A coupling technique for interface simulations applied to the fields of ship hydrodynamics and multiphase flow computations is presented. The technique takes advantages of mass conservation property of the volume-of-fluid method and sharpened interface computation of the Level-Set approach. An improved scheme for the gradient computation of the Level-Set function during re-initialisation is also introduced. A solver with the present coupling is built into the interFoam solver of the OpenFOAM platform. Three test cases, i.e. a free rising air bubble in still water, dam-break simulation with a hump in dry bed channel and free surface flow around a container ship are conducted to demonstrate the capability of the new solver. A good agreement between the simulated results and the benchmark and/or measured data shows the significant potential of the present technique in both academic research and practical applications.