What wind conditions are suitable for wind propulsion?

The most attractive wind/wave combination for an effective wind propulsion takes place between 5-8 Beaufort (BF) scale, and for some ships which sail around 10-12kn even in BF 4. The Global wind probability chart has also shown statistically that the higher range of average global wind speeds (probability over 10%) happens around 5-8 m/s, which corresponds to BF 4-5.

Therefore, the slower the ship sails, the better global wind utilization she achieves over time.

The probability of wind speed is widely scattered globally. These phenomena generate the following possible problems related to the wind propulsion utilization in the oceans:

• Ship speed is critical for the wind propulsion energy harvesting capacity,
• Wind blow direction may not coincide or be synchronized with wave direction,
• Ocean currents may also act as an extra force to the hull of the ship, thus impacting either negatively or positively wind propulsion efficiency

Because of these factors, weather routing is also highly important for optimising the wind propulsion performance.

Global winds tendencies exist in local regions. For example, in Northern Europe and in specific in the Baltics and North Sea, the wind forces are more intense and more prevalent compared to the Mediterranean Sea, with the exception being the Aegean Sea in Greece and the Southern coast of France. Therefore, despite their possible smaller sea time utilization due to regional trading, small and medium size cargo and passenger ships may highly benefit from wind propulsion devices in certain regions such as North Sea and Baltic Sea due to their smaller size and required propulsion power.

– Information courtesy of Konstantinos Fakiolas’ book ‘Wind Propulsion Principles’, Edition 1 –