1.1.2 The global
load and design criteria given in this Chapter are also provided to
enable the designer/Builder to check global hull strength against
ductile failure modes involving gross deformation.
1.1.3 The global
load criteria are divided into two categories:
-
Hull girder loads
The types of hull girder loads which are to be considered for
strength purposes are distinguished on the basis of their frequencies
and they are defined as follows:
-
Still water bending moments and associated
shear forces arising from mass distribution and buoyancy forces.
-
Vertical wave bending moments and associated
shear forces arising from low frequency hydrodynamic forces.
-
Dynamic bending moments and associated shear
forces arising from high frequency bottom slamming.
-
Primary loads for multi-hull craft
These loads arise from the interaction between the hulls and
waves.
1.1.4 Alternative
methods of establishing the global load and design criteria will be
specially considered, provided that they are based on model tests,
full scale measurements or other generally accepted theories. In such
cases, full details of the methods used and the results are to be
provided when plans are submitted for approval.
1.1.5 Longitudinal
strength calculations are to be carried out and submitted for approval
for craft as required in Pt 6 Hull Construction in Steel, Pt 7 Hull Construction in Aluminium and Pt 8 Hull Construction in Composite, as appropriate,
covering the range of load and ballast conditions proposed, in order
to determine the required hull girder strength. The calculations of
still water shear forces and bending moments are to cover both departure
and arrival conditions and any special mid-voyage conditions caused
by changes in ballast distribution.
1.1.7 The vertical
acceleration at the LCG, a
v, in terms of g,
as defined in Pt 5, Ch 2, 3.2 Vertical acceleration, as appropriate,
is not to be taken less than 1,0 for the purpose of determining the
global load and design criteria.