- Lengthening, Powering
Main objective of this analysis is to establish the practical limits of ship size that can still be propelled effectively. For that purposes two typical single-propeller IWW ships were chosen – MV “Hendrik” and MV “Rheinland”. Through the analysis draught and breadth of the ships were kept constant, while different ships lengths were considered (virtual lengthening was performed within Task 6.1). Although the increase of ship length leads to the increase of ship displacement and therefore to increase of propeller loading for the same ship speed, the propeller diameter could not be changed due to limited space.
Virtual repowering was done for both vessels. Contemporary high-speed Diesel engines were considered for retrofitting (derived from general application engines applied in the road vehicles that satisfy all present requirements concerning emissions etc.) as these are more efficient, cleaner, cheaper (for maintenance too) and lighter than conventional ship engines. More advanced propulsors (then Diesel engines, conventional propellers etc.) suppose to be investigated within other MoveIt WP, as for instance WP2 – Hydrodynamic improvements, WP4 – Power etc., WP6, in general, deals with mature and proven technologies.
Amongst the lessons learned within Task 6.3, it was concluded, that the power needed for achieving certain speed is not significantly influenced by lengthening, so the same power train (engine/gearbox/propeller) was considered for all lengthening steps. Water depth, however, is the main factor that influences power.
Also, original naked propeller was replaced with a propeller in nozzle as these are considered to be more effective for IWW shallow draught vessels.