Propeller Roughness

1. Poor hull condition has often been noticed to be as a cause of fall off in performance with time in service, although in practice a significant contribution to the reduction in performance may well have been due to propeller roughness
2. Admittedly, in absolute terms propeller roughness is less important than hull roughness, but in terms of energy loss per unit area, propeller roughness is significantly more important
3. In economic terms, high standards of propeller maintenance are therefore more cost - effective compared with hull maintenance
4. The twin propeller application with twin rudders, the roughness control is to be maintained in similar way that with propellers and with hull