The main belt was about 225 mm thick, the main deck 115 mm, and the turret faces 330 mm. Concentrating both quadruple main turrets forward let the ship present a narrow target while using all heavy guns, with considerable volume ahead of vital spaces. The secondary battery mixed three quadruple and two twin 130 mm dual-purpose mounts, a weight-saving choice that left the aft defense heavily dependent on the quadruple mounts. A colleague reported seeing design papers with six quadruple 130 mm mounts, but the identification remains uncertain and may instead concern an early Richelieu study. The fitted light anti-aircraft battery included eight 37 mm guns and thirty-two 13.2 mm machine guns. Two assembled floatplanes and a partly stowed third aircraft supported reconnaissance, explaining why sources can correctly give either two or three aircraft.
Chapter · 34:47-39:15
All-forward guns shaped Dunkerque's protection and firepower
The class paired eight forward 330 mm guns with a protected narrow fighting aspect, dual-purpose secondary batteries, and an internal aircraft hangar.