Large ship rudderstock assembly dismounting tool and dismounting method thereof

The invention discloses a large ship rudderstock assembly dismounting tool and a dismounting method thereof, and relates to the technical field of ship repair. The tool comprises a steering engine room, a stern, an upper rudder bearing, a rudderstock, a lower rudder bearing, a dull rudder and a rudder blade, the stern is arranged at the tail of the steering engine room, and one end of the rudderstock is installed on the steering engine room through the upper rudder bearing and the other end of the rudderstock is installed on the dull rudder through the lower rudder bearing; the rudder blade is installed on the dull rudder, and a hoisting process hole is formed in the position, located above the rudderstock, of a stern deck of the steering engine room. A maintenance process hole is formed in the position, below the lower rudder bearing, of the rudder blade. The upper rudder bearing comprises a millstone, a tiller, a plunger rod pin, an upper nut, a plunger head and a hanging ring. According to the large ship r