Japanese fleet at the [Battle of the Eastern
Solomons](http://en.wikipedia.org/wiki/Battle_of_the_Eastern_Solomons) had the
following numbers, which were reasonably typical for a battle of this size:

  * 3 carriers
  * 1 seaplane tender (essentially a light carrier)
  * 2 battleships
  * 16 cruisers
  * 25 destroyers (more than the above 22 ships combined in raw number)
  * Several smaller/non-combat boats

A fleet of 2 carriers, 1 battleship, 2 cruisers, and 1 destroyer is rather
absurd in comparison; it's putting far too many resources in the large ships,
and not enough into protecting them. A swarm of small ships would pose big
problems for a fleet like this. While such a fleet would have excellent
offensive capability given the number of ships, they wouldn't have especially
good defensive capabilities, and would be an attractive target for enemy
attacks (basically a glass cannon).

In addition, the flagship was the most important ship in any operation. The
commanding officer of the operation was on the flagship, and crippling or
sinking the flagship would not only damage enemy morale, but also their
communications and strategy. Making a ship that was designed to be relatively
expendable, like a destroyer, would be a bad idea. The enemy forces would
likely all target the destroyer, and the fleet would be in serious trouble if
it sank, usually forced to retreat.

Typically, the flagship was one of the largest ships in any given operation,
being difficult to sink, well-defended, and powerful enough to boost the
morale of other ships in the operation. A small ship being the flagship would
probably have problems with respect as well as being an easy target. While
there were a couple cases where a destroyer was used as the flagship for an
operation, these were generally only in cases that the whole fleet consisted
of only destroyers, or when the original flagship was too heavily damaged to
continue (such as in the [Battle of
Guadalcanal](http://en.wikipedia.org/wiki/Naval_Battle_of_Guadalcanal)).

* * *

With all that said, none of this really applies very well to the Kancolle
universe, at least in the game. Destroyers had a predominantly tactical,
defensive role, but the game's battle system doesn't do much to emulate this.
In game, most of the advantages of destroyers (evasion and speed) aren't
particularly unique to them; one can replace destroyers with larger ships
without much loss. This _will_ incur larger ammunition and fuel costs, but it
isn't necessarily a bad strategy or one that the enemy forces will have any
way to exploit.

Indeed, once one progresses far enough in the game, even _more_ unbalanced
fleets become commonplace. Later missions require more and more firepower,
which is increasingly hard to meet with weaker ships like destroyers and
cruisers. The game is also generous enough with resources that the fuel and
ammunition consumption become relatively unimportant. Since the number of
ships you can bring to a battle is limited (as are your enemy's, preventing
any kind of swarming strategy), it's often better for high-level missions to
only deploy battleships and carriers. If you're well prepared, it's relatively
rare that such large ships will take any serious damage, and with some
strategy there's essentially no risk of them sinking. If anything, the single
destroyer would be the weak link defensively, and unlike in the real world,
where losing a single destroyer in an otherwise good battle would be seen as a
big victory, in the game you can't afford to throw away experienced destroyers
regularly.

Making the destroyer your flagship would offer it some protection, since in-
game flagships can't be sunk, but if it reaches a heavily damaged level (which
is quite plausible) you'll be forced to retreat. There are other benefits for
the flagship, such as increased leveling and a chance to have attacks hit
other ships instead. There are strategic benefits to both large and small
ships being flagship, but in any case it's not crazy to make a weak ship like
a destroyer the fleet's flagship.

I suspect there's no good in-universe reason to consider this strategy crazy
or impossible, at least based on what we know now about battles in the
Kancolle universe. In the game, it wouldn't really be at all, given the right
circumstances. The anime hasn't presented us with any explanation, and it has
an original story (since the game has almost no story), so we can't really
find any answer there. But in the context of actual WWII-era naval battles, it
would indeed be a crazy, illogical decision to make a fleet like this, and
there are no historical examples of such a fleet.

