The Design of a Marine Structure must be carried out based on the analysis of the functions to be fulfilled by the structure and of the expected extreme operational loads, but also based on a detailed analysis of the extreme environmental conditions (such winds, currents, tides, waves) on which the structure will be subject to, in order to ensure a sustainable investment. The role of the designer is to ensure its resistance to extreme combined loads while controlling the cost of the structure. At the same time, the impact of the marine structure on the marine or coastal environment should be carefully assessed and minimized.