3.1.1 An inclining test should be required for
the first unit of a design, when the unit is as near to completion
as possible, to determine accurately the light ship data (weight and
position of centre of gravity).
3.1.2 For successive units which are identical
by design, the light ship data of the first unit of the series may
be accepted by the Administration in lieu of an inclining test, provided
the difference in light ship 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 lightweight
survey, is less than 1% of the values of the light ship 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,
semisubmersible 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.
3.1.3 The results of the inclining test, or those
of the lightweight survey together with the inclining test results
for the first unit should be indicated in the operating manual.
3.1.4 A record of all changes to machinery, structure,
outfitting and equipment that affect the light ship data should be
maintained in a light ship data alterations log and be taken into
account in daily operations.
3.1.5 For column-stabilized units:
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.1 A lightweight survey or inclining test should
be conducted at the first renewal survey. If a lightweight survey
is conducted and it indicates a change from the calculated light ship
displacement in excess of 1% of the operating displacement, an inclining
test should be conducted, or the difference in weight should be placed
in an indisputably conservative vertical centre of gravity and approved
by the Administration.
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.2 If the survey or test at the first renewal
survey demonstrated that the unit was maintaining an effective weight
control programme, and at succeeding renewal surveys this is confirmed
by the records under paragraph 3.1.4, light ship displacement may
be verified in operation by comparison of the calculated and observed
draught. Where the difference between the expected displacement and
the actual displacement based upon draught readings exceed 1% of the
operating displacement, a lightweight survey should be completed in
accordance with paragraph 3.1.5.1.
3.1.6 The inclining test or lightweight 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.