scope:

This Def Stan 02-305, in conjunction with the documents referred to herein, specifies the minimum requirements which must be met by the Main Gearing Contractor and other authorities, during the design, manufacture, installation and commissioning of a Main Propulsion Gearbox intended for use in vessels for the Royal Navy. 

This Standard will be called into use by the Contract placed on the main gearing Contractor to design and/or manufacture a Gearbox. As this Standard also places responsibility on Prime Contractors or other manufacturing/installation authorities, it will also be called into use by contract concerned with the building of vessels and Shore Test Facilities (STF). 

The extent of the equipment covered by this Standard is as follows: 

The Main Gearing, which comprises: 

The gearcase, and all gears, shafts (main and lay), oil seals, dipsticks, clutches, brakes, couplings and bearings contained therein; 

The input flexible coupling, including control of the interface with prime mover output flange and its satisfactory performance where applicable; 

The gearbox output flange(s) and main shaft flexible coupling where applicable;

The responsibility for the successful installation and commissioning of the high speed line(s), including balancing.

The lubricating system internal to the gearbox downstream from the gearbox supply point(s) (to be defined). For further information and guidance refer to Def Stan 02-309; 

Gearbox Atmospheric Control:

Venting; 

Dehumidification.

All local controls and surveillance instrumentation associated with the main gearing, including the local Plant Control Unit (PCU), if specified; 

uxiliary drives required by the System Requirement Document (SRD) as follows: 

For gear driven units mounted on the gearcase or, when integral on the drain tank; 

For driven units mounted remotely, e.g. on the vessel's structure. 

The main thrust bearing, only if stated in the SRD. Requirements relating to the design and manufacture of main thrust bearings are given in Def Stan 02-304; 

All other gearbox auxiliaries (e.g. turning gear, dehumidifier, etc.) required by this Standard or by the SRD; 

The electrotechnical equipment associated with the gearbox (e.g. control and surveillance instrumentation) and with those items mounted directly on the gearcase (e.g. turning gear) or, when integral, on the drain tank (e.g. motor driven Lubricating Oil (LO) pumps). The term 'Electrotechnical' includes all items such as motors, starters, junction boxes, cable conduit and wiring; 

Gearbox seating arrangements.