Steady sailing performance of a hybrid-sail assisted bulk carrier

The steady sailing performance of a sail-assisted bulk carrier is investigated utilising towing-tank derived hydrodynamic derivatives and wind tunnel measured aerodynamic properties of the sails and the ship. The aerodynamic characteristics investigated include the ship hull at the fully-loaded draught, the sail–sail interaction effects for two sets of four identical hybrid-sails, and the sail–hull interaction effects for the same two sets of identical sails in the presence of the selected bulk carrier hull-form. This is in addition to lift–drag measurements of single isolated sails of each shape. The form of the two sets of soft sails was rectangular and triangular. This paper is concerned with assessing the benefits of a sail-assisted ship operation, and hence a steady-state rather than complete time-domain integrations of the governing equations are reported. The results of the completed analysis suggest that the benefits of the derived sail generated driving force are greater than the overhead of equipping the ship with a selected system of hybrid-sails. Sail-assisted ships could represent an important contribution to an improving global environment by reducing the demands for a driving force through the propeller.