With the commissioning of steelmaking open-hearth furnaces, the quality of steel for East Friesian Lamberan cannons changed substantially. Before the pen "Fun" Pavilion www.biquge.info, Marin just asked old John and other cannon casting craftsmen to use high-quality wrought iron smelted in a reverberatory furnace, although the quality was better than that of other European countries' artillery, but the strength of the cannon body was not enough.

After all, wrought iron is soft, and it is used to cast artillery, and the toughness is enough, but the strength of the pipe wall is not enough. So, the artillery needed to be cast very thickly.

But now, thanks to the use of open-hearth furnaces, Marin has medium and low carbon steel, which is more suitable for casting cannons. Although it is said that due to technical limitations, Marin's current craftsmen are not skilled in controlling the carbon content, resulting in unstable steel quality, medium carbon steel is often smelted into low-carbon steel, and low-carbon steel is often smelted into medium-carbon steel (high-carbon steel quality is a good control point, using graphite clay lining can be used, similar to the crucible steelmaking method). But in any case, as long as it is not high-carbon steel, it is suitable for casting cannons, which is much better than wrought iron cannons.

So, after using steel, the gun body can also be "slimmed down......

To this end, Marin gave the foundry the task of developing a large-caliber, short-barreled Karen naval gun (also called the Karon gun......

In fact, Marin was assigned a total of two artillery research and development tasks. John Sr. and his team were mainly responsible for upgrading the original 12-pounder wrought iron heavy gun. Marlin's request was that the total weight remain the same, but the caliber should be upgraded from 12 pounds to 18 pounds. In other words, after the upgrade, Old John's iron cannon became an 18-pound "Hongyi cannon".

The second task is to develop a large-caliber, short-barreled Karen naval gun. However, this team is not with John Sr.'s team. The main craftsmen of this team are the group of local blacksmiths who Marin went to help Old John learn his skills.

Now, years later, these blacksmiths are also skilled at casting 12-pound wrought iron cannons. This time, Marin separated them separately and set up a new R&D team to begin the development of large-caliber, short-barreled Karen guns. After all, John Sr. was British, not his own. Important things, Marin still believes in his own people more. Therefore, he used this group of artillery craftsmen from his own serfs to make Karen cannons.

As a military and nautical fan, it is impossible for Marin not to be unaware of the place of the Cullen gun in the British Navy. The Cullen's close-range fire within 500 meters was a key to the Royal Navy's victory.

The Cullen cannon has two major advantages: first, it has a large caliber, and it can shoot heavy iron balls to smash enemy ships. The larger the iron ball, the more likely it is to smash the hull of an enemy ship. The Peksan cannon of the mid-19th century is an outstanding representative of this. The weight of the shell alone of 68 pounds could easily smash through the thickly reinforced side of an enemy ship.

Although, to destroy enemy ships, the Pexan artillery relied mainly on explosive shells. However, if it could not smash open the side of the enemy ship and explode inside the enemy ship, the Pexan cannon would not be so powerful, and the destructive power of the battleship would be limited. Therefore, the weight of 68 pounds of its shells is also very important. The Peksan cannon is a classic large-caliber, short-barreled heavy gun, which belongs to the upgraded and strengthened version of the Karen naval gun.

Second, the Cullen gun had a fast rate of fire. The longer the barrel of the front-loading gun, the more difficult it is to reload and the longer it takes to load. At the same time, the long-barreled artillery, because it was much heavier than the Karen gun of the same caliber, was also difficult to reset.

For example, the 32-pound Cullen gun weighs only 771.8 kilograms and is only 1.2 meters long. The 18-pound "Hongyi cannon" weighs 2 tons, that is, 2,000 kilograms, and the gun body is about 3 meters long.

In other words, the shells of the 32-pounder Cullen cannon weighed almost twice as much as the "Hongyi Cannon", but the weight of the cannon was only about one-third of that of the "Hongyi Cannon...... If you change to a 32-pound long-barreled cannon, God knows how much......

The heavier the gun, the more difficult it is to reload, but it is also very troublesome to reset, and many sailors are needed to help move the gun to reset. The heavier the artillery, the more difficult it is to reset.

This also leads to the fact that for the same caliber of artillery, the Cullen gun is much easier to reload or reset. Then the average rate of fire was naturally higher. Generally speaking, a skilled Royal Navy artilleryman, using a long-barreled heavy gun, will take at least 2 minutes or more to fire a shot (Note: Because of the complex environment on board, the rate of fire is slower than on land. Because, the artillery of the battery on land is not easily displaced, and the recoil is directed to the ground, but there is no need to reset, which saves a lot of time and has a higher rate of fire. ）。 And the Karen cannon, it only takes about 1 minute to fire a shot.

……

Although, the long-barreled artillery has a longer firing range. Perhaps for bombing land targets, long-barreled guns are more effective, and shore defense artillery is also more suitable for long-barreled guns. However, in naval battles, the range of long-barreled guns is meaningless.

