Tetrahedron is working on a new design for large offshore cranes that can lift higher. This is necessary due to the increasing size of offshore wind turbines, and the inability of the conventional cranes to scale up without needing a larger ship that is carrying them. To compute the forces working on the trusses of the crane structure, Tetrahedron has developed the software program Automatic Crane Engineer (ACE). Right now the program can already optimize the cross-sectional area of the bars, but the optimization should be extended to include the shape of the structure itself. The goal of this research is therefore to extend ACE with the necessary functionalities to perform shape optimization of the cranes. The research to achieve this goal is structured in two phases. In the first phase, the literature review part, the two research questions have been answered: the formulation of the crane optimization problem is defined and the best optimization methods for this problem have been chosen and implemented in Python. These are the Interior point method as proposed by Byrd, Hribar and Nocedal and the Method of moving asymptotes by Krister Svanberg. As a third method, the Sequential Least Squares Programming method by Dieter Kraft is also tested. The Method of Moving Asymptotes seems the most promising for the crane optimization problem.