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Why does a boat yaw at low speed?
Do you recognise the feeling? You are approaching the jetty, ease off the throttle, and suddenly your boat barely responds to the helm. The bow drifts wherever it wants, and reversing becomes a nightmare. You are not alone — this problem affects almost every owner of a boat with an outboard motor or Z-drive.
The cause is simple: at low speed, too little water flows past the motor's rudder to generate sufficient steering force. The propeller pushes water straight backwards, but at walking pace the hull has almost no hydrodynamic resistance at the bow. The result: the stern follows the motor, but the bow does as it pleases.
Outboard motors and stern drives: a particular challenge
On a boat with an outboard motor or stern drive (Z-drive), the entire steering function depends on the motor itself. There is no separate rudder working independently of the engine. This works well at speed, but at walking pace — manoeuvring in a marina, approaching a dock — you lose control. Crosswinds make it worse. And reversing with an outboard motor, without help, is barely manageable.
The solution: an auxiliary rudder
An auxiliary rudder — also called a trim tab — is an extra rudder blade permanently mounted below the waterline, behind the motor. It corrects the water flow at low speed, even when the motor is barely generating thrust.
The Ruddersafe auxiliary rudder is designed specifically for outboard motors and stern drives. It uses a patented design where the rudder blades attach to the existing motor bracket. No drilling required anywhere on the boat. Fitting takes approximately 20 minutes with a standard spanner.
What difference will you notice?
- Stable at low speed — your boat holds course even when you reduce power.
- Reversing becomes manageable — the rudder also works in reverse, something most outboard motors cannot do unaided.
- No more yawing in swell or crosswind — Ruddersafe acts as a stabiliser.
- More precise manoeuvring — less throttle and stress alongside the dock.
Customer Herman Sieger on his experience: "Boating is a pleasure again! I want to fit one on my other boat too."
Compatible with almost all motors and boats
Ruddersafe makes types for virtually all outboard motors from 5 to 300 hp, for Volvo Penta Z-drives, and for both single and twin-motor configurations. The correct choice depends on your motor type and the length of your boat.
Not sure which type suits your boat? Use our decision guide: which Ruddersafe type fits my boat? or browse the full Ruddersafe range.
Tested and approved
The Ruddersafe auxiliary rudder has been extensively tested and positively assessed by ANWB Waterkampioen, the leading Dutch watersports magazine. 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.
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