4.6.1 Cargo tanks should be
supported by the hull in a manner which will prevent bodily movement
of the tank under static and dynamic loads while allowing contraction
and expansion of the tank under temperature variations and hull deflections
without undue stressing of the tank and of the hull.
4.6.2 The tanks with supports
should also be designed for a static angle of heel of 30° without
exceeding allowable stresses given in 4.5.1.
4.6.3 The supports should be
calculated for the most probable largest resulting acceleration, taking
into account rotational as well as translational effects. This acceleration
in a given direction may be determined as shown in figure 4.1. The half axes of the “acceleration
ellipse” should be determined according to 4.3.4.2.
4.6.4 Suitable supports should
be provided to withstand a collision force acting on the tank corresponding
to one half the weight of the tank and cargo in the forward direction
and one quarter the weight of the tank and cargo in the aft direction
without deformation likely to endanger the tank structure.
4.6.5 The loads mentioned in 4.6.2 and 4.6.4 need
not be combined with each other or with wave-induced loads.
4.6.6 For independent tanks
and, where appropriate, for membrane and semi-membrane tanks, provision
should be made to key the tanks against the rotational effects referred
to in 4.6.3.
4.6.7 Antiflotation arrangements
should be provided for independent tanks. The antiflotation arrangements
should be suitable to withstand an upward force caused by an empty
tank in a hold space flooded to the summer load draught of the ship,
without plastic deformation likely to endanger the hull structure.