.1 Load lines should be assigned to self-elevating
units as calculated under the terms of the 1966
Load Line Convention. When floating or when in transit from
one operational area to another units should be subject to all the
conditions of assignment of that Convention unless specifically excepted.
However, these units should not be subject to the terms of that Convention
while they are supported by the sea-bed or are in the process of lowering
or raising their legs.
.2 The minimum freeboard of units which due to
their configuration cannot be computed by the normal methods laid
down by the 1966 Load Line Convention should
be determined on the basis of meeting applicable intact stability,
damage stability and structural requirements in the afloat conditions.
.3 Where it is necessary to assign a greater than
minimum freeboard to meet intact or damage stability requirements
or for any other restriction imposed by the Administration, Regulation 6(6) of the 1966 Load Line Convention
should apply. When such a freeboard is assigned, seasonal marks above
the centre of the ring should not be marked and any seasonal marks
below the centre of the ring should be marked. If a unit is assigned
a greater than minimum freeboard at the request of the owner, Regulation 6(6) need not apply.
.4 Where wells such as moonpools are arranged
within the hull, the volume of the well should be deducted from the
volume of displacement of the unit used for the calculation of the
block coefficient. An addition should be made to the freeboard, equal
to the volume of the well divided by the waterplane area to compensate
for the loss of buoyancy.
.5 The procedure described in 3.7.3.4 should apply
in cases of small notches or relatively narrow cut-outs at the stern
of the unit.
.6 Narrow wing extensions at the stern of the
unit should be considered as appendages and excluded for the determination
of length (L) and for the calculation of freeboards. The Administration
should determine the effect of such wing extensions with regard to
the requirements for the strength of unit based upon length (L).
.7 Self-elevating units may be manned when under
tow. In such cases a unit would be subject to a bow height requirement
which may not always be possible to achieve. In such circumstances,
the Administration should consider the extent of application of Regulation
39(3) of the 1966 Load Line Convention to such units, having regard
to the occasional nature of such voyages on predetermined routes and
to prevailing weather conditions.
.8 Some self-elevating units utilize a large mat
or similar supporting structure which contributes to the buoyancy
when the unit is floating. In such cases the mat or similar supporting
structure should be ignored in the calculation of freeboard. The mat
or similar supporting structure should, however, always be taken into
account in the evaluation of the stability of the unit when floating
since its vertical position relative to the upper hull may be critical.