Just when the war broke out in Persia, the Qin army was not idle in the Khanate of Xhosa.

Of course, the most anxious thing is the Xhosa people. The autumn harvest is coming, and if they are still besieged, they will definitely be dead when there is no foreign aid. The only foreign aid they may be counting on is the Great Cannibal. It is not the Great Cannibal that is an alliance with them, but the Great Cannibal cannot ignore it when the Great Qin people attack the Xhosa people.

Unfortunately, the news of the great cannibal defeat again finally reached the ears of the Xhosa people, so it became a bit ridiculous to stay in the castle and wait for "there is a change behind the Great Qin Kingdom".

The people of Daqin took the initiative to attack the Dashi Army, not for the land of Persia, but for the Xhosa strategy. Of course, they also obtained a million-double dingkou and about one province, which was a side gain.

So the Xhosa must take the initiative.

This is exactly what the Qin army is willing to see.

Although the Xhosa people were full of righteous indignation, united as one, and had powerful cavalry, they were still disappointed in front of the army with a large number of firearms, such as the despicable weapons. In fact, in front of the Xhosa people who had extraordinary combat power, if the Qin army was replaced with a normal Roman, the Xhosa people would definitely win.

But unfortunately, they encountered the Qin army that was still as moving as a mountain!

In the end, they retracted back to the castle in shame.

At this time, they were a bit like the Battle of Jin'anzhai between the Later Tang and the Khitan after more than a hundred years. Yelu Deguang surrounded the army of the Later Tang with a total number of people. The people surrounded, including Zhang Jingda, Gao Xingzhou, Fu Yanqing, etc., were all famous generals of the Later Tang Dynasty. Zhang Jingda was even more famous in the battle with the Khitans on the border.

But Yelu Deguang's 50,000 elite cavalry still scared Zhang Jingda. After one defeat, he no longer dared to go out to attack the camp. Instead, he trapped the camp and waited for the court to send reinforcements. In the end, the reinforcements did not come, and the camp had to kill the horses and survive after a long period of time.

Of course, waiting for the enemy to attack the city and suddenly counterattack when the enemy is tired is also a way, but the Qin army obviously will not give them this opportunity at this time.

As soon as things happened in Persia, the Romans became better and better. It was time for the Qin people to attack the Xhosa people with all their might.

In early July, the south wind blew on the Caspian Sea.

A large Caspian-class ship sailed from Baku Port and headed north along the west coast of the Caspian Sea.

......

This is a new ship built by the shipyard of Babola Port (the closest port to Surrey, the capital of Hainan Prefecture). The largest Caspian class is still 40 meters long, wide and high. The middle deck is a straight deck, which can place heavy artillery.

As the newly released kilogram-weight Gonggong cannon, it is obvious that the big ship is the place where it can best play, but unlike the land cannon, this time the Qin Navy designed all the carrier-based artillery guns into cannons. In other words, whether it is 500 kilograms, 800 kilograms or kilograms of Gonggong cannons, the body-bar ratio (the ratio of the length of the gun body to the caliber of the gun barrel) is about 16 times.

In this case, if the shell of the Gonggong cannon is still 30 cm, the body of the cannon needs at least 480 cm. This is too long. If the thickness of the cannon wall is still three cm, the entire cannon body will be extremely heavy.

So, we can only take the second best, changing the diameter of the shell to 25 cm smaller than the first. In this way, the length of the ship-based version of the Gonggong cannon is 4 meters, the weight of the gun body and the gun mount is about 1,500 kilograms, and the weight of the shell is about 130 kilograms, which requires 65 kilograms of black gunpowder to be pushed.

After the previous 800-jin cannon body-tube ratio was changed to 16 times, the diameter of the shell became 20 cm, the length of the cannon body became 3.2 meters, and the weight was 66 jin. It required 33 jin of gunpowder to be pushed. The total weight of the cannon body and the cannon stand was about one thousand jin, which actually became a thousand jin cannon.

Similarly, the diameter of the 500-kilogram artillery shells in the past became 15 cm, the weight became 28 catties, the length of the cannon body became 2.4 meters, and the total weight was about 600 kg, but in custom, it was still called the 500-kilogram cannon.

Therefore, starting from the summer of the fourth year of Zhaoxiang, the ship-based version of the Navy of the Great Qin Kingdom was uniformly called "1500 kilograms, 1000 kilograms, 500 kilograms".

However, due to the approaching cannon shape, the initial velocity of the cannon ejected will increase significantly. The benefit is that at the same distance, the cannon shells will be stronger from the earth's gravity, and the smaller the decrease will be achieved for each flight distance. If it attacks within a range of one or two hundred meters, the decrease can be controlled within one meter.

This is too advantageous in naval battles. A gunner with rich experience can adjust the gun shooting angle in advance based on the waves and the degree of shaking of the ship, and then shoot at a roughly flat angle to hit the target.

Secondly, the flight distance will naturally be greatly improved, and the effective range will reach four to five miles.

In the past, if the cannon was loaded with a shotgun, the effective range was 40-50 meters. If it was a cannon, the effective range would be increased to about 80-100 meters!

Of course, the maximum range of shotguns is far more than that, but if it is launched according to its maximum range, the effect will be greatly reduced, because the barrage of shotguns will become larger and larger, and the shotguns per unit area will become more and more sparse, and the ultimate lethality is really suspicious.

