Kongo Class: Fast Battleship or Battlecruiser

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Kongo Class: Fast Battleship or Battlecruiser

Postby VoidSamukai » Fri May 04, 2018 4:58 am

Warning: This post is just my opinion and my opinion only. I am not a naval historian nor do I intend to make myself appear as one. I am just some guy with a post idea in his head. You have been warned, so don’t get too triggered.

Sleek. Fast. Powerful. The main reason why Iowa was ever created. And most importantly: waifu material. These descriptions all refer to one of Japan’s most famous class of warships: The Kongo class.

But were these ships battlecruisers, or fast battleships as the Japanese Navy classified them in 1938?

First, a bit of background on the Kongos:

The Kongo class started their lives as battlecruisers ordered by the Japanese just prior to World War One. The ships were based upon the British’s own Lion class Battlecruisers with the main gun armament upgraded to 4 twin 14 inch guns and 16 casemate mounted 6 inch guns. Armour-wise would start of with 8 inches of belt armour and 2.5 inches on the deck. This lack of armour was in common with British battlecruiser philosophy at the time: firepower and speed over armour protection. And at a speed of 27.5knots, the Kongos were definately fast. While Kongo was built in Britain so that Japan could learn about British construction techniques, the 3 other ships of the class; Hiei, Kirishima and Haruna were all built in Japan. Thus Kongo became the last Japanese battleship/battlecruiser ever built outside of Japan: from the Fuso class onwards Japan would be building her own homegrown battleships.

The careers of the Kongo class during World War One consisted mostly of patrolling the home waters and escorting troop convoys. A very boring career. But from post-World War One onwards the Kongos would go on to live very interesting lives. In the 1930’s Kongo, Haruna and Kirishima ended up going through 2 major refits that increased armour protection and new boilers to help which, along with a lengthening of the ship, increased the ship to 30 knots. Hiei was originally converted into a training ship where her armour belt, 3rd main turret and secondaries were removed in accordance to the Washington Naval Treaty but later was upgraded to match her sister ships.

Despite the modification, all four ships were lost during the war: Hiei to aircraft attacks during the Battle of Guadalcanal, Kirishima during an engagement with battleships South Dakota and Washington, Kongo to the submarine USS Sealion and Haruna to air attacks while it was in port. And thus the story of the 4 sisters and the most successful surface capital ships to serve the Japanese Navy during World War Two came to an end.

Until they were brought back to life in Kantai Collection as cute anime girls that seemed to have consumed way too much sugar and in Arpeggio of Blue Steel where they were brought back because why not.

Now, onto why the Kongos were battlecruisers and not fast battleships.

Unlike with the controversial Alaska class, where many good arguments were made on both sides, the Kongo is much easier to properly define as only one side seems to have the solid arguments to their case.


Even after the second modification to her, which involved increasing the amount of armour, the Kongo’s armour was nothing short of bad compared to other true battleships rebuilt at the same time and were from the same era. Her main belt armour remained the rather thin 8 inches of belt armour, just now covering more of the ship. To make a comparison as to how lackluster the armour was: most pre dreadnought battleships that were built before Kongo’s generation had thicker armour than Kongo herself. Kongo’s armour is right in the ballpark of other battlecruisers such as the Renow, a battlecruiser built around the same era as Kongo and also heavily modernised prior to World War Two, with 9 inches of belt armour and Dunkerque with 8.9 inches. Even the Alaska class with her 9 inch of belt armour was better protected than Kongo and the Alaskas were not known to be well armoured ships, though it should be noted that Alaska was 3 decades newer than Kongo so the obvious improvements and advancements in ship building should be taken into consideration.

This was understandable since the Kongos were reflective of the British battlecruiser concept where firepower and speed were more important compared to armour. And this shows when Kongo is compared to other battleships of the same era. Fuso and Ise had 12 inches of belt armour, the Queen Elizabeth class had 13 inches of belt armour and the Nevada class with 14 inches of belt armour. In all these cases, Kongo’s armour was not well armoured compared to the majority of the battleships of Kongo’s time, which was in line with battlecruiser design of the time, particularly the British battlecruiser design that Kongo was based on.

However, Kongo’s armour isn’t as bad as you may think it to be. It is far from as good as most other contemporary battleships, but some battleships manage to have armour that is only marginally better.

