Type 139-159 (FU Proportional Amplifier AS)
Raytheon Anschütz Type 139-159 (FU Proportional Amplifier AS) — Proportional steering control for variable valve modulation.
Inspector Detail
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Common issues
- Rudder feedback unit (angle transmitter) misalignment causing offset between ordered and actual rudder angle
- Amplifier drift causing rudder hunting or sluggish steering response
- Terminal and connector corrosion in the damp steering gear compartment causing intermittent faults
- Torque motor coil degradation reducing proportional solenoid valve response
- Relay/contactor wear affecting changeover between Bridge, Local and Emergency modes
- Alarm system false trips from loose or aged connections
Inspection checklist
- Function-test changeover between Bridge, Local (steering gear compartment) and Emergency control modes
- Verify the rudder angle indicator agrees with actual rudder position at both extremes and at midships
- Check hard-over to hard-over steering time against the vessel's SOLAS requirement
- Inspect terminal connections and cabling for corrosion, chafe and secure termination
- Test the alarm system (power failure, hydraulic fault, phase failure) for correct bridge annunciation
- Confirm the proportional solenoid valve responds smoothly, without overshoot or hunting
- Check insulation resistance of the control circuits
Service intervals
| Full steering gear operational test | before departure, per SOLAS |
| Emergency steering drill | at least every 3 months, per SOLAS |
| Terminal/connection inspection and tightening | annually |
| Insulation resistance test of control circuits | annually |
| Torque motor/amplifier calibration check | per maker's schedule, typically annually or at dry-docking |
Critical spares
- Torque motor coil / proportional solenoid coil, if separately replaceable
- Terminal/connector kit
- Control relay(s)
- Rudder angle feedback transmitter (potentiometer or synchro unit)
- Control cabinet cooling fan, if fitted
Safety
- Steering gear is a SOLAS-critical safety system - work on the amplifier must only be done with hydraulic power isolated and the rudder secured against unintended movement
- Emergency steering procedures must remain immediately available to the crew during any control-system maintenance
- Electric shock risk when working on live control cabinets - isolate and prove dead before opening
Class survey
Steering gear control systems fall under SOLAS Ch. II-1 and are surveyed at every annual, intermediate and renewal survey. Class witnesses the full steering test, including changeover between Bridge, Local and Emergency control and the emergency steering drill, and expects documented evidence of the required hard-over test time and correct alarm function.
Components & Design
Component data being added…
Technical Data
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Common failures & inspection points
Verify dual CAN-bus connections are properly terminated, monitored, and functioning in redundant configuration per IEC 61162-460
Test wire break alarm function (Type 148-620 device) - confirm 24V monitoring triggers immediately upon disconnection and halts follow-up steering without rudder movement
Measure actual rudder angle using Type 136-065 indicator against command signal; verify ±1° accuracy and <50ms response time per IMO SOLAS requirements
For Type 139-155/159 proportional amplifiers: verify torque motor current, solenoid valve modulation, and time to full rudder deflection (<30 seconds); test at Bridge/Local/Emergency modes
ComPilot 20: Verify all pre-wired connections per installation drawings, test earth continuity, confirm 24VDC supply voltage regulation ±10%, and validate emergency steering bypass circuit function
Type-general inspection and maintenance points for this equipment category — not model-specific.
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