Scapa Bay Naval Base is the anchorage of the Royal Navy's main fleet in the British Isles, located in the Orkney Islands, north of Scotland. The location is strategically important at the point where the German sea transport line enters and exits the North Sea.

Undoubtedly, the base also had some tempting targets for German submarines, and many battleships of the British main fleet were stationed here, such as the well-known battlecruiser HMS Hood and the battleship HMS Royal Oak.

But like other impregnable fortresses, Scarpa Bay was heavily fortified, and the British stationed a large number of troops here to defend it. On the shore defense, there were hundreds of large-caliber guns, and intensive anti-aircraft fire was also arranged.

And at sea, especially against a possible submarine attack. During World War I, the UB-116 submarine commanded by Urmsman infiltrated Scapa Bay in October 1918, but sank due to a mine, killing all of its crew. The operation led all senior British naval officials to believe that any attempt to breach Scapa Bay would be impossible.

But God is a god who doesn't like to brag about human, so anyone who brags and is firm in his thoughts will not end well. For example, all ships that are called unsinkable, such as the Titanic on its maiden voyage and Bismarck on its first battle, did not end well. The same examples include Pearl Harbor, which the Americans considered invulnerable, and the Maginot Line, which the French considered invulnerable......

In the words of Accardo's admonition to Submarine Force Commander Dönitz, any attacker "requires the most daring and aggressive spirit, extraordinary courage and great skill." So this time the Germans intended to take it by surprise. Even if they had to deal with not only the heavily defended Royal Navy, but also the unpredictable currents, which were powerful enough to put the submarine in danger by deviating from its intended course.

Accardo had been secretly working with Dönitz on a surprise attack, and both of them wanted to try to get a German submarine to dive into the waters of Scapa Bay and deal a heavy blow to the Royal Navy, so that the British would lose their advantage and collapse within a few years.

The reason why the Führer attaches so much importance to a tactical attack is not as superficial as Dönitz, because Accardo wants to use a successful attack to hide the killing move he really has in his hands.

The outcome of the naval battle off the coast of the Netherlands was confirmed as early as 1937 in Accardo. Although the German navy lacked the courage to fight a decisive battle and postponed the victory until the beginning of 1938, Accardo was already preparing for this victory.

One of the next steps was how to make the victory unforgettable, and this follow-up plan could be said to be an important step in Arcardo's disrupting the rise of the nation's maritime power. Accardo actually has a lot of fears in his heart, one of which is the fear of the United States destroying its production capacity without interference.

If American industry were to run at full speed, Germany might be able to compete without interference, but if the British blockade was added and dragged down, Germany would only return to the old path of defeat.

The geographical superiority of the United States cannot be changed, and Germany cannot threaten the American mainland for a while - this is a humble statement, in fact, Accardo also knows that let alone threaten the American mainland, he does not even have the strength to look at the east coast of the United States now.

On the other hand, once the powerful American industry is operational, Germany will have to face the threat of ten or even twenty American aircraft carriers. Accardo did not want to show the United States the right path to develop its navy so early, and he hoped to unravel this mystery as late as possible, so that the US Navy would be caught off guard.

Germany's steel was limited, and the war with France and Belgium had caused a break in Germany's steel imports, and the existing reserves were not enough for Germany to develop its own navy, land and air forces. Although Accardo vetoed the plan to build battleships and heavy cruisers under great pressure from the Navy, the steel saved was only enough for him to produce seven aircraft carriers. In other words, if he only used the original resources of the navy, his current navy would almost be at the end of its development.

Therefore, it is necessary to build a strong navy before the Americans react, a navy strong enough to dominate the Atlantic, and an elite maritime force with aircraft carriers as the core. In this way, even if the United States enters the terrifying stage of mass production of aircraft carriers in the later stage, it can rely on the accumulated family funds to ensure that the Atlantic defense barrier is foolproof.

So how to keep the British and American admirals from noticing the German aircraft carrier fleet? How to make the British Royal Navy, which was already hurt, take the attention away from the German aircraft carrier fleet? Accardo decided to create another miracle to conceal his true intentions.

