A campaign is made up of multiple units and many skirmishes. On the battlefield of the Coral Sea, there are many small forces in action. Including reconnaissance aircraft flying in the sky, as well as submarines under the surface of the sea, speedboats on the surface, radars on the ground, and so on. These forces are not the main force and cannot act as the main force, but they are absolutely irreplaceable. All the servicemen in these posts have a common goal, that is, victory, and make their own contribution to victory. Their contribution on the battlefield is no less than that of the officers and men of the task force, and no less than that of the pilots of the carrier-based air force, and they are also part of this battlefield.

In order to be able to discover the whereabouts of the US fleet in a timely manner, more than 20 submarines received orders during the campaign deployment stage and immediately went to the ports of Brisbane, Port Vila, and the outside of Noumea, to carry out reconnaissance missions, monitor passing ships, and send out information as quickly as possible.

Some of these submarines have just arrived in the war zone, and some are returning to port after completing the task of breaking diplomatic relations, and all of them have been in place as fast as possible after receiving the telegram.

At that time, the Imperial Submarine Force mainly carried out diplomatic break-breaking combat missions in two directions (this is the primary task of submarines), one of which was the route between the Hawaiian Islands and the continental United States, and the other direction was the route from the continental United States and the Hawaiian Islands to the Australian mainland.

The submarine forces of the Imperial Navy had two main forward bases in the Pacific Ocean, one being Saipan in the middle of the Mariana Islands. At that time, the port on Saipan had been converted into a submarine base.

In addition to a large number of docks for submarines, there is also a large amount of ground infrastructure, including a diesel depot with a capacity of 2.5 million liters (the submarine land is diesel. and not heavy fuel for battleships, or gasoline for aircraft). An ammunition depot with a capacity of 6,000 torpedoes (torpedoes were the weapon of choice for submarines, at that time the torpedoes used by submarines and destroyers were basically the same, with only minor differences, and aviation torpedoes were completely different from ship torpedoes), and a large camp with a capacity of 8,000 officers and men. There are a large number of supporting entertainment facilities in it (the treatment of submariners is the highest in the navy). The base can support the operation of more than 120 submarines, and the submarines deployed in this direction are mainly concentrated in the Central Pacific Ocean, as well as on the routes from the Hawaiian Islands to the United States.

The other submarine base is Rabaul. In fact, Rabaul is not a submarine base, there are not even some basic facilities here, not even a port. At that time, all the warships that went to the Southwest Pacific Theater were anchored in the port of Rabaul, because there was not enough dock, so these warships could not dock at the dock. At that time, more than 80 submarines deployed in the southwest Pacific were based here, and then went south to destroy the routes of the Coral Sea, and some even advanced to the southeast of the Australian Road. Attack the U.S. military convoy over there.

Submarines are the most obscure of all branches of the Imperial Navy, with a huge fleet and flying aviation. Compared with the vigorous Marine Corps, the submarine force has hardly any amazing performance on the battlefield.

Imperial submarines have three main tasks, one is to break the diplomatic battle, and the other is to reconnoitre. The third is free hunting. In the first few years of the war, submarines mainly carried out the first two missions, and it was not until a large number of new submarines entered service that free hunting was included in the captain's task list. As a characteristic of submarines, concealment is the most important factor in their attack and even survival, which is also destined for the position of submarines on this vast battlefield.

Liao Hongpeng is such an unknown submarine captain. If he is unknown, it may not be accurate, after all, he has a well-known Lao Tzu and a powerful brother-in-law, but there are not many people who really know that Liao Hongpeng is the son of Liao Hanxiang and the brother-in-law of Tan Renhao. This is also Liao Hongpeng's character, because he Lao Tzu served as the commander of the theater in the Pacific Theater, but after receiving a new submarine, he asked to go to the Southwest Pacific Theater instead of serving in the Pacific Theater, because he didn't want to be influenced by his Lao Tzu, who was full of aviation combat ideas and theories, or more accurately, he didn't want others to think that he was relying on his own Lao Tzu to struggle.

Since the "Second Battle of the Marianas", Liao Hongpeng has been sent to the southwest Pacific. The submarine under his command was numbered 211, which was a new type of submarine of the "C" type.

In May, he completed his fourth combat patrol and was given a vacation of about a month. But he didn't go home, he didn't even leave the submarine, because during this time his precious submarine would undergo a major improvement.

At the beginning of the 25th century, the Germans were the first to invent a device that could greatly improve the performance of submarines: the snorkel. Previously, submarines had to surface to recharge their batteries, because diesel engines consume a lot of oxygen when they are running, and submarines have no oxygen supply below the surface. And it takes several hours to fully charge all the batteries, during which time submarines are the most vulnerable, and more than sixty percent of the submarines lost by the Tang Empire were discovered by anti-submarine aircraft while charging (or before and after) and then sunk. And Germany lost more submarines as a result! Because of this, most submarines choose to float and recharge at night and dive under the sea during the day, which greatly limits the tactical use of submarines, and reduces the ability of submarines to seize fighters on the battlefield, so they miss too many opportunities.

Solving the problem of charging difficulties has become the key to improving the survivability and combat effectiveness of submarines, and before the emergence of power systems that do not require air, the only way is to allow submarines to obtain air under the surface of the sea, so that diesel engines can run, batteries can be charged, and even submarines can sail at high speeds under the surface. And the "snorkel" was invented to solve this problem. The technique of the "snorkel" is not complicated, in fact, it is to extend a pipe connected to the submarine out of the sea, so that air can enter the inside of the submarine. And the most critical technology of the entire "snorkel" is:

How to avoid the water rushing in! It is impossible for a submarine to remain at a constant depth when sailing, up and down is certain, in addition. It is also impossible for the sea to be completely calm, especially in rough conditions.

