Scattered snowflakes floated down the dark sea and the sky was already dark. As the cold air from the Arctic Ocean continued to move south, the climate on the North Atlantic Ocean became unpredictable. The escort warships and the entire fleet began a routine anti-submarine emergency turn again. The bow of the ship was paddling the water surface, and the waves hit the ship's body and made a rhythmic "swinging" sound.

In the North Atlantic Ocean, sailing without attacks is a luxury for every British crew member. Since the fall of France, Britain has lost 269 merchant ships and more than 1.4 million tons of cargo in just four months. Seventy percent of the merchant ships were sunk by German submarines.

However, with the establishment of an increasingly strict escort system and the widespread application of new anti-submarine technologies such as sonar, anti-submarine patrol aircraft, and new deep-water bombs, it is becoming increasingly difficult for German submarines to find good opportunities for attack.

As we all know, during the last World War, the submarine force, as a maritime weapon of the German Navy, caused a great blow to the Allies, and became an underwater demon that scared merchant ships from all countries. The German Navy has always been at the world's leading level in submarine technology. Although the development of military technology in the past 20 years after the war was a bit slow, German submarines are still far ahead of countries around the world in terms of comprehensive performance.

However, as control of the Strait of Gibraltar fell into the hands of the Axis Group, the surface ships of Germany, Austria and Italy gradually began to penetrate into the Atlantic Ocean to blockade and break the enemy's war. The combat mission of the German submarine force was quietly changing, from the main force of attack in the past to the vanguard of reconnaissance and monitoring the enemy's movements.

Since November, the German Submarine Command informed all boats of the latest combat regulations of the Navy: it is not allowed to risk attacking the enemy's escort transport fleet under the conditions of immature time, but to monitor the target and report the information to the Navy General Command as soon as possible.

Therefore, starting from November, the "record" of the German submarine force has decreased significantly. Of course, the advantage of this is that the losses of the submarine force have also been minimized.

"Sir, we have arrived at the target sea area No. 152!" The German Navy U48 submarine, which is carrying out combat cruise missions, took advantage of the night to quietly float out of the sea.

During World War I, the German Navy built nearly 500 submarines of various types. After the war, only more than 80 U-boats and 50 U-48-class submarines numbered after the war were retained. Before this war, the German Navy built only 22 new submarines of type 5 for experimental nature, and started from U-1. In fact, the U-48 submarine was one of the first 60 U6c/39 ocean-type attack submarines built in batches by the German Navy after the outbreak of the war. It has similar performance to the tonnage of the U7d/40 submarine built for China. The submarine is slightly different. This type of submarine is equipped with a 75mm deck gun and is not equipped with a rocket launcher.

Since the submarine sets sail, the navigation officer will mark the submarine's route and specific location arrival time on the chart based on the submarine's speed, heading and other data. The common practice of the navies in various countries is to number each sea area in a square of 30x30 nautical miles on the chart for easy communication. At different times, these numbers will be replaced and changed. Before the ship leaves sail, the Navy will provide each ship with three charts marked with the latest sea area numbers for use during contact.

"Go forward at one-third of the speed!" Major Schultz, the captain on the bridge, heard the report and used a sound tube to give an order to the boat. "Start the radar, pay attention to searching the western sea!"

Due to the interference of the cold current, the waves on the sea surface will surging, and the waves will occasionally pour onto the submarine's small bridge. The crew on duty on the bridge are wrapped in a wet raincoat and are alertly searching for the nearby sea surface. This is actually not very useful. In this era, radar and sonar are actually much further than the search range of the crew's eyes, but most captains are still more willing to believe in human eyes.

It was dark in the distance, and there was nothing else to move except the monotonous sound of waves.

Since the invention of the underwater snorkel, theoretically, the submarine does not need to float out of the water from time to time to charge the battery, and only needs to be kept at the depth of the periscope to stay under the water. But in fact, the underwater snorkel sometimes fails, and crew members prefer to let the submarine float up at night and breathe fresh air.

Due to the emergence of anti-submarine patrol aircraft and airborne radar, the enemy's anti-submarine distance has increased a lot. Now, unless the enemy's routine cruise is not visible at all, submarine commanders generally do not surface during the day, unless there are some failures.

Major Schultz watched the bridge for a while, and saw that there was no movement, he slid from the bridge to the cabin below. After taking off his raincoat and cover, he sat on a chair in the dining room in his shirt and drank hot coffee.

"Sir, we won't miss them, are we?" The naval staff sat opposite the captain with a telegram in his hand. He was referring to the British HZ-11 transport fleet, and the Admiralty Department had mobilized at least six submarines in this sea area to track the whereabouts of the fleet.

"It shouldn't be that we have four submarines nearby. A huge fleet cannot escape the surveillance of all sonars unless they return." Schultz said calmly. Such a huge fleet will inevitably have some unexpected situations. It is common for a day or two to be missing in the voyage."

"Will we attack first?"

“No, you need to report it up first.”

At this time, in the dimly lit sonar room, the submarine duty officer wearing headphones was always paying attention to the situation in the sea.

"Report, high-speed propeller was found at 220 directions! There should be more than one ship!" When Schultz was about to return to the captain's room, a loud report from the speakers in front of the periscope was heard.

"Wow, wow..." The submarine alarm sounded.

"Prepare to dive!" Schultz ran back to the captain's command position and said loudly.

The submarine began to dive. Through the thin pressure-resistant shell, the sound of filling water into the water cabinet could be heard. The hull made a squeaking sound when diving rapidly, which was terrifying. After a while, everything outside suddenly fell silent and the submarine had completely sunk into the water.

"The periscope length is raised, the periscope is raised! Report the situation in each part!" Schultz issued an order.

"Yes, sir, the depth is 13 meters! Everything is normal." The report from the pressure control room came from the amplifier, followed by reports from the power compartment, torpedo compartment and other parts. Everything is normal.

The crew who operated the horizontal rudder of the boat head and tail was staring at the depth meter on the side of the large rudder wheel. The third deputy Pratt stood next to the trim adjuster, and the sound of the echo rangefinder came from the loudspeaker, and the sounds of many propellers were mixed together.

"Very good. Now, let's rise by one meter!" Schultz's voice was very firm. The waves on the sea surface were very big, and it would occasionally submerge the periscope. The periscope in front of him was quietly rising, and Schultz was manipulating the periscope and searching the sea surface. After a while, his hand stopped, "Be good, there are more than a hundred boats. Not good, dive quickly!"

Schultz found that suddenly a destroyer left the formation and headed towards their location.r1152
Chapter completed!