An experimental investigation on wave runup along the broadside of a single point moored FPSO exposed to oblique waves

• Wave runups along FPSO broadside are significant in non-collinear environments.
• A wider range of broadside suffers from green water events in shallower water.
• Green water tends to be more frequent with increasing severity around the midship.
• The vessel׳s vertical motions affect wave runups slightly in shallow water.
• The wave runup is higher when the gap between floater and seabed is smaller.

The Floating Production, Storage and Offloading unit (FPSO) has been extensively deployed for offshore production but often suffers from the wave runup and green water incident in harsh ocean environments. It occurs not only at the bow but also along the broadside in non-collinear environments causing damage to deck equipment. An experimental study was carried out to investigate the wave runup and green water of a 300kDWT FPSO in shallow water, considering non-collinear environments and different water depths. It reveals that the wave runup and green water along the broadside can be significant in oblique waves, especially at the locations around the midship. The water depth and the gap between floater and seabed have an important influence on wave runup and green water in shallow water condition, while the impact of vessel vertical motions is relatively small and negligible. A wide range of the broadside is seen to suffer from green water incidents in shallower water, which tends to be more frequent with increasing severity around the midship, where the water accumulates from incident waves and reflective waves. The substantial results will improve the understanding of wave runup characteristics along the broadside and provide much-needed benchmarks for numerical prediction.