When the low sound came, all the officers and men on the "Wujiang," including Ran Wenqiang, were startled.

The sound came from the west, that is, from the side of the military port.

However, Ran Wenqiang then made an accurate judgment that it was an irregular explosion, not a slapping sound made by the submarine's active sonar.

Apparently, the remaining officers and soldiers had detonated the planted explosives and began to destroy the infrastructure inside the port.

As for the mines that have been laid, they are all activated by remote control, that is, an electronic signal is sent to bring the fuses on the mines into working condition.

Of course, this is also a signal for war.

According to the plan formulated before, unless the Bran Kingdom sent marines to forcibly land without declaring war, it would have to wait until the two sides officially declared war before carrying out the blasting operation, and this was also a signal sent to the "Wujiang" to let the "Wujiang" go to meet as planned.

Now, of course, we have to take out the 3 destroyers first.

In addition, it is necessary to find the Bran submarine hidden nearby and avoid the anti-submarine helicopters that will arrive soon.

It's difficult, but it's not hopeless.

The key is timing.

If anything, it's luck.

About 30 seconds after the torpedo was fired, the sound of an explosion was heard.

According to the relative position calculation, when the three Bran destroyers intercepted the noise of the "Wujiang", they must have been disturbed by the sound of explosions in the harbor, and they may not be able to make an accurate judgment, and it is very likely that they will automatically ignore the noise from the east, and they will not be able to discover the "Wujiang".

In addition, the two anti-submarine helicopters on the east side may not be able to intercept the noise emitted by the "Wujiang" due to the noise of the explosion.

The advantage of anti-submarine helicopters is their speed, and in terms of submarine search capabilities, they are inferior to anti-submarine warships.

The key is that all 3 torpedoes are self-guided throughout the process.

This arrangement fully reflects that Ran Wenqiang is an experienced submarine commander.

Although he was not prescient, when he made the decision to attack, Ran Wenqiang chose a way to attack that was most beneficial to him.

That's 3 "Y-9S" heavy dual-purpose torpedoes, which, after leaving the launch tube, no longer need submarine control.

In the initial stage, the three torpedoes were actually controlled by an inertial system.

That is, only when attacking an enemy ship more than 10 kilometers away, that is, when the target is relatively close, will the inertial navigation system be chosen to control the mid-range range.

If the distance is too far, then the line guide must be chosen, and the submarine provides rest instructions for the torpedo to ensure that the torpedo can catch up with the target.

After waiting patiently for more than ten minutes, Ran Wenqiang had to admit that he was starting to worry too much.

3 violent explosions in a row, indicating that all 3 "Y-9S" hit the target.

Subsequently, some strange noises were heard, and the computer of the "Wujiang" judged that the hull was "broken," and an enemy ship was torpedoed in two.

If it is a mission to break diplomatic relations in the North Sunset and the torpedo hits the transport ship, then this creepy sound will continue for a long time. In the process of sinking, the hull of the ship is squeezed by the seawater, which will deform and then make various sounds.

If they were close enough, the officers and men of the submarine could even hear the cries for help from the crew and the sound of a hard object hitting the bulkhead in desperation.

During the last war, many submarine officers and men even suffered from depression as a result!

It is not surprising that a torpedo blew the destroyer in two.

The "Y-9S" can be said to be the most advanced dual-purpose heavy torpedo in the Imperial Navy, and even the world's most advanced dual-purpose heavy torpedo, in addition to the use of a thermodynamic propulsion system, has a strong self-guidance capability.

When attacking surface ships, the "Y-9S" uses an active/passive sonar plus wake composite guidance mode.

The key is actually wake self-guidance.

The reason is also very simple, theoretically it is impossible to interfere with a torpedo controlled by wake guidance, because no interference means can imitate the wake generated by a large warship at high speed, so as long as it is locked by the torpedo, unless it can run out of the torpedo's range, it will definitely be overtaken.

As for the power, it goes without saying much at all.

The 250-kilogram thunder head is loaded with 150 kilograms of high-energy explosives, and its explosive power is equivalent to 300 kilograms of TNT explosives.

Crucially, the torpedo exploded under the water's surface.

When dealing with surface warships, the "Y-9S" adopts the active sonar depth fixing and magnetic proximity mode, that is, the active sonar controls the torpedo to reach directly below the target battleship, and then detonates it at a depth of 3 to 5 meters from the target battleship, so as to maximize the power of the thunder head.

In the tests done by the Imperial Navy, the "Y-9S" can blow up a 4,000-ton warship in two!

