L28/32H

Common issues

• Hydraulic oil contamination (water ingress or particulate) accelerating vane seal and bearing wear
• Vane or stator seal leakage causing internal by-pass, reduced rudder torque and slow response
• Rudder stock/tiller coupling key or taper showing signs of working loose under cyclic torque
• Non-return or relief valve sticking, causing erratic rudder movement or failure to hold position
• Follow-up (telemotor/feedback) linkage wear leading to a helm-order/rudder-angle mismatch
• Bearing wear in the rotor/stator assembly increasing radial clearance and internal leakage
• Corrosion or coating failure on the ram/vane housing in the steering flat

Inspection checklist

• Check hydraulic oil level, condition and cleanliness (sample analysis) per PMS
• Function test the steering gear from main and emergency control positions, confirming rudder angle indication matches actual rudder position
• Time full helm-to-helm movement and compare against the required response time
• Inspect vane/stator seals and housing for external leakage
• Check rudder stock coupling, key and locking arrangements for movement or wear marks
• Verify relief valve settings and non-return valve operation
• Confirm isolation valves between power units are operable and correctly tagged for changeover
• Test steering gear alarms (power failure, low oil level, overload) at the bridge and in the steering flat
• Confirm the emergency steering procedure and communication between bridge and steering flat is functional

Service intervals

Critical spares

• Vane/stator seal kit
• Rudder stock coupling key
• Relief valve
• Follow-up/feedback linkage components
• Hydraulic oil filters

Safety

• Steering gear hydraulics operate at high pressure - a failed hose or fitting can cause severe injury from oil injection
• Loss of steering without a rehearsed emergency steering procedure is a direct navigational safety hazard
• Moving vane/ram components can crush or trap during manual or emergency operation - isolate power before working inside the housing
• Rudder movement during testing must be coordinated with the bridge to avoid injury to personnel near the rudder stock

Class survey

Steering gear is subject to SOLAS Ch. II-1 requirements for main and auxiliary systems, including changeover testing before each departure and periodic full function tests recorded for class. Surveyors will want PMS records of oil sampling, relief valve testing and rudder stock coupling checks, plus evidence the emergency steering drill has been carried out.