After the battle cruiser was completed, Sun Hao then thought of the underwater submarine, as for the destroyer, Sun Hao felt that he could just build dozens of advanced power, armor, and firepower. Originally, destroyers could not dominate the victory or defeat of naval battles, and destroyers in World War II were even more responsible for hunting submarines and air defense.

Sun Hao did not expect much from the destroyer, but he attached great importance to the submarine, and Sun Hao knew that the potential role of the submarine was incomparably huge. Whether it was World War I or World War II, the role of submarines is self-evident. Britain was even miserable by German submarines, and both merchant ships and surface ships were killed by German submarines.

When it comes to submarines, whether it was World War I or World War II, the most eye-catching performance was the German U-boat. However, Sun Hao felt that the German submarine had the best record, the ability was that of the Kou country, and the comprehensive technology was that of the United States, but the submarines of these two countries were not as eye-catching as the German submarines, because these two countries had aircraft carrier formations.

German submarines mainly sank merchant ships, and very few destroyers and cruisers were sunk by German submarines. Most of the submarines in the United States are to gnaw hard bones, and her main opponent is the battleship, and the only regret is that the torpedo technology of the United States was very imperfect in the early stage of World War II.

The performance of the US submarine is not bad, and to a large extent, it also takes advantage of the low anti-submarine capability of the Kou country.

Of course, the US submarine is indeed better than the German submarine of the same period before XXI in terms of comfort and staying power. These submarines of the United States sabotaged trade between Kou and Germany, blocked the transportation of strategic materials, and became the behind-the-scenes heroes of the victory of the war.

In the early days of the Pacific War, due to the heavy losses caused by the Pearl Harbor incident, the Pacific Fleet did not have enough warships to stop the aggressive offensive of the Kou State, and the submarine forces (mainly the Gato-class) launched the famous "Wolf Pack Operation" to attack the communication line from the Kou State to the Pacific Islands, giving the Pacific Fleet valuable time to prepare for war, and was able to turn the tide in the later Battle of Midway and the Battle of Guadalcanal, and finally defeated the Combined Fleet of the Kou Nation.

In the Philippine Sea Naval Battle, the USS Horse Mackerel (SS-244) sank the aircraft carrier "Xianghe" of the Kou Navy, and the USS Mackerel (SS-218) sank the aircraft carrier "Dafeng", achieving a more brilliant record than the aircraft carrier of the United States in this battle (the aircraft carrier unit only sank one "Flying Eagle").

In the Battle of Sibuyan in the Battle of Leyte Gulf, the Sea Carp (SS-227) defeated the heavy cruiser "Atago", and the Minnow (SS-247) attacked the heavy cruiser "Maya".

It can be seen from this that the US submarine poses a huge threat not only to transport ships, but also to warships with combat effectiveness. On the other hand, the improved Balaou-class Kayu (SS-328) sank the light cruiser Isuzu, and the Shooting Fish (SS-311) sank the aircraft carrier Shinano (converted from the Yamato-class battleship, which was more than twice the size of all aircraft carriers in the world at the time) before the end of the war. ）。

The Garao (SS-368) sank the light cruiser "Tama", the USS Redfish (SS-395) sank the aircraft carrier "Yunryu", the Atlantic Pomfret (SS-411) sank the aircraft carrier "Condor", and most of the destroyers and coastal defense warships carrying out anti-submarine missions in the Kou Kingdom were also sunk.

During World War II, the Chinese submarines sank a total of 1,113 merchant ships of the Kou Army, with a total tonnage of more than 5.32 million tons. This does not include the sinking of other hostile countries.

According to the analysis of historical experts, in fact, Germany had a certain advantage in Seiko back then, and there is really no record of Germany being very strong at that time in other aspects.

On the contrary, the main reason for Germany's provocation of World War II was its economic crisis, the country's economy was on the verge of collapse, and the unemployment of domestic workers seriously threatened the Nazi rule, so the best way for the Nazis to reverse this sentiment was to vent the anger of the people on the war.

On the one hand, you can vent your anger and on the other hand, you can revive the national economy by plundering resources through war, which is a good thing that kills multiple birds with one stone, but you can't stop the car while fighting, and you forget your true strength and purpose.

At the beginning of the war, Germany's military strength was not the largest, and Britain's military strength in Europe at that time should be the strongest.

