When submarines ambush merchant ships, they have always faced a problem, that is, the speed of submarines, especially the speed of submarines, cannot catch up with merchant ships. Generally speaking, the surface speed of submarines in this era is still much faster than that of merchant ships, but the underwater speed is quite tragic, often less than 10 knots, and at this speed can not run for dozens of minutes, it will run out of power in the battery, so, generally speaking, after discovering a merchant ship, the submarine will first observe the direction of the merchant ship, and then run in a circle from the water to the front of the merchant ship, and then dive underwater, waiting for the merchant ship to sail into the fish by itself. Thunder's range. What, you say go straight ahead, like an assault ship to stop a merchant ship acting alone, and then like a fish . Minecraft sink it like that? Please, this is the time of the Great War, and merchant ships are not necessarily unarmed, generally speaking, on a merchant ship, it is really not difficult to install one or two cannons, just the small piece of less than 1,000 tons of submarines, swaggering past the water, carelessly, bitten by the cannons on the armed merchant ships, I am afraid that it will be finished immediately. In fact, the German Navy Zhenhai had such a cute and stupid hat, and then the submarine was sunk by merchant ships. The captain was naturally killed and laughed for the world. So, the submarine or something still hides under the surface of the sea with fish. Thunder Yin people are more convenient.

But once the merchant ships had escort destroyers, the situation was different. Because when the submarine discovers the merchant fleet, if it wants to run in front of the merchant fleet at high speed on the water, it has to worry that it will be discovered by the destroyer and killed by random gunfire. Moreover, even if the ambush is successful, after launching an attack, it will be attacked by destroyers, especially after the destroyers of the British will soon be equipped with active sonar. A single submarine ambushing a merchant fleet escorted by a destroyer can become particularly dangerous.

However, the submarine side is not without a solution, in fact, the later Dönitz invented a set of special tactics for the merchant fleet escorted by destroyers, and once beat the British merchant fleet to the head, this set of tactics is the famous "wolf pack tactics" in later generations.

Of course, this tactic cannot be directly given to the Germans, it must be done by more subtle means, and as for how to do it, that is Greystone's business.

……

"Captain Hafs, you are charged with violating military orders by attacking targets that have not been identified as enemy vessels. Please come with us. "The submarine U-11 had just landed in the port of Kiel, and the captain, Captain Hafs, had just come out of the submarine, jumped on the gangplank, and was about to hurry through all the formalities, and then go to the city to find a bar, and be merry and merry, when he was stopped by several gendarmes, and one of the leading ensigns showed him his papers, and said this to him.

"Hell yes!" Hafs stared at the second lieutenant viciously, "Lao Tzu sank tens of thousands of tons of British merchant ships, and let tens of thousands of tons of materials that should have been used to kill the Germans sink to the bottom of the sea, not only did you not give Lao Tzu the Iron Cross, but you wanted to arrest me?" Is there something wrong with your brains? ”

"Captain Hauffs, please calm down." The second lieutenant of the Judge Advocate General's Office looked down at his toes, "You know, I didn't give this order, I just carried it out. We ask for your cooperation. ”

"What the hell!" Captain Hafs muttered. He also knew that this matter was not actually about the second lieutenant of the Judge Advocate General's Office in front of him, he was indeed just carrying out orders. Moreover, the second lieutenant had always been quite polite, so he didn't want to lose his temper with him, it didn't make sense.

"Deisler, I'll leave the mess to you after the ship is stopped. I have to go with the Judge Advocate Advocate Now. Captain Hafs tried to calm himself down, turned around, and said to his deputy.

"Captain Hafs, besides, I have been ordered to take all the sailing records with me." The second lieutenant said again.

"Ah, Deisler, go and get them. Hell alive it! Captain Hafs was a little out of control again. Yes, any sailor who stayed on a small ship of several hundred tons, drifting in the Atlantic Ocean for three months, would not be in a very good mood. Especially when you feel that you have made a contribution, but you have been wronged.

……

"Captain Hafs, please tell us more about how you ordered the sinking of the Anne." In a small dark room, a lamp shone directly on Captain Hafs's face, making it impossible for him to see the faces of the people who were asking him questions. Hafs was trained to deal with the interrogation of the Allies in the unlikely event that he was captured. He knew that doing so was actually a means of increasing the psychological burden on the person being interrogated. However, Captain Hafs felt that it was useless at all, and besides, he felt that he had not done anything wrong anyway, so he did not intend to hide anything.

