Swirl And Counter-swirl

A steel construction improves propulsion

The propeller is unquestionably a marvel of fluid dynamics and production engineering. But what looks so perfect also has its weaknesses. The propeller may generate the thrust needed to drive the vessel forward, but it also creates undesired swirl in its wake which reduces its efficiency ratio. Acting on the tried and tested principle of fighting fire with fire, the Hamburg-based company Becker Marine Systems has developed the Becker Twisted Fin®. A duct with an integrated fin system is fitted in front of the propel ler which produces a counter-swirl to the propeller in the upstream water flow.

The pre-swirl fin now partially cancels out the negative effect of the swirl in the propeller’s slipstream. The balance sheet therefore becomes more positive. The bottom line is a substantial energy saving, which can amount to as much as 4 per cent. Hamburg Süd is the first shipping company to use this technology on container vessels – namely on the ships of its “Santa” class.