Wärtsilä Single input gear
A single‑input reduction gearbox that connects a low‑speed main engine to the propeller shaft, delivering speed reduction and torque multiplication in a compact, integrated unit.
Inspector Detail
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Common issues
- Gear tooth wear or pitting from insufficient lubrication or an incorrect oil viscosity grade
- Thrust bearing wear showing up as increasing axial float over time
- Misalignment between the engine output flange and gearbox input causing vibration and coupling wear
- Lube oil cooler fouling reducing cooling capacity and raising running oil temperature
- Water ingress via a leaking oil cooler causing bearing corrosion
- Flexible coupling element wear where fitted between engine and gearbox
Inspection checklist
- Take a gear oil sample for wear metal and water content analysis
- Check oil pressure and temperature against the normal operating range
- Inspect for oil leaks at shaft seals and casing joints
- Check alignment between engine output and gearbox input against the maker's tolerance
- Check thrust bearing axial clearance/float
- Listen for, and where instrumented measure, abnormal gear mesh noise or vibration
- Verify low oil pressure and high temperature trip/alarm functions
Service intervals
| Gear oil sample analysis | typically every 1000-2000 running hours or per the maker's schedule |
| Full oil change | commonly every 1-2 years depending on oil condition/analysis results, not a fixed calendar rule |
| Alignment check | at every dry-docking or after any work disturbing the engine or gearbox mounting |
| Thrust bearing clearance check | at the maker's major overhaul interval |
Typical wear limits
| Gear backlash and thrust bearing axial float | checked against the maker's new-build and wear-limit clearance band, which is model-specific - do not assume a generic figure, confirm against the gearbox's own manual |
| Lube oil cleanliness | commonly maintained within an ISO 4406 code appropriate to the gear and bearing type - confirm the actual target against the maker's lubrication specification |
| Oil wear-metal trend | a step increase in iron/copper/babbitt wear metals versus the unit's own baseline trend is treated as the practical limit, rather than a single absolute number |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Input and output shaft seals
- Oil filter elements
- Thrust bearing set
- Flexible coupling elements, if fitted
- Casing joint gasket set
Safety
- Stored rotational energy in the shaft line - lock out and apply turning gear/shaft brake before internal work
- Hot oil and casing surfaces during and shortly after running
- Crush hazard at open couplings during alignment work - keep hands clear while barring
Class survey
Reduction gears enrolled under Continuous Survey Machinery are typically opened for inspection on a rolling schedule, or have that requirement deferred against oil analysis trending subject to class approval; alignment records are checked especially after any repair affecting the shaft line.
Components & Design
Component data being added…
Technical Data
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