SvMay
New Member
Dear forum members,
I am contacting you regarding a persistent steering issue on my Bavaria Vision 50 (2007) equipped with a Lewmar steering system with WRG11 reduction gearbox.
I have spent considerable time diagnosing this problem and would greatly appreciate your technical input, as I am running out of possible causes.
Symptoms:
* Steering feels relatively smooth when stationary or manoeuvring slowly.
* Under load (especially around **4–6 knots under engine or sail**) steering becomes significantly heavier.
* The boat consistently tends to pull towards port under engine and sail.
* Steering towards starboard is noticeably heavier than towards port.
* My autopilot struggles under load and can no longer steer effectively.
Work already carried out
Autopilot system
The following components have been checked or replaced:
* New **Raymarine ACU400**
* New **rudder reference sensor**
* Autopilot clutch replaced
* Drive motor tested directly on battery power and confirmed operational
* Power supply and voltage drop investigated
* Cabling upgraded and checked
The autopilot drive itself appears mechanically functional.
---
Steering system investigation
I then moved to the mechanical steering system.
Actions performed:
* Steering chains and system tension checked and adjusted.
* Chain over-tension was suspected and corrected.
* Dual steering wheel synchronization checked.
* Quadrant and steering geometry inspected.
* Rudder bearings have been replaced in the last 2 months.
* Locking nut / preload adjusted and tested.
Additionally, we removed the quadrant completely during diagnosis.
The entire steering assembly around the rudder stock was dismantled and inspected.
However, we were unable to fully remove the bearing connected to the tiller arm / WRG11 assembly, because this component appears to be welded onto the shaft.
Despite dismantling the surrounding system, this specific assembly could therefore not be completely separated and independently tested.
---
Rudder investigation
Because symptoms only occurred under hydrodynamic load, the rudder itself became suspect.
The rudder had previously been:
* split open
* dried
* re-laminated
After hauling the vessel out, it became clear that the rudder blade profile had become distorted.
The yard that previously repaired the rudder has acknowledged that the distortion likely resulted from their repair process (foam filling causing deformation / bulging of the profile).
The rudder has since been corrected and re-profiled.
However, the problem was already there before they did the rudder, i just rhought it was beacause of the bearings. Anyways, after relaunching the vessel, the original steering issue still remains.
---
Important diagnostic finding
One very important observation:
When the rudder is disconnected from the quadrant, the rudder turns extremely freely (“like a feather”).
This strongly suggests that:
* the rudder stock and bearings themselves are not heavily binding,
* and that the problem may lie further up in the steering mechanism.
This leads me to suspect:
* WRG11 reduction gearbox
* Mamba bevelhead / steering gearbox bearings
* steering geometry or gearbox alignment under load
### My technical question
Could a problem inside the Lewmar WRG11 reduction gearbox / Mamba steering gearbox (for example worn bearings, internal drag, asymmetrical resistance, alignment issue or internal load bias) realistically produce the following behaviour:
* steering significantly heavier under hydrodynamic load,
* heavier steering in one direction,
* apparent pull toward port,
* autopilot overload behaviour,
while still feeling reasonably normal when unloaded?
Any documentation, troubleshooting guidance, known issues or recommended diagnostic procedures for the *Mamba / WRG11 system would be greatly appreciated.
Thank you very much for your time and assistance.
Kind regards,
Mike
Bavaria Vision 50 (2007)
I am contacting you regarding a persistent steering issue on my Bavaria Vision 50 (2007) equipped with a Lewmar steering system with WRG11 reduction gearbox.
I have spent considerable time diagnosing this problem and would greatly appreciate your technical input, as I am running out of possible causes.
Symptoms:
* Steering feels relatively smooth when stationary or manoeuvring slowly.
* Under load (especially around **4–6 knots under engine or sail**) steering becomes significantly heavier.
* The boat consistently tends to pull towards port under engine and sail.
* Steering towards starboard is noticeably heavier than towards port.
* My autopilot struggles under load and can no longer steer effectively.
Work already carried out
Autopilot system
The following components have been checked or replaced:
* New **Raymarine ACU400**
* New **rudder reference sensor**
* Autopilot clutch replaced
* Drive motor tested directly on battery power and confirmed operational
* Power supply and voltage drop investigated
* Cabling upgraded and checked
The autopilot drive itself appears mechanically functional.
---
Steering system investigation
I then moved to the mechanical steering system.
Actions performed:
* Steering chains and system tension checked and adjusted.
* Chain over-tension was suspected and corrected.
* Dual steering wheel synchronization checked.
* Quadrant and steering geometry inspected.
* Rudder bearings have been replaced in the last 2 months.
* Locking nut / preload adjusted and tested.
Additionally, we removed the quadrant completely during diagnosis.
The entire steering assembly around the rudder stock was dismantled and inspected.
However, we were unable to fully remove the bearing connected to the tiller arm / WRG11 assembly, because this component appears to be welded onto the shaft.
Despite dismantling the surrounding system, this specific assembly could therefore not be completely separated and independently tested.
---
Rudder investigation
Because symptoms only occurred under hydrodynamic load, the rudder itself became suspect.
The rudder had previously been:
* split open
* dried
* re-laminated
After hauling the vessel out, it became clear that the rudder blade profile had become distorted.
The yard that previously repaired the rudder has acknowledged that the distortion likely resulted from their repair process (foam filling causing deformation / bulging of the profile).
The rudder has since been corrected and re-profiled.
However, the problem was already there before they did the rudder, i just rhought it was beacause of the bearings. Anyways, after relaunching the vessel, the original steering issue still remains.
---
Important diagnostic finding
One very important observation:
When the rudder is disconnected from the quadrant, the rudder turns extremely freely (“like a feather”).
This strongly suggests that:
* the rudder stock and bearings themselves are not heavily binding,
* and that the problem may lie further up in the steering mechanism.
This leads me to suspect:
* WRG11 reduction gearbox
* Mamba bevelhead / steering gearbox bearings
* steering geometry or gearbox alignment under load
### My technical question
Could a problem inside the Lewmar WRG11 reduction gearbox / Mamba steering gearbox (for example worn bearings, internal drag, asymmetrical resistance, alignment issue or internal load bias) realistically produce the following behaviour:
* steering significantly heavier under hydrodynamic load,
* heavier steering in one direction,
* apparent pull toward port,
* autopilot overload behaviour,
while still feeling reasonably normal when unloaded?
Any documentation, troubleshooting guidance, known issues or recommended diagnostic procedures for the *Mamba / WRG11 system would be greatly appreciated.
Thank you very much for your time and assistance.
Kind regards,
Mike
Bavaria Vision 50 (2007)
