8.5.1 An inclining test should be required for
the first unit of a design, when as near to completion as possible,
to determine accurately the lightship data (weight and position of
centre of gravity).
8.5.2 For successive units which are identical
by design, the lightship data of the first unit of the series may
be accepted by the Administration in lieu of an inclining test, provided
the difference in lightship displacement or position of centre of
gravity due to weight changes for minor differences in machinery,
outfitting or equipment, confirmed by the results of a deadweight
survey, are less than 1% of the values of the lightship displacement
and principal horizontal dimensions as determined for the first of
the series. Extra care should be given to the detailed weight calculation
and comparison with the original unit of a series of column-stabilized,
semi-submersible types as these, even though identical by design,
are recognized as being unlikely to attain an acceptable similarity
of weight or centre of gravity to warrant a waiver of the inclining
test.
8.5.3 The results of the inclining test, or deadweight
survey and inclining experiment adjusted for weight differences, should
be indicated in the Operating Manual.
8.5.4 A record of all changes to machinery, structure,
outfit and equipment that affect the lightship data, should be maintained
in the Operating Manual or a lightship data alterations log and be
taken into account in daily operations.
8.5.5 For column-stabilized units, a deadweight
survey should be conducted at intervals not exceeding five years.
Where the deadweight survey indicates a change from the calculated
lightship displacement in excess of 1% of the operating displacement,
an inclining test should be conducted.
8.5.6 An inclining test or a deadweight survey
should be carried out in the presence of an officer of the Administration,
or a duly authorized person or representative of an approved organization.