Leading the way in eco-conscious shipping
The Becker Mewis Duct® is one of the most efficient energy-saving devices on the maritime market. It improves the efficiency and environmental compatibility of ships. On average, energy savings of up to 10% can be achieved on slow and full-form ships such as tankers and bulkers.
The Becker Mewis Duct® improves hydrodynamic efficiency by optimising the inflow to the propeller. This leads to a reduction in the required propulsion power and thus to a direct reduction in power consumption and CO2 emissions. This energy-saving device is therefore particularly relevant in the context of the current requirements of the International Maritime Organization (IMO), especially with regard to the Energy Efficiency Design Index (EEDI), the Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII). Thanks to the improved efficiency of the propulsion system, ships equipped with a Becker Mewis Duct® can improve the EEXI value and reduce the CII rating.
The Becker Mewis Duct® can be installed during regular dry docks. It is not necessary to remove the propeller. This measure offers an effective and comparatively simple way to fulfil the current and future IMO requirements.
By continuously improving and adapting these technologies, Becker Marine Systems remains an important partner for ship owners worldwide and actively supports the goals of Green Shipping to reduce pollutants and emissions in the maritime industry.
Easy installation for newbuildings and retrofits
Newbuildings
Installation of the Becker Mewis Duct® can easily be performed during the docking or block stage with minimal effort on part of the shipyard. The yard is able to implement the installation in the production schedule.
The Becker construction team adapts the interfaces of the Becker Mewis Duct® and the ship according to the ship’s steel structure.
Retrofits
The Becker Mewis Duct® can be retrofitted during regular dry dockings or even intermediate dry dockings, the propeller does not have to be dismantled for this. Becker’s expertise ensures that installation is performed as quickly as possible, taking five days on average. Installation is carried out by the yard under Becker’s supervision to ensure professional installation. The Becker Mewis Duct® design of the interfaces to the ship provides the highest strength and stiffness in accordance with classification societies.
Advantages of the Becker Mewis Duct®
- Reduction of fuel consumption and CO2 emissions by improving the hydrodynamic efficiency of the propeller
- Supporting ship owners in fulfilling IMO requirements regarding EEXI and CII
- Easy installation during regular dry docks
- Reduction in operating costs through savings in propulsion power of up to 10%
- Wide range of applications and proven effectiveness: over 1,600 ships already successfully equipped with Becker Mewis Duct®
Optimisation of ship propulsion with the Becker Mewis Duct®
Wakefield equalisation
The Becker Mewis Duct® straightens and accelerates the hull’s wake into the propeller and usually also produces net forward thrust (Illustration 1).
Reduction of propeller hub vortex
An optimised flow field behind the duct significantly reduces the hub vortex, leading to improved thrust and flow towards the rudder (Illustration 2).
Contra-rotating swirl
Due to individually placed fins, a counter-rotating pre-swirl to the direction of propeller operation is generated, recovering rotational energy from the propeller slipstream (Illustration 3).
The Becker Mewis Duct® combines all three of the hydrodynamic principles: The Becker Mewis Duct® harmonises and stabilises flow and generates a pre-swirl to reduce the rotational losses in the propeller slipstream. This generates additional thrust. The fins are asymmetrically profiled and arranged to generate a homogenous flow distribution.
In summary, the Becker Mewis Duct® is a very flexible approach to reduce losses in the aft ship flow since it can handle very different ship wakes. Depending on the application, it can also be designed as a device, which focuses on the generation of pre-swirl for slender or highly optimized vessels. Alternatively, the duct ring can be optimised to gain losses within a non-uniform ship wake.
The Becker Mewis Duct® is most effective on
- Bulker
- Gas carriers
- General cargo
- Tanker
Evolution of the Becker Mewis Duct®
Becker Mewis Duct®: Designed to make shipping more efficient and environmentally friendly.
The fin and nozzle profiles have been optimised with twisted fins to enhance the pre-swirl effect.
The duct design has been modified from a full ring to a semi-ring to reduce drag.
The duct has been extended with fins.
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