Iron Cross

At this time, Japan was not aware that Britain and the United States had deployed so many troops to deal with the Yamato class, but due to the development of the war in the South Pacific, the fate of a series of warships also changed: the Yamato, which was hit by five torpedoes, left the fleet accompanied by three destroyers to return to the country for repairs after hastily replenishing in Rabaul, and the Musashi, which had been officially commissioned, was ready to depart from the mainland to Singapore and prepare to serve as the new flagship of the Combined Fleet; due to the sinking of the Fuso, Hori Teikichi simply let the slow-moving Yamashiro leave the 2nd Fleet and join the 8th Fleet's combat sequence, and asked the 8th Fleet's remaining troops to maintain the security of the South Pacific, where the troops had been greatly reduced (poor Mikawa Gunichi); since there were only three battleships left in the 2nd Fleet (Nagato, Mutsu and Musashi), considering that the Indian Ocean attack force was insufficient, at his strong request, the Ise and Hyuga, which were originally planned to be converted into aviation battleships, canceled the subsequent conversion tasks, and together with the Musashi, they were urgently supported and incorporated into the 2nd Fleet.

The No. 5 turret of the Hyuga, which exploded in an artillery training accident in mid-May, was still damaged at this time. Due to lack of time for repair, the turret could only be hastily removed and a steel plate was covered at the opening to install a new 25mm triple machine gun on it. However, the two Ise-class ships did not get any benefits in the past few months. Before participating in the Aleutian Campaign, the Hyuga tested and installed the No. 22 sea warning radar. When returning to Japan, it still maintained the correct route for the fleet in bad weather. Captain Chiaki Matsuda strongly advocated this, while the Ise tested and installed the No. 21 air warning radar, and the effect was said to be good. Therefore, the two ships installed the No. 21 and No. 22 radars before leaving the mainland. Only these two old ships in the hundreds of warships in the entire Combined Fleet got this benefit.

The victory in the South Pacific naval battle had an all-round impact on the subsequent development of the Japanese Navy: in view of the outstanding performance of the Yamato in this battle, the plan to convert the third ship of the Yamato class (Shinano) into an aircraft carrier was suddenly abandoned. Instead, everyone changed their position and advocated continuing to build it as a battleship. Even Yamamoto Isoroku and Hori Teikichi held this view, and hoped that it could be completed before the end of June 1944. Therefore, the construction of the Shinano, which was supposed to be suspended for reconstruction, was not only not stopped, but also accelerated. The two seaplane carriers Chiyoda and Chitose The ship was to be converted into a light aircraft carrier, but the seaplane reconnaissance planes discovered the enemy first in this battle, which was of great significance to the entire battle. The two ships, which had 24 seaplanes and could provide an additional 1,000 tons of fuel, suddenly highlighted their value to fleet operations, and the Navy Ministry eventually gave up the idea of ​​conversion; Ibuki was one of the Suzuya-class heavy cruisers, and was originally planned to be converted into an aircraft carrier. Because the heavy cruisers were of great value and three Aoba/Furutaka-class heavy cruisers were lost in the Guadalcanal Battle in recent months, the conversion task was simply abandoned and the ship was built as a heavy cruiser.

There was resistance within the Navy Ministry to abandoning a large number of reconstruction tasks, but the attitude of the mobile fleet commander Tsukahara Jishizo was very clear. What was most lacking now was qualified aircraft carrier pilots and excellent carrier-based aircraft. It would be troublesome if a lot of aircraft carriers were built without aircraft or pilots. Hoffman privately expressed his appreciation for this pragmatic attitude. Historically, Japan had many aircraft carriers in the Marianas Campaign, but there were no aircraft carriers available. The aircraft carriers that were built with great effort finally became baits. It must be said that it was a huge irony.

For the Combined Fleet, aircraft carriers were still in urgent need. After a series of reconstruction plans that were abandoned halfway, the materials originally prepared for the reconstruction of aircraft carriers became abundant. At the same time, based on the great value of aircraft carriers, the Navy Ministry's urgency for the construction of regular aircraft carriers of the Yunlong class increased significantly, and all materials were guaranteed first. Therefore, the construction speed of the three ships of Yunlong, Amagi, and Katsuragi began to speed up. According to the idea of ​​the Military General Staff, it would be best if they could be put into service by the end of 1943. In order to speed up the progress, a group of people racked their brains for this. Since the drawings of the Yunlong class had been sent to Germany for reference, someone in the Shipbuilding Headquarters suddenly thought that they could entrust Germany to manufacture the components and prepare to transport them back for installation after the Indian Ocean campaign. After contacting Hoffman, he also expressed his approval, because Germany was also preparing to start building a new aircraft carrier in the Italian shipyard with the Yunlong class as the master version, and the two sides hit it off. According to the agreement between Japan and Germany, this finished component is converted according to the 3:1 ratio of special steel in the Japan-Germany agreement (that is, Germany can provide components at one-third of the tonnage of special steel). Both sides have made a good calculation - for Japan, this is a free pick-up, and for Germany, it was originally promised to provide it to Japan. Providing finished products not only reduces the consumption of special steel but also accumulates manufacturing experience. If Japan does not want it in the end, it is okay, and it can be used by itself.

