Marin's worries became a reality. Through the information brought by some businessmen, he learned that the Frisian aristocratic republic across the sea was very dissatisfied with Marin's aggressive recruitment of Frisian fishermen.
Most of the harvest of these Frisian fishermen was handed over to the nobles of Frisia. However, Marin's recruitment of them was tantamount to directly robbing the interests of the Frisian nobles.
Therefore, the parliament of the Frisian Noble Republic in Groningen is discussing whether to teach Marin some lessons...
These Frisian nobles did not dare to kill Marin. That would break the rules and offend the emperor, giving the emperor an excuse to annex. However, it is no problem to send troops to attack Texel Island, plunder it, and bring back the recruited Frisian fishermen by the way, and others will not gossip. Because it was Marin who robbed the Frisian fishermen first.
Of course, Marin will not sit still, so he plans to strengthen the defense of Texel Island...
Although Texel is an island, it is quite special. Because, this island cannot be landed on all sides.
Mainly, two-thirds of the coast around Texel Island is a very shallow shallow sea area. Whenever the tide ebbs, two-thirds of the shallow sea around Texel Island will turn into silt-stacked beaches. After high tide, it becomes a shallow sea again. If a ship is sent to land in these areas, the ship can easily run aground. Small boats are fine, big boats must not approach the coast in these areas, or they will definitely run aground.
In the entire Texel Island, only the Mars Waterway in the southern sea area and the Odesschild area on the southeast coast belong to areas with sufficient water depth, which is suitable for larger ships to dock and land.
Therefore, to guard against the attack of the Frisian noble republic, it is enough to deploy defenses in the coastal areas of the south and southeast of the island. Among them, the focus of defense is on the two places of Thorenche and Odesshild and the nearby coast.
The most effective way to defend against ships attacked by the Friesian Noble Republic is probably to build forts. The fort can place heavy artillery to bombard the incoming enemy ships.
Moreover, forts are generally built of stones, which are highly resistant to iron ball shells. Ships, however, are different. Today's ships, until the mid-19th century, have wooden hulls. The anti-strike ability of iron ball shells is very limited. The wooden warship and the coastal defense artillery in the stone fortress are bound to suffer. Moreover, coastal defense guns can be made very large and heavy, and they are full of power. The artillery on wooden boats is often subject to great restrictions and cannot be made too heavy. Otherwise, if a small boat is equipped with a cannon, the recoil of the cannon might overturn the wooden boat.
As a result, Marin immediately made a decision to build coastal defense forts in the two ports of Thorenche and Odesschild to guard against possible attacks from the Frisian Noble Republic.
Texel has no cannon-making ability, nor cannon-making craftsmen. It is still the end of the 15th century, and the cannon-casting craftsmen are definitely considered the top talents in Europe. Even in those big countries, craftsmen who can cast cannons are high-end talents. Marin can easily recruit gun craftsmen, but it is difficult to recruit cannon craftsmen. Therefore, he can only choose to buy guns.
To this end, Marin sent people and hired Jewish businessmen to help them find out the source of the artillery...
After inquiring, Marin learned that the level of cannon casting in the Holy Roman Empire was very average, and only small bronze cannons could be cast for land warfare. This is because the Holy Roman Empire is a land-based country. Moreover, the southern part of the empire is close to the Alps, and the artillery needs to be portable and able to cross the Alps. Therefore, the cannon cannot be made very large. The artillery needed for coastal defense forts must be heavy artillery. Therefore, the artillery of the Shenluo Empire obviously does not meet the requirements.
In addition, France is also a country that attaches great importance to casting guns, and its casting technology is good. However, Marin lost a lot of face because of Charles VIII. Therefore, it is impossible to buy guns from the French.
Therefore, Marin can only turn his attention to other countries-Britain, Portugal and Spain...
However, the feedback from the people sent out is not very good...
According to the feedback from the people sent to Spain and Portugal, the most popular in Spain and Portugal at present is the bronze breech-mounted cannon—that is, the Fran cannon as it was called in the Ming Dynasty.
This kind of gun has a range of only 2,000 feet (666 meters, recorded in the Ming Dynasty), and it is absolutely not suitable for coastal defense guns. Even if it is used as a naval gun, its power is a little too small.
