Research on a cost-effective measure dedicated to stabilizing offshore wind farm crew transfer vessels

The rapidly growing offshore wind industry is calling for more crew transfer vessels to deliver increasing number of minor maintenance tasks as about 75% of onshore wind turbine failures are related to the minor errors occurring in the electrical and power electronic systems of the turbines. The situation in offshore wind farms may be worse due to the wet, salty and corrosive air in offshore environments. Due to the limitations of small hull and deck spaces, there is difficulty to apply the proven motion stabilization techniques to wind farm crew transfer vessels. Consequently, the present crew transfer vessels have limited capability in providing safe transfer between the vessel and wind turbines, particularly in rough sea waves. To tackle this issue, a new motion stabilization technique is studied in this paper by using both numerical analysis and experimental testing approaches. Through investigating the vessel's motions under different wave conditions before and after applying the proposed technique, it is found that the heave, roll and pitch motions of the vessel, especially in its resonant frequency regions, have been successfully constrained after applying the proposed stabilizing technique. Moreover, the amount of motion reduction can be further improved through optimizing the size of stabilizers and their underwater distance.