For the purpose of calculating the adverse heeling moment due to a shift of cargo surface in ships carrying bulk grain it shall be assumed that:
- In filled compartments which have been trimmed in accordance with grain code , a void exists under all boundary surfaces having an inclination to the horizontal less than 30° and that the void is parallel to the boundary surface having an average depth calculated according to the formula:
Vd= Vd1+0.75 (d-600) mm
Vd = average void depth in millimetres
Vd1 = standard void depth from table below
d = actual girder depth in millimetres.
In no case shall Vd be assumed to be less than 100 mm.
- Within filled hatchways and in addition to any open void within the hatch cover there is a void of average depth 150 mm measured down to the grain surface from the lowest part of the hatch cover or the top of the hatch side coaming, whichever is the lower.
- In a filled compartment, untrimmed, which is exempted from trimming outside the periphery of the hatchway by the provisions of grain code , it shall be assumed that the surface of the grain after loading will slope into the void space underdeck, in all directions, at an angle of 30° to the horizontal from the edge of the opening which establishes the void.