Hydrodynamic energy-saving upgrade solution: Installation of a pre-swirl guide vane (PSV) in front of the propeller (PSV has fixed blades that create a pre-swirl in the flow field in front of the propeller, increasing propulsion efficiency and reducing energy loss from stern flow). + HVAF anti-vortex fins, while trimming the propeller blades, reducing propeller load and improving engine-propeller matching. Improved main engine conditions lead to a decrease in power of about 7%~8% at the same RPM, reducing main engine fuel consumption and effectively reducing ship CII. It is expected that installing the pre-swirl guide vane will increase propulsion efficiency by about 2%. When sailing at 14kn, adding the pre-swirl guide vane and anti-vortex fin combination energy-saving device below the load, design, and structure of the 57000 fleet's sister ship can save main engine power by 13.4%, 13.6%, and 12.5%, respectively, compared to a non-energy-saving device.