3.3.1 The final waterline, taking into account
sinkage, heel and trim, should be below the lower edge of any opening
through which progressive flooding may take place. Such openings should
include air pipes and those which are capable of being closed by means
of weathertight doors or hatch covers and may exclude those openings
closed by means of watertight manhole covers and flush scuttles, small
watertight cargo tank hatch covers which maintain the high integrity
of the deck, remotely operated watertight sliding doors and sidescuttles
of the non-opening type.
3.3.2 In the final stage of flooding, the angle
of heel due to unsymmetrical flooding should not exceed 15°. This
angle may be increased up to 17° if no deck immersion occurs.
3.3.3 The stability in the final stage of flooding
should be investigated and may be regarded as sufficient if the righting
lever curve has, at least, a range of 20° beyond the position
of equilibrium in association with a maximum residual righting lever
of at least 100 mm within this range. Unprotected openings should
not become immersed at an angle of heel within the prescribed minimum
range of residual stability unless the space in question has been
included as a floodable space in calculations for damage stability.
Within this range, immersion of any of the openings referred to in
3.3.1 and any other openings capable of being closed weathertight
may be authorized.
3.3.4 The Administration should be satisfied that
the stability is sufficient during intermediate stages of flooding.