Theoretically, 1 "Y-9S" can sink or damage a large warship, and 2 can sink or damage a 10,000-ton warship.

Even against aircraft carriers, only 3 or 4 are needed.

In fact, according to this indicator, the "Nanjiang" class large attack submarine has only four torpedo tubes, that is, when using three torpedoes to attack the enemy's aircraft carrier, it can still leave one torpedo for self-defense, so that it will not be unable to return fire when it encounters danger because of the light.

However, the 4 torpedo tubes are indeed a little less.

In previous exercises, the "Nanjiang" class suffered enough from the lack of torpedo tubes, and only then did it improve the increase of vertical launch tubes from the third batch.

In addition, on the next generation of large attack submarines that replaced the "Nanjiang" class, the number of torpedo tubes was increased to 6.

Within 2 minutes, 3 torpedoes hit the target.

Subsequently, Ran Wenqiang gave the order to turn south.

The two anti-submarine helicopters did not fly away, but after flying about 20 kilometres east of Scarpa Bay, they turned eastward and headed back.

The threat of anti-submarine helicopters is indeed great, but compared with submarines, there is a significant gap in endurance.

Crucially, the Royal Navy of Bran will definitely not let the aircraft carrier come to the adventure.

Without being sure that there were no Imperial submarines ahead, the carriers of the Royal Bran Navy would remain in the open sea and would never approach Scapa Bay rashly.

To figure out what's going on outside Scapa Bay, relying on just a few anti-submarine helicopters is certainly not enough.

Although an "invincible" class can carry more than 20 "Sea King" anti-submarine helicopters, due to the limitation of the flight deck area and aviation service capabilities, it can only dispatch a maximum of 8 at a time, and under normal circumstances, it is very good to be able to send 4 aircraft.

Even if you count the anti-submarine helicopters carried by escort warships, an anti-submarine fleet can use more than a dozen at a time.

This anti-submarine force can at most clear the sea area near the fleet.

Otherwise, the Royal Navy would not have procured and equipped hundreds of shore-based long-range anti-submarine patrol aircraft.

When conducting anti-submarine warfare in the open ocean, anti-submarine patrol aircraft are the absolute main force.

Perhaps, the anti-submarine patrol aircraft of the Royal Navy of Bran were already on their way.

However, even if they arrived, it would take several hours of extensive search before they could determine if there were any Imperial Navy submarines in the vicinity.

A few hours is enough for the "Wujiang" to dive for dozens of nautical miles.

In fact, it only takes three hours at most for the "Wujiang" to leave the anti-submarine search area of the Royal Navy of Bran, and then it will be able to reduce its speed.

Sailing at high speeds all the time will not only make a lot of noise, but also consume more electricity.

Although as the most powerful large attack submarine today, the "Nanjiang" class spared no effort in the design of the solid-state lithium-ion battery with a total mass of more than 500 tons, so as to obtain almost perverted submersible performance, but it does not mean that it can always sail under the surface, and the high-speed navigation consumes much more electrical energy than normal cruise, and the distance and time of diving are much shorter.

Theoretically, if you sail at the maximum design speed of 33 knots, it will only take 8 hours to use up all the power in the battery.

If the diving speed is reduced to 6 knots, it can dive for more than 800 hours, and the diving distance can reach an astonishing 5,000 nautical miles.

Obviously, for a submarine commander, when to sail fast and when to sail slowly is a subject to mastery.

It is also a key tactic of modern submarine warfare.

If anything, any large attack submarine will sail in a relatively safe sea area for dozens of hours in a snorkel state, or more than a dozen hours on the surface of the sea, charging its batteries with a gas turbine before entering the patrol area, that is, before entering a state of combat readiness.

As long as conditions permit, any captain will complete the patrol task in a submersible state, and then float and recharge after leaving the patrol area, that is, on the way back.

To put it simply, it is to avoid floating in dangerous patrol areas as much as possible.

In most cases, a large attack submarine will not carry out combat readiness patrols for more than 30 days, and the general return time is limited to 28 days, that is, less than 4 weeks.

It is precisely for this reason that when the "Nanjiang" class was designed, the Navy proposed 6 knots of 5,000 nautical miles, that is, 830 hours of diving time. After deducting 28 days of combat readiness patrols, there is still about 15% of the remaining electrical energy that will allow the submarine to leave the dangerous sea.

Only this time, the "Wujiang" did not leave the patrol area.

After a quick dive for three hours, that is, almost 100 nautical miles, Ran Wenqiang ordered to slow down and immediately made a full rudder turn.

