Section 4 Operating conditions

4.1.1 The design and arrangement is to be such that the machinery can be started and controlled on board, without external aid.

4.1.2 Machinery is to be capable of operating at defined power ratings with a range of fuel grades specified by the engine, boiler or machinery manufacturer and agreed by the Owner/Operator.

4.1.3 Machinery is to be capable of operating satisfactorily in accordance with the manufacturer’s stated operating conditions within an operational profile specified for the ship by the Owner/Operator and agreed by the manufacturer/system designer.

4.2.1 The main and auxiliary machinery is to be designed and installed such that it operates satisfactorily under the conditions as shown in Table 1.4.1 Inclinations.

Table 1.4.1 Inclinations

Installations, components	Angle of inclination, degrees, see Note 1
	Athwartship		Fore-and-aft
	Static	Dynamic	Static	Dynamic
Main and auxiliary machinery essential to the propulsion and safety of the craft	15	22,5	5 see Note 2	7,5
Emergency machinery and equipment fitted in accordance with Statutory Requirements	22,5	22,5	10	10
Note 1. Athwartships and fore-and-aft inclination may occur simultaneously. Note 2. Where the length of the craft exceeds 100 m, the fore-and-aft static angle of inclination may be taken as:
where L WL = craft waterline length, in metres

4.2.2 The arrangements for lubricating bearings and for draining the crankcase and other oil sumps of main and auxiliary engines, gearcases, electric generators, motors, and other running machinery are to be so designed that lubrication will remain efficient with the craft inclined under the conditions as shown in Table 1.4.1 Inclinations.

4.2.3 Deviations from these conditions may be accepted taking into consideration type and size of the craft and the class notation. The Shipbuilder is to ensure that the main and auxiliary machinery is capable of operating at the proposed angles of inclination.

4.3.1 In the Chapters where the dimensions of any particular component are determined from shaft power, P, in kW (H, in shp), and revolutions per minute, R, the values to be used are to be derived from the following:

• For main propelling machinery, the maximum shaft power and corresponding revolutions per minute giving the maximum torque for which the machinery is to be classed.
• For auxiliary machinery, the maximum continuous shaft power and corresponding revolutions per minute which will be used in service.

4.4.1 The rating for classification purposes of main and essential auxiliary machinery intended for installation in sea-going ships to be classed for unrestricted (geographical) service is to be based on a total barometric pressure of 1000 mb, an engine room ambient temperature or suction air temperature of 45°C, a relative humidity of 60 per cent and sea-water temperature or, where applicable, the temperature of the charge air coolant at the inlet of 32°C. The equipment manufacturer is not expected to provide simulated ambient reference conditions at a test bed.

4.4.2 In the case of a ship to be classed for restricted service, the rating is to be suitable for the temperature conditions associated with the geographical limits of the restricted service, see Pt 1, Ch 2, 3.5 Service area restriction notations.

4.5.1 Main and essential auxiliary machinery and equipment is to be capable of operating satisfactorily under the conditions shown in Table 1.4.2 Ambient operating conditions.

4.5.2 Where it is intended to allow for operation in ambient temperatures outside those shown in Table 1.4.2 Ambient operating conditions, the permissible temperatures and associated periods of time are to be specified and details are to be submitted for consideration. Propelling and essential auxiliary machinery, see Pt 1, Ch 2, 3.10 Application notes 3.10.1, is to retain a continuous level of functional capability under these conditions and any level of degraded performance is to be defined. Operation under these circumstances is not to be the cause of damage to equipment in the system and is additionally to be acceptable to the National Authority of the country in which the craft is to be registered

4.6.1 Auxiliary engines coupled to electrical generators are to be capable under service conditions of developing continuously the power to drive the generators at full rated output (kW) and in the case of reciprocating internal combustion engines and gas turbines, of developing for a short period (15 minutes) an overload power of not less than 10 per cent, see Pt 16, Ch 2, 9.2 Rating In the case of reciprocating internal combustion engines, they are to be tested at works trials as required by Pt 10, Ch 1, Table 1.11.1 Scope of works trials for engines.

4.6.2 Engine builders are to satisfy the Surveyors by tests on individual engines that the above requirements, as applicable, can be complied with, due account being taken of the difference between the temperatures under test conditions and those referred to in Pt 9, Ch 1, 4.4 Ambient reference conditions. Alternatively, where it is not practicable to test the engine/generator set as a unit, type tests (e.g. against a brake) representing a particular size and range of engines may be accepted. With engines and gas turbines any fuel stop fitted is to be set to permit the short period overload power of not less than 10 per cent above full rated output (kW) being developed.

4.7.1 In order to maintain sufficient manoeuvrability and secure control of the ship in all normal circumstances, the main propulsion machinery is to be capable of reversing the direction of thrust so as to bring the ship to rest from the maximum service speed. The main propulsion machinery is to be capable of maintaining in free route astern at least 70 per cent of the ahead revolutions corresponding to the maximum continuous ahead power for which the vessel is classed.

4.8.1 Interlocks are to be provided to prevent any operation of engines or turbines under conditions that could cause a hazard to the machinery and personnel. These are to include ‘turning gear engaged’, ‘low lubricating oil pressure’, where oil pressure is essential for the prevention of damage during start up, ‘shaft brake engaged’ and where machinery is not available due to maintenance or repairs. The interlock system is to be arranged to be ‘fail safe’.

4.8.2 Where machinery is provided with manual turning gear, warning devices or notices may be provided as an alternative to interlocks as required by Pt 9, Ch 1, 4.8 Machinery interlocks 4.8.1.