However, because the age of sailing has just entered, Europeans do not pay much attention to the power of naval guns. Therefore, it is reasonable to popularize such a small powerful bronze cannon. The development of artillery technology in Europe was around the 16th century. Due to the needs of naval warfare, heavy artillery such as the "Hongyi Cannon" was developed.
Moreover, bronze artillery cannot be made with a large caliber at all. Because, bronze has a major flaw - it tends to soften when overheated.
Bronze cannons with smaller calibers are fine, but larger caliber ones are different. A large caliber gun has a high chamber pressure. When the gun barrel overheats, the gun wall softens. Bronze is not as soft as pure copper when it is overheated, but it softens eventually. Small-caliber guns have good chamber pressure, but large-caliber guns can easily deform the inner wall of the barrel when fired under overheating conditions because of the high chamber pressure. In this case, the artillery will be useless.
Therefore, bronze cannons cannot be cast too large, but only small and medium-sized ones. If you want to cast heavy artillery, you can only choose to cast artillery with iron. Moreover, cast iron cannons cost much less than bronze cannons. After all, before the development of the Falun Copper Mine in Sweden and the acquisition of Japanese copper by the Dutch, the price of copper in Europe was still very expensive. The cost of casting heavy artillery with a large amount of copper is absolutely high.
Marin was disappointed at first, but there was good news from the UK...
The personnel sent to Britain to buy guns were divided into several groups. The first few groups of people failed to bring good news. But the troops sent to Sussex (or Sussex) in England brought back good news.
Sussex County is located on the southeast coast of England. It has always been a developed area in the UK and is also the center of iron smelting in the UK. Since Dijon, France produced cast iron blocks in the middle of the 15th century, this technology has gradually spread to the outside world, and it was spread to Weld in Sussex, across the sea from France, more than ten years ago.
So, a cannon-casting craftsman in Weald, Sussex, began to try to use cast iron to cast cannons. Because cast iron is much cheaper than bronze.
After more than ten years of experimentation, the cannon foundry in Sussex used cast iron blocks to cast a long-barreled cast iron Koufirin cannon.
According to the description of the subordinates, this cast iron gun, which is still being tested, belongs to the 12-pound gun. Originally, the old gunsmith Johnson wanted to cast an 18-pound Kou Feilin long-barreled gun. However, the cast iron technology of this age...
When the old Johnson used the 18-pound caliber, the barrel often exploded due to steel quality problems. For this reason, Johnson Sr.'s nephew was seriously injured and disabled. In desperation, the old Johnson had to reduce the caliber without reducing the overall weight, making the cast iron gun a 12-pound class.
Old Johnson almost exhausted his family's wealth in order to develop this front-mounted heavy cast iron gun. Right now, he has only made initial progress. Old Johnson's goal was to upgrade the cast iron gun to an 18-pound heavy gun. Then, using this unique technology, find the king to receive the reward...
"The 18-pound Kou Feilin long-barreled cannon... Could it be... this is the legendary 'Hongyi Cannon'?" Marin was taken aback.
He remembered that more than a century later, the first batch of Hongyi cannons sold by the Portuguese to Ming seemed to be the 18-pound Koufeilin long-barreled cannon salvaged from a sunken British ship. And this old cannon maker named Johnson may be one of the earliest developers of the Hongyi Cannon...
"Talent, never let go!"
Therefore, Marin ordered to send people to Weald, Sussex, England, to recruit the old Johnson family to Texel Island to cast cannons for Marin.
Marin's men had already inquired about it, because there were still aftermaths of the British "Red and White Rose War", and Henry VII was still struggling to clean up the domestic opposition. Therefore, he hasn't noticed the casting of cannons yet. Old Johnson, on the other hand, is not considered a formal and imperial cannon-caster in the kingdom, but a folk cannon-casting craftsman who once collaborated with regular craftsmen to cast cannons. Moreover, Old Johnson's cast iron cannon has not yet been finalized for production, nor has it been recommended to the kingdom, let alone adopted and valued.
Therefore, Old Johnson is not yet considered a British national treasure-level cannon-caster. Therefore, it is not difficult to recruit the old Johnson, at least it will not be blocked by British officials.
Malin specially sent the mayor of Den Burg, Heidel Lerman, to lead a team to Weald, Sussex, to secretly recruit the old Johnson family. After offering a "high salary" of 1 shilling per day to the young people of the old Johnson family (the daily salary of a general craftsman is only 3 pence), Johnson, the cannon-making family, moved to Den Burg, Texel Island as a whole, and began to specialize in horses. Lin Zhupao.