Then, the towed sonar was released and sailed at a lower speed for more than an hour.

After confirming that there was no abnormal noise in the rear, that is, it was not tracked by other submarines, Ran Wenqiang ordered to withdraw the towed sonar, and rose to the periscope depth, releasing the antenna of the ultra-low frequency communication station.

This set of radio stations is the most important communication equipment on the submarine.

The reason is also very simple, only the ultra-long-wave signal emitted by the ultra-low frequency radio can penetrate the sea water and send the message to the submarine below the sea surface.

Unfortunately, the penetration capacity of ultra-long electromagnetic waves is also very limited, and there are clear restrictions on the depth of the submarine dive.

Normally, when a submarine is on patrol, it will rise every 2 to 4 hours and release a communication antenna.

In addition, the communication efficiency of ultra-low frequency radio stations is very low,

For this purpose, a number of directive messages are usually sent.

If it is necessary to send complex messages, ultra-low frequency radio stations are often used to send command signals, float on the submarine, at least after the communication mast is stretched out of the sea, and then contact the submarine through other means, especially communication satellites, especially to send complex commands.

This approach sounds complicated, but it can effectively protect the concealment of the submarine.

In the event of a major event, the relevant instructions are also transmitted through the subwoofer radio.

This time too.

It took more than ten minutes to receive the first telegram.

As before, the Kingdom of Bran had officially declared war on the Empire a few hours earlier, before the remaining officers and soldiers had blown up the port infrastructure.

Prior to that, the combat units carried by the three Bran warships had entered Scapa Bay by helicopter and speedboat.

In other words, the kingdom of Bran is actually fighting without a declaration.

Of course, this also illustrates a problem.

Why should those 3 destroyers risk approaching Scapa Flow, instead of searching for submarines in the relative safety of the open sea.

This made Ran Wenqiang very emotional, because if he had done it earlier, it would have been impossible for the assault force carried by the three destroyers to enter Scarpa's Bay.

Just, what can this be?

Even if the three Bran warships were sunk, they would not be able to prevent the outbreak of war, and they would also have to maneuver to evade, and there would be no way to pick up the officers and soldiers who stayed behind.

However, this arrangement is also tentative.

Obviously, the Royal Navy of Bran did not expect that the Imperial Navy had left behind a large attack submarine, or had not made corresponding arrangements after thinking about it.

By the time the alarm is generated and the anti-submarine helicopters are sent, it will be too late.

There is one more point.

The helicopters carried by the three destroyers were responsible for transporting the commandos, and they did not carry out anti-submarine search missions, so they needed to be covered by anti-submarine helicopters arranged by the aircraft carriers in the rear.

Obviously, it is very likely that something went wrong when cooperating with each other, and it was not able to connect!

If that were the case, it would be a very serious mistake.

This also explains another question of Ran Wenqiang.

The Royal Navy of Bran thought it could take Scarpa Bay in one fell swoop with a sneak attack, so it did not send submarines, let alone the most advanced Trafalgar-class.

As expected, several large attack submarines of the Bran Royal Navy may have all gone to Lu Xinhai to blockade Alexandria, which was controlled by the Imperial Navy.

Subsequently, the "Wujiang" stretched out the communication mast to the surface of the sea to receive information sent by the communication satellite.

Among them is the combat order from the Lu Xinhai detachment.

Find an opportunity to return to the Auckland Islands, to be precise, to the waters north of the islands, and pick up the officers and men evacuated from Scarpa Bay tomorrow night.

Apparently, the detachment command made adjustments to the deployment.

However, this also shows from one aspect that the officers and soldiers who remained in Scapa Bay withstood the attack of the Bran assault force, but they certainly could not hold the military port.

Time is very short, and if the "Wujiang" cannot return in time, the dozens of officers and men will be cornered.

However, this also means that the "Wujiang" must be in danger.

In fact, when he received this telegram signed "Provisional Commander of the Lu Xinhai Detachment," Ran Wenqiang immediately understood what General Li Shenzhi meant.

The "Wujiang" is still part of the Beixi Luoyang Squadron, so there is no need to obey the command of the Lu Xinhai Detachment, and even if the temporary commander of the Lu Xinhai Detachment is also the commander of the Beixi Luoyang Fleet, his powers are different, so this telegram does not have mandatory effect.

Li Shenzhi did this, but it was actually decided by Ran Wenqiang according to the actual situation.

If it's too risky, don't take any chances.

It is a pity that among the officers and soldiers left behind, more than 40 are officers and soldiers on the "Wujiang", and Ran Wenqiang will definitely not abandon his brother.