Bai Zhizhan originally wanted to go to the "South Zhuhai", but Li Mingbo and others resolutely opposed it.

It's just that the night was not peaceful at all.

Although the minesweepers have been swept three times repeatedly, and there are still a few of them in front, there is no need to worry about mines, but Bai Zhizhan always feels that there is a greater risk of entering the narrow sea before taking the Kibu fortress, and he is not sure when he will be attacked.

The point is, there are many harbors along the narrow sea coast where torpedo boats can hide.

In the southern part of the Bab el-Mandeb Strait, there are many isolated islands.

If you want to say anything, it is not a problem to hide dozens or even hundreds of torpedo boats.

Because the tonnage of the torpedo boats is very small, the size is not much larger, and they must have been camouflaged, so even if reconnaissance planes are sent to search during the day, they may not be able to find out.

At night, this is even more so.

On the Guia side, the Nuland Navy's torpedo boats caused a lot of trouble for the Imperial Navy.

For example, in the battle against Transit Island, more than half of the ships lost by the Imperial Navy were related to the torpedo boats of the Newland Navy.

There is already enough information to prove that the Royal Navy of Bran has long obtained the blueprints of PT boats, and in Alexandria, north of the Shivan Canal, there is a small shipyard capable of producing PT boats, and the construction of torpedo boats does not require much steel, and the requirements for supporting factories are not high.

As for torpedoes, it was even less of a problem for the Royal Navy of Bran.

From a defensive point of view, the Royal Navy of Bran had a reason to deploy torpedo boats in the narrow sea, and to use them as the main combat platform.

If the alliance has completed the integration of forces and achieved unified command, then the torpedo boats of the Nuland Navy may be hidden in the narrow sea.

In addition, there is a concern about the submarines of the Royal Navy of Bran.

Although the Kingdom of Bran is the first victim of unrestricted submarine warfare, and the Royal Navy of Bran also attaches great importance to anti-submarine, it does not mean that the submarines of the Royal Navy of Bran are very poor, let alone that the Royal Navy of Bran ignores submarines because of noble sentiments.

If anything, I just haven't been given the right opportunity to perform.

There are at least 20 Bran Royal Navy submarines in Luxinhai, and all of them are small submarines that are well suited for operating in coastal waters.

Prior to this, these submarines were mainly used to monitor the blockade of the large ports of the Raleigh Kingdom, especially the military ports.

Although there were not many of them and there were fewer opportunities to be obtained, the results were very impressive, not only sinking several large warships of the Raleigh Navy, but also sinking many transport ships. Especially after Malta was occupied by the Hinder Army, these submarines became very active.

The reluctance of the Raleigh Navy to send a fleet to fight at sea had nothing to do with these Bran submarines.

In addition, the Manman army has not been able to increase its troops to Malta, especially the deployment of air defense units, and even the delivery of ammunition and supplies cannot be guaranteed, which is also related to the blockade of sea routes.

Obviously, sending several submarines to the narrow sea, there are no difficulties.

Not to mention a few, even if only one submarine quietly approaches the fleet, seize the opportunity to launch the torpedo, maybe you can take out 2 large aircraft carriers.

In a narrow sea area, it is impossible for the task force to disperse.

These worries about Bai Zhizhan also have a lot to do with the fact that he is not very clear about anti-submarine warfare and does not believe in new anti-submarine weapons.

That's right, the aforementioned sonar.

Although in the beginning, the Imperial Navy invested in the development of sonar to improve the efficiency of mine clearance, especially to clear sunken mines and anchor mines, but after the outbreak of the Great War, with the increase in the threat of submarines, the Imperial Navy discovered that sonar can also be used to detect submarines.

To say, it is still the only effective means of detection.

Prior to this, anti-submarine warfare ships could search for submarines only by means of sounds.

Because of passive detection, there are many problems.

After discovering the submarine, the most approximate way to determine the direction of the submarine, that is, the direction in which it is located. Even later, the principle of radio monitoring was used to determine the position of the submarine by detecting the angle of the radio, using two listening devices at the same time, it would have to be close enough.

In addition, sound waves are reflected from the bottom of the sea to the surface of the sea, which can interfere with the listening phone.

It is precisely because of this that in the era of relying on microphones, anti-submarine warships mainly rely on the advantage of endurance, stay in the sea area infested by submarines, wait until the submarine's electrical energy or oxygen is exhausted, have to float up to recharge and breathe, and then use naval guns or depth charges to sink the submarine.

For this reason, anti-submarine warfare is often a contest of endurance.

In addition, a little bit of luck is needed.

Sometimes, even if you stay for 2 to 3 days, you still get nothing in the end.

This method is obviously not feasible for antisubmarine warfare, which is mainly based on escort operations, and it is impossible to let an antisubmarine warship stay in a squatting spot just because it has discovered an object that is suspected to be a submarine under the sea.

It was not until the advent of sonar that the situation with anti-submarine took a turn.

The key is that the sonar can accurately lock on to the submarine, so that the anti-submarine warfare ship knows where to fire, which greatly improves the hit rate of the water bomb.

According to the tests done by the Imperial Navy, sonar increased the attack efficiency of anti-submarine destroyers by 20 times!

It is precisely for this reason that since the beginning of the year, the Imperial Navy has successively equipped anti-submarine warfare ships with sonars, and used the opportunity of rest and maintenance to organize skills training for captains and other key officers. Starting this year, the Naval Academy has also launched a course dedicated to training sonar operators.

Of course, the Imperial Navy has more than just sonar as an anti-submarine weapon.

Delivered to the Navy along with sonar, which played a role in anti-submarine warfare, there were also rocket-propelled depth charges.

Relying on rocket propulsion, the deep-water home bomb has a long-range attack capability for the first time, allowing anti-submarine warships to fire at submarines from thousands of meters away, and no longer have to sail above submarines to drop bombs as in the past, and can play the role of sonar more effectively.

In addition, in order to increase the density of dropped bombs, the Imperial Navy developed specialized launchers.

Actually, it was inspired by the army's rocket artillery.

To put it simply, it is to combine the launch tubes together, invest a large number of depth charges in the target sea area, and increase the hit rate by increasing the density of the bombs.

It can also be said to be a cover blow.

Unlike rocket artillery, the launch tubes are not parallel, but have a certain angle, ensuring that the launched depth charges are spread throughout the sea.

Now, submunitions are also used, that is, several, or even dozens of small depth charges are installed on a rocket.

This inspiration actually came from a bold speculation.

Almost all of the submarines that returned after being injured were severely damaged and lost their ability to dive, so that not many submarines with less damage were able to return. A young staff officer of the submarine force suggested that all the submarines that did not return were sunk, so minor injuries that were not taken seriously were more fatal.

It is precisely for this reason that there are miniature cluster depth charges with a single mass of 50 kg and a charge of only 8 kg.

Because it is lighter and smaller, it can increase the number of bombs by several times when the same amount of bombs is thrown, which is equivalent to expanding the coverage area by several times.

Later, the Imperial Navy developed a magnetic induction proximity fuse, which allowed depth charges to be detonated near submarines without the need to directly hit the submarine or determine the detonation depth before launching, which not only improved combat efficiency, but also greatly improved the hit rate.

Of course, rocket-thrust depth charges that attack in a cluster manner are extremely threatening, even with water-pressure fuses.

The Imperial Navy was also forced out, after all, the threat of the Nuland submarine was too great, so that the Imperial Navy must vigorously develop anti-submarine technology.

It is precisely with the anti-submarine weapon that there is the capital to attack the narrow sea.