The first batch of sixteen new UX.XI./41D large ocean-going attack submarines developed by the Germans finally entered service, which gave the commander of the German submarine force, Admiral Dönitz, the ability to begin the implementation of his long-planned "North American battle plan".

In another time and space, even though the Germans suffered a fifteen-year period of stagnation in submarine development after World War I due to the limitations of the Treaty of Versailles, their submarine construction technology was still about a decade ahead of the whole world during World War II. And in this time and space, the technical reserves and industrial capabilities of the Germans in submarine research and development are much deeper than in another time and space.

In Germany, about twenty light underwater high-speed submarines equipped with turbine engines of the "Walter" closed-cycle system have already been put into real combat. However, because the "Walter" underwater turbine engine is still in the actual stage, these submarines equipped with hydrogen peroxide fuel engines are only about 300 tons, and can only operate in the near sea at present, and the German Navy's latest UX.XI./41D large ocean-going attack submarine still uses the traditional diesel-electric propulsion method.

The UX.XI./41D submarine has an underwater displacement of more than 3,000 tons and is equipped with four MAN 2,800 hp 12-cylinder-pair piston diesel engines, with a total power of more than 10,000 hp. The surface speed of the submarine can reach 23.5 knots, which is enough to follow the surface fleet, and the two 5,200 horsepower main propulsion motors equipped with it allow the submarine to achieve a high speed of nearly 19 knots underwater, although its endurance at this high speed is less than 2 hours, but it is enough to get rid of the tracking of most surface anti-submarine ships and anti-submarine aircraft.

The UX.XI./41D submarine is equipped with a total of eight torpedo tubes in the front and two in the rear, and two 12-tube submarine box 310mm rocket launchers, which can be called the most powerful submarine in the world in terms of performance and firepower.

Due to the fact that the displacement is already close to that of an ocean-going destroyer, even the latest sectional construction technology is used. The construction of the first 16 submarines of this class took much longer than the VII.D/40 submarines currently being built by the German Navy, and it took almost a year for the submarines to be assembled.

Reinhardt? Major Haldegen was assigned to the 26th Submarine Group, a consist of sixteen UX.XI./41D ocean-going submarines, as Squadron Leader of the 101st Submarine Squadron and Captain of the U-400. After taking over the submarines, General Dönitz gave the 26th Submarine Group a week to allow the commander and crew of the newly formed submarine force to adapt and test the performance of these latest submarines.

Due to the excellent table of the surface fleet forces. The German Navy did not fall into the mistake of frenzied submarine construction like another time and space, but the size of the German submarine force still swelled rapidly to more than 400 ships after the war, and the number of equipment was still far ahead of the rest of the world.

With the rapid enhancement of the anti-submarine capability of the British and US navies and the establishment of the escort system, it has become difficult for the submarine force to find suitable prey and attack opportunities in the Atlantic waters. After the United States entered the war, the German submarine forces had achieved good results on the east coast of the United States and the Caribbean. Major Haldegen was awarded a Knight of the Order of the Oak Cross for his outstanding achievements in sinking 10 enemy merchant ships totaling more than 57,000 tons during Operation Drumming. But in the second half of 1941, with the establishment of the American escort system. Having learned the latest anti-submarine tactics and some new anti-submarine weapons from the British, the losses of the German submarine forces began to increase sharply, and Admiral Dönitz had to order the submarine forces to withdraw from the Caribbean, temporarily terminating Operation Drumming.

The nearly 150 submarines equipped by the German Navy before the war could no longer meet the requirements of the current naval warfare, and General Dönitz urgently needed to replace these obsolete and old submarines with new ones, so the latest UX.XI./41D large ocean-going attack submarine construction plan was born.

Reinhardt? Major Haldegen led the crew to receive the newly assembled U-400 submarine directly at the old Volkeng factory in Stettin, and began its first test at sea in the afternoon of the same day. The newly commissioned submarine needed to carry out a thorough inspection of the main components of the hull, such as the watertightness of the hull and the reliability of the electrical and power systems, to make sure that they would not go wrong during the combat voyage.

The shipbuilding techniques of the German shipyards had been well tested in several large-scale naval battles since the start of the war. In addition to some necessary adjustments to some equipment during navigation, the U-400 showed excellent performance at full speed and in extreme diving. It has a top speed of 23.7 knots on the surface. The maximum underwater speed is 18.8 knots, and it can still reach such a high speed at a depth of 50 meters, which is far more than the VII.D/39 submarine U-123 under his original command.

The control system of the UX.XI./41D submarine has been improved from the original rudder control system to the aircraft-type push-pull rod control mode, which greatly reduces the difficulty of the crew to control the submarine, and the automatic operation of the whole boat has also been greatly increased, such as the semi-automatic loading mode of mine and loading and rocket loading.

Due to the large amount of water discharged. The UX.XI./41D submarine has a much larger interior space than the original submarine, and the upper part of the front and rear battery compartments is laid with a deck, separating the officers' quarters, dining room, galley and crew cabins, and the living conditions in the submarine have been greatly improved, with a total of 45 berths. Basically, more than two-thirds of the crew will have a resting place. The power compartment of this class of submarines is soundproofed, while the diesel engine is mounted on a rubber shock-absorbing base, which greatly reduces the noise in the boat. At the same time, the new air conditioning and ventilation system has been installed in the boat, and the air in the boat is much cleaner than before.

Overall, the new submarines have improved much in terms of comfort, enough to make their crews feel several times better during long and boring sea operations.

After completing a short period of seaworthiness training in the Baltic Sea, Major Haldegen returned to the Kiel Naval Base with the 101st Submarine Squadron. That night, November 16, 1941, Haldegen received his first operational order since taking over as Captain of the Submarine Squadron, which required him to command four ocean-going submarines of his squadron to follow the 26th Submarine Group across the North Atlantic to the eastern waters of the United States, with the mission of attacking valuable American or other Allied ships and blockading American ports with shipborne mines.

Operation Drumming was restarted after a three-month hiatus. (To be continued......)