Maritime Emission Manager Course

In shallow water both frictional and wave making resistances increase. The reasons are:

• Flow velocities under the hull increase as well as the wetted surfaces increase. Both of these increase the ship’s frictional resistance in shallow waters.
• The waves created under shallow water take more energy from the ship than those in deep water for the same speed. This increases the wave making resistance.

Because of the above, shallow water can have a significant impact on ship resistances. Table below shows the fuel consumption increase (%) for different water depths D in meter and speeds X in knots (MariEMS 2017).

Figure 36: Increase in fuel consumption (%) as a function of speed and water depth