VANKORLAAR-HOLLAND, nieuwe generatie klassieke schepenEfficient CPP propulsion systems, Technical/management support
General: Servogear Ecoflow Propulsor Fuel consumption Controllable pitch propellers Propeller tunnel design Reduction gearbox/Servo system Shaft Brackets Effect rudders Propulsive efficiency Contact

ServogearControllable pitch propellers

From their earliest days, Servogear has strived to produce premium controllable pitch propellers (CPP). The majority of their clients are operating vessels with varying load and speed conditions. The optimal design condition of a fixed pitch propeller unfortunately coincides only part of the time with operational conditions.
The Ecoflow™ CPP can be adapted to every “off-design” operational condition, simply by adjusting the blades to the optimal pitch position.

The propeller hub is of well-known and proven design. Both the propeller hub and the blades are made of NiAlBz material, and have feathering position capabilities, which can be used by sailing vessels to reduce resistance, or by multi-screw motor vessels for special operational conditions.

Brief comparison of CP-propeller and FP-propeller:

  1. Acceleration of a vessel with CPPs is considerably better than the equivalent with FPPs, because with a CPP the pitch can be increased as both the vessel speed and load increase.
    For a FPP the pitch will be too high during acceleration, causing severe cavitations that easily overload the engine.
  2. Most modern vessels are equipped with an automatic overload control system, integrated as part of the remote control system.
    Should the engine be overloaded, the pitch will be reduced automatically to the programmed load curve of the engine.
  3. If there are high variations in displacements on the vessel (from running fully loaded in strong ahead wind, for example, to running empty in tail winds) then a CPP will give much higher total efficiency than any other propulsion system. In general, when running at various “off-design” conditions, the efficiency of a CPP is far greater than with a FPP.
  4. Between dockings, the fouling of a hull increases resistance. With a CPP, by altering the pitch, the engine can still run at an optimum load.
  5. With CPPs, when running in harbours, the speed of a vessel can be reduced all the way down to zero. Manoeuvring is very smooth and precise with no sudden movements, as is often not the case with FPPs.
  6. Engines run optimally in various load / weather conditions when CPPs are used. See examples below.
  7. Because of higher efficiency, the CP propeller offers better long distance range at cruising speed than FPPs.

A typical engine performance curveA typical engine performance curve




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