7.1 General
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Statutory Documents - IMO Publications and Documents - International Codes - 1989 MODU Code – Code for the Construction and Equipment of Mobile Offshore Drilling Units, 1989 – Resolution A.649(16) - Chapter 7 – Machinery and Electrical Installations for Self-Propelled Units - 7.1 General

7.1 General

  7.1.1 The requirements of this chapter apply to units which are designed to undertake self-propelled passages without external assistance and are not applicable to units which are fitted only with means for the purpose of positioning or of assistance in towing operations. These requirements are additional to those in chapters 4, 5 and 6.

  7.1.2 Means should be provided whereby normal operation of propulsion machinery can be sustained or restored even though one of the essential auxiliaries becomes inoperative. Special consideration should be given to the malfunction of:

  • .1 a generator set which serves as a main source of electrical power;

  • .2 the sources of steam supply;

  • .3 the arrangements for boiler feedwater;

  • .4 the arrangements which supply fuel oil for boilers or engines;

  • .5 the sources of lubricating oil pressure;

  • .6 the sources of water pressure;

  • .7 a condensate pump and the arrangements to maintain vacuum in condensers;

  • .8 the mechanical air supply for boilers;

  • .9 an air compressor and receiver for starting or control purposes; and

  • .10 the hydraulic, pneumatic or electrical means for control in main propulsion machinery including controllable pitch propellers.

However, the Administration, having regard to overall safety considerations, may accept a partial reduction in capability from full normal operation.

  7.1.3 Main propulsion machinery and all auxiliary machinery essential to the propulsion and the safety of the unit should, as fitted in the unit, be capable of operating under the static conditions required by 4.1.4 and the following dynamic conditions:

  • .1 column-stabilized units 22.5° in any direction;

  • .2 self-elevating units 15° in any direction;

  • .3 surface units 22.5° rolling and simultaneously pitching 7.5° by bow or stern.

The Administration may permit deviation from these angles, taking into consideration the type, size and service conditions of the unit.

  7.1.4 Special consideration should be given to the design, construction and installation of propulsion machinery systems so that any mode of their vibrations should not cause undue stresses in this machinery in the normal operating ranges.

Parent topic: Chapter 7 – Machinery and Electrical Installations for Self-Propelled Units
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