Abstract: To provide the auxiliary float of a floating structure which can prolong the lifetime of the floating structure by reducing external force acting on the brace and can be used even at very deep water by increasing buoyancy, and to provide a remodeling method of the floating structure. The auxiliary float (11) comprises two floats (12) coupled, respectively, to lower portions of two lower hulls (1) constituting a floating structure, two main coupling members (13) for coupling the floats (12) to each other, and four sub-coupling members (14) for coupling the main coupling member (13) and the float (12). The auxiliary float (11) is produced in advance and the floating structure is mounted on the auxiliary float (11), and then the lower hull (1) and the float (12) are connected, thus remodeling the floating structure.

Abstract: Problems To provide the auxiliary float of a floating structure which can prolong the lifetime of the floating structure by reducing external force acting on the brace and can be used even at very deep water by increasing buoyancy, and to provide a remodeling method of the floating structure. Means for Solving Problems The auxiliary float (11) comprises two floats (12) coupled, respectively, to lower portions of two lower hulls (1) constituting a floating structure, two main coupling members (13) for coupling the floats (12) to each other, and four sub-coupling members (14) for coupling the main coupling member (13) and the float (12). The auxiliary float (11) is produced in advance and the floating structure is mounted on the auxiliary float (11), and then the lower hull (1) and the float (12) are connected, thus remodeling the floating structure.