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Why does a boat wander at low speed?
Do you know the feeling? You are heading towards the jetty, throttle back, and suddenly your boat barely responds to the helm. The bow wanders off on its own and manoeuvring in reverse becomes a nightmare. You are not alone. This problem affects virtually every owner of a boat with an outboard motor or sterndrive.
The cause is simple: at low speed, too little water flows past the engine's rudder/skeg to generate sufficient steering force. The propeller pushes water straight backwards, but at low speed the vessel has almost no hydrodynamic resistance at the bow. The result: the stern follows the engine obediently, but the bow does whatever it wants.
Outboard motor and sterndrive: a specific challenge
On a boat with an outboard motor or sterndrive (Z-drive), the entire steering function depends on the engine itself. There is no separate rudder operating independently of the engine. That works fine at speed, but at trolling or walking pace — when docking or motoring slowly through a busy harbour — you lose control. Crosswinds make it even worse. And reversing with an outboard motor? Without assistance, it is virtually impossible.
The solution: an auxiliary rudder
An auxiliary rudder — also called a trim tab or auxiliary rudder — is an additional rudder blade mounted beneath the water surface, behind the propeller. It redirects the water at low speeds, even when the engine is generating minimal thrust.
The Ruddersafe auxiliary rudder has been specifically developed for outboard motors and sterndrives. It utilizes a patented design where the rudder blades attach to the existing cavitation plate of your engine. You don't need to drill anything or alter your boat. Installation takes an average of 20 minutes with a standard spanner.
What will you notice in practice?
- Stable at low speed — your boat holds its course even when you throttle back.
- Reversing becomes controllable — the rudder also works in reverse, which is rarely the case with conventional outboard motors.
- No more wandering in waves or crosswinds — Ruddersafe acts as a stabilizer.
- More precise manoeuvring — less throttle and less stress at the dock.
Customer Herman Sieger on his experience: "Boating is a joy again! I want to install one on my other boat too."
Suitable for almost all engines and boats
Ruddersafe produces types for virtually all outboard motors from 5 to 300 hp, for Volvo Penta sterndrives, and for both single and twin engine setups. The correct choice depends on your boat length and drive type: outboard motor or Volvo Penta sterndrive.
Not sure which type fits your boat? Use our selection guide: which Ruddersafe type fits my boat? or explore the complete Ruddersafe range.
Tested and approved
The Ruddersafe auxiliary rudder has been extensively tested and rated positively by ANWB Waterkampioen. Read the full test report on our ANWB test report page.
Ready to order?
View our Ruddersafe Standard types (from €136.20) for outboard motors, or the Ruddersafe Volvo Penta types (from €220.00) for Z-drives.
Ordered before 12:30? We dispatch the same working day. Free delivery available.