As for the old Johnson's problem of bombing, Marin actually had a solution. The blasting of cast iron guns is nothing more than the pig iron used for casting guns. There are too many impurities, such as sulfur and phosphorus, which make the gun barrel brittle. Moreover, the carbon content of pig iron is too high, although its strength is high, its toughness is insufficient, so it is not suitable for casting cannons. Wrought iron and medium and low carbon steel are actually suitable for casting guns.
Regarding how to make steel, although Marin is not a professional, he has also learned a lot of theories from many time travel novels. For example, he knew that an important secret of the early British iron cannons that were not easy to explode was the use of reverberatory furnaces for secondary refining of pig iron.
The so-called reverberatory furnace is a relatively closed furnace (including air inlet and outlet). After pig iron and scrap iron are put into the furnace, the heat in the furnace cannot escape due to the relatively closed space, and after reaching the furnace roof and furnace wall, it is reflected back to concentrate and refine the iron materials. After several hours of refining, plus adding some slagging agent (the simplest slagging agent is quicklime, which can be used to remove sulfur and phosphorus). Then, after cleaning up the waste slag (because of the density problem, the waste slag usually floats on the molten iron, just fish it out), and then get wrought iron or steel (the carbon content needs to be controlled).
The well-known steelmaking open hearth furnace is actually just adding a regenerator inside the reverberatory furnace.
The British Empire fully mastered the reverberatory furnace refining technology in the 18th century, which also made the iron cannons cast by the British have excellent quality and are not easy to explode. Because the French did not understand this technology, until the early 19th century, naval guns were still easy to blow up. It was not until the mid-19th century that France and other European powers initially learned about reverberatory furnace refining technology. But then, the open hearth furnace appeared, and mankind entered the era of open hearth steelmaking. And artillery has also entered the era of forging cannons from casting cannons.
(The so-called forging gun is to place the steel column under a large hydraulic press of several thousand tons or even tens of thousands of tons, and cold forge it under high pressure and high pressure, so that the internal structure of the steel column is extremely compact and strong. Then, the forged A good steel column is drilled with a high-strength drill bit to get a very strong and durable barrel. The cast artillery, because the molecular structure of the gun body is relatively loose, can withstand a chamber pressure that is higher than that of a forged artillery of the same volume. The guns are much lower. Therefore, the early cast guns generally had thick barrels. Modern forged guns have thinner barrels.)
Marin is not a major in steel, but he has read a lot of related technical posts. He can't do it himself, but he can still direct others to do it.
Such as this reverberatory furnace, the structure is very simple. He can completely direct the craftsmen to make one, and then make high-quality wrought iron and steel. Then, cast the cannon with wrought iron or medium and low carbon steel, which is definitely much better than the cast iron cannon with a lot of impurities in this era, and it is not easy to explode the chamber.
Of course, the reverberatory furnace technology is an "advanced technology" that only appeared in the 18th century, and Marin naturally cannot disclose it casually. Therefore, he considered using serfs whose freedom was restricted to do this. Because serfs could not leave their place of residence at will, and they had no conditions to leak their technology. Even the life and death of the serf's family are in the hands of the lord, and the risk and cost of betrayal are extremely high. The craftsmen recruited like Old Johnson are free in identity. If someone else offered a high price, he might not be able to resist leaking the technology. Moreover, before the old Johnson came to Texel Island, he signed an agreement with Haider Lerman, stipulating that Texel Island should not restrict their personal freedom. In this regard, Marin must also abide by the contract. Otherwise, he would not be able to recruit more craftsmen.
Of course, those are things for later. The most important thing for Marin right now is to let the Johnson family help him cast more 12-pound cast iron guns for coastal defense.
At present, 3-pound guns, 4-pound guns, and 6-pound guns are more popular in Europe. Cannons over 10 pounds are considered heavy guns. Marin used a 12-pound gun on the coastal fort, which was definitely enough to suppress the warships of the Friesian Noble Republic.
Because, according to intelligence, on several warships owned by the Frisian Noble Republic, the largest caliber artillery is only a 6-pound gun, and it is not an opponent of a 12-pound gun at all.