The Control Bunker was right on the edge of the 65m cliff top. From here, there is an excellent view over the whole of the Bay of the Seine. This two-storey control bunker also served as the battery command post. The building was known as the “Leitstand†or command centre. On the upper level, covered by a concrete slab supported by four metal cylinders, was the observation deck. On the lower floor could be found the map room, the radio room, the Officer’s room and, most importantly, the range-finder room with its observation slit which looked out at sea from behind glazing, through a radius of 220’
Looking into the Range-Finder room
A lookout gazed out to sea through binoculars. When an enemy target was sighted, the range-finder, an optical device five metres in diameter was used to calculate the distance from the battery to the target so that that the guns range could be adjusted accordingly. Further calculations were then carried out by naval gunners and parallax connectors to compensate for the distance of 300m between the control bunker and the batteries themselves.
Front View of the Control Bunker
Instructions were then transmitted to the casemates by field telephone linked by cables buried deep underground. Of all the Normandy coastal batteries, the Longues battery was doubtless the best equipped in range-finding instruments. In fact many batteries still had not been equipped with range-finders at the time of the Allied invasion. The army coastal artillery batteries suffered worst in this respect.
Front View looking into the Control Bunker's Slit
