1.3.1 Forces which have to be absorbed by suitable
arrangements for stowage and securing to prevent cargo shifting are
generally composed of components acting relative to the axes of the
ship:
- longitudinal;
- transverse; and
- vertical.
Remark:
Note For the purpose of stowage and securing cargo, longitudinal
and transverse forces are considered predominant.
1.3.2 Transverse forces alone, or the resultant
of transverse, longitudinal and vertical forces, normally increase
with the height of the stow and the longitudinal distance of the stow
from the ship's centre of motion in a seaway. The most severe forces
can be expected in the furthest forward, the furthest aft and the
highest stowage position on each side of the ship.
1.3.3 The transverse forces exerted increase directly
with the metacentric height of the ship. An undue metacentric height
may be caused by:
- improper design of the ship;
- unsuitable cargo distribution; and
- unsuitable bunker and ballast distribution.
1.3.4 Cargo should be so distributed that the
ship has a metacentric height in excess of the required minimum and,
whenever practicable, within an acceptable upper limit to minimize
the forces acting on the cargo.
1.3.5 In addition to the forces referred to above,
cargo carried on deck may be subjected to forces arising from the
effects of wind and green seas.
1.3.6 Improper shiphandling (course or speed)
may create adverse forces acting on the ship and the cargo.
1.3.7 The magnitude of the forces may be estimated
by using the appropriate calculation methods as contained in the Cargo
Securing Manual, if provided.
1.3.8 Although the operation of anti-roll devices
may improve the behaviour of the ship in a seaway, the effect of such
devices should not be taken into account when planning the stowage
and securing of cargoes.