.1 The hull form of this type of unit makes the
calculation of geometric freeboard in accordance with the provisions
of Chapter III of the 1966 Load
Line Convention impracticable. Therefore the minimum freeboard of
each column stabilized unit should be determined by meeting the applicable
requirements for:
-
.1 the strength of unit's structure;
-
.2 the minimum clearance between passing wave
crests and deck structure (see 2.6.1);
and
-
.3 intact and damage stability requirements.
.2 The minimum freeboard should be marked in appropriate
locations on the structure. Where practicable, such marks should be
visible to the person in charge of mooring, lowering or otherwise
operating the unit.
.3 The main deck of each column stabilized unit
should be made weathertight, as far as practicable.
.4 In general, heights of hatch and ventilator
coamings, air pipes, door sills, etc., in exposed positions and their
means of closing should be determined by consideration of both intact
and damage stability requirements. In particular, all openings which
may become submerged before the heeling angle at which the required
area under the intact righting arm curve is achieved should be fitted
with weathertight closing appliances. Weathertight closing appliances
should also be fitted to openings which lead to spaces the volume
of which was included in the calculation of cross curves of stability
and to sanitary discharges originating in such spaces and which lead
through the shell. With regard to damage stability, the requirements
in 3.6.4.1 should apply.
.5 Administrations should give special consideration
to the position of openings which cannot be closed in emergencies,
such as air intakes for emergency generators, having regard to the
intact righting arm curves and the final waterline after assumed damage.