Winding drum replacing and bag laying mechanism for submarine bag laying device

The invention provides a winding drum replacing and bag laying mechanism for a submarine bag laying device. Chain transmission is adopted by the winding drum replacing mechanism, paws with holes are evenly installed on a chain, and winding drums are clamped by clamping winding drum fixing buckles into the holes of the paws with the holes; a hydraulic motor serves as a power source and drives the chain to rotate in one direction in an intermittent mode through a ratchet chain wheel; when the winding drums clamped by the paws with the holes rotate to the inner side of the space below along with chain transmission, bag laying paws clamp driving buckle sets of the winding drums, the fixing buckles of the winding drums are driven to retract and not clamped into the holes of the paws with the holes any more, and the winding drums are loosened from the paws with the holes; the bag laying paws and the winding drums are driven by the bag laying hydraulic motor to rotate clockwise by 90 degrees to be located on a winding drum base, and grouting bags are wound on the winding drums through the cooperation with a crawling mechanism of the submarine pipeline outward crawling type bag laying device, and bag laying can be completed along with the rolling of the winding drums. By the adoption of the winding drum replacing and bag laying mechanism for the submarine bag laying device, laying of the grouting bags can be completed automatically underwater, and it is guaranteed that laying of the multiple grouting bags can be completed underwater at a time through the device.