"Bow torpedo preparation." All the mines were released, and Zhao Qi was also relieved, what he had to do now was to disturb the other party and let them start, so that these warships could hit the mines.

"Ascend periscope." Zhao Qi raised the periscope and quickly glanced around. "Heading 060, maintaining a speed of three knots, torpedoes No. 1 and No. 2 are launched."

The two torpedoes quietly broke out of the torpedo tubes, drew a straight waterline in the waves, and rushed to a 'Mississippi' class battleship, the unprepared battleship was directly hit by the waterline armor in the middle, the Boston Empire's unadvanced shipbuilding technology and disadvantage in steelmaking technology were undoubtedly revealed, and the torpedo with the armor-piercing blasting warhead directly opened two large holes in the warship, and the alarm bells of all warships sounded.

"Heading 091, keep speed, torpedoes No. 1, No. 2 continue to fire." Zhao Qi was unmoved, still issuing the order and continuing to fire torpedoes at another battleship.

Finally, after firing five rounds of torpedoes, sinking two cruisers and damaging two battleships, Zhao Qi ordered to dive to about ten meters and began to withdraw from Jialan Bay, and the submarine turned on the sonar system at the same time to prevent it from hitting the reef.

The chaos in Garland Bay is not over, and the panicked Boston sailors don't know where the enemy is coming from, so they can only fire their cannons everywhere and desperately fill the boiler with coal, hoping that the warship can move faster, but unfortunately they don't know the road, and the losses will be greater.

The Pennsylvania-class battleship, the lead ship of the Pennsylvania, equipped with a new steam turbine, was the first to start, and it was about to sail out of Garland Bay at full speed, only to trigger the submarine's torpedo in the channel.

Unlike a car, a warship does not have a braking system, and the only way to stop moving forward is to reverse the propeller. However, it takes time to reverse, especially for a large warship like the Pennsylvania, which has a large weight and inertia, and under the impetus of inertia, the battleship slid forward more than ten meters and hit three mines again.

The mines produced by the Chinese Empire were powerful and filled with TNT explosives unique to the Chinese Empire, and as a result, these four mines caused irreparable damage to the battleship, and the captain had to order to run aground on the beach at full power to avoid blocking the shipping lane.

Seeing what happened to the Pennsylvania, everyone finally realized that mines had been laid near their warships, and all the warships did not dare to move, and now it was pitch black, and no one knew where the mines were, so they had to wait until daytime.

However, Zhao Qi had already calculated their reaction, and just two hours before dawn, the sea began to rise. The turbulent sea water poured into Jialan Bay, and also brought the drifting mines laid by Zhao Qi at the exit into the harbor.

The two anchored warships closest to the exit were hit by mines one after another, one of which was the Mississippi-class battleship that was torpedoed.

Originally, due to the torpedo hit, the damage was very large, and the breach was barely blocked, but this time it was attacked by two more mines, and two new large holes appeared, and the blocked breach also leaked again due to violent vibrations.

The Boston sailors fought for an hour, but the water in the cabin became more and more, and the captain had no choice but to abandon the ship.

Although the other battleship was hit by five mines, fortunately it was not damaged before, and it was a new type of 'Pennsylvania' class battleship with good sinking resistance, and although it needed major repairs, it was not in danger of sinking.

It was only after dawn that they discovered that a few mines had been washed ashore by the tide, but fortunately this did not cause the Bostonians to suffer further damage. The Boston Imperial Navy immediately counted the casualties, and the results were extremely frustrating.

One Pennsylvania-class and one Mississippi-class battleship was sunk, one battleship each was seriously wounded, two cruisers were sunk, and one was accidentally wounded by artillery fire from several sides. The combat effectiveness of the Eastern Ocean Fleet in Boston was weakened by a small amount, and they knew that this was just a small warning given to them by the Imperial Chinese Navy, and the commander had no choice but to order to return home.

This operation has increased Zhao Qi's record by a heavy 50,000 tons, which is the record of sinking a large warship, and this sneak attack battle has also confirmed Zhao Qi's position as the first trump card in the submarine force of the Chinese Empire.

Later, after Zhao Qi sorted out the process of the surprise attack on Jialan Bay, it was compiled into the textbook of the submarine academy, and became a compulsory course for every generation of submarine commanders as a classic combat example.

After receiving the news of Zhao Qi's victory, Fang Xiaoyu was very happy, he personally ordered to send a salvage fleet to Jialan Bay to carry out salvage missions, most of the salvaged ships were dismantled, only the stranded 'Pennsylvania' was turned into a military theme park by Fang Xiaoyu after renovation, and placed on Honolulu Island for people to visit, so that the face of the Boston Empire was lost home.

The Bostonians were not fools either, and while repairing their warships, they found that the damage came from two weapons, one was a mine and the other was a torpedo.

These two injuries reminded them of the submarines of the Chinese Empire, but now that the Boston Empire knew that they could not defend themselves against such weapons, they did not dare to rashly declare war on the Chinese Empire, so they could only suffer a dumb loss.

The Boston Empire had not introduced submarines and had not studied them, so in order to develop such a powerful underwater weapon and study countermeasures, they could only turn to the Thar Empire for help.

At this time, submarine warfare was in full swing on the stormy ocean, and the merchant fleets on both sides suffered huge losses, even the losses of the Boston Empire were not small.

Therefore, both warring sides began to study ways to deal with submarines, and finally they found that in order to deal with submarines, they had to use flexible small warships, and the 'Swordfish' class destroyers that the Chinese Empire was now equipped with were actually the best choice.

In the past, they laughed at the Chinese Empire for not having the money to build big ships, so they used these small warships to support the scene, but now they realized that they had long been prepared for anti-submarine warfare.

With this understanding, both countries began to concentrate on the development of destroyers for use against submarines. Destroyer is a type of ship with a low technical threshold and a short construction period.

The level of technology of both the Saar Empire and the Yaman Empire was not low, and it was still very easy to design and build such a destroyer, and it only took them a month to draw the drawings of the ships that could be put into service.

Later, the two countries put the most basic equipment developed for submarines, underwater hydrophones and depth charges, on destroyers, these two equipment are also very simple, although still very rough but basically able to meet the needs, with such destroyers, they finally have rudimentary anti-submarine capabilities.

Not enough attention had been paid to such small warships before, and it was not considered how practical the destroyers were, and two months later, the destroyers of the Sahr and Yaman empires were launched almost simultaneously.