A quadruple mounting is not simply two twins in one box. More guns bring more mechanisms and more interactions between the guns, including the effects of firing and concussion within the turret. The impressive twelve-gun concept consequently becomes a logistical and maintenance burden. Its 23-knot speed also leaves it short of the tactical mobility expected of a fast battleship, even though its armor and firepower would remain formidable.
Notable Point · 25:30-28:50
The maintenance cost of concentrating guns in one turret
Adding guns to a turret increases not just barrel count but interactions, concussion effects, maintenance burden, and tactical compromise.