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Even though ships are the most effective means of transport with lowest emission rates, every opportunity should be taken to decrease emissions. From a hydrodynamic perspective there are two ways of accomplishing this:
1. Increasing the hydrodynamic efficiency of the propeller itself.
2. Decreasing the drag caused by the ship and its propulsion components.
Solutions developed by Becker:
1. The uneven wake of the ship causes the propeller to work inefficiently, resulting in rotational losses which do not contribute to the generation of thrust. Our Mewis Duct® is a power-saving device assembled in front of the propeller. It features a wake equalising nozzle which harmonizes the flow towards the propeller and pre-swirl generating fins that minimize rotational losses. For bulky and slower ships (up to 16kn service speed) fuel savings of up to 9% can be achieved with corresponding reductions in green house gases, nitrogen oxide and sulphur.
2. The rudder generates about 5% of the ship’s overall drag. This is influenced by the rudder profile, the different lateral flow conditions at the top and bottom of the rudder and turbulence caused by propeller swirl and additional drag caused by rudder operations for staying on course. Becker achieves reduced resistance by implementing thinner rudder profiles employing high quality material and forged steel, twisted leading edge (TLKSR®) towards different flow directions of propeller swirl, highly manoeuvrable flap rudders generating greater steering forces and thus requiring smaller rudder angles for low resistance course keeping and reduced hub vortex by the use of rudder bulbs or in combination with corresponding propeller hub cap arrangements.
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