Finally, someone had a brainwave and thought that since the aircraft carrier components can be made by Germany, why can't the Yamato-class components, especially the armor belt, be made by the Germans? The German Krupp company is very experienced in this, and Japan's construction level and experience were learned from Germany. However, there is still controversy among the navy itself as to whether to provide the Yamato blueprints to Germany (Hoffman said: I don't want the Yamato, just give me the Gale blueprints for practical use)

The last ship that changed its fate was the German luxury passenger ship "Scharnhorst", which was a fast cruise ship built by the North German Lloyd Company. Due to the outbreak of the European War, the ship could not return to Germany and remained in Kobe. The Japanese Navy had contacted Germany to buy this ship and prepared to convert it into an aircraft carrier (agreeing to pay after the war). Since other plans to convert aircraft carriers were cancelled, the ship naturally got rid of the conversion task and was used by the Navy as a troop transport ship, and even the purchase procedure did not have to go through. The Japan-Germany agreement stipulated that Germany would give Japan 1 million tons of ship tonnage, which was converted into the first batch of 12,000 tons.

Due to the powerful Japanese destroyers of all levels and their outstanding torpedo performance in this naval battle, they had little use except for searching and rescuing pilots who fell into the water. Instead, they found that the fleet's air defense force was extremely weak. In addition, in the early Guadalcanal operations, various types of destroyers not only did not find the feeling of night battles and torpedo battles, but repeatedly gained the upper hand in playing the role of mouse express, so the development ideas of the Ship Administration Headquarters were shifted. The production task of the Shimakaze class was cut, and the production task of the Akizuki class air defense destroyer was increased. Unlike in history, due to the close bilateral relations between Japan and Germany, the Akizuki class went to another extreme. The main gun design changed from 100mm to the German 88 gun, and was prepared to use both high and low-altitude dual-purposes, and the torpedo tubes were completely cancelled. The whole improvement idea was called the Akizuki modification. In addition, because Japanese ships were repeatedly sunk by American submarines, considering the high-density frequency of trade and material transportation with Germany in the future, the navy proposed the construction requirements of anti-submarine destroyers. According to the requirements of weak anti-ship firepower, slightly inferior air defense capabilities, relatively outstanding anti-submarine capabilities, average speed (escort mission speed does not need to be fast), and the construction cost is as low as possible (because it needs to be built in large quantities), the development idea of ​​the D-type destroyer (that is, the British and American escort destroyer) was proposed, and it was decided to build the Matsu-class and Orange-class destroyers.

In the design process of the D-type destroyer, in order to adapt to mass production, the design of each part was simplified. For example, in order to reduce the difficulty of construction, most of the hull curves were changed to straight lines. In addition, the material grade used has also declined. In the past, Japanese destroyers used different strategies for hull structural materials to reduce weight: DS steel (special steel) was used in key parts, and the thickness of the plate must be reduced if possible. However, DS steel has poor productivity and is difficult to weld. In order to reduce costs and make way for other ships, the D-type destroyer completely abandoned the use of DS steel and used a large amount of HT steel (high-tensile steel) to replace DS steel. Even HT steel is saved as much as possible. Its use is limited to the upper deck and part of the outer plate of the bottom of the ship. The remaining parts are all replaced by MS steel (ordinary steel). Based on this position and based on the scenario of large-scale transportation needs in the future, the Shipbuilding Headquarters was also very interested in the Will Wheel promoted and built by Germany. On the one hand, it directly took the drawings to imitate them, and on the other hand, it planned to carry out Japan's own simplified design according to this idea (Japan is notoriously stingy). From the perspective of construction period evaluation, if built according to German drawings, the speed of Japanese shipyards may not be as fast as that of Germany, but it is more than enough to exceed Italy, France, the Netherlands and other countries.

Originally, the Japanese Navy's "Reform Plan 5" was unable to take into account the large-scale production of new ships, reconstruction of old ships, and repair of damaged ships at the same time due to the limited capacity of the shipyards, resulting in far fewer new ships than damaged warships. However, the victory of the South Pacific Campaign changed history, allowing Japan to cancel a large number of reconstruction tasks and get rid of the task of repairing a large number of damaged ships. Not only can the subsequent new construction plans be completed ahead of schedule, but in turn, some ships that were forced to be discontinued can be completed on time (such as Ibuki).

In addition to warships, the situation of aircraft also underwent major changes. When Ozawa's three-man team sent back the news of the great success of the improved version of the Zero fighter (Bf-119) to the country, the Naval Aviation Headquarters, which was deeply touched, immediately became interested. They immediately thought of the "Tien Shan" carrier-based attack aircraft and the "Comet" carrier-based explosive aircraft, which had advanced indicators but had never been used on ships. Of course, the problems of the two were different: the problem with the Tianshan was that it was too heavy and difficult to take off, and the problem with the Comet was that it was too fast and landing became a problem (the Comet often rushed ahead of the Zero fighter in the Battle of the Marianas). The ultimate reason was that Japan's technical accumulation in the field of aviation development was weak. Therefore, the drawings were immediately handed over to Germany, hoping to rely on external brains for improvements.