How treaty battleships traded belt armour for torpedo defence

The comparison of King George V, North Carolina, Littorio, and Nelson shows how treaty battleships distributed protection differently. King George V and North Carolina appear designed for easier access to their armour. In most classes, belt thickness tapered downward while torpedo-defence spaces took over more of the underwater burden and consumed internal volume. Littorio is the exception in this comparison, while Nelson's system appears unusually efficient for a navy trying to build the smallest viable battleship. Maximum belt thickness alone therefore gives an incomplete picture of treaty-era protection.