The reason why Germany gives people the feeling of invincibility and runs over the land of Europe like a bulldozer is that the war came suddenly and other countries did not do enough to defend themselves, and the other is that the weak attitude adopted by European countries, especially Britain and France, indulged Germany, and it was Germany that got carried away and burned the war all over Europe without any care.

At that time, the German navy was not strong, and there was no concept that the naval battle was already the aircraft carrier integrated fleet was about to dominate the sea and defeat it, and seeing that the submarine had achieved good results, it was crazy to study and build submarines.

Aircraft carriers were a new thing at that time, the Germans were more enthusiastic about artillery giants before World War II, battleships were the mainstream at that time, and the future of aircraft carriers was not very clear.

In contrast, Yamamoto 56 of the Combined Fleet of the Kou State is much more astute, and it is precisely under his vigorous advocacy that the Kou State will mobilize the strength of the whole country to build aircraft carriers, and only then will the Kou Navy after Pearl Harbor run rampant in the Pacific Ocean.

Similarly, there is the idea of building armored clusters, and Guderian in Germany is Yamamoto Fifty-six in the German Army.

We can't look at the pre-World War II perspectives with today's thinking. Before the war, countries were still immersed in the thinking of the decisive battle of the fleet and the cannons of giant ships, and the aircraft carrier was just a partial division in the fleet establishment.

It was only the success of the Kou people that made the aircraft carrier highly valued by various countries, but the Kou country at that time did not get rid of the idea of cannon giants, otherwise it would not have used the strength of the whole country to build the Yamato and Musashi battleships.

In the later period, the German Navy still attached great importance to aircraft carriers, but unfortunately encountered an Imperial Marshal who was under his control of even flies, making trouble everywhere and trying his best to restrain him, and he did not accept the fact that the aircraft still had to be under the command of the Navy, which greatly delayed the development of aircraft carriers.

In hindsight, Germany's neglect of aircraft carriers was a major strategic mistake, and although Dönitz's wolf pack caused an earth-shattering and seemingly lively attack in the Atlantic, it did not actually affect the amount of aid received by many allies, and if Germany had an aircraft carrier fleet and used aircraft to attack Allied transport lines, the effect would obviously be very different.

For many reasons, Germany vigorously developed the road of submarines.

But during World War II, the countries that were really powerful in submarines were not only Germany, but also Kou and Mi. The power of German submarines is mostly due to the movie propaganda of later generations, which created the world's concept that German submarines are very powerful.

It is worth mentioning the amphibious assault ship that evolved from the Akitsu Maru, to the strategic nuclear submarine that evolved from the I-400 class, the fireboat in the amphibious tank, and the oxygen torpedo with a range longer than the gunboat. In fact, the Kou people also have a big brain, but they are also very flexible and can solve problems. If it weren't for the resource and war constraints, the technology of the Kou people would be terrifying.

The design of the I-400 to the service to overcome the difficulties is simply breathtaking. A submarine can't carry a hangar to make a chain ship, the plane takes off not enough to use a catapult, the aircraft engine needs to be preheated before it can be started, and the fuel is directly preheated, so as to avoid the danger of staying on the surface for a long time and the carbon monoxide released by the underwater preheating engine cannot be dispersed.

It's a pity that the powerful submarines of the Kou country were born at the wrong time, and there is no record at all, after the surrender of the Kou country, these powerful submarines were either towed away by the United States or sunk into the icy seabed.

However, at that time, the United States towed the I-400 and I-401 and I-402 boats to the mainland of the United States for further research, and later built a more powerful diving aircraft carrier than the I-400, with a displacement of more than 40,000 tons, which can carry more than 40 aircraft, and the take-off platform is the back of the submarine. The back of this submersible aircraft carrier is built directly into the flight deck of the aircraft carrier, through which the aircraft can take off and land directly.

It's just that there was no concept and technology of stealth at that time, and the submarine aircraft carrier had no power to fight back against the depth charges of the enemy's anti-submarine warfare ships. The huge submarine aircraft carrier has great strategic value, but due to the poor defense performance and high cost, the United States finally gave up the submarine aircraft carrier and concentrated on the development of water aircraft carriers.

The Gatto-class submarines of the United States in World War II are actually very strong in combat, but later movies rarely publicize their achievements. The Gato-class submarines sank the world's largest aircraft carrier at that time and assisted in sinking the world's most powerful battleship at that time, which shows that their record is also very strong.