Thread: Longues Sur-mer Battery

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 Officers 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

To improve detection of enemy movements, the range-finding post was backed up by two observation posts located a few kilometres east and west of the battery. Had the batteries been equipped with radar, they would have been highly effective, but as it was, not one battery in Calvados was so equipped. There were radar stations nearby at Douvres-la- Delivrande, Arromanches and at the Point de la Percee, but these stations were not controlled from the sea front and, even if they were able to inform the battery of the co-ordinates of any enemy target, this system turned out to be patently ineffective as the radar station reported first to its superiors.

German radar station map room

In any case, by the spring of 1944, following intensive Allied bombing raids, the radar stations were no longer operational. On the morning of the D-Day landings, 74 out of the 92 radar stations in Normandy had been put out of action. To make up for the difficulty of firing at night, the battery was equipped with to powerful 150cm searchlights, one to the east and one to the west of the control bunker which were individually operated from concrete covered installations. These searchlights were practically vulnerable, however, as one well imagines.

In June 1944, the Longues-ser-Mur control bunker still showed some weakness which were felt during the battle. First of all, the bunker was unfinished and if the battery commander wished to look out to sea, he had to go upstairs to the observation deck as the range-finder room on the ground floor opened out on to the cliff face. The task of clearing the ground in front of the bunker had been left until last so as to conceal it from the enemy spotters. The rock has, however, now been cleared away and the sea can be seen through the front lookout slit. This is thanks to the film “The Longest Day� where in a memorable scene they brought this control bunker back to life. The second weakness lay in the difficulties encountered in transmitting information to the four casemates as each wave of bombing caused heavy damage to the network of telephone cables.

An Iron rung ladder at the back of the bunker was used to reach the top floors observation room.

Despite being buried under 2 metres of earth, the cables were unable to withstand the 1000kg bombs which left in their wake craters 7 metres deep and 20 metres across. So the control bunker was cut off from its guns after each bombing raid. Unlike St Marcouf, where the battery commander decided to leave the telephone cables running along the ground so as to be able to repair them quickly, a method which proved particularly effective on D-Day, this battery took no alternative measures. There were other possible solutions too, such as the optical method which involved painting figures on large boards. This method worked less well, and sometimes not at all, as the visibility of the gunners was marred by the smoke from their own guns and from enemy shells and bombs. On D-Day morning the command centre was cut off from its guns and Longues was very soon cut off from its seafront commander at Cherbourg as well, because overhead wires were systematically cut throughout the battle zone, often by resistance fighters.

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