The challenge of rectifying a shortcoming in buckling capacity in the critical area can be solved in two alternate ways, either by reducing the compressive load or increasing the structure’s capacity to withstand the load.

A reduction in the allowable still water bending moment will reduce the compressive load in the lower part of the hull girder cross section. This is probably the most cost-effective way provided the cargo operations allow such a measure. Not all ships may utilise their full potential with regard to container loading on the hull girder, and in such case this may be the best way out of the problem.
The alternative is to increase the buckling capacity, which involves steel work. In most cases, this will be a minor job involving limited additional steel and may typically be carried out afloat, probably with a riding crew. Intercostal buckling stiffeners need to be installed in the critical area. This is illustrated in the model snapshots shown above.

The reason why the intercostals work is simply that the aspect ratio of the plate field is changed by dividing the plate up into almost square panels. The effectiveness of the orientation of the stiffeners is quite significant as can be seen from the comparison above. Two plate fields of the same dimensions are subjected to the same loading, one transversely stiffened and the other longitudinally stiffened. The ratio of the critical buckling stresses is 1.9, indicating that the longitudinal orientation is almost twice as effective as the transverse orientation.

The orientation and location of the intercostals are shown in the figure below, where the flat green bars are the modifications needed. The dimensions are typically some 150 x 12 mm flatbar section to be fitted in between the vertical framing. Depending on the size of the ship, the total steel weight should only amount to a few tonnes.