There are battleships with armour that is not that much thicker than the Kongos, like the Andrea Doria and Conte di Cavour class of battleships, which had only a 9.8 inch belt, the HMS Agincourt with 9 inches of belt armour (which for the record is the same as the Renown class Battlecruisers built just two years later) and the Gangut class with a 8.9 inch of belt armour (though to be fair to Gangut she was a design of the era of the first generation of battleships and not the second generation like Kongo so her armour could be excused, not to mention she was much smaller than the Kongo in terms of maximum displacement)

But you will find it hard to discover many people who would say that these ships were well armoured battleships. Hell, the first German Battlecruiser Von Der Tann, built years before to these battleships, with her 9.8 inch of belt armour was on par to these battleships in terms of protection (though obviously her firepower was not the same level). Even Bellerophon, the oldest class of dreadnoughts that the British built, had a 10 inch armour belt and she wasn’t considered that well armoured compare to ships like South Carolina and Nassau. When compared to ships like Orion and Iron Duke with 12-13 inches of belt armour, these battleships did not favourably compare in terms of their armour protection.

It is only when you are comparing the Kongo to practically the worst armoured battleships does her armour not look terrible. Again, compare to most other battleships, with belts of armour ranging from 12-14 inches thick, Kongo’s armor is not that ideal at all to take massive hits.

A battleship’s main function was to be able to engage other enemy battleships in line of battle. To do this the battleship must have armour thick enough to protect itself from enemy battleship shell fire. And if the Lion, the ship Kongo was based upon, was anything to go by in terms of survivability against battleship caliber guns at Dogger Bank, Kongo’s armour is not going to save her from battleship shells. Even after modification during the battle of Guadalcanal Hiei was damaged considerably by the 8 inch and 5 inch guns of the cruisers in the battle, so one could imagine what would happen if they were to face against much bigger shells.

Well, it could be argued that Kirishima did succumb to the firepower of USS Washington, but that engagement was not really a fair fight: it wasn’t just a case of a battlecruiser verses a battleship but more importantly a ship from pre World War One fighting against a modern battleship built in 1941. It is to be expected that the ship that had the most guns, the biggest guns, the thickest armour and was the most modern to win in the engagement. South Dakota was also in the battle, but she was out of action for a good part of it so she wasn’t able to contribute much to sinking Kirishima.

But for all the weaknesses in the armour, the Kongos did have some advantages compared to other battleships of the time.


Where Kongo lacks in armour, she makes up for in speed. At 30 knots the class were amongst the fastest large gun warships that served during World War Two. This high speed was due to the fact that Japan wanted to use the Kongos not only as a fast battlewing to support the cruiser squadrons (we will get back onto this later), but also to help escort the growing Japanese Carrier force and protect them from enemy attack. This was very similar to the Iowa class that would come much later in 1943, where the higher speed meant they were more useful compared to the slower Montana class which was why the Montanas were never built and why the Iowas were kept after World War Two.

Compared to the 24-25 knots of the other modernised dreadnoughts like Fuso, Nagato, Queen Elizabeth and the even 28 knots like the Andrea Doria class, the Kongos speed advantage allowed it to be used alongside cruiser forces and was a big reason why they were used so much more compared to other Japanese battleships. This increase of speed at the expense of armour was not something true fast battleships would have, such as HMS Hood which had armour protection on par with the Queen Elizabeth class at the time, the Nagato which had the same armour as the Ise class and the Iowa class which had the same armour as South Dakota. These fast battleships did not need to sacrifice armour for their increase of speed, though Nagato was definitely less armored compared to ships like Nelson and Colorado.

Battlecruisers however did sacrifice some armour to attend the high speeds they needed to do their designed role engaging enemy cruisers. Ships like Renown had 9 inches of armoured belt compare to the 13 inches of the Queen Elizabeth class, Derfflinger with 12 inches of belt armour compared to Konig with 14 inches all removed between a third to a quarter of the armour of the complemtory battleships as well as some guns in order to be much faster: Renown at 32 knots versus Queen Elizabeth’s 24 knot top speed and Derfflinger at 28 knots versus the Konig with 22 knots. Kongo with her 8 inch of belt armour and 30 knot top speed versus Fuso with 12 inches of belt armour and 24 knot top speed is yet another example of this philosophy.

Fun fact, it was this high speed that caused the Americans to build the Iowa class, since they didn’t have any battleships that could catch her. And considering the fastest battleships the US had at the time were 28 knots and most of the fleet being consisted of ships that were lucky to break 21 knots, having faster battleships were definitely appealing to have. So there you go: the Iowa class were created to counter ships that were 3 decades older than they were.

Doctrine and Use in Battle:

This is where the Kongos place as a battlecruiser is most cemented. Their usage, and the reason why they were more active compared to ships like Fuso, were not of that of the main battleline like true battleships but rather as a fast wing that would not only support the Japanese cruiser forces, but also attack and sink the enemy cruiser forces a well. A role the battlecruiser was originally intended for and one where the ships would be most effective at, during the battle of Guadalcanal.

