The detection equipment did not exist, of course, this is nonsense when the eyes were opened, and just a few dozen minutes ago, the U106 was fired on the hull with active sonar. The earliest active sonar, that is, the underwater echolocation device, was developed by British meteorologist Lewis. Richardson invented it in 1912, when the famous "Titanic" shipwreck occurred, so the expert decided to invent a device to detect icebergs hidden in the water.

Richardson's invention was a complete failure in terms of use, because the technical conditions at that time limited the detection range of echolocation, and the doctor's iceberg detector was not practical. By 1913, the German physicist Alexander Murphysic. Bem, also using the principle of echolocation, invented the echo detector to measure the depth of the seabed under the ship, and obtained the relevant patent, and the echolocation system entered the military's field of vision for the first time.

At the end of World War I, because of the deep threat of German submarines, Britain and the United States and other countries have started projects on anti-submarine detection equipment, and all countries have invested considerable efforts in seawater acoustic research, hydrophone technology has developed rapidly, and has become the standard configuration of surface anti-submarine ships after the war.

At that time, only the Royal Navy had made a breakthrough in active echo detection devices, and was regarded by the British Navy as the highest level of secrecy, and even professional scientific journals were not allowed to publish information related to these technologies.

In the early twenties, the British Navy had already experimented with active sonar equipment on an F-class destroyer, but the active sonar performance at that time was still very primitive, and it could only detect the depth of the submarine, but could not accurately measure the bearing, course and speed of the submarine, so it could only be used as an auxiliary aiming device for submarine attacks. At that time, in the whole of the world, only the French Navy developed a similar active sonar system, which is said to be not much behind the British Royal Navy.

Active sonar technology was considered top secret by the British, and with the exception of the well-informed naval executives, all the operators involved were given strict gag orders, and the secrecy of this technology was arguably so successful that Britain's allies were unaware of it.

The development of sonar technology in the United States was also very early, but because of a series of reasons, such as the world economic crisis, the reduction of military spending, the rise of conservatives, the indifference of the upper echelons of the Navy, and so on, the development process of the Americans' active sonar was not only extremely slow, but also distorted in technology, and as a result, the sonar performance of the early US Navy was very poor, so that for a long time, hydrophones were the only effective anti-submarine detection equipment equipped by the US Navy.

Historically, it was not until the British Royal Navy transferred their sonar technology to the United States free of charge at the beginning of World War II, and on the basis of the British Navy's technology, the United States finally developed a reliable active sonar system before the outbreak of the Pacific War, and began to equip troops in the middle and late stages of the war.

Now, the name of this active echo detection system is not called sonar (SONAR Sound navigation and ranging) but "submarine detector" (ASDIC ANTI-Submarine Division), the name of sonar was changed by the British after the United States entered the war in World War II in order to cater to the American side, at that time the British Empire in order to win the war, has completely ignored the discipline.

Now that world history has changed, and the war in Europe has ended, there is no such thing as the free transfer of sonar technology, at this time the active sonar of the British Royal Navy is still called submarine detectors, and the existence of sonar is still the top secret of the state.

Captain Fujiki didn't know where he heard the rumors of the existence of this equipment, and perhaps he was a little unsure in his heart, so he wanted to find out the Germans, and if the Germans insisted on such a thing, then it would be the turn of the Navy's intelligence department to have a headache.

The Japanese Navy didn't know about the existence of active sonar at this time, and even if they got the information in this area, they might think it would be a rumor that the British ghost animals were used to confuse themselves, as Robin said. The Type 93 underwater receiver that Japan is currently equipped with is still an imitation of the German-made underwater hydrophone, and with the level of underwater detection technology that Japan currently has mastered, at this time it does not even know the principle of active sonar, let alone conduct any related research.

