On the same day, Tan Renhao handed over the analysis report on the United States that they had summarized during this period to General Gan Yongxing. Gan Yongxing also organized a group of staff officers and personally led these staff officers to make a detailed analysis of the preparations that the Imperial Navy needed to make before the war with the United States and the difficulties that the Imperial Navy might face after the outbreak of war, and formulated a series of battle plans in advance. This is precisely the essential work of the Naval Staff.

In the following days, Tan Renhao focused on collecting the submarine forces of the Imperial German Navy. At that time, the German Empire and the Tang Empire had an intelligence-sharing agreement, and both sides would exchange war reports in a timely manner. Every two days, a piece of information transmitted by the Ministry of Foreign Affairs arrives at the command of the Navy. Tan Renhao, they can only use the information provided by the German Navy to judge the situation in the Atlantic.

It can be said that the Imperial German Navy is the ancestor of submarine warfare. After the birth of submarines, many countries were suspicious of this new type of warship (the Tang Empire was no exception), and some traditional naval powers also considered submarines to be a "despicable" warship, a warship that could only be attacked from behind, and was not worthy of participating in naval battles. These views are all extremely wrong, war is used in all its extremes, and the word "despicable" does not exist in the dictionary of war.

Before World War I, in addition to spending great efforts to form a high sea fleet to counter the British Grand Fleet and seize the control of the Atlantic Ocean, Germany also made great efforts in submarines, and before the outbreak of World War I, the German Navy formed a force with more than 30 submarines, which was also the most powerful submarine force in the world's navies at that time.

In World War I. The German Navy made a lot of efforts to break the British naval blockade (in order to obtain the assistance of the Tang Empire) and complete the naval blockade of Britain (the most effective way to defeat the British), the German High Seas Fleet made great efforts, but after the Battle of Jutland (the Germans won a tactical victory, but the British firmly grasped the strategic superiority), the High Seas Fleet was no longer able to move forward to the North Sea. Challenge Britain's maritime supremacy. From this time on, submarines became the sharpest weapon in the hands of the German Navy. And the German Navy also began to develop submarines in full force.

Since the outbreak of World War I, the submarines of the German Navy have been carrying out combat missions to blockade the British maritime lifeline, and by 1298 (1916 AD), the submarine forces of the German Navy have sunk more than 3,500 British merchant ships with a total tonnage of 12 million tons, which is almost half of the total tonnage of merchant ships owned by Britain before the war! By 1300, the German Navy's submarines had sunk 23 million tons of enemy merchant ships. Britain was almost completely paralyzed. Had it not been for the United States' intervention in the war (Britain had exchanged its military rights in the Bahamas for 120 old destroyers and received a large amount of military aid from the United States), Britain would have been defeated in '01, and the outcome of World War I would have been very different.

It was precisely because of the crazy performance of German submarines during World War I that during the post-war peace talks, Germany, Britain and France reached a regional agreement, and Germany retained only 80 submarines after the war, while Britain promised not to send the Grand Fleet into the German side of the North Sea in peacetime. France, for its part, pledged not to exceed 100,000 on the west bank of the Rhine (within 20 km). Later, in the "Songjiang Naval Armaments Treaty", because of the strong advocacy of Britain, France and the United States, restrictions on submarines were written into the treaty. Of course, after the war, no country strictly implemented the treaty, and still less did any country relax its armament development.

On the eve of the Great War, before and after the expiration of the Treaty of Matsue. The German Navy accelerated the expansion of its navy, of which the submarine force accounted for the lion's share. It was at this time that the Type 7 submarine was launched, and after the construction of the first two submarines, the German Navy ordered 78 submarines in large quantities, and then placed a second order three months before the war, bringing the total number of submarines to 160. On the eve of the outbreak of the war, the German Navy already had 59 Type 7 submarines (dozens of other submarines were too small and too short in range to carry out ocean-going operations).

