3.7.2 Surface 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 - 3.7 Freeboard - 3.7.2 Surface units

3.7.2 Surface units

  .1 Load lines should be assigned to surface units as calculated under the terms of the 1966 Load Line Convention and should be subject to all the conditions of assignment of that Convention.

  .2 Where it is necessary to assign a greater than minimum freeboard to meet intact or damage stability requirements or for any other restriction imposed by the Administration, Regulation 6(6) of the 1966 Load Line Convention should apply. When such a freeboard is assigned, seasonal marks above the centre of the ring should not be marked and any seasonal marks below the centre of the ring should be marked. If a unit is assigned a greater than minimum freeboard at the request of the owner, Regulation 6(6) need not apply.

  .3 Where wells such as moonpools are arranged within the hull, the volume of the well should be deducted from the volume of displacement of the unit used for the calculation of the block coefficient. An addition should be made to the freeboard, equal to the volume of the well divided by the waterplane area to compensate for the loss of buoyancy.

  .4 The procedure described in 3.7.2.3 should also apply in cases of small notches or relatively narrow cut-outs at the stern of the unit.

  .5 Narrow wing extensions at the stern of the unit should be considered as appendages and excluded for the determination of length (L) and for the calculation of freeboards. The Administration should determine the effect of such wing extensions with regard to the requirements for the strength of unit based upon length (L).


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