2.5 Typical approved loading conditions
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC/Circular.920 – Model Loading and Stability Manual – (15 June 1999) - Annex – Model Loading and Stability Manual - Section 2 – Guidance to the master - 2.5 Typical approved loading conditions

2.5 Typical approved loading conditions

  2.5.1 As a minimum, the following loading conditions should be compiled and calculated for any ship in accordance with MSC/Circ.456:

  • .1 lightship condition;

  • .2 docking condition;

  • .3 loading conditions as stipulated in 3.5.1, 4.2.5 and 4.5.7 of the Intact Stability Code (resolution A.749(18)), as amended; and

  • .4 table of summary of loading conditions.

  2.5.2 Assumptions for calculating loading conditions should be in accordance with 3.5.2, 4.1.8 and 4.5.8 of the Intact Stability Code, as amended. Where icing is likely to occur the loading conditions should take this into account.

  2.5.3 As calculated loading conditions will be used by the master to obtain a realistic picture of the cargo carrying capabilities of the ship, it is recommended to include a limited number of fully loaded conditions with approximately half capacity of consumables on departure. The consequential surplus of cargo carrying capacity may be partly used for low ballast if the excess cargo is to be loaded on deck. The subsequent arrival condition with 10% consumables should be provided as well.

  2.5.4 If, due to the nature of the cargo and its typical stowage pattern, stability may become the limiting parameter for the loading concept in general (e.g., containerships, ro-ro ships, ships carrying timber on deck), the calculated loading conditions should present "limit conditions" with regard to load line and stability requirements either for departure or arrival or both.

  2.5.5 Each presented condition of loading should include:

  • .1 A sketch of the ship indicating pictorially the main items of deadweight included in the displacement, side view and top view if useful.

  • .2 A table showing lightship mass and all components of the deadweight together with the positions of their centres relative to the defined reference planes.

  • The summation should show the displacement and the positions of its centre. Positions should be shown along the vertical and longitudinal axes. For containerships and ro-ro ships, the inclusion of the transverse co-ordinate is recommended. The free surface moments of slack tanks for zero degree heel should be included in this table in accordance with 3.3 of the Intact Stability Code, as amended.

  • .3 A diagram showing the curve of righting levers plotted against the angle of inclination. The righting levers are to be corrected for free surface effects in accordance with 3.3 of the Intact Stability Code, as amended. Wind and/or other heeling lever curves should be superimposed on the diagram as appropriate. The scales used in this diagram should be the same for each loading condition in the manual.

  • .4 A summary of the appropriate condition should contain as a minimum:

    • .1 displacement;

    • .2 corresponding draught (i.e. draught at centre of flotation);

    • .3 moment to change trim one unit (metre or centimetre);

    • .4 longitudinal position of centre of buoyancy;

    • .5 longitudinal position of centre of mass;

    • .6 longitudinal position of centre of flotation;

    • .7 trim over perpendiculars;

    • .8 draught at forward perpendicular;

    • .9 draught at after perpendicular;

    • .10 draught at mid between perpendiculars;

    • .11 total free surface moment for initial stability;

    • .12 vertical position of the transverse metacentre (for trimmed condition if trim exceeds 1% of the length of the ship);

    • .13 vertical position of the ship's centre of mass, uncorrected and corrected for free surface effects;

    • .14 transverse metacentric height uncorrected and corrected for free surface effects; and

    • .15 a statement giving the limiting value or values of stability parameters taken from data under 3.6 and the comparison with corresponding values achieved.

  • .5 Draught and other hydrostatic data to be obtained from immersed gross volume in sea water (D = 1.025 t/m3). If the ship is intended to operate in areas of less water density the appropriate immersed gross volume may be used if agreed by the flag State Administration.

  • .6 Draught statements should refer to bottom of keel. This should be clearly indicated.

  2.5.6 Each calculated loading condition should be commented or explained highlighting the specific features of the particular condition with regard to:

  • .1 operating limits (see 2.4.8);

  • .2 ballast operations between departure and arrival due to fuel consumption, water soaking of deck cargo or other reasons;

  • .3 limitations to stowage factor of cargo or to average container masses per tier;

  • .4 restrictions to the positioning of ship's equipment and other heavy masses or usage of swimming pool;

  • .5 amount and distribution of consumables;

  • .6 minimum filling of slack ballast tanks to avoid excessive sloshing (in the case of high initial stability); and

  • .7 any other important aspects.

Parent topic: Section 2 – Guidance to the master
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