3.5.3 Column stabilized units
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Statutory Documents - IMO Publications and Documents - International Codes - 1979 MODU Code – Code for the Construction and Equipment of Mobile Offshore Drilling Units – Resolution A.414(XI) - Chapter 3 – Subdivision, Stability and Freeboard - 3.5 Extent of damage - 3.5.3 Column stabilized units

3.5.3 Column stabilized units

 In assessing the damage stability of column stabilized units, the following extent of damage should be assumed:

  • .1 Only those columns on the periphery of the unit should be assumed to be damaged and the damage should be assumed in the exposed portions of the column.

  • .2 Columns which are subdivided into watertight compartments by watertight flats should in general be assumed to be damaged within anyone compartment enclosed by watertight flats. Columns should be assumed to be flooded by damage having a vertical extent of 3.0 metres occurring at any level between 5.0 metres above and 3.0 metres below the draughts specified in the Operating Manual. Lesser distances above or below the draughts may be applied to the satisfaction of the Administration, taking into account the actual operating conditions. However, the extent of required damage region should be at least 1.5 metres above and below the draughts specified in the Operating Manual and where a watertight flat is located within this region, the damage should be assumed to have occurred in both compartments above and below the watertight flat in question.

  • .3 No vertical bulkhead should be assumed to be damaged, except where bulkheads are spaced closer than a distance of one eighth of the column perimeter at the draught under consideration, measured at the periphery, in which case one or more of the bulkheads should be disregarded.

  • .4 Horizontal penetration of damage should be assumed to be 1.5 metres.

  • .5 Footings should be assumed to be damaged when operating in a light or transit condition in the same manner as indicated in 3.5.3.1 to 3.5.3.4 or in 3.5.2, having regard to their shape.

  • .6 All piping, ventilation systems, trunks, etc., within the extent of damage should be assumed to be damaged. Positive means of closure should be provided at watertight boundaries to preclude the progressive flooding of other spaces which are intended to be intact.

Parent topic: 3.5 Extent of damage
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