In the first year of the war, German submarines set a new World War I record. From mid-August 21 to early August 22. German submarines sank a total of 786 enemy (including neutral) merchant ships with a total tonnage of 6.5 million tons on the Atlantic route. And in World War I, the annual record for German submarines was 6.2 million tons. During the year, Germany lost 38 submarines and added 149 new submarines. In other words, in the first year of the war, the German submarines caused Britain and France to lose 30% of their merchant ships and choked the British and French land.

In fact, the results of the German submarine forces during the year were mainly concentrated after March 22. In the four months from March to early August, German submarines sank 498 merchant ships, with a total tonnage of 4.2 million tons. The reason for the "brilliance" of German submarines is that since March 22, German submarines have changed their tactics, from the previous individual "hunting" to group operations, often concentrating several submarines or even dozens of submarines to attack the merchant fleet covered by escort warships, and this tactic has been vividly called "wolf pack tactics".

1 year of submarine warfare was not cruel, at that time the scale of the German submarine force was very small, and the submarines that could carry out the combat mission of breaking diplomatic relations in the ocean were actually more than 40 (part of the Type 7 submarines were assigned to the training unit), and at that time the British Navy controlled the exit of the North Sea (Shetland Islands), German submarines were in danger before passing through the North Sea and entering the North Atlantic, and the losses were extremely heavy, and many submarines were discovered and sunk by British anti-submarine patrol aircraft and anti-submarine ships before they advanced to the predetermined sea area.

At the end of 1, Germany sent troops to capture Norway, and by the beginning of 22, Norway was defeated, and the German submarine forces received the coveted, Atlantic-oriented submarine base. The purpose of the German occupation of Norway before the British sent troops was to allow submarines to enter and exit the North Atlantic freely, so that the submarines could block the British sea routes

It was from this time that the energy of the submarine forces of the German Navy burst out. By the beginning of 22 years. The number of Type 7 submarines in the German Navy that could carry out combat missions reached 89 (another 12 were used for training), and Dönitz (the founder of the German Navy's submarine "wolf pack tactics") also became the commander of the German Navy's submarine forces in this year, and immediately issued a new combat order.

The "wolf pack tactics" are actually not complicated. The German Navy first set up patrol areas for submarines, and this area was generally a necessary route for the merchant fleet. There are generally several to more than a dozen submarines in each sea area. If a submarine discovers a merchant fleet, it immediately summons other submarines by radio (normally, a submarine telegram is first sent to the German Naval Submarine Command, which then forwards the telegram to other submarines in the nearby seas). At that time, there were no effective means of communication between submarines), and then a preset sea area waited for the arrival of the fleet. And in general. The submarine that first discovered the merchant fleet would be in charge of tracking and constantly reporting the position, navigation, and speed of the merchant fleet. Attacks are generally carried out at night (this must be taken into account when choosing the sea area to be attacked). In the event of an attack, there are usually two or three submarines responsible for diverting the escort destroyers (almost all of these submarines go to the dead, but many of them do come back alive, and the submarines under the command of the best submarine captains usually do this task). After the formation of the escorting destroyers was disrupted, other submarines swarmed up again, quickly resolved the battle with torpedoes and artillery, and withdrew before dawn. If the attack is not completely successful, another attack will be organized the next night, or other "wolf packs" will be called in to organize another attack on the next leg of the flotilla's course.

This tactic is very effective, much more efficient than the previous solitary "hunting". It was also from this time that it began. German submarines became the "sea wolves" in the North Atlantic, the killers of the British and French merchant fleets, and the big hand that choked the lifeline of Britain.

It can be said that the submarine forces of the Tang Empire were divided from the German submarine forces. In the blockade operation against Japan, the submarine forces of the Tang Empire absorbed the experience of the German submarine forces. In the North Pacific theater, the "sea wolves" of the Tang Empire were also after adopting the "wolf pack tactics" (starting in May 22). Japan's aid has been drastically reduced, and Japan has shown its weaker side. If there are no submarines, I am afraid that if the Tang Empire wants to **** Japan, it will have to wait until at least the end of 23 years.

