Optimisation of a corrosion-protective coating for a new boat landing system used in offshore wind turbines

Driven by the highly increasing demand of clean energies, offshore wind farms have experienced a great development over the last decade. In this context, maintenance and repairing operations constitute a significant issue during the exploitation of wind farm installations, with the access to wind platforms being a critical point of the process. Most of these operations are performed by using service vessels approaching to boat landing systems, which are basically secondary structures attached to the main structure of the wind turbine. Two conditions must govern the service vessel-boat landing system interaction: the safety of the personnel completing the maintenance and repairing works, and the structural reliability of the proper boat landing system. In this regard, such reliability is mainly jeopardised by the aggressive marine environment, which may cause corrosion processes if the structural material is not conveniently protected. The main strategy to avoid corrosion in this type of structures is to provide protective coatings, which in this particular case must have an adequate behaviour not only against the proper marine environment, but also against the abrasion and the impact loads generated by the violent contacts between the service vessel and the boat landing system. These could, eventually, eliminate the protective coating and let the structural material directly exposed to the marine environment. This work develops a comprehensive analysis to define a protective coating that provides simultaneously an adequate corrosion protection and a sufficient resistance against abrasion and impact loads. The final solution consists of 3 consecutive layers: thermal sprayed aluminium, a two-component polyamine cured pure epoxy, and a two-component chemically curing aliphatic acrylic polyurethane topcoat.