Towing Operation Methods of Offshore Integrated Meteorological Mast for Offshore Wind Farms

Abstract

An offshore integrated meteorological mast (OIMM) is introduced which has great application potential for the development of offshore wind turbine power. This innovative OIMM features in two aspects: the integrated construction and the integrated transportation. Its integrated techniques enable this OIMM to be prefabricated onshore and transported by a relatively small tugboat to the installation site. It is efficient in construction, rapid in transportation and saving in cost. The towing process is an important section for the integrated transportation, which makes the towing operation necessary to investigate. With the numerical simulation software MOSES, the hydrodynamic behavior of the towing operation is investigated. Two special wet towing methods (surface towing and submerged towing) are adopted and analyzed in terms of the towing resistance, towing speed, fairlead position and the motion response. The results show that for both towing methods, to obtain a higher speed by increasing the towing force is uneconomic since the towing resistance increases a much higher percentage than the towing speed dose. Surface towing has a smaller resistance but larger motion response compared to submerged towing. The submerged towing shows a clear descending heave motion. The heave and pitch motions are smaller with the lower fairlead position and fluctuate less with deeper submerged depth.