The frenzied attack of German submarines (Don Imperial submarines) finally changed the position of the United States in the war. In the first half of '22, German submarines sank eight American-flagged ships (all of which were registered in the United States) in the attack, and in the same period, the submarines of the Don Empire also sank five American merchant ships. Under the International Maritime Law, an attack on these vessels is an attack on the United States. As a result, in July 22, the United States almost entered the war because of this.

At the end of July. Tang, Germany, and the United States began negotiations on the issue of submarine operations in the Atlantic and Pacific Oceans. At this time. The United States was not capable of entering the war (the American Congress would not rush into the war because of an attack on merchant ships, otherwise in World War I. The United States had already entered the war), and the Tang Empire and the German Empire did not want to get into trouble with Xindi at this time (the Tang Empire was going all out to take out Japan, and the German Empire, after withstanding the attack of the Anglo-French forces, had to block Italy in the south and meet the Russian Empire in the east).

In July, the negotiations almost broke down (in '22, when the United States was most likely to enter the war), but both sides made concessions, and the talks finally ended in September. Both the Tang Empire and Germany pledged not to send submarines into the routes of the United States to attack merchant ships, and the United States also promised not to send escort warships to the side of the theater, and all ships carrying supplies to the belligerents were not allowed to fly the American flag to avoid misfire.

This agreement was beneficial to both sides, and it was at this time that German submarines had been operating in the waters east of the Mid-Atlantic (at Glenwich Zero, 32 degrees West), and this invisible line became the life and death line of the British and French merchant fleets. The escort warships sent by the U.S. Navy were only responsible for sending the merchant fleet here, which was then taken over by British and French escort warships. To the east of this line, German submarines could attack any ship with impunity.

By the time the U.S. Congress passed the Lend-Lease Act (mid-23), Britain and France had lost more than half of their merchant ships, and although the shipyards in Britain and France were already working at full capacity to produce new transport ships (and even canceled the construction of many warships for this purpose) to replace the lost merchant ships, the rate of replenishment was still far from keeping up with the rate of loss. By June '23, Britain and France had quickly acquired a large number of merchant ships from the United States (most of them old ships, some of which had been built before World War I), but Britain and France were almost unable to support them.

The United States passed the Lend-Lease Act at this time to help Britain and France tide over the difficulties, which actually gave Germany and the Tang Empire a reason to declare war on the United States. As a result, the Tang Empire endured, and it was impossible for Germany to declare war on the United States alone. The Lend-Lease Act did not have much impact on the Tang Empire, because the Tang Empire's navy had already turned the tide at this time and was completing the blockade of Japan, and the Tang Empire had enough strength to trap Japan so that none of the American ships could reach Japan. On the contrary, the German Navy's high seas fleet was still incapable of challenging the British and French navies, and the blockade of Britain and France could only rely on submarines, which in turn could only deal with merchant ships.

"Actually, we have already stopped Germany once." Tan Renhao's comprehension ability is super strong, and he has already found the way from these seemingly irrelevant information. "Germany has endured it for several months, and now that we have basically solved the Japanese problem, and the focus is shifting to the west, Germany has started unlimited submarine warfare again, probably Germany has endured enough!"

"You mean that it is impossible for us to prevent Germany from stopping unrestricted submarine warfare?" Hao Dongjue didn't see things as they really were so quickly.

Tan Renhao nodded slightly. "The Kaiser must have held back for a long time, and Germany must have misjudged our strength. Now the purpose of their unrestricted submarine warfare is to force the British and French to death, to try to kill the French first, and drive the British back to the island. But the crux of the matter is not in the Atlantic, but on our side! ”

Both of them were silent, the Tang Empire and the United States were the two protagonists in this war, and Germany's actions would inevitably upset the balance, and when the time came, it was uncertain who would die!