Multi-Body Mooring System

Abstract As part of the engineering team responsible for evaluating vessel behaviour and motion, it is essential to assess critical offshore operational scenarios. One such scenario involves the mooring of a cargo barge to a construction vessel/barge operating in anchor mode, particularly during pipeline laying and structural lifting activities. This configuration affects the motion response of the construction vessel and reduces the allowable operational weather window. In other words, if the design excursions are limited to certain values for the operation purpose so weather limits to be reduced till fulfil the allowable excursions. The analyses impacted by this setup are pipeline laying analysis, dynamic amplification factor (DAF) analysis, mooring analysis, and subsea installation analysis. The primary objective of this paper is to determine the optimal mooring system (from connector’s mechanical properties point of view) between the cargo barge and the construction vessel that minimizes vessel motion under selected weather conditions. A multi-body mooring case study and its related conditions have been analysed and evaluated using MOSES software. The optimum mooring configuration corresponds to the lowest motion response of the construction vessel, thereby enhancing workability limits and ensuring safety, reliability, and operational efficiency. The selection, arrangement, and design of fenders and soft mooring lines are critical in managing the interaction between the cargo barge and the construction vessel and act as the key to achieving an effective mooring solution.