Rudder Bulb – improving propeller efficiency through optimised flow

When a propeller generates thrust, it does not merely produce the desired forward propulsion. At the same time, a powerful hub vortex forms around the propeller’s hub, containing energy that does not contribute to propelling the vessel forward. This turbulent flow increases drag and reduces the propeller’s efficiency. The rudder bulb is a hydrodynamic option from Becker Marine Systems that is mounted on the leading edge of the rudder, directly behind the propeller hub. Its purpose is to reduce the hub vortex and direct the propeller flow so that a greater portion of the supplied energy is converted into usable propulsion. The result is more efficient interaction between the propeller and rudder, which can contribute to lower fuel consumption, improved propulsion efficiency, and reduced energy losses.

How does the Rudder Bulb work?

When is a Rudder Bulb appropriate?

The Rudder Bulb is particularly suitable for vessels where high energy efficiency, low fuel consumption, and good propulsion efficiency are priorities. The solution is often used on:

• Container ships
• Tankers
• Bulk carriers
• RoRo and RoPax ships
• Passenger ships
• Offshore vessels
• Other vessels with high power output and continuous operation

Rudder bulbs are often combined with Becker Flap Rudders and other rudder solutions from Becker Marine Systems to optimize the interaction between the propeller and the rudder.

Advantages of the Rudder Bulb

• Reduces the hub vortex behind the propeller hub.
• Provides a more uniform water flow toward the rudder.
• Improves propulsion efficiency.
• Reduces hydrodynamic energy losses.
• Can contribute to lower fuel consumption.
• Improves the interaction between the propeller and the rudder.
• Has no moving parts and requires virtually no additional maintenance.