After the European Union declared war on the Empire, the Naval Command ordered the Submarine Command to send submarines to attack the shipping routes of European countries and the northwestern coast of Africa.

Initially, submarine forces were able to attack transport ships sailing on the western routes of Europe, and Spain and the Kingdom of West Francia did not have convoy and light control mechanisms in place after entering the war. Merchant ships sailed along the western coast of Europe, mostly alone, with little to no ships patrolling and protecting them at night.

Due to the chaotic management of shipping in European countries, and the fact that they did not adopt the mechanism of communication and escort like the Tang people, this gave the imperial submarine force a great opportunity. The submarines of the Imperial Navy did not even need to adopt the "wolf pack tactic", and only used a single boat safari to sink a large number of merchant ships, and some submarines even surfaced simply to attack passing merchant ships with naval guns in order to save torpedoes.

By December 305, in just five months, the Imperial submarines had sunk a total of 587 ships from Spain, the Kingdom of West Francia and Sweden on the west coast of Europe and the North Sea, with a total tonnage of more than 3.5 million tons, mainly West Francian and Spanish merchant ships.

More than 6,000 seafarers or passengers have been killed in the series of attacks in the European Union.

Along with this series of attacks at sea, a new batch of ace captains with a sinking tonnage of more than 50,000 tons naturally emerged in the submarine force.

The Imperial submarine forces dealt a heavy blow to the industrial production of European countries, especially the Spanish and West Frankish colonies in West Africa, which lost a quarter of all merchant ships. This has even affected the supply of sugar, rubber, coffee, and cocoa within Europe. With the loss of 30 percent of the tankers, many cities on the coast of the British region are also experiencing shortages of oil supplies.

The Spanish and Frankish navies, unable to endure such a heavy blow, had to draw a large number of destroyers to establish a new escort system, which was extended to the British Isles at the beginning of Republic 307.

With the establishment of the escort system, the achievements of the Imperial submarine forces were rapidly reduced, and it was rare to find a suitable opportunity to attack.

However, just as the Battle of Shetland began, 48 ocean-going submarines of 12 submarine detachments quietly left the mouth port of Nanda River in South America and the new Liaodong base in North America and sailed to European waters.

In the current Imperial Navy, about 20 light underwater high-speed submarines equipped with "Jiangxia-style" closed-cycle system turbine engines have been put into actual combat. However, because the "Jiangxia-type" underwater turbine engine is still in the experimental stage, these submarines equipped with hydrogen peroxide fuel engines are only about 300 tons, and can only operate in the offshore sea at present, and the latest Type 05D ocean-going attack submarine of the Imperial Navy still uses the traditional diesel-electric propulsion method.

The Type 05D submarine has an underwater displacement of more than 2,600 tons and is equipped with four Wuhu-style 2,800-horsepower 12-cylinder diesel engines, with a total power of more than 10,000 horsepower. It can reach a surface speed of 22.5 knots, which is enough to follow the surface fleet, and its two 3200 horsepower main propulsion motors enable this class of submarines to obtain a submersible speed of nearly 12 knots underwater, although its endurance at this high speed is only less than 2 hours, but it is enough to get rid of most surface anti-submarine ships and anti-submarine aircraft tracking.

The Type 05D submarine is still equipped with a total of eight 610 mm torpedo tubes in the front six and two in the rear, and two 15-tube submarine box 280 mm rocket launchers, which can be called the world's best performing first-class submarine in terms of performance and firepower.

Major Li Haiming was transferred to the 21st Submarine Group of the Atlantic Fleet, where he served as the captain of the 2nd Submarine Detachment and the captain of the SMU 532 submarine.

Due to the outstanding performance of the surface fleet, the Imperial Navy did not fall into the mistake of frantically building submarines and conducting large-scale submarine warfare, but the size of the Imperial submarine force still rapidly swelled to more than 700 ships after the start of the war, and the number of equipment is still far ahead of all countries in the world.

With the rapid enhancement of the anti-submarine capabilities of the two Frankish kingdoms and the Spanish navy and the establishment of the escort system, it has become difficult for the submarine forces that have been in the limelight since the start of the war to find suitable prey and attack opportunities in the Atlantic waters. Under normal circumstances, submarine forces are now dispatched together with the surface fleet to carry out surveillance and reconnaissance missions, and large-scale individual combat deployments are rarely carried out.

The control system of the Type 05D submarine has been improved from the original rudder control system to the aircraft-type electro-hydraulic push-pull rod control mode, which greatly reduces the burden of the crew to control the submarine. With the application of various electrical equipment, the level of automatic operation of the whole ship has also increased greatly, such as the loading of mines and rockets have achieved semi-automatic loading methods.

Due to the increase in displacement a lot, the interior space of the Type 05D submarine is much larger than that of the original ocean-going submarine, and the upper part of the front and rear battery compartments in the boat is laid with a deck, which separates the officers' quarters, dining rooms, galleys and crew quarters, and the living conditions in the boat have been greatly improved, with a total of 48 berths, which can basically ensure that more than two-thirds of the crew have a separate resting place. In addition, the power compartment of this class submarine is also equipped with sound insulation facilities, and the diesel engine is all installed on a fixed rubber shock-absorbing base, which greatly reduces the noise in the boat. The new refrigeration, air conditioning and ventilation systems are also installed in the boat, and the living conditions and air quality in the boat are much fresher than before.

Overall, the comfort of the new ocean-going submarines has improved considerably, enough to make the crews feel many times better than in the past during long and boring sea operations.

In the waters of the South Atlantic, due to the blockade of the surface fleet of the Tang Empire, if there was no escort by the main fleet, the merchant ships going to Europe were basically extinct, and the imperial submarine force was mainly fighting against the submarines of the two Frankish navies. In fact, this kind of confrontation is quite dangerous, in terms of radar and sonar technology, the empire is comparable to the two Franks and other countries, no one is much more advanced than the other, and who can sink the opponent's submarines on both sides depends mainly on luck.

At present, the only places where the Imperial submarine forces can make contributions are the waters of the North Atlantic and the coastal areas of Europe, and being able to be fortunate enough to be on duty on the coast of Europe in the previous stage is tantamount to participating in an adventurous gold rush trip. At present, the merchant ships of European countries in the Atlantic waters are concentrated in Europe and North Africa, and as long as they sink a few 10,000-ton ships or cruise ships, then the honor, reward, and promotion of submarine commanders and divers are just around the corner.

However, the European Union established a tight escort system a few months ago, and those good old days are gone.

Read the URL: n.