Common issues
- Heading disagreement between the master compass and bridge repeaters
- Follow-up or synchro signal loss to autopilot, radar and VDR
- Power interruption forcing a full re-settle of the fibre-optic gyro (roughly 30 minutes)
- Corroded or loose repeater cable connections causing intermittent heading dropout
- Interface/compatibility issues after bridge system (VisionMaster) software upgrades
- UPS/battery backup degrading, shortening ride-through on a power blip
Inspection checklist
- Compare master gyro heading against the magnetic compass and GPS course-over-ground on a steady course
- Check every repeater compass reads the same heading as the master
- Test alarm functions: power failure, heading fail, follow-up fail
- Inspect cabling and connectors at the master unit and distribution units for corrosion
- Confirm settling time after power-up is within the maker's specification (approx. 30 min)
- Check heading data interface to autopilot, radar, ECDIS and VDR for correctness
- Verify UPS/battery backup autonomy and condition
- Check mounting and vibration isolation of the master compass unit
Service intervals
| Heading accuracy cross-check vs. reference | each watch, per bridge procedure |
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| Full alarm and interface function test | annually, at periodical survey |
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| Battery/UPS backup capacity test | annually |
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| Connector and cable inspection | annually or at drydock |
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Typical intervals for this design class, not the manufacturer’s figures for your model. The manufacturer’s manual is binding.
Typical wear limits
| Heading accuracy vs. reference | generally expected within about 0.5-1 degree depending on the applicable IMO gyrocompass performance standard - confirm against the type-approval figure, not treated here as a fixed value |
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| Settling time after power restoration | should return to normal within the maker's stated window (around 30 minutes) - a materially longer settle time points to a gyro unit fault |
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Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Repeater compass unit
- Power supply/UPS module
- Interface/distribution board
- Connecting cables and connectors
Safety
- Loss of heading reference during restricted visibility or pilotage - confirm backup procedures are in place before starting maintenance
- Electrical hazard when working on the live power supply/distribution unit
- Do not remove power from the gyro without first confirming the autopilot is in standby/manual
Class survey
Heading and steering-related equipment falls under SOLAS V statutory requirements. Class expects a documented heading accuracy check against a reference, functioning alarms, and a working interface to autopilot/VDR/ECDIS at each periodical survey; a gyro failure is treated as a seaworthiness-affecting defect.
Estimated lifetime: Fibre-optic gyrocompass electronics of this class typically remain serviceable for 15-20 years of continuous operation before major electronics renewal is needed, subject to power quality and vibration environment - confirm against Sperry Marine's product lifecycle documentation for the NAVIGAT 2100.