Section 1 Plans and particulars

1.1.1 Particulars of the gearing are to be submitted with the plans for all propulsion gears and for auxiliary gears where the transmitted power exceeds 110 kW (150 shp), as follows:

1. Plans and information demonstrating conformance with the applicable Rules and Standards as stated in scope.

2. Shaft power and revolution for each pinion.

3. Number of teeth in each gear.

4. Reference diameters.

5. Helix angles at reference diameters.

6. Normal pitches of teeth at reference diameters.

7. Tip diameters.

8. Root diameters.

9. Face widths and gaps, where applicable.

10. Pressure angles of teeth (normal or transverse) at reference diameters.

11. Accuracy grade Q in accordance with ISO 1328 or an equivalent Standard.

12. Surface texture of tooth flanks and roots.

13. Minimum backlash.

14. Centre distance.

15. Basic rack tooth form.

16. Protuberance and final machining allowance.

17. Details of post hobbing processes, if any.

18. Details of tooth flank corrections, if adopted.

19. Case depth for surface-hardened teeth.

20. Shrinkage allowance for shrunk-on rims and hubs.

21. Type of coupling proposed for engine applications.

1.2.1 Specifications for materials of pinions, pinion sleeves, wheel rims, gear wheels, and quill shafts, giving chemical composition, heat treatment and mechanical properties, are to be submitted for approval with the plans of gearing.

1.2.2 Where the teeth of a pinion or gear wheel are to be surface hardened, i.e. carburised, nitrided, tufftrided or induction-hardened, the proposed specification and details of the procedure are to be submitted for approval.