Large waves of a few meters, or even a dozen meters, are also common. And the snorkel can't stick out of the sea too much, otherwise it will lose its concealment, so it is very likely that it will not be air that will be sent into the submarine, but seawater! Ultimately. The Germans used several very ingenious methods, that is, to install a floating valve at the ground port of the snorkel, if the snorkel is submerged, then the valve will automatically close, and as long as the port of the vent pipe is on the sea, then it will automatically open, the whole mechanism is very simple.

The Tang Empire introduced this technology in March, first installed it on a submarine, and after several tests, immediately began to install snorkels for all the "C" submarines at that time. Because the conning tower of the Type "B" submarine was too small (the snorkel was mounted on the conning tower), it could not be adopted immediately, and some modifications had to be made. So the first to equip the snorkel is the "C" type submarine.

The whole improvement work took 20 days to complete, and Liao Hongpeng immediately organized the crew to conduct sea trials, and the results of the tests made him very satisfied, and the submarine could directly use diesel engines under the sea surface. Sailing at a speed of 8 knots is no problem at all, and it also ensures that the battery is kept to the maximum level, so if it is attacked, the submarine can dive immediately without worrying about running out of batteries and being forced to float.

After completing the acceptance work, the 211 submarine immediately rushed to the Southwest Pacific Theater, and in early July, the submarine came to Rabaul, where it was replenished with fuel, fresh water, and food, and then the submarine went on the road again to start the Coral Sea battlefield. At that time, the Coral Sea was a key area of the Empire's submarine activities and was called the "hardest hit area" by the Americans.

The C-type submarine lasted more than 60 days, and one C-type submarine once set a record of 93 days of activity. In other words, after leaving Rabaul around July 10, the submarine could patrol the Coral Sea until at least early September.

In the first four combat patrols, he cooperated with several other submarines in this area and had already killed at least 30 American ships, and the No. 211 submarine alone sank at least eight merchant ships with 42 torpedoes, and Liao Hongpeng's achievements have accumulated to 850,000 deadweight tons. This time, there were 18 torpedoes on his submarine, 8 of which were in torpedo tubes.

In addition, there was an 80 mm gun and a 20 mm gun on the deck of the submarine, but he did not want to use either of them.

By the end of July, Liao had sunk only two small fishing boats (requisitioned by the U.S. military) with artillery, and by early August, he had received a new order to immediately go to the periphery of Port Vila to collect information on the activities of the U.S. fleet. That is, the Project 211 submarine no longer performs a break-up operation, but a reconnaissance operation.

This task annoyed Liao Hongpeng a little, his submarine still had 18 torpedoes unused, and in reconnaissance operations, the first task was to report the whereabouts of the enemy fleet, not to fire torpedoes at enemy warships. That is, it is quite possible that he will finally return to Rabaul with all the torpedoes! But an order is an order, and after having the first mate check the food and fresh water reserves on the submarine, Liao Hongpeng ordered the submarine to go to Port Vila.

On 5 August, submarine 211 reached the southwest of Port Vila, east of the Coral Sea, and lurked about 120 nautical miles from Port Vila. The submarine arrived at night, and Liao Hongpeng had the snorkel removed (the snorkel at that time was patchworked, and it could be dismantled and tied to the submarine when not in use). He no longer needs to maneuver quickly, and he doesn't need to sail at high speeds. One of the major characteristics of the reconnaissance mission is that the submarine approaches the port from under the sea during the day, and then waits for the enemy fleet to appear, and at night retreats to the outer sea area to float up to recharge the battery, by the way to let the crew breathe fresh air, and the snorkel will reduce the underwater speed of the submarine (using the battery state), and it is easy to expose the submarine, so the snorkel is not suitable at this time.

This waited for several days, and it was not until the 10th, when the US fleet arrived in Port Vila, that Liao Hongpeng had his first income. His submarine was about 95 nautical miles southwest of Port Vila and was about to be recharged, when he spotted the huge American fleet. Before dawn, Liao Hongpeng's submarine followed behind the butt of the US fleet for more than four hours, roughly figuring out the size of the US fleet, and then sent a telegram in the early morning. This is exactly the intelligence of the U.S. fleet that headed for the port of Brisbane.

Then came days of boring waiting. This is the most difficult thing to consume in a reconnaissance mission, not only those crew members are very irritable, but even Liao Hongpeng is no exception. As if it were doing a routine inspection, the submarine No. 211 began to approach Port Vila in the early hours of the morning, dived around four o'clock, and then circled below the surface at a speed of four knots. After dark, the submarine returned to the open sea, and after 50 nautical miles from Port Vila, surfaced to begin charging the batteries, and then turned again in the early hours of the morning......

It's literally an "endless loop", and there's almost nothing to do other than this mechanical voyage. As time passed, the mood of the officers and men on the submarine began to become impetuous. By the 19th, the submarine had been out on a combat patrol for 40 days, which was the limit of the ability of officers and men to bear, or the limit of the physiological endurance of most people, and the 40-day boring life was very easy to make people crazy, and at this time there were no fresh vegetables and fruits on the submarine, only canned food, and those meat products that had no taste no matter how they were eaten.

"Lao Liao, should I be ready to return?"

Liao Hongpeng glanced at the constellations in the sky, and then nodded, he was about to order the submarine to return to Port Vila, when he saw some faint flashes on the sea in the distance, and the first mate immediately saw those flashes, which were not issued by the stars, they were sent from the battleship, and then, the alarm of the emergency dive came to mind.