Marine Engineering

These consist of hydro-dynamically based thrust augmentation devices also called as energy saving devices. These devices can be considered to be operating in three basic zones of the hull as follows i.   Located before the propeller. ii.  Located at the propeller. iii. Located after the propeller. Before the propeller 1. Pre-swirl Stator (PSS) It consists of a set of blades right in  front of the propeller. The aim is to  reduce the rotational losses in the  propeller slipstream by introducing a  rotation in the inflow to the propeller. PSS increases the hull efficiency and  hence the total propulsive efficiency.  DNV classification society has  reported a 6% power saving in design  draught but just about 1% in ballast  in a Kamsarmax bulk carrier that gives  indication of the potential of PSS for  the full form vessels. 2.  Becker Mewis Duct It is a Pre-swirl Stator with  Accelerat...