Berlin, Linden Strasse Scholssplatz Palace.

Fifty-seven-year-old Kaiser Wilhelm II reclined on a red-cushioned throne in his military uniform, his right hand covering his white-gloved left hand, which had been atrophied by polio at birth and would remain as smooth and shiny as ever.

On either side of the long oak table in front of the emperor, there are columns of Prime Minister Bateman. Holvik, Minister of the Admiralty and Commander-in-Chief of the German Navy, Alfred Holwick. Feng. Field Marshal Tirpitz, Chief of the General Staff of the German Army, Erich. Feng. Field Marshal Falkingham, Chief of Intelligence of the General Staff, Colonel-General Ludendorf, Chairman of the Military Reform Commission. Feng. Colonel-General Khordotsev and other important military and political figures.

Once or twice a month, Wilhelm II, the self-appointed Generalissimo of the German army, was not only nominally commander-in-chief of the German army, but in fact held the supreme power of the country, he was free to appoint officials, and he had the most important military directives, for which he had to keep abreast of the changing situation as much as possible – although in general he could only obtain reports from trusted ministers and generals.

Prime Minister Holvik has just reported on the situation in the domestic affairs, and now it is Tirpitz's turn to speak.

The bald-headed, brain-led, two-broom-like beard of Field Marshal Tirpitz is the "father of the German High Seas Fleet", and since his appointment as Reich Admiral in 1897, the German Navy has grown from one of Europe's last coastal defense fleets to the world's first-class ocean-going fleet: by the time of the outbreak of the Great War, Germany was able to assemble 33 battleships against the British 61 battleships, of which the ratio of dreadnoughts was 15 to 27, in addition, the German Navy also had 5 relatively protective battlecruisers, To counter 10 lightly armored battlecruisers built in the British Navy based on Field Marshal Fisher's "speed is armor" philosophy.

A simple comparison of the British and German capital ship numbers is of no practical significance, because in order to defend its colonial interests in Asia, the British Empire must also draw considerable forces to contain the Chinese navy, which has risen rapidly after the Asian-Russian War, so that the disparity in strength between the German High Seas Fleet and the British Grand Fleet in the North Sea seems to be less than that great.

However, in the tragic Battle of the Dogel Sandbank, the High Seas Fleet lost 3 battle cruisers and the outdated armored cruiser Blucher, and the excellent commander of the reconnaissance fleet, Vice Admiral Hipper, sank with the flagship "Sedlitz", which directly led to the Kaiser's order that all capital ships should not sail out of the Kiel Bay without his permission.

Even more tragic was that the main forces of the High Seas Fleet, which were densely packed in Kiel military harbor on the orders of the Kaiser, were subjected to a sudden air strike, and the German bureaucrats, who thought that they could protect themselves from the threat of torpedoes by installing old mine nets on their battleships, could not have imagined that the British air-dropped torpedoes, equipped with new minehead cutters, would cause the terrible consequences of sinking or damaging 10 dreadnoughts in one morning - even worse than the damage caused by Chinese carrier-based aircraft during the raid on Pearl Harbor (excluding the obsolete former dreadnoughts, The U.S. lost a total of 8 dreadnoughts in the Battle of Pearl Harbor, but these losses became permanent because the squadron then captured Oahu in lightning).

For most of the next six months, the remaining warships of the High Seas Fleet took refuge in the depths of the Baltic Sea and served as extravagant coastal support gunboats under the threat of Russian mines. Even though the damaged warships were repaired one by one, and the newly completed battleships were put into service one after another, the will to fight lost in the battles of Dogle and Kiel was not restored for a long time, and the Kaiser not only forbade any capital ships, including battlecruisers, to enter the North Sea, but even did not allow more than eight capital ships to "anchor in Kiel Bay at the same time." ”

As a result, in addition to a few insignificant attack ships, only the U-boat unit, which had been prominent since the beginning of the war, remained in the ocean.

At the beginning of the war, the German Navy had only 28 submarines numbered with the letter U and numbers, of which 4 were unsuitable for combat, 4 were under refurbishment, and the remaining half were old kerosene-powered submarines. By comparison, the French Navy had 38 submarines, the British 76, and the Russian 23 – although most of them were older and inferior to the Germans.

There were many shortcomings in the performance of early U-boats: slow speed, limited range, and short dive time. It usually enters the patrol sea area by surface navigation, finds the target by luck, and then approaches in a submersible state through complex route calculations, and uses naval guns to attack after launching torpedoes underwater or floating according to the situation. The noisy and constant smoke of the U-boats in the surface state is enough to alert the enemy at a distance, and the lack of accurate underwater positioning equipment makes submarine operations difficult. All this made the Navy's top brass lack confidence in the nascent U-boat force, and certainly did not have high expectations.

In the first month of the war, the U-boat unit made several voyages in formation—each cruise lasted only five to seven days, due to range limitations—and not only did it achieve nothing, but also lost two submarines, many of which were forced to return early due to mechanical problems, which seemed to confirm Tirpitz's pre-war assertion that "Germany does not need submarines."