Even if they were still vulnerable to gun fire but hey when were pre-Hood non-German battlecruisers known for their durability?

Aside from cruiser leading, the Kongos were also used for as Carrier Escorts since their high speed enabled them to keep up with the fast Japanese carriers of the time and that they were the only Japanese battleships able to do so. Plus, they were seen as old and the most expendable of the large ships at their disposal so if they sunk they still had enough battleships for the decisive battle that the Japanese envisioned and came to nothing at all.

You would think that one of the refiners of aviation warfare would have realised carrier warfare and not surface warfare would ultimately dominate the Pacific War.

Interestingly, this carrier defense role was actually similar to the rebuild of the Renown class battlecruisers, which focused on boosting ship’s anti aircraft defenses in order to help defend against enemy air attacks and to escort carriers.

But for the most part, their role as a fast wing to assist the Japanese cruisers rather than stand in the line of battle even after all of the modifications were done hints to just how much battlecruiser the Kongos were compared to battleship.

The only time that these ships would become part of the main battlefleet alongside battleships would be when Japan rounded up all the ships she had left after years of massive loses for one final stand. All things considered, she would probably have been better suited escorting the decoy carrier force instead and leave the Ise class as true battleships and have them being in the Centre Force. But hey, hindsight isn’t exactly free isn’t it.

Fast Battleship Designation:

So, why were the Kongo class designated as fast battleships? Why do people call the Kongos battleships when their specifications and abilities were more inline with battlecruisers?

To say that it is because the navy called them battleships is not a good enough excuse on its own. Especially since this is the same country that calls the Izumo class Helicopter Destroyers despite the fact that they bear more resemblance to helicopter carriers.

One reason why the Japanese decided to redesignate the Kongos as battleships may be due to political reasoning. Battlecruisers had somewhat of a negative connotation after the Battle of Jutland where 3 British battlecruisers were sunk to massive explosions. This negative accusation with such ships is also one of the reasons why the US were so against calling the Alaska class Battlecruisers and instead opted for Large Cruiser instead.

As to why other people call them battleships in hindsight however…

...well there is the fact that the ships were up armoured prior to the war, which people have rightfully brought up, but as shown the armour was still not enough to protect against battleship caliber shells so that point is moot. Aside from that...

...I got nothing.

In all the forums and posts on the internet I have looked through, no one had been able to come up with a good enough argument for the Kongos being battleships and not battlecruisers that was not due to some political name calling or just taking the official designation of warships too literally and not giving it much thought. But maybe there is some source that can give a reasonable explanation that I have not seen or taken in considering in this article. Who knows.

But unlike the Alaska class, or the Scharnhorst class, one side has nearly all the reasonable arguments and the other has only straws to grasp on. This is not a debate, this is just a one sided argument that the fact it is a thing is surprising. But maybe there is a good reason out there that I have yet to discover.


The Kongos started their lives as battlecruisers and ended their lives as battlecruiser. Or as a floating AA fortress in Haruna’s case. The whole concept of them being fast battleships is just bizarre and holds no to little amount of water. Only compared to ships like Ganguat, Agincourt and Andrea Doria which had some of the worst armour fitted on a battleship, does her armour seem not so terrible. And even then since these ships weighed a good bit less than Kongo after their refits (in the case with Gangut and Andre Doria), their thinner armour becomes even more excusable, though not quite something to ignore. When compared to ships their size and age like Nevada and Fuso with their 12-14 inch armour belts, Kongo’s armour and higher speed fits more in line with the battlecruiser role that she was originally built for, not the fast battleship concept that HMS Hood pioneered and Iowa class perfected, where both ships had armour comparable to the battleships of their size and age. The renaming to ‘battleships’ seems more political than actually what the Kongos were truly capable of and when taken into comparison of other ships that Kongo was a commentary of, she slides much better into the battlecruiser category than the battleship category that the Japanese Navy gave her.

Now, onto a bonus round where we look at an article about why Battlecruisers sucked in battle. An article that, if we were to be honest, is about as much usefulness in understanding battlecruisers as the US Intelligence in 1942 in understanding the specifications of the Yamato.

Here is the link to the article: http://www.wearethemighty.com/articles/ ... in-a-fight

Now, here is my defense of the Battlecruisers mentioned.

First off: Akagi is not a battlecruiser. She was an aircraft carrier and thus shouldn’t even count. If she is to count, then it should be assumed battleships are failures since Kaga was converted from a battleship hull. So let’s get her off the table right away. She was a carrier, not a battlecruiser so she shouldn’t be in this discussion.

