Use of torsion box in a container ship?

In a container ship the hatch openings are quite big with only a marginal distance on main deck of about 1.5 ft between the hatch opening and the shide shell. This is done so as to maximise the space for stowing containers as they cant be stowed correctly once inside the hold which is not the case with bulk carriers.

Now, the ship is always in motion which leads to a racking effect as well as a diagonal movement which produces a torsion on the main deck. Since the breadth of the main deck plating in way of the hatch openings is less, there is seriuos concentration of stresses there which cause cracking of the deck plating.

In order to prevent the material failure, torsion boxes are fitted with welded joints on the side shell as well as on the deck plating which prevent the torsion produced by twisting.