Full-rotation crane for mariculture work ship

The utility model relates to the technical field of marine cranes, and provides a full slewing crane for a marine fishery breeding work ship, which comprises a base, a tower body, a slewing mechanism, a slewing bearing and an arm frame, the slewing mechanism is mounted on the tower body, the end part of the arm frame is hinged to the tower body, a variable-amplitude oil cylinder is mounted between the arm frame and the tower body, and the variable-amplitude oil cylinder is hinged to the slewing bearing. The two ends of the amplitude variation oil cylinder are connected to the arm frame and the tower body respectively, and amplitude variation of the arm frame is achieved through stretching and retracting of the amplitude variation oil cylinder. A front arm is arranged at the front end of the arm frame, a main pulley is installed on the front arm, and a protection frame is arranged on the outer side of the main pulley. The crane can be more suitable for ocean hoisting working conditions with large-volume loads,