Second, the reason why Battlecruisers suffered during the Battle of Jutland was either they were facing far superior numbers, like the German Battlecruisers versus the rest of the Grand Fleet during their Death Ride, or due to the poor handling of cordite on the British battlecruisers. Poor armour protection on the British ships was not the main reason as to why their battlecruisers explode in such spectacular fashion, though it certainly didn’t help their situation against massive caliber shells.

Hood versus Bismarck was not only a lucky hit on the German’s part, but also what happens when you pit a ship against another ship of comparable size and firepower that is 20 years more modern.

As for the other three ships of the Kongo class that were the main target of the article: well the three ships did not survive the engagements nor did they did particularly well. But let’s try to defend them and their lack of success.

Hiei was lost to air attacks after being damaged during a naval engagement. This by this time should not come as too big of a shock. Just a year prior the more modern HMS Prince of Wales and the equally outdated battlecruiser Repulse were both lost of air attack and both ships started off the battle as undamaged as well, though their fire controls and internal temperatures were not the best state in the tropical environment. And given the lackluster performance of the Japanese 25mm AA/AT guns along with its FCS during the war, it is no surprise that the Hiei would suffer a similar fate. Disappointing? Not really. Unexpected? No.

As for the naval battle prior to her sinking, it is definitely not the shining moment for the Hiei as she was struck by 3 destroyers and some torpedoes. But considering that her sister would succumb to the same number of torpedoes later in the war and she was still afloat shows that she wasn’t completely helpless in the battle. And she did survive the encounter if not badly damaged due to multiple fires and damage to the steering gear.

Makes you wonder why people continue to call these ships battleship but I have already gone through that.

Kirishima was a case of what happens when you pit two modern battleships against one old battlecruiser. It was an even more uneven fight than Hood vs Bismarck. Hood was less older compared to Bismarck compare to Kirishima and South Dakota and Hood’s design was more in line with the fast battleship concept with capable armour protection and high speed. Kirishima’s design was just high speed and no armour. And if we consider the guns, while Bismarck’s guns were better than Hood’s, at least Hood had the same number of guns and the guns were of the same caliber. Compare to the US battleships, Kirishima had not only a smaller caliber that were of an older design, but she had less of them: 8 vs 9. It would be very disturbing if the Kirishima came out on top of this engagement and to the surprise of no one, she was the one sunk in the end.

It would be like pitting the HMS Duncan, a pre dreadnought battleship, against two Orion class battleships which were two generations more advanced than Duncan. It would be a nasty shock if the Duncan was able to win the battle.

Kongo’s loss to just two, or possibly one torpedo hit as some sources claim, was not exactly the first time a battleship was loss to minimal damage underwater. To be fair to HMS Audacious though when she was sunk after hitting just a single sea mine, considering warships at her time placed very little emphasis on defense against underwater explosions her loss wasn’t that disturbing once the facts are taken into consideration.

However, the HMS Barham is a good example to compare Kongo’s sinking to. Like Kongo, Barham was constructed during World War One and was modernised in the interwar period. She was a Queen Elizabeth class battleship and yet, despite the additional protection added against torpedo attacks, like with Kongo, she was sunk by just 3 torpedoes. And she sunk in less than 6 minutes whereas Kongo was sunk in about 150-160 minutes of the torpedo strike. If anything the Kongo handled the torpedo attack better than the Barham so the logic that Kongo’s sinking indicates the failures of battlecruisers is not exactly holding much water.

All in all, this article fails to actually talk about why battlecruisers were failures by giving examples that really don’t prove anything other than old ships are not as good as modern ships. Japan’s battlecruisers were not failures, in fact, they were highly successful compare to the other battleships during the time, and only fell apart in situations that ranged from just not in their favour to one sided not in their favour.

Well, that is my opinion on the classification of the Kongo class. What are your opinions of the matter. Let me known in the comment section and give me some good reasons. Until then, this is the AbyssalKageryu signing out.

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Re: Kongo Class: Fast Battleship or Battlecruiser

Postby paul.mercer » Fri May 04, 2018 9:01 pm

Hi there,
A most interesting post, I hope that our resident experts will reply in kind.
One small point you said
@Sleek. Fast. Powerful. The main reason why Iowa was ever created. And most importantly: waifu material. These descriptions all refer to one of Japan’s most famous class of warships: The Kongo class.'
I'm not sure that a Kongo would get anywhere near being a match for an Iowa.
Comments please Gentlemen!

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Re: Kongo Class: Fast Battleship or Battlecruiser

Postby VoidSamukai » Sat May 05, 2018 2:37 am

Well the US created Iowa to counter the Kongo class because the Kongos were so fast compare to the other US Battleships at the time. Even the faster of battleships could make only 27 knots compare to Kongo's 30 and the Standards were even worse at only 21 knots each. As such , the Iowa created the Iowas to be fast enough to catch and destroy the Kongos.

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