Most of China’s offshore FPSOs are single point mooring models, with the application of internal turret single point mooring systems being the most common. Their iconic structures are buoy and hydraulic locking mechanisms. The hydraulic locking mechanism is installed on the deck inside the moonpool, usually with 8–12 hydraulic locking arms to clamp and lock the buoy, integrating the single point mooring system with the entire hull and achieving rapid reconnection and release of the FPSO offshore. The hydraulic locking mechanism bears all the vertical loads of the single point mooring system and is one of the key load-bearing structures in the floating internal turret single point mooring system.