For timber deck cargo ship:
For ships loaded with timber deck cargoes and provided that the cargo extends longitudinally between superstructures (where there is no limiting superstructure at the after end, the timber deck cargo should extend at least to the after end of the aftermost hatchway) transversely for the full beam of ship after due allowance for a rounded gunwale not exceeding 4% of the breadth of the ship and/or securing the supporting uprights and which remains securely fixed at large angles of heel, the Administration may apply the following criteria .
- The area under the righting lever curve (GZ curve) should not be less than 0.08 metre-radian up to e = 40° or the angle of flooding if this angle is less than 40° .
- The maximum value of the righting lever (GZ) should be at least 0.25 m .
- At all times during a voyage, the metacentric height GMo should be positive after correction for the free surface effects of liquid in tanks and, where appropriate, the absorption of water by the deck cargo and/or ice accretion on the exposed surfaces.
Additionally, in the departure condition the metacentric height should be not less than 0.10 m.