After receiving Robin's affirmative answer, Fujiki looked a little depressed, and it was clear that the German's answer was not what the captain wanted to hear. It's easy to understand, if this kind of detection equipment really exists, then Captain Fujiki, who has tested the intelligence, has made a great contribution, even if it is not enough to be promoted, at least he can get a certificate of superiority (merit), and the future of the captain will be bright. But now that it has been confirmed that this equipment is just a rumor, then Fujiki's credit will be reduced by at least half, and the feeling is that he can't even think about it, and at most he will get a commander's comment, the officer has a flexible mind and is a diplomatic talent.

Robin patted Fujiki on the shoulder for comfort, then turned to Kijima and said, "Colonel, let's go to the next cabin." ”

"Oh, no problem, Captain, please go this way." Kijima stepped forward quickly, squeezing Fujiki behind with one shoulder.

"There's the bow torpedo compartment in front." Guidao led the way and introduced it attentively.

The top of the cabin of the Haida III submarine has reached a height of more than three meters, so the soldiers' cabins are all three-layer sleepers, compared to the internal space of the German submarine is much narrower, even the U106 is a large ocean-going submarine, all of them are double-berthed. At this time, the Japanese sailors on the Yi 60, except for the personnel on duty at the post, all went to the deck through the rear entrance, leaving space in the cabin for friendly people to visit.

The width of the aisle in the cabin is about one and a half meters, and there is a storage space under the floor for stacking supplies such as rice biscuits, and this is also the dining room for the soldiers on board, when they set up folding tables in the aisle, put away the middle and upper hammocks, and then the soldiers sit face to face on the bottom bunks on both sides, and enjoy their own three dishes and one soup.

The Japanese army used to use a split food system, and everyone had the same meal during the meal, which was much more hygienic than the large poon choi method used by the national army at that time. Each detachment of sailors was equipped with a communal kettle, the kind of large aluminum kettle usually used to boil water, which contained barley tea, which was an indispensable drink for the Japanese navy, second only to the kombu miso soup that was a must-have for good meals.

Among the supplies exchanged on Kijima were two bottles of special miso produced by the Kure Port Naval Food Processing Factory, and a small bottle of refined concentrated soy sauce (in Japanese, the small wooden barrel containing food is called a bottle) for the navy.

Miso was introduced to Japan during the Tang Dynasty of China, but it was already a seasoning unique to Japan, and it is made by fermenting boiled soybeans with salt and koji, and then steaming them with water and other ingredients to create a rich miso soup. Fifteen kilograms of miso like this, after being boiled into miso soup, is enough to provide a platoon of infantry for a week.

Concentrated soy sauce is a unique invention in Japan, they mix soy sauce with kelp and dried bonito to make a delicious and rich high-salt sauce, which only needs a few dozen grams of this sauce to taste when cooking a large pot of dishes, compared with the original ordinary soy sauce, this concentrated sauce greatly reduces the burden on the logistics unit.

In fact, the Japanese Navy's submarine unit is also equipped with more concentrated miso powder and soy sauce powder, which are the products of the above two seasonings after dehydration, and only need to add water to melt before use, and you can cook normally. On long-distance voyages, this seasoning powder can save more space in the cabin, but because the voyage is not long, and there are many valuable naval cadets in the personnel, the regular supplies are chosen.

Patting the miso bottles stacked next to the bulkhead, made of white wood with hemp rope on the outside, Robin followed Kishima into the bow torpedo compartment of the I-60.

The first thing that catches your eye is the white rice bag neatly arranged on the floor of the torpedo compartment, and the second is a huge torpedo placed on a spare mine rack, and the torpedo shell of the metal primary color shines with a cold light under the fluorescent lamp on the ceiling.

"Type 95 oxygen torpedo." Captain Robin thought, and then the German Navy captain crossed his arms and watched with great interest the "extremely high secret" of the Imperial Japanese Navy in front of him.

PS: I'm going to the hospital tomorrow, the specific update depends on the situation, I'll send a notice tomorrow.

Thank you all for your support, and the author will continue to work hard.