How can a man forget the pain of a severed finger? The answer is simple, and that is to find a way to cut off one of his arms! Driven by this idea, Accardo drew up this plan with Dönitz as early as 1937, when the invasion of Poland began. The purpose of this plan is to use a brilliant submarine victory to divert the attention of the world's navies from aircraft carriers and to divert their attention to the "real secret weapon -- submarines."

German naval intelligence did a great deal of preparation for this, and collected some intelligence information about Scarpa Bay through the Luftwaffe and some of the submarines patrolling the sea, the merchant ships that passed through the area before the war, and the pervasive spy department. On 11 September 1937, just before the war with Poland, an improved Luftwaffe seaplane managed to take some clear photographs of the base, and on 13 September of the same year, the submarine U-216, patrolling the waters off Scarpa Bay, ventured close to Scarpa Bay to bring back some valuable reports.

After a careful study of the above information, the command of the submarine forces of the German Navy concluded that it was necessary to attack at night, since the current at the bottom of the sea was relatively slow at that time. The next question is to determine who will carry out the attack.

Now we all know that this person is Prien, the one who is now commanding the submarine in Scapa Gulf. He was indeed dumbfounded, because in front of his eyes was a huge fleet that he had never seen in his life.

How big was this fleet? There were four aircraft carriers, the Ark Royal, the Brave, the Glory, and the Athletic, and there were as many as five battleships, including the Revenge, the Sovereign, the Duke of York, the Queen Elizabeth, and the Barham, and there were too many other cruisers to count, and there was no end in sight to the destroyers.

This is probably the largest fleet ever built by man, and if you count the German High Seas Fleet, which was sunk by Operation Rainbow in the vicinity, it has collected almost half of the warships built by mankind.

The problem now in front of Prion is not that he can't find a target, but that there are too many targets for him to decide which one to attack. His submarine could fire 6 torpedoes in one go, 4 in the first and 2 in the rear, and in order to ensure the destruction of his target, he also had to ensure that several torpedoes attacked one target at the same time.

This was too much for Prien, so he scoured the water and found what he thought was the perfect position to attack. Then he decided to have a good time, and he personally got back into the submarine and came to the front torpedo launch bay. There he hurried almost all of his crew and began to assign tasks.

In order to get as many results as possible, he found several ropes, hung them from the ceiling of his submarine, and with the help of these ropes, he used the principle of leverage to have his crew hold torpedoes in front of the torpedo hatch and wait for loading.

"In a moment I'll fire three of the four torpedoes in front, and then you'll immediately load the two torpedoes in the lower position, and then I'll fire another salvo at another target. Then you have about 10 minutes to reload the two torpedo pods. Prien said to his crew.

As he spoke, he explained: "When you load, I will turn the submarine around and shoot the torpedo in the tail! Then I will turn the bow again and attack the fourth target, and after these torpedoes are fired, we will retreat." ”

"Is there a problem?" he finally asked, looking up.

Dozens of pairs of eyes stared at him, and their eyes were full of righteousness. They knew that the British would come back to their senses in the middle of such an attack, and the destroyers would quickly block the entire port, and their chances of escaping from ascension were negligible.

"No problem, Captain!" said the torpedo mechanics with a smile, "Don't worry! We'll let the British know how good our German submarines are." ”

Prion bowed deeply: "You are the best soldiers in the Empire!

"The world is invincible!" everyone shouted in suppressed voices.

Prion took aim at a huge silhouette in the faint light, judging by the mouth of the wheel, which should be a British aircraft carrier, which looked at least 20,000 tons. And not far from this aircraft carrier, there is also a huge battleship, which is the main reason why Prion chose to attack here first.

"Aim at the target!" Prien kept his eyes on the scope, staring intently at his target, and gently gave the first command.

"The torpedo is ready!" replied the torpedo operator.

"Bow torpedo tubes No. 1, 3, 4, ready!" Prien continued.

"Torpedoes No. 1, 3, 4!" replied the torpedo operator.

"Launch!" Prien shouted his first attack order of the day.

"Fire!" the torpedo operator pressed the button to fire the torpedo.

"Bang!" everyone in the boat heard the sound of the submarine firing torpedoes, and as the tremors and noise, three torpedoes with bubbles ejected from the front of the U-211 submarine and swam quickly towards their targets in the dark night.