Flap rudders

Our flap rudder series provides both excellent manoeuvring performance whenever there is a requirement for high manoeuvrability and efficiency, with a smaller required rudder area.

A Flap rudder produces more side force than a classic rudder of equivalent size. Depending on shipowner requirements, a flap rudder may be used to reduce the overall area of a rudder whilst maintaining equal lift forces or may be used whenever there is a requirement for high manoeuvrability. Therefore, a good understanding of owner’s operation requirements is vital. The rudders can also be optimised for higher speeds and the leading edge of the rudder can be twisted to improve the efficiency and cavitation characteristics of the rudder.

Flap Rudder Profiles

Flap Bulbous – For Low to Medium Speeds

Flap Medium – For Medium Speeds

Flap Slim – For High Speeds

Flap Bulbous – For Low to Medium Speeds
A Bulbous profile with flap that provides extreme low-speed manoeuvring performance.

Flap Medium – For Medium Speeds
A medium profile with flap that provides high manoeuvring performance and propulsive efficiency.

Flap Slim – For High Speeds
A slim profile that provides high propulsion performance and manoeuvring with high strength flap mechanism for reliable operation at medium to high speeds.

With a flap rudder solution, vessels achieve a higher manoeuvrability. By using a KONGSBERG flap rudder, vessel operations in lower speeds and limited operational space will generate huge potential in terms of safety and performance. The KOGNSBERG Flap Rudder is suitable for both newbuild and retrofit, wherever manoeuvrability and effiency play a leading role.   

Support Types

Three different support principles:

  • Direct Trunk Support
    • In combination with the Direct Trunk Support, KONGSBERG rudder portfolio is unlimited in size and enables high manoeuvring and propulsion efficiency at all vessel sizes.
    • Aft Ship optimization
    • Improved performance
    • No rudder size limitation

  • Neck Bearing Support
    • Neck Bearing Support provides all vessels, whose size do not require Direct Trunk Support all the traditional rudder benefits.
    • Robust and well known
    • Simple and easy maintenance

  • Heel Support
    • Heel Pintle Support provides vessels all the traditional advantages of full spade rudder design with enhanced system stability.
    • Enhanced system stability
    • Durable in ice and protects propeller from foreign objects


Available Trunk Configurations

  • Standard: Basic design for integration into hull
  • Standard with Steering Gear foundation: Fit all KM Steering Gear
  • Extended: Designed for minimum installation time, optional fairwater and hull plating


Key Features

  • Open water, nozzle, and ice-class compliant
  • Promas solution with twisted leading edge
  • Rudder Health Monitoring


Key Benefits

  • Easy installation and maintenance
  • Optimised rudder profile
  • Custom-built to fit vessel
  • Optimal performance
  • Low life cycle costs
  • Highest possible lift
  • Inhouse Hydrodynamic Research Center and production

Services and support

  • 24/7 Technical support

    Our 24/7 technical support team is there to help at any time, day or night, wherever your vessel is.

  • Conversions, retrofit and refit

    We understand the importance of having the right parts, available in the right place, at the right time.

  • Training

    Ensure that your crew is properly and thoroughly trained. This will reduce operational risk, downtime and maximise return on asset investment.

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