After another hour, the sky was completely bright and the green Spanish coast was clearly in sight.

Diving to a depth of about 13 meters, the SMU 532 continued to unhurriedly head towards the southern part of the Gulf of Cadiz at a speed of about 10 knots, dragging two not-so-obvious white tracks behind it.

At this time, the Spaniards had already deployed some anti-submarine patrol planes in the coastal areas, and the Tang Navy had previously ordered the withdrawal of submarine forces from the coast of West Francia and the North Sea because the anti-submarine patrol planes of West Francia and East Francia had suppressed submarines very strongly, and these West Francian anti-submarine bombers equipped with radars could be on duty day and night over the coast, and the latest sea-detection radars equipped with the planes could detect submarines that surfaced more than 30 kilometers away.

However, Li Haiming still ordered to insist on sailing at the periscope depth to carry out an important technical test of the Navy's technical department: the latest passive radar receivers developed by the Imperial Navy can receive electromagnetic waves emitted from enemy planes before enemy patrol planes even detect them, so as to detect the enemy in advance and evade.

This is an extremely dangerous job, and if these machines do not work well, the submarine runs the risk of being attacked by enemy aircraft. Fortunately, the latest Gema41 new detection radar equipped on the Imperial submarine has greatly improved its efficiency due to the introduction of the latest magnetron technology from the Austro-Hungarian military, and can detect surface ships 20 nautical miles away and air targets 45 nautical miles away, which is another important guarantee for the safety of submarines.

On February 25, SMU532 used this new passive radar to successfully evade five groups of enemy anti-submarine patrol aircraft, and on February 26, four groups of enemy anti-submarine aircraft flew overhead. Obviously, the airborne radars of the United States and Britain are not yet able to penetrate the sea water at a depth of more than 10 meters and discover submarines that are diving under the surface.

However, there was still an enemy patrol plane hovering overhead for a while, and Li Haiming did not order the submarine to dive to evade, but only ordered the submarine to stop and quietly suspend under water, and in this way it went around with the enemy plane for more than 10 minutes. He knew that scientists had developed a magnetic anomaly detection device capable of detecting submarines underwater, and it was estimated that the enemy plane might have been equipped with something similar.

This was a new situation, and after the enemy plane left, Major Li Haiming immediately reported the situation and the results of his own speculation to the submarine command.

On the afternoon of 26 February, four submarines of the 2nd Submarine Detachment were slowly sailing along Spanish waters towards the Gulf of Cádiz, and near the entrance to the Strait of Gibraltar, they spotted a small cargo ship of about 1,000 tons. The cargo ship happened to be within the attack range of SMU532, and Li Haiming thought about it for a while while at the periscope, but still gave up this "gadget". If an attack is launched at this time, it may cause a distress signal, which will lead to a full-fledged sea and air search of the submarine by the enemy near the Strait of Gibraltar, which will not be conducive to the next operation of the entire detachment. If you don't alarm the Spaniards now, it will be easier to get a bigger result by diving into the north-east port of Cádiz or the shipping channel of the port of Lisbon after dark.

Major Li Haiming planned to do a lot of work here, and then he just slipped away and went to the Bay of Biscay on the west coast of West Francia.

After maneuvering with enemy patrol aircraft, the excellent performance of the new submarine made him appear more confident.

Li Haiming ordered the formation to continue sailing south, crossing the shipping lane from Gibraltar to Northwest Africa, and then laying an ambush at the edge of the shipping lane.

The 2nd Submarine Detachment waited for the first "prey" to enter the ambush circle just before dawn, and the officer on duty reported that the radar had spotted a convoy of five large merchant ships heading for the Gulf of Cádiz.

It was close to 6:15 a.m. and the sky was getting brighter.

The submarine dived underwater, and after a while, Li Haiming saw through the periscope a scene that all submarine commanders coveted: five freighters with a tonnage of about 10,000 tons lined up in a column, smoothly sailing on the sea towards their ambush site, and there were no warships around to escort them.

Inside SMU 532, the crew is ready for battle, and the killing machine has already bared its sharp teeth. Through the thin hull, the crew could hear the louder and louder ping-pong sounds coming from the sonar room, sharp and vibrating. The echo detector emits a higher pitch than usual when capturing multiple targets, fluttering more violently, with a special timbre.

Li Haiming decided to attack a large oil tanker at the end of the convoy first, and he ordered the submarine to approach nearly a kilometer and fire a torpedo. After about a minute, the torpedo hit the target. The hit tanker suddenly burst into flames, the hull tilted, and the crude oil loaded on the ship spewed a thick black smoke, covering the hull.

Li Haiming no longer cared about the burning oil tanker, and ordered to turn the head of the boat and approach the other ship in front. The ship looked like it was supposed to be a standard 8,177-ton ocean-going freighter built in wartime batches. The submarine was faster than the cargo ship at periscope depth, and quickly entered the attack position. Because the cargo ship was fleeing, Li Haiming ordered two torpedoes to be fired one after another, but the torpedoes directly blew up the cargo ship, and the cargo ship quickly capsized towards the sea, and the bow of the ship was raised high.

At this time, the other three steamers were also torpedoed, and it seems that the others did not do a bad job.

"Tell the other submarines to retreat first, and we'll pick up the people who fell into the water before leaving!" Li Haiming said that there were some crew members who had fallen into the water floating on the sea, and the chivalry he had learned from the Imperial Naval School made Li Haiming feel that he should save these poor people first.

The submarine floated from underwater, revealing its blackened body, and sailed towards the cries for help that had fallen overboard. The waves crashed against the low foredeck, wetting everyone who went up to the bridge.

Li Haiming grinned and pointed to the several people who were swimming in the sea, smiled at Linde and said, "Who is going to fish them up?" ”

Deputy Captain Hu Chengen said: "Let's go over, the current deck is too small, not as good as the original." He said as he led Walter and Karn down the gangway to the deck.

At this time, the brighter it was, Lin De, who was standing beside Li Haiming, felt a little nervous.

At this time, the radarman in the cabin reported: "The plane was spotted in the direction of the stern and flew at a low altitude." ”

"Shouldn't we dive?" Lind said.

"It should be fine, we're saving people, that's what everyone did." "I've seen Europeans like this several times, and they won't attack us. ”