This study entailed the estimation of wind loads performed using computational fluid dynamics (CFD) simulations for four typical offshore vessels and for a Floating Production, Storage, and Offloading (FPSO) and shuttle tanker in a side-by-side configuration on offloading. For all vessels, under the wind heading condition, four meshes were used to carry out the verification and validation (V&V) study to check the numerical uncertainty. The CFD simulation results for the aerodynamic coefficients were compared with wind tunnel tests from the Offloading Operability 2 JIP. All CFD simulation results show generally good agreement with the experimental data, and the overall trend of the coefficients are well captured. In addition, the effect on the gap sizes between the FPSO and shuttle tanker in the range of 4–30 m was examined. On this basis, the shielding effect was analyzed according to the size of the gap between the two ships.