80-100 meters, which is the effective range of ordinary stair bows at this time. At this distance, the shotgun of a Qin army cannon can cause large-scale damage to it.

If used on a ship, due to the increase in initial speed, if an enemy ship is bombarded at a short distance, its kinetic energy is actually far above the thirty-centimeter communal artillery used by the Army!

According to the situation where ships of other forces are generally thin and large inflowed, as long as they hit effectively, a shell with a diameter of 25 cm is enough to destroy an enemy ship, and a shell with a 20 cm is enough to make a warship lose its combat effectiveness in a short period of time!

If you use naval cannons to bombard the enemy's coastal city walls, the effect can actually reach 1.5 times the effect of using thirty-centimeter cannons in land combat!

In other words, it is equivalent to using a land battle weighing 750 kilograms to attack the enemy city wall with Gonggong cannon shells!

......

Feng Changqing's eldest son, Feng Ce, the navy commander, stood on the first deck of the big ship, and felt a lot of emotion.

Compared with previous ships, this Caspian-class ship has not only changed the artillery loading, but also has a long inclined truss on the bow and a spinnaker is installed on it.

Behind it, the first mast, main mast, and rear mast remain unchanged. The main mast has four cross sails, and the front and rear masts have three sides. With the spinnaker on the bow inclined truss, the ship will eat more wind and will be faster.

When Fengce received the order to go north to Derbint, it happened to catch the strong south wind. After eating the wind, the ship could reach 60 miles on the west coast of the Caspian Sea. It was only more than 400 miles from Baku Port to Derbint. In other words, this Caspian-class ship arrived in one day!

As mentioned earlier, Derbint is the second largest city in the Khonsa Khanate, and it is also the castle that is the narrowest distance between mountains and seas from Baicheng to the south to Baku Port.

It is because of this that in the past, in order to deal with the nomadic tribes in the heart of the North Caucasus, the Persians built the Derbint line here, which is actually exactly the same as the Shanhaiguan line in China.

The city of Derbint is stuck in the narrowest place, with its east gate only one mile from the harbour!

Moreover, they built a city wall just a distance of this place!

However, it is precisely because they mainly dealt with the northern nomads, and they are almost unprepared for the port on the south side of the city wall (nomads cannot be stronger than the Persians at sea). At this time, if the Qin Navy's cannons can bombard the city wall in the harbor, it is very likely that this section of the city wall will be destroyed and then attack its east gate along this section of the city wall!

Feng Ce and his friends set out in the early morning. It was almost dusk when they arrived here. In the port of Derbint, Ma Lin, the general manager of the Great Qin Kingdom who had been waiting for his guide to the south, personally told him about the city of Derbint in front of him.

"Xiaofeng, look, each side of the Derbint Castle is about two miles, a total of eight miles, but there are walls that extend from the sea to the mountains west of the castle, and it stretches for about a hundred miles in total. Just like the side walls of the Tang Dynasty, they are all built on steep mountains, and it is impossible to break through the mountains."

"Even if it is broken, it is impossible to pass the army. So I can only deal with the castles and walls by the harbor. The castles here are not as wide as the Persian hinterland, but their solidity is no less than the Persian rammed earth walls. They do not have rammed earth, and they are all made of neatly polished white stones. The average height is about three zhang and the average thickness is about one zhang. The stones are glued with clay mixed with fish glue, which is very reliable."

"If you use Gonggong cannons in land warfare, it will probably be effective if it hits ten days and half a month. However, in that case, our country's treasury will be tight. But if you use Gonggong cannons in ships, I guess it will be enough for up to three days."

Feng Ce nodded, "Don't worry, General, start the test of the cannon now."

"boom......"

The first thing he started was a five hundred kilogram cannon. In fact, based on the initial speed, his 15-centimeter shells caused damage to the city walls more than that of the Land War Gonggong cannon. The 16-fold speed cannon made a roar after instantly igniting and pushing out with fourteen kilograms of black gunpowder.

At this time, the artillery was aimed at the section of the city wall about a hundred meters away. When the artillery shot the shells at a five-degree elevation angle, there was almost no movement except for a broken sound in the distance.

However, when Ma Lin put down the telescope, the voice was also trembling.

"It's hit! The stone is broken!"

Feng Ce followed his fingers and looked at the telescope. He saw that the twenty-eight-pound shell hit a white stone into two pieces, and the black gap was clearly visible in the telescope!

However, such shells have no other effect on the city walls made of all of them, which are more than three meters thick than the city wall, except for breaking the rock.

"boom!"

The second thousand-pound cannon was blew up. Compared with the five hundred-pound cannon just now, its roar was lower. The 66-pound cannon did not hit the city wall because a swell happened to come from the north just now, which suddenly raised the side of the ship a lot.

"boom!"

According to the rules of the Qin army, when the navy tests artillery, all the artillery on both sides of the ship's side are loaded and fired one by one. If the gun in front does not hit, the artillery of the same amount is allowed to start testing the second artillery immediately!

This gun had a perfect grasp of the waves. The gun was fired just as the swell had retreated. This time the attack was also very effective. Not only did it break a huge rock, it also cracked it into several pieces!

Ma Lin's eyes became more and more excited. He was waiting for the most powerful cannon on the ship to test the cannon.

"boom......"
Chapter completed!