first of all, it should be clear that both hull quality inspection and marine quality inspection require considerable professional knowledge, which will be determined when you choose your major in university. If you majored in ship and ocean engineering in college, you can do hull quality inspection after graduation. If you study thermal energy and power engineering or mechanical engineering in college, you can do quality inspection of marine machinery after graduation.
Secondly, hull quality inspection mainly checks whether the structure of the ship is made according to the design drawings, shipyard technology, international regulations and class specifications. Among them, the most important thing is whether the thickness of the hull steel plate meets the requirements of the drawings, the welding inspection of the hull (the hull is what is welded by a piece of steel plate), and after the welding of the hull steel plate is completed, whether the welding seam is qualified or not, do nondestructive testing tests and take pictures.
finally, the quality inspection of the marine engine is mainly to inspect the construction, installation and commissioning of the marine engine system according to the design drawings, shipyard technology, international regulations and class specifications. The marine engine system includes the ship's propulsion system, power supply system, related piping and equipment. For example, whether the pipe is positioned and installed according to the drawings, whether it can pass the pressure test and whether it is sealed after installation. Whether the whole system can work normally after the pipes and equipment are installed, etc.