The offshore converter platform (OCP) functions as a substation to transfer energy generated by offshore wind turbines to an onshore substation to be widely distributed. This paper focuses on the temporary stools and upper grillages that structurally support the OCP topside during the fabrication stage. At the yard, one of the issues is temporary stools exposed of buckling and settlement, which will affect the structural integrity of the temporary stool in supporting the weight of the topside. Therefore, this analysis aims to determine the correct configuration and dimension of the temporary stools to function as an effective support for the topside. By utilizing the SACS software to conduct global structural analysis, the stress of each temporary stool and topside member is found, and the critical temporary stool location is analyzed further with ANSYS for finite element analysis to locate the local stress and deformation with a non-linear approach. Static analysis results in normal and settlement conditions indicate overstress as the UC member and deflections on the structure surpass the allowable criteria. Therefore, there are three modification iterations for the temporary stool, in which the third modification with the temporary stool dimension of OD323.9 × 17.48 obtained a maximum stress of 302.58 MPa and maximum deformation of 5.705 mm. To conclude, this temporary stool configuration and dimension is able to support the fabrication process of the topside structure and can replace the OD323.9 × 12.70 temporary stool, especially in critical locations.