Aspects of the Mean Surge Drift Force for Single-Point Moored Vessel

At many offshore locations, particularly those affected by severe metocean environments, wind and waves are essentially collinear during storms. Due to weather-vaning of ship-shaped floating units (SSFU) at single-point moorings (SPM), the surge component of the wave drift load significantly contributes to the extreme mooring line response associated with slow-drift oscillations. In this paper the effect on the surge drift force from parameters such as the bow shape and the linear heave and pitch motions of the SSFU is analyzed using numerical modeling based on linear potential theory. The shape of the bow is found to be important for the drift loads. It also influences peak loads that may develop on the bow under the largest wave heights, which might threaten the structural integrity of the fore ship.