For the next two days, the submarine spent most of its time at sea. In fact, when sailing at snorkel depth, the SMU40 submarine sails less susceptible to the effects of waves, but has the highest speed, but it is clear that the vast majority of crew members are not willing to stay underwater for a long time, preferring to float on the surface of the sea and endure the pain of turbulence.

The purpose of the Fifth Submarine Force's operation this time was not to the waters of the South China Sea, which are currently hotly contested, but to go to the Bass Strait and the Balintang Strait between Taiwan and Luzon to look for fighter planes and wait for an opportunity to attack the Japanese convoy. Since the United States and Japan have deployed a large number of land-based combat aircraft in Taiwan and Luzon, the Axis surface fleets are not active in this area at present, and can only use submarine forces to carry out diplomatic break-breaking operations.

Suffering heavy losses in the Battle of Sumatra, especially after the Axis fleet entered the South China Sea, the Japanese Navy had lost its supremacy in the South China Sea and had to rely on the island chain of the South Sea and the protection of land-based combat aircraft to maintain a fragile maritime connection with the Malay Peninsula.

At present, it is difficult to see the activities of Japanese warships from the Gulf of Tonkin to the waters of the Dongsha Islands, and the US Far East ships have never even left Manila Bay. It is only after entering the Bass Strait that the prey on the surface of the water gradually increases.

According to the plan, the 5th Submarine Force first went to the Bass Strait, which is now the busiest part of sea traffic between Japan and the South Seas. But there is information that the Japanese, with the help of the United States and Great Britain, have begun to create their own escort system, and the United States has already provided Japan with thirty old destroyers for escorting convoys.

If there are a particularly large number of Japanese escort warships on this route, then the 5th Submarine Squadron will continue to sail eastward to the area around the Northern Mariana Islands for "hunting", because a large part of Japan's strategic supplies are currently transported back to Japan through this route.

On the 3rd day after leaving Fangcheng Fangcheng Port, the 5th Submarine Squadron finally arrived at the Balintang Strait, however. Lin Feng did not rush to sneak into the battlefield, but waited quietly away from the fairway. It was not until the sun was setting west that he commanded the submarine formation to carefully sail the route from Manila to Tokyo.

The submarine sails at the depth of the surface snorkel, and if you carefully distinguish it in the air, you can still see a white track brought out by the periscope and the surface snorkel. However, at this point the sky began to darken. It is difficult for enemy patrol aircraft to detect the traces of these submarines unless they are cruising at ultra-low altitudes below 300 meters.

The Bass Strait and the Balintang Strait, the sea lanes connecting the South China Sea and the Pacific Ocean, are more than 220 nautical miles wide, nearly twice as wide as the Adriatic Sea. This sea area is currently the main shipping route connecting Japan with the South Seas, and the sea transportation is indeed busy. However, the Japanese have significantly strengthened the escort force in this area, and the convoys are all under the strict protection of the escort fleet, and the sea area of Guò is grouped during the day, and the night shipping has completely stopped.

The 5th Submarine Squadron cruised in the Bass Strait and the Balintang Strait for two days, but could not find a suitable time to attack. So Lin Feng ordered the entire submarine formation to continue eastward and turn to the Mariana route to look for opportunities.

After seven days of boring sea voyages, the 5th Submarine Squadron finally arrived in the southern part of the Mariana Islands, and at dusk, Lin Feng commanded this submarine force to cautiously sail towards Saipan, the most important sea transit base in the Northern Marianas.

When the sun was sinking in the west and the sky was getting dark, the entire submarine formation was already approaching the port of Tara Peg in the northwest of Saipan, in the periscope. The black silhouette of Cape Canavera appears at the end of the sea below the evening sky.

"Half the speed, all boats are ready for battle!" As the commander, Major Lin Feng, gave a new order. Four submarines lined up in a fan shape and began to approach the port of Tara Peg.

Saipan is about 21 kilometers long from north to south and 7 to 12 kilometers wide from east to west, making it the largest island in the Northern Marianas. The Northern Mariana was a German colony in the Pacific Ocean that was occupied by Japan during World War I, but the Japanese were forced to surrender all occupied German colonies after World War I. Moreover, Germany and Austria took the opportunity to extort war reparations of up to 500 million marks.

This is one of the main reasons why the Japanese have always hated Germany and Austria in their hearts, and the Japanese have never reflected on their strategic mistake of taking the opportunity to occupy the German colonies during the First World War, but have always been attached to Germany and Austria because of this war reparation, although they only paid less than 200 million marks in reparations before World War II.

The Germans had always wanted to build a naval base on Saipan, but there was strong opposition from the Americans. There was an agreement between Germany and the United States that neither Germany nor the United States would build fortifications or military bases on the islands of the western Pacific, so the defense of Saipan and the American-occupied island of Guam was very weak, which also caused the area to be reoccupied by Japan after the outbreak of full-scale war.

This is tantamount to a slap in the face of the Germans again, which made Kaiser Wilhelm II furious, but there was nothing to be done about it for the time being.

The Chinese submarine was slowly approaching the port of Tara Peg at the depth of the snorkel, and Sa Shijun, under the guidance of the sergeant major on the 1048 dive, used the auxiliary periscope on the guò boat, and followed Lin Feng's example, constantly searching the sea surface.

In the periscope, a gray silhouette appears like a matchbox swimming at the entrance to the harbor.

"What is this? Warship or merchant ship? Sa Shijun's eyes left the eyepiece of the periscope and he raised his head and asked.

Lin Feng also pointed the main periscope over there, and after taking a look, he said, "That's a Japanese torpedo boat, patrolling near the harbor, sir!" ”

According to Sashijun's experience, it was still about 6 nautical miles from the port of Tara Peg, and the Japanese patrol boat could not find itself at all.

"Turn off the diesel engine and change the speed to a third!" Lin Feng shouted into the microphone, "The other submarines are on guard outside the port, we need to get close to the port to reconnoitre!" After about two minutes, he gave a new order again: "Keep the current course, put away the periscope, and dive to 30 meters!" ”

It seems that he was ready to personally direct the submarine in a dangerous reconnaissance operation at close range.

The submarine has no weapons for self-defense except for torpedoes, and its defenses are weak and very slow, and even if it encounters a gunboat of 100 tons, it can be dangerous.

When it sails on the water, its maximum speed is only half that of a destroyer, frigate, or gunboat. SMU40 ocean-going attack submarine is currently the most advanced submarine in the world, this class of submarine adopts a double-hull structure, the cross-section of the pressure-resistant hull is a figure-8, and the lower half of the pressure-resistant hull is the battery compartment, and the battery capacity has increased by 4 times compared with the past, which greatly improves the underwater speed and cruising distance of the submarine. When submerging, it was able to run continuously for up to 1 hour at a maximum speed of 17.5 knots, propelled by two 2,400 hp main propulsion motors, which gave it a good chance of escaping the destroyer's pursuit.

All in all, the submarine's weaknesses make it a surprising force at sea like an assassin hiding in the dark, but not enough to dominate a sea area like a surface ship force.

Now, this adventurous game has just begun. (To be continued......)