Twisted Flap Rudders (TLFKSR).


The Twisted Leading Edge Flap Rudder TLFKSR is a Becker Flap Rudder in combination with Twisted Leading Edge KSR (King Support Rudder) mounting and has the following benefits:
  • Best manoeuvring performance at low speed due to flap
  • Minimised cavitation erosion due to incorporation of twisted leading edge
  • Reduced fuel consumption due to rudder profile adapted to propeller flow
  • Reduced risk of vibration
  • Low installation height of steering gear position

Becker’s Twisted Flap Rudder is especially suitable for faster applications such as Ro/Ro, Ro/Pax, cruise vessels and car carriers.

Twisted Leading Edge Rudder family.

Conventional rudders are placed behind the propeller with the rudder cross section arranged symmetrically about the vertical rudder centre plane. However, this arrangement does not consider the fact that the propeller induces a strong rotational flow that impinges on the rudder blade. This results in areas of low pressure on the blade that induce cavitation and associated erosion problems. To avoid cavitation and to improve the manoeuvrability performance of a full spade rudder, Becker has enhanced the development of twisted leading edge rudder types.

More characteristics:

  • Extended uncritical rudder angle sector
  • No rudder horn, no gap cavitation
  • Optimised profile
  • Higher propulsion efficiency
  • Reduced profile thickness

Becker rudder designs with twisted rudder profile: KSR support (Twisted Leading Edge Rudder TLKSR®, Twisted Leading Edge Flap Rudder TLFKSR)


About KSR (King Support Rudder).

The KSR (King Support Rudder) design extends the trunk into the rudder blade and makes it possible for Becker’s full spade rudders, such as the TLKSR® Twisted Leading Edge Rudder, the FKSR Flap Rudder or the Schilling® KSR with unchallenged manoeuvrability to be supplied for vessels of any type and size. With the KSR design Becker can supply full spade rudders of practically any size.

Becker rudder profiles for the KSR design:

  • Becker Twisted Leading Edge Flap (TLFKSR)
  • Becker Twisted Leading Edge (TLKSR®)
  • Becker Flap (FKSR)
  • Schilling® KSR
  • NACA (KSR)

In order to avoid typical disadvantages of conventional rudders, Becker Marine Systems has developed the KSR (King Support Rudder) bearing arrangement concept. With this arrangement the trunk is extended into the rudder blade so that the lower neck bearing is positioned as close as possible to the vertical centre of pressure on the rudder. This results in reduced stresses and bending moments in the rudder blade as well as in the rudder stock.

The reaction forces in the neck and carrier bearings are much smaller, making it a very rigid rudder and with a consequently high natural frequency above the exciting frequency of the propeller, making the risk of the resonance very unlikely. Vibrations are reduced to a minimum.