Prop Shaft Alignment Calculator
Calculate alignment tolerances and verify shaft runout per ABYC P-6 standards
Alignment Results
Alignment Status
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Max Allowable Gap Difference
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Measured Vertical Difference
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Measured Horizontal Difference
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Angular Misalignment
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Recommended Shaft Runout Limit
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Coupling Face Runout Limit
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ABYC P-6 Alignment Standards
| Coupling Type | Gap Tolerance | Notes |
|---|---|---|
| Solid Flange | 0.001"/inch diameter | Most critical alignment |
| Flexible | 0.002"/inch diameter | Per manufacturer spec |
| CV Joint/PSS | 0.003"/inch diameter | More tolerance allowed |
Shaft Alignment Guidelines
Measurement Procedure
Use feeler gauges at four points (top, bottom, port, starboard) around the coupling face with faces together but not bolted.
Rotate shaft 90 degrees and re-measure to check for shaft bend vs. misalignment.
Engine should be at operating temperature when performing final alignment.
Common Issues
Vertical misalignment: Adjust engine mounts or shim under engine feet.
Horizontal misalignment: Shift engine sideways on mounts.
Angular misalignment: Combination of vertical and horizontal adjustment at front/rear mounts.