Orwell Offshore has carried out studies relating to the Side-To-Side (STS) offloading of LNG carriers. These have ranged from the studies of possible mooring arrangements and the deployment of fenders between vessels, through to the analysis of vessel motions moored side to side.

Using design software in conjunction with hydrodynamic analysis tools, Orwell Offshore can provide detailed studies of mooring arrangements, including line lengths and relative positions of vessels at all points during the loading/offloading process.

Using Bureau Veritas’ HydroStar program, motions of vessels in STS mooring configurations can be analysed. HydroStar is a three dimensional potential flow solver, which provides a complete solution to first order problems of wave diffraction and radiation. It is able to assess the motions of multiple bodies and the effects of their interactions on motions.

Using the vessel motions output from HydroStar, Orwell Offshore is able to carry out studies on the operability and downtime of vessels in specific sea states and loading conditions. Using OrcaFlex, offloading hoses and mooring lines are able to be modelled accurately, enabling time domain simulations to be carried out on vessel motions in realistic sea states.