Because, as a carrier of artillery, the warship cannot help shaking on the sea surface because of the relationship between wind and waves and the recoil of artillery. Especially in the era of wooden boats, the hull was more affected by the sea conditions and swayed more.

And the side guns of the naval guns, that is, transverse. The ship is rocking, and it is basically rocking horizontally. This was a tragedy, as the broadside guns could not lock on to the target when aiming at the enemy ship. You've just taken aim at the enemy ship, but the hull shakes, and the angle of fire immediately changes. The distance is short, but the distance is about long, and a slight change in the shooting angle will cause a large error.

So, on a rickety battleship, the range of the guns is meaningless. The longer the range, the greater the error......

Of course, this is at sea. If it is in the area of inland lakes and lakes, it is a different story. For example, during the Second Anglo-American War (1812-1814), the water battles on the inner lakes on Lake Erie and Lake Ontario caused the long-barreled guns on American warships to be more calmly aimed at British ships and bombardment ships outside the range of British warships Cullen. The British ships were all equipped with Cullen guns, which had a short range and could not hit American ships. When they wanted to get closer, the American ship ran away and played the British ship like a "kite". Therefore, it is not appropriate to equip the Cullen cannon with a short range. If you encounter the kind of rogue play of the United States, you may suffer a loss. Of course, when it is changed to the Atlantic, the hull is shaking badly, and this obscene tactics of the US military may not be useful. On the inner lake, because of the calm wind and waves, the long-barreled cannon shooting is more accurate.

After this battle, the British finally realized that it was not possible to use only the Cullen cannon. If you encounter a scoundrel like Lao Mei, you will suffer. So. Later, on British battleships, the Cullen cannon and the long-barreled cannon were used together. In close combat, the main use of the Cullen cannon is to destroy enemy ships. And when the distance is long, they use long-barreled guns to bet on each other's hit percentage......

However, above the sea, if the distance is too far, even if the long-barreled cannon has enough range, it will basically not be able to hit. Therefore, when the British warships fought at sea, they basically got within 500 meters of the enemy ships and gave full play to the advantages of the Cullen guns.

Even, the Royal Navy has a tactic of shooting closely. For example, the "Battle of Trafalgar" in which Nelson was killed was because Nelson's flagship "Victory" and the French capital ship "Awe" bombarded each other, and even a broadside battle occurred. Nelson himself, because of his proximity, was targeted and killed by the French musketeers.

In short, in naval battles in the era of sail warships, the closer the distance, the higher the artillery hit rate. If it is sideways, it is basically a bomb and an accurate. At that time, everyone was completely comparing calibers.

But at long distances, even at a distance of 500 meters, the hit rate of naval guns was surprisingly low, only one or two percent. If you hit from a distance, you will win the lottery......

There is experience in the ready-made British Royal Navy, why not Marin? Therefore, Marin ordered the development of the Cullen cannon, and in the future naval battles, it was also necessary to shoot closely, and use the heavy shells and high rate of fire of the Cullen cannon to directly defeat the enemy ships......

However, Marin didn't want to take too many steps to avoid hitting the egg. Therefore, Marin asked the newly independent local artisan foundry to develop the 12-pounder Cullen cannon first. Wait until the technology matures, in the development of 18 pounds. Then, and so on, advance to 24 pounds. Then, march on the most common 32-pounder Karen......

Of course, in this era, the success rate of heavy artillery casting is very low, and generally there is no success rate of 20%. In other words, the scrap rate is as high as more than 8%.

But Marin often went to forums in his previous life and knew how it worked. It is because, in this era, there was no "Rodman Law" that appeared during the American Civil War.

The so-called Rodman method is the "controllable cooling technology of the inner mold" when casting the gun. Specifically, it is to make the inner wall of the barrel cool no slower than the appearance. In the case of natural cooling, the outer layer is cooled first, and then the inside. However, in this way, due to the reason of thermal expansion and cold contraction, it is easy to cause the outer barrel to shrink first, squeezing the inner layer of "thermal expansion", which is easy to cause internal cracks in the gun body, and then lead to scrapping.

However, if the "Rodman method" is used to accelerate the cooling of the inside of the barrel, it is not easy for the outer layer to have a "hoop" effect on the inner layer, and it is not easy to produce internal cracks. In this way, the success rate of casting heavy artillery has been greatly improved, reaching more than eighty percent. Moreover, the service life is also longer, even five times longer than that of guns cast in the old way......

Marin gave the principle of the "Rodman Law" to these cannon smiths who were born in their own serfs, and asked them to cast cannons according to this principle.

Of course, how to speed up the cooling of the inner wall of the barrel, Marin only knows the principle, not the process. This point needs to be explored by the artillerymen themselves. Once successful, it will be convenient to cast heavy artillery later......

At that time, the Marin warships will use heavy artillery to bomb all the warships of any opponent who dares to compete with him for supremacy at sea......