Traveling through the late Ming Dynasty to promote Chinese civilization

Chapter 253: Do We Need Heavy Artillery?

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After listening to Liang Xiaoming's introduction, Liu Ye was pleased but also raised a question: "Since explosive shells are so good, why did we only use shotgun shells and solid shot before? And this bombardment doesn't sound like it's particularly difficult to operate, so why didn't we just equip it in large quantities from the beginning?"

Liang Xiaoming touched his flushed cheeks and laughed, “It’s not as simple as you think. Accidental shell explosions were unavoidable even in the 17th century, let alone in the more technologically primitive 17th century. If the shell were detonated due to carelessness, and the gunpowder exploded in the process, it would be a disaster for expensive warships. So before the Pexamin bombardment, warship commanders were reluctant to put explosive shells on board – the combat effect was not good, and there was also a high risk.”

Liu Ye nodded: "That is indeed a very real problem."

"As for why bombardment guns weren't equipped before, the reason is quite simple: although the barrels were slightly shorter than cannons and the weight was much lighter than cannons of the same caliber, the explosive shells fired by the 8-inch bombardment guns commonly used in the 19th century weighed about 30 kilograms, which is about 68 pounds in British units. The gun barrel alone weighed 3 tons, not counting the more than 1 ton gun mount. Such heavy guns were not even possible on the 280-ton displacement Wuxiang-class, let alone the 500-ton Wuyi-class."

"68 pounds? My goodness!" Liu Ye exclaimed in astonishment. "This shell weighs almost as much as our mortar, right?"

Liang Xiaoming nodded: "The explosive shell fired by a 10-inch mortar weighs 80 pounds, which is indeed not too far off."

“I understand. The bombardment cannons are too heavy for the Wuxiang and Wuyi classes. Instead of forcing a few of these heavy cannons on, it would be better to equip them with more lightweight Caron cannons, so that they can take advantage of their mobility while ensuring sufficient firepower.”

"That's right. Equipping the Wuxiang-class and Wuyi-class warships with bombardment guns is like a small horse pulling a large cart, it's not enough. Now that a large 1000-ton warship is about to be launched, with a suitable platform, bombardment guns can finally be put into use."

Liu Ye asked expectantly, "Has the cannon been made yet?"

Liang Xiaoming thought for a moment: "The principle of this cannon is not too complicated. The technical details have already been verified on mortars and howitzers. The difficulty lies in casting the cannon barrel..."

"What's so difficult about casting cannon barrels?" Liu Ye asked in surprise. "We've cast cannons of all lengths and sizes. Isn't it just a matter of refining white cast iron and then casting cannons using iron molds?"

Liang Xiaoming became serious: "Climbing the peak of technology is a never-ending process. Casting such a large heavy artillery piece is a completely new challenge for me. Can building a small car be the same as building a heavy truck? The barrel of this three-ton cannon has a wall thickness far exceeding that of small and medium-sized artillery pieces such as mountain guns and field guns. The biggest problem is that due to the thickness of the inner and outer walls and the large difference in surface area, the cooling rate of the inner chamber and the outer surface is different during the casting process. This causes the outer layer to cool first and the inner layer to cool later. In particular, the inner layer is under greater stress when it cools last and is prone to cracking..."

Liu Ye seemed to understand but not quite: "The principle that the outside of the cannon barrel cools first and the inside wall cools later is easy to understand. But what about the fact that it is prone to cracking under greater stress, and what are the consequences?"

"Simply put, uneven cooling between the inside and outside will cause cracks. They may not be easily visible to the naked eye, but during combat, the gun barrel will expand due to repeated firing of shells, and the cracks will grow larger and larger, eventually leading to a barrel explosion!"

Liu Ye exclaimed in surprise: "Such a big cannon, if it explodes, many people will die!"

"More than that, if such a cannon were installed on the gun deck, the entire gun deck would be open-ended with no internal cover. If one cannon explodes, it would cause other gunpowder to explode as well, and the entire ship would be destroyed!"

Liu Ye tentatively asked, "It's so dangerous, so let's not do this bombardment thing, shall we? Anyway, once all these ships in the shipyard are launched, we'll form a fleet of 12 Wuyi-class ships plus two thousand-ton warships, along with a dozen or so Wuxiang-class patrol ships to protect the perimeter. I don't believe we can't beat Zheng Zhilong."