Wärtsilä fixed pitch propellers are manufactured by the Wärtsilä CME Zhenjiang Propeller Co., Ltd joint venture company. At this facility fixed pitch propellers with diameters from 1 to 12 meters and up to 120 tons of weight can be produced. Since the joint venture company was established in 2004, more than 2000 propellers have been produced. Furthermore, Wärtsilä CME is able to take advantage of the extensive experience and databases of LIPS and Wärtsilä with regard to propeller design and production technology.
The propeller and shaft line design tools are based upon long experience with calculations, model test results, Computational Fluid Dynamics (CFD), and full scale results.
Propeller efficiency, noise and vibration requirements are the main considerations for propeller designs that can be applied for a wide variety of speeds and power densities, and for any type of ship. The unique Wärtsilä Cunial® propeller material provides excellent casting, machining and fatigue properties.
Monobloc Fixed Pitch Propellers are propellers casted in a single piece with the hub and blades. Wärtsilä FP propellers can be produced to meet all requirements regarding the number and size of the blades. The FP propeller guarantees maximum efficiency and minimum noise and vibration levels thanks to tailor-made designs using the latest available technology. The Cunial® material used provides excellent casting, machining, and fatigue properties. An additional advantage is the ease of reparability. A fixed pitch propeller is the choice when optimum efficiency, reliability and robustness are required. Fixed pitch propellers are usually installed for ocean going vessels, for example :
- Container vessels.
- Bulk carriers.
- Dry cargo vessels.
- Passenger liners.
Each ship’s hull has its own characteristics. In order to achieve the highest possible overall efficiency of the vessel, the propeller must be perfectly matched with the engine and hull. Propeller designs are always tailored to the specific application, and for this modern design tools are utilised by a vastly experienced hydrodynamic design team.
Wärtsilä’s hydrodynamic engineers are also specialized in high-end Fixed Pitch Propeller designs for more advanced applications, such as:
- Research vessels
- Navy vessels
These vessels commonly have typical requirements related to under water radiated noise levels.
For additional fuel savings, Wärtsilä Fixed Pitch Propellers can be equipped with Wärtsilä’s fuel saving EnergoProFin propeller cap, or with Wärtsilä’s optimised manoeuvring and propulsion Energopac solution. In cases where the propeller is heavily loaded, a High Performance Nozzle can be installed. OPTI Design produces even greater fuel savings by being able to thoroughly analyse the performance of both the propeller and the propeller-hull interaction.
- Optimal performance and efficiency, while minimizing noise and vibration levels.
- Improved vessel EEDI/EEOI.
- Tailor-made designs using the latest available technology.
- Excellent hydrodynamic guidance.
- Fixed pitch propulsion solutions for all power levels.
- Minimised propeller weights with Wärtsilä’s unique Cunial® propeller material.
- A reliable propulsion solution for all classification and applications.
- Complies with EPA Vessel Permit 2013 requirements (EAL application).
- Available with pollution free stern tube arrangement.
- Easy installation.
- Easy to maintain, good reparability characteristics.
- Increased fuel savings when used with Energopac, EnergoProFin and OPTI Design.
Wärtsilä’s extensive design knowledge and modern design tools can enable significant efficiency increases when retrofitting propellers. Existing propellers that are based on older design principles or different operational conditions, such as slow steaming, can be replaced so as to reduce fuel oil consumption. Efficiency improvements of up to 15% are possible.
The main reasons for a propeller replacement are :
- Improved efficiency.
- Change in operating profile, such as slow steaming.
- The propeller is too severely damaged and cannot be repaired.
- Upgrading of the propeller design to modern standards.
- Lower propeller induced pressure pulses.
- Poor initial design.
Each ship’s shaftline has its own design and requirements. The propeller shaft installation has a proven and effective basic design, which enables easy installation :
- Hydraulic tool sets.
- Hydraulic nut assembly.
- Hydraulic ring.
- Propeller and intermediate shafts.
- Hydraulic coupling flange.
- Hydraulic sleeve coupling.
Shaftline accessories’ scope of supply
- Efficiency rudder (Energopac).
- High performance nozzle.
- Propulsion control system.
- Build-up propellers.
- Sterntube with or without bearings.
- Seals and bearings.
- Thrust bearings.
- Torque measurement device.
- Turning device.
- Shaft grounding device.
- Shaft brake.
- Rope guard.
- Net cutter.
- Hydrodynamic optimisation and detailed propeller design.
- Shaftline design.
- Alignment calculation.
- Whirling vibration calculation.
- Jackload calculation.
- Evaluation of jackload measurement.
The OPTI Design methodology is based on years of proven experience, during which time more than 10,000 FPP’s and 20,000 CPP’s have been produced. They are designed using the most advanced technology and state-of-the-art equipment to ensure the highest possible levels of performance and efficiency. As a result, owners and operators gain the benefits of lower operating costs and a reduced environmental footprint through less fuel consumption and fewer exhaust emissions.
With OPTI Design the focus is on the vessel’s total propulsive efficiency, which in the end determines its fuel consumption. This propulsive efficiency depends in turn on the efficiency of the propeller and the interaction between the propeller and the vessel. This interaction is defined in the propulsion theory represented by the hull efficiency and the relative rotative efficiency.
In the past the flow along the aft ship and the propeller were separately optimised. While the propeller flow along the vessel hull, as represented by a wake field, is always taken into account, the interaction between ship and propeller, however, was assumed not to change for different propeller designs. With modern Computational Fluid Dynamics (CFD) tools it is now possible to calculate the ship and the propeller together, and thus find the best combination.
A further benefit is that the CFD calculations can be made for both model scale and full scale conditions. Where until now the performance was always judged using a model scale test, the CFD makes it possible to analyse the performance at full scale, which is in the end what really matters for the ship owner.
The Wärtsilä EnergoProFin is an energy saving propeller cap with fins which are connected to the rotating propeller. It improves propulsive efficiency by weakening the hub vortex, and by recovering kinetic energy from the rotating flow aft of the propeller blades.
The EnergoProFin provides average fuel savings of 2%, with payback times of less than one year.
Related articles : Wartsila Controllable Pitch Propeller Systems