"I don't know which ship you're talking about Anne." Captain Hafs said, "There are some ships, I only recorded their type and flag on board, not the name of the ship. ”

"So, you didn't inspect the ship in accordance with the regulations?" A voice asked.

"Inspect the vessel in accordance with the regulations? Do you have a pit in your head? You mean, to get us stupidly to the surface, and then send two people on board the enemy's transports, inspect their cargo, and then register them all, and then sink them? We are submarines, not battleships! If we dare to go out to sea, those damn merchant ships - God knows if there are cannons hidden on them. I am responsible for the lives of my sailors, only fools will come out to die! "If that could be a reason to arrest me, the captain of every submarine in the Empire should be arrested." Because the guys who don't do it like me are already dead! ”

"So, tell me about you and your ship on August 17th." In the face of Captain Hafs's complaints, the few questioners did not seem to be affected in any way.

"August 17th? It was like this that day......"

……

On August 17, in an area of the northeastern Atlantic.

The weather was not very good on this day, from the morning, there was a strong wind, the waves on the sea were very large, and the U-11 submarine, with a displacement of only 860 tons, could only dive underwater at this time to avoid the wind and waves. And this damn wind blew for more than two hours, and although measures were taken, such as letting all the sailors who could lie down lie down and all the sailors who could sit down, in order to reduce the loss of oxygen, the air inside the U-11 submarine gradually became more and more turbid, and the oxygen content in the air became less and less. All the sailors were short of breath, and even Captain Hafs felt dizzy - a sign of a lack of oxygen.

"Float up, surface." Although the wind and waves have not decreased significantly, the submarine can no longer stay in the water at a depth of nearly 100 meters, otherwise, it will not be long before everyone will be suffocated.

The wind and waves on the sea were a little lighter, but the U-11 still shook badly. Captain Hafs had the forced ventilation system turned on, intending to quickly ventilate the inside of the submarine before diving again. Strange to say, after only ten minutes, the wind and waves began to decrease significantly, and Captain Hafs gave up his intention of letting the submarine dive again, and peeked out from the submarine's control tower, raised his binoculars, and began to search for sea targets.

The sea was empty, and there was still nothing but undulating waves. At this time, the rain clouds in the sky gradually dispersed, and the midday sun shone down through the cracks in the clouds, illuminating some of the distant waves as bright as silver. Captain Hafs took a deep breath, the humid, slightly chilly air of the Atlantic Ocean made him feel exceptionally refreshed. He raised his binoculars again, intending to look around the coastline one more time, and then handed them to Richardson, the lookout, and went down to the cabin. By the way, let the other officers also come out to blow the wind and get some fresh air.

As he turned his telescope to four o'clock, he suddenly noticed that from below the sea level, a mast, and then another, and then another......

From the position in which these ships appeared, and the direction in which they sailed, Hafs immediately made the judgment that this was a British or French merchant fleet bound for the Americas.

Hafs didn't know how many ships there were in this merchant fleet, he only saw a few masts at the moment, and he didn't know if there were escort destroyers in this merchant fleet, destroyers were much shorter than merchant ships, and when he saw them, it would be very close. Captain Hafs watched quietly for a while, then ordered the submarine to slow down and move slowly in a semi-submersible manner (that is, only the conning tower was exposed, and the entire hull was submerged under the sea), which significantly reduced the area of the submarine exposed on the sea, and the submarine itself was painted a gray-blue color close to the sea, which greatly reduced the possibility of the opponent finding the submarine from a distance. It is beneficial for submarines to observe the opposing ships at a much closer distance.

At this time, in Hafs's telescope, the hulls of those ships had gradually risen from below sea level, and Hafs quickly saw that these were container ships. The speed is around 12 knots.

Hafs mentally calculated the speed and course of both sides, then left the control tower, closed the watertight hatch, and descended into the cabin.

"Get the charts out!" Hafs shouted, and someone immediately spread out the chart in front of Hafs.

"We are now in this position, the convoy is in this position, and their course should be like this...... "We first dived and sailed in the direction of 260 at a speed of five knots for twenty minutes, and then surfaced and turned to the direction of 15 at a speed of 030,...... So after about three hours and forty-five minutes, we will be able to get to this position, dive down, and wait for them to be delivered. Captain Hafs pointed to the charts and ordered, "Now, get busy at once, boys, business is here!" ”