Controllable Pitch (CP) Propellers
Scana Propulsion offer CP-propellers in the following product range:
- Four-bladed propellers
- Hub diameter from 520 – 1900 mm
- Propeller diameter from 1600 – 8000 mm
- Power range from 500 – 20.000 kW
- CP-propellers with servo motor either in the gear, in the shaft line or in the propeller hub.
- Blade design of high skew or normal skew
- Propellers are made of NiAl Bronze or stainless steel
Scana Propulsion propeller packages consist of:
- Propeller hub and blades
- Stern tube and stern tube seals
- Propeller shaft
- Shaft couplings
- Propeller nozzle
- Remote control system
- Temperature sensors, earthing devices etc
Fixed Pitch (FP) Propellers
Scana offer FP propellers in a complete propulsion package with gearbox including design, propeller shaft, stern tube bearings, seals and nozzle when required. Scana FP are available as mono-block or with adjustable bolted propellers for fine-tuning of the propeller and possibility to adjust and optimise the propeller during the vessel’s lifecycle. The FP-propeller range follow the range of Scana Propulsion Thorque™ and gearboxes.
Propeller systems can be offered as an integrated Scana propulsion system with gearbox, or as a stand-alone product.
Design criteria of a Scana Propulsion CP propeller
- The blade angle of CP propellers varies from full ahead to full astern pitch.
- A CP propeller offers a higher maximum bollard pull, as it is possible to optimise the relation between rpm, pitch and power.
- With variations in operating conditions, propeller performance is enhanced with a CP-propeller due to optimum pitch/advance ratio.
- A CP propeller increases flexibility if available engine power is reduced.
- For a nozzle propeller it is possible to demount propeller blade with propeller inside the nozzle.
Optimised Scana Propeller Systems
Scana Propulsion serves a large variety of vessel applications. There is a continuing demand for propeller designs to be optimised in order to achieve the highest energy efficiency. All Scana CP and FP propeller configurations are designed for the particular ship.
Propeller blade data, such as diameter, pitch, rpm, skew and load distribution, are always carefully selected to give the best solution with respect to both efficiency and noise/vibration characteristics. Tailor-made blade design ensures optimum propeller efficiency with lowest possible vibration and noise levels.
Changeable propeller blade bearings in propeller hub
The propellers ranging from 68/4 and upwards are all normally delivered in stainless steel hub with changeable propeller blade bearings in hub. The bearings are made of high performance self-lubricating and wear resistant bearing material. This application increases the lifetime of the propellers with years of operation.
Feathering propeller is an option on standard CP-propeller systems.
On a feathering propeller the blade angle can be arranged in line with the water flow. This reduces the water resistance and gives the following advantages:
- Power reduction by shutting down one of two propellers in twin screw systems
- Allows for maintenance at sea of one shaft line while the other is in operation.
With twin screw installations and one side out of operation it is possible to reduce requirements for the shaft brake with CP-propeller.
Up to 30% higher thrust at low speed compared to an open propeller.
Scana Propulsion is optimising the propulsion efficiency by applying the best nozzle profile to the vessel, based on given service profile.
Scana HE nozzle profile
The Scana HE nozzle is recommended for ships with high bollard pull requirements, and low propeller loading at higher speed. The Scana HE nozzle also has a better astern performance than the 19A nozzle.
19A nozzle profile
The 19A nozzle is recommended for many installations since it has a good overall performance in different running conditions.
37 nozzle profile
The 37 nozzle is recommended for vessels with high priority to astern performance. The forward bollard pull will be at the same level as for the 19A nozzle, but at higher speeds the performance is not competitive compared to the 19A nozzle.
Utilising state-of-the-art hydrodynamic knowledge
Scana Propulsion bases its hydrodynamic expertise in propeller design on calculation methods of the latest hydrodynamic theories and tank test results.
Scana Propulsion has participated in international joint industry projects (JIP), to get first hand knowledge of test results from theoretic knowledge and through development of practical methods for accurate predictions of full scale performance.
The JIP-programs have been developing analytic methods, and design- and analysis tools deeply rooted in ground breaking results from research projects where hundreds of CFD-calculations have been implemented in simulator software for evaluation of the performance of manoeuvring in propulsion systems.
These projects represent the state of the art in propulsion with global major propeller manufacturers and research institutes in Norway, The Netherlands, Germany, and China participating with the same goal – to establish modern and accurate design and analysis tools, and to secure long term competence development in key area of this discipline.
- Wageningen TT JIP Series (2015-2018)
- Full Scale Performance Prediction For Energy Efficient Ship Design (2013-2016)
- CD Propeller Series Phase I & II (2011-2016)
- Low Speed Manoeuvring Project (2009-2012)
- Norwegian Propeller Forum I & II (2004-2011)