Section 1 General requirements

1.1.1 This Section is to be read in conjunction with the requirements ofVol 2, Pt 1 General Requirements, Vol 2, Pt 2 Prime Movers, Vol 2, Pt 3 Transmission Systems and Vol 2, Pt 4 Propulsion Devices.

1.1.2 Unless otherwise advised, it is the responsibility of the Builders as main contractor to ensure, in co-operation with the Enginebuilders that the information required by this Chapter is prepared and submitted.

1.1.3 The requirements of this Chapter are applicable to main propulsion systems formed by engines, turbines or electric motors, directly driven or geared to the shafting.

1.2.1 For main propulsion installations, the shafting is to be aligned to give reasonable bearing reactions and bending moments, and to meet any specified coupling conditions at the forward end of the shafting at all conditions of vessel loading and operation. The Builder is to position the bearings and construct the bearing seatings to minimise the effects of movements under all operating conditions.

1.2.2 Shaft alignment calculations are to be carried out for main propulsion shafting rotating at propeller speed, including the crankshaft of direct drive systems or the final reduction gear wheel on geared installations. The Builder is to make available shaft alignment procedures detailing the proposed alignment method and checks for these arrangements.

1.2.3 Calculations for single engine geared installations having a screwshaft diameter less than 300 mm are not required.

1.2.4 The shafting systems on naval ships may be required to operate under onerous conditions which may affect the shaft alignment and attention is drawn to ,Vol 2, Pt 1, Ch 3, 3.3 Calculations and specifications 3.3.16 regarding operation of machinery outside of its optimum envelope.

1.3.1 For resilient mountings, see Vol 2, Pt 1, Ch 3, 5.9 Ventilation.

1.4.1 Where the shafting system incorporates flexible couplings, the effects of such couplings on the various modes of vibration are to be considered, see Vol 2, Pt 5, Ch 2 Axial Vibration, Vol 2, Pt 5, Ch 3 Lateral Vibration and Vol 2, Pt 5, Ch 4 Shaft Alignment.