The Roberts-class monitors served in North Africa, Sicily, Salerno, and Normandy, accumulating substantial operational records in only a few wartime years. Amphibious shipping did more than carry troops: the assault also depended on vessels able to suppress defences and support the advance ashore. Modified landing craft could deliver rockets and lighter gunfire, but a monitor's pair of 15-inch guns supplied a different scale of destructive power. Fire-control resources normally used to coordinate a battleship's larger battery were focused on those two guns in one turret and on one level. That concentration made the Roberts class a compact source of battleship-scale firepower within the wider landing force.
Chapter · 25:34-26:57
Concentrating battleship-scale support on two guns
The Roberts class made a small number of very heavy guns central to amphibious operations by concentrating the spotting and control resources that a battleship spread across several turrets.