This paper reports a preliminary 3D numerical study of submerged oil spilling from a damaged Double Hull Tanker (DHT) using a VOFbased multiphase flow solver within the framework of the open-source CFD package OpenFOAM. In order to reflect the different features of two typical oil spilling scenarios, i.e. grounding and collision, two cases with spilling holes being located on the bottom and side wall of the DHT, respectively, are simulated. The numerical results are compared with the experimental data. Satisfactory agreements are achieved. The hydrodynamic features, particularly the role of the viscosity and turbulence effects, are discussed.