Then the situation gradually reversed: in early September, Otto. Captain Hessin's U21 was lucky enough to sink the British light cruiser "Pathfinder"; Two weeks later, Otto. Captain Wavedigan's U9 sank 3 armored cruisers of the British Navy's 7th Cruiser Squadron north of the Strait of Dover in one fell swoop, with a total tonnage of more than 36,000 tons, killing 62 officers and 1,397 soldiers; Three weeks later, Captain Wavedigan's 500-ton kerosene-powered submarine added the old protective cruiser Hawke to the list.

This series of victories proved the power of submarines, and the Germans cheered, but the British were terrified, and the home fleet was forced to leave the Scapa base and take refuge in the Irish seas - which was naturally seen as a small submarine defeating the world's most powerful fleet.

By the end of 1914, the German Navy's U-boat forces had sunk a total of 310,000 tons of Allied and neutral ships, and had lost only five submarines themselves. ”

After Pearl Harbor, the United States joined the Entente and declared war on Germany, which was the Kaiser's greatest fear and desire to avoid, but the enraged Emperor ordered an unrestricted submarine war on December 31, 1915, using the entire Atlantic Ocean as a theater of war, and any ship flying the flag of a hostile country, including the United States, was attacked without warning, and the most beautiful book city within 200 nautical miles of the coast of Britain and France was off-limits, and any ship that entered, even if it was flying the flag of a neutral country— Attacks are to be carried out without warning.

At the beginning of 1915, however, the size of the German U-boat force was still limited, and although new diesel-powered submarines began to enter service, at the beginning of the unrestricted attack war against merchant ships, only 30 submarines were available, and another 29 were under construction.

Even so, with the gradual resumption of use of Belgian ports occupied by the German Army, U-boat units could devote more time to combat patrols than to patrol areas from bases closer to the patrol area, or to advance the patrol area into the depths of the Atlantic Ocean to attack less easily protected routes.

At the beginning of the campaign, the U-boat force achieved great success, sinking 170,000 tons of various ships in the first month alone—not including the results of submarine minelaying, which sank more than 600,000 tons in the first three months, causing great panic on the part of the Allies.

However, since April, because Britain began to use aircraft and airships to carry out anti-submarine patrol missions on a large scale, and laid dense mine obstacle areas on the passage from German U-boat bases to the high seas, and British and American merchant ships have been equipped with artillery, the results of U-boat operations have not been further expanded, and the average number of sunk from April to June has remained at about 150,000 tons.

Beginning in May, at the request of China, Tirpitz ordered the dispatch of U-boat units into the Mediterranean to fight in order to disrupt British shipping to the East via the Suez Canal.

Due to the lack of anti-submarine equipment and combat experience in the Mediterranean, the 4th Submarine Detachment, which was based in the port of Bora (Austria-Hungary) in the Adriatic Sea and Constantinople (Turkey) in the Black Sea, sank 130,000 tons in July alone, breaking the record of 300,000 tons for the first time in the total number of U-boat units sunk that month.

In the second half of 15 years, as Britain and the United States put more aircraft and destroyers into the British coast to carry out anti-submarine patrol missions, and at the same time intensified the offensive and minelaying of U-boat bases along the North Sea coast, the losses of U-boats entering and leaving the North Sea continued to increase, Tirpitz then ordered more submarines to be put into the Mediterranean theater, in addition to a small number of ocean-going submarines smuggled into the Strait of Gibraltar, mainly to dismantle more inshore submarines and transport them to their destinations by rail.

In October of that year, the number of U-boat units in the Mediterranean rose to a record 218,000 tons, and the Suez Canal route was nearly paralyzed, achieving what the Turkish Army's frontal attack from the Sinai Peninsula had failed to achieve at the beginning of the year.

In the first 11 months of 1915, the U-boat force had a total of more than 2.5 million tons, at the cost of 49 submarines sunken or missing—far more than the number it had at the start of the campaign.

After the attack on Kiel, in view of the fact that there was only U-boat force left in the effective naval force that could be used to threaten the Entente, Tirpitz ordered that in addition to repairing the damaged warships in time, the construction of some capital ships should be suspended, and resources were freed up to build more submarines, and by the end of November of that year, the number of new submarines in service was 102, and the total number of submarines in service was still as high as 83 compared to the losses.

What Tirpitz did not know was that in another time and space history, although on September 15, 1915, Wilhelm II was forced by the United States to order the cessation of unrestricted submarine warfare, and the entire 1915 U-boat force still achieved a record of 1,307,900 tons of ships, and the price paid for this was 27 submarines. The number of submarines in service that year was 52, and by the end of the year the total number of submarines in the German Navy reached 54.

“…… Clearly, we are faced with a difficult choice: to seize the opportunity of the British Navy to suffer heavy losses after the Battle of the Bay of Bengal and try to return the High Seas Fleet to the ocean; Or go all-in on unrestricted submarine warfare, which now looks promising—at the expense of costly capital ship planning and giving up slipways and steel to tiny submarines? ”