Reducing vessel resistance through grid orientation Protective grids at bow-thruster openings interact with the external hull flow and can therefore influence vessel resistance. Aligning the grid bars with the incoming flow appears to be the hydrodynamically favourable solution, as it minimises the direct resistance of the grid itself. The CFD analysis showed that the overall behaviour is governed by more than the grid resistance alone. The transverse grid orientation changed the flow through the bow-thruster tunnel and the surrounding pressure distribution, ultimately resulting in the lowest overall vessel resistance.

