Why Nelson and Rodney carried all main guns forward

The design placed magazines and armament forward while separating them from boiler rooms, reducing the protected length that needed heavy armour. This made a nine-gun 16-inch broadside possible within the 35,000-ton limit and dockyards that had not received the expansion once planned for the First World War. Concentrating the protected citadel let designers devote more of the allowed displacement to armour and firepower. The trade-off was speed: a two-shaft machinery arrangement left the ships slower than the fast battleships that later warfare favoured. A third shaft, more boilers, and a modest sacrifice in protection might have produced a 28- or 29-knot ship, though that was not the balance chosen in the 1920s.