What are the main difficulties in aircraft carrier manufacturing?

Most of the hull can be penetrated (it is not guaranteed to be world-class, but it can be used anyway). The difficulty is to control the weight of the hull. China's technology is so crude that it needs more steel to build a ship with the same displacement. If we want to strengthen local strength, reduce noise and strengthen hull vibration, we need to build more structures, need better engines with higher thrust, consume more fuel, draw too much water and be hit by torpedoes more easily. It is not easy to load a considerable number of fighters, and it is more stable after injury. Welding, in fact, the most important thing in shipbuilding is welding, and the welding quality seriously affects the performance of ships, especially warships. However, the extensive low-quality welding can meet the needs of civil ship construction, and there are not many orders for military ships, which leads to the development of marine welding seriously unable to keep up with the needs of aircraft carriers. Marine equipment, China basically can't, from engines (Ukrainian) to catapults (as if they were borrowed from Europe), are basically copied or bought, and Japan and South Korea have completely bombed us, not to mention the old United States and Europe. Whether a ship is advanced depends on its equipment, just like a person, not by his appearance and background, but by whether he has goods in his stomach.