A cargo ship having at least one cargo tank positioned in a hold of said ship, said cargo ship comprising: a cargo hold having two ends, two sides, a bottom and a top; transverse structure members (11, 15) and longitudinal structure members (12, 13, 14) within said hold, said transverse members (11, 15) spaced at intervals within said cargo hold; a cylindrical cargo tank, longitudinal stringers on each side of said hold fixed to said transverse structural members (11, 15); characterized in that the cargo ship further comprises: at least three pedestal pairs mated to an outside surface of said tank below a circumferential diameter of said tank; each said pedestal pair positioned on said tank at a location coincident with one of said transverse structural members (11, 15), where said longitudinal stringers are positioned to support said pedestals; transverse stops fixed to said longitudinal stringers so as to constrain movement of said cargo tank pedestals in the transverse direction but not in the longitudinal direction; longitudinal stops at one axial location so as to constrain said pedestals in said longitudinal direction but not said transverse direction, wherein said transverse and longitudinal stops (30, 41) are spaced to allow limited movement of said pedestals between said stops (30, 41) in order to maintain cargo tank stresses within safe levels. a cargo hold having two ends, two sides, a bottom and a top; transverse structure members (11, 15) and longitudinal structure members (12, 13, 14) within said hold, said transverse members (11, 15) spaced at intervals within said cargo hold; a cylindrical cargo tank, longitudinal stringers on each side of said hold fixed to said transverse structural members (11, 15); characterized in that the cargo ship further comprises: at least three pedestal pairs mated to an outside surface of said tank below a circumferential diameter of said tank; each said pedestal pair positioned on said tank at a location coincident with one of said transverse structural members (11, 15), where said longitudinal stringers are positioned to support said pedestals; transverse stops fixed to said longitudinal stringers so as to constrain movement of said cargo tank pedestals in the transverse direction but not in the longitudinal direction; longitudinal stops at one axial location so as to constrain said pedestals in said longitudinal direction but not said transverse direction, wherein said transverse and longitudinal stops (30, 41) are spaced to allow limited movement of said pedestals between said stops (30, 41) in order to maintain cargo tank stresses within safe levels. at least three pedestal pairs mated to an outside surface of said tank below a circumferential diameter of said tank; each said pedestal pair positioned on said tank at a location coincident with one of said transverse structural members (11, 15), where said longitudinal stringers are positioned to support said pedestals; transverse stops fixed to said longitudinal stringers so as to constrain movement of said cargo tank pedestals in the transverse direction but not in the longitudinal direction; longitudinal stops at one axial location so as to constrain said pedestals in said longitudinal direction but not said transverse direction, wherein said transverse and longitudinal stops (30, 41) are spaced to allow limited movement of said pedestals between said stops (30, 41) in order to maintain cargo tank stresses within safe levels.