Although the coastal artillery batteries tended to have more elaborate personnel bunkers and shelters, they also had more need for these defenses. In April 1944, Allied bombers began a systematic campaign against the coastal batteries facing the Channel. The personnel bunkers could generally withstand a direct hit by most bombs, and in reality a heavy air raid on a battery would generally result in only one or two hits on any of the structures. German engineer documents record a few instances of failures of bunkers to air attack, generally due to construction faults. Whether the bunkers were penetrated or not, the bombing campaigns were a frightening prospect for the troops huddled within. While the attacks did not cause heavy casualties among the gun crews, they often compromised the effectiveness of the batteries by ripping up vital communication wires between the fire-control bunkers and the gun casemates, obstructed the gun embrasures with craters and dirt, and tore up communication trenches between the bunkers.
THE SITES AT WAR
The gun batteries along the Pas-de-Calais took part in a desultory campaign of bombardment against the English coast around Dover starting in 1940 and continuing well into 1944. This resulted in a continuing campaign of counter-bombardment from British batteries as well as a prolonged air campaign against the “Iron Coast” gun batteries. Although the air campaign was not especially effective in disabling the fortified casemates, the battery sites soon took on the appearance of a lunar landscape due to the many bomb craters. There was also some exchange of fire between coastal batteries and British warships over the years and the heavy gun batteries along the Pas-de-Calais frequently fired upon coastal shipping in the Channel.
The Allied campaign against the coastal batteries was intensified in 1944 and extended to upper and lower Normandy and parts of Brittany in April 1944 as part of the run-up to the D-Day invasion. The campaign was intentionally conducted also at sites other than the D-Day beaches to keep the Wehrmacht guessing where the actual landings would take place. The bombardment campaign had very mixed results, in some cases effectively neutralizing some batteries such as the army coastal battery on Pointe-du-Hoc, in other cases failing to have any appreciable effect on the battery such as at Merville, while in other cases having mixed success such as Longues-sur-Mer, where the gun casemates were intact but their performance degraded due to the destruction of the cabling between the fire-control post and the guns.
The D-Day landings in lower Normandy on June 6, 1944, quickly overwhelmed the defenses. The coastal batteries with very few exceptions had been disabled before the landings and, even in the case of the few batteries that engaged the landing fleet such as the St. Marcouf, Azeville and Longues-sur-Mer batteries, they were quickly suppressed. The only defenses that posed a significant problem were those at Omaha Beach, and this was due primarily to the presence of more defenses, more and better troops, and a more challenging defense configuration due to the bluffs along the beach compared to the other D-Day beaches.[1]
The Czechoslovak 47mm Festungspak 36(t) was so widely used in the Atlantic Wall that several standardized bunker designs were developed to accommodate it. This shows the interior of one in the Cherbourg defenses. (NARA)
One of the problems of the coastal gun casemates was that they prevented full traverse. During the fighting for Cherbourg, MKB Hamburg removed portions of the incomplete casemate to permit a wider arc of fire for its 240mm gun. (NARA)
Once the D-Day landings took place, there was no immediate evacuation or weakening of other portions of the Atlantic Wall since senior German commanders remained convinced for several weeks that the Normandy landings were only a feint and that other landings would occur elsewhere along the coast. Elements of the Atlantic Wall defenses were involved in continual combat through June as the US First Army advanced up the Cotentin Peninsula, culminating in the VII Corps attack on Cherbourg in late June 1944. Although Cherbourg had been ringed with defenses as part of the Festung policy, in reality these defenses were not adequate to stop the US Army. The outer crust of Cherbourg defenses served to delay the US advance, but they were comprehensively breached within a few days of intense combat. The defenses in Cherbourg itself were mostly oriented seaward and so played little role in the city fighting. Indeed, the traditional French fortified defenses around the port played as much a role in the defense as did the newer Atlantic Wall defenses, such as Fort Roule in the center of the city and the fortified harbor. The heaviest fortifications, such as the numerous navy coastal artillery batteries, played little or no role in the fighting since their ferro-concrete carapace limited the traverse of their guns to seaward targets. This experience would be repeated in the subsequent battles for the Channel ports, where most of the work on the Atlantic Wall fortifications proved to be in vain due to this fatal shortcoming.
Further fighting ensued along the Atlantic Wall after the breakout from Normandy in late July that unleashed the Allied advance along the coast toward the Pas-de-Calais and toward Brittany. St. Malo at the junction between lower Normandy and Brittany was the scene of an intense urban battle made all the more difficult for the US Army by the traditional walled fortifications of the port. The assault on St. Malo by the 83rd Division began on August 5 and took nearly two weeks of fighting, finally being overwhelmed on August 17. Even then, German defenders held out on the offshore fortifications of Cézembre until September 2. The port of Brest was one of the most heavily fortified along the Atlantic Wall and US armored spearheads began probing its defenses on August 7. The city was gradually surrounded and a full-blooded attack began on August 25 by VIII Corps of Patton’s Third Army. Although the fortifications and gun positions of the Atlantic Wall defenses played some role in the defense of Brest, for the most part they were not especially useful for the defenders except in some limited sectors. Once again, traditional French fortifications such as Fort Montbarey and Fort de Portzic proved more troublesome than the newer and much smaller Atlantic Wall bunkers, most of which were oriented seaward. As in the case of Cherbourg, the German garrison was eventually overwhelmed, but in the interim, the Kriegsmarine managed to demolish the harbor facilities. As a result, the US Army decided against a direct assault on St. Nazaire or Lorient, preferring to simply bottle up the German garrison rather than sacrifice large numbers of infantrymen for a shattered port. The same would be the case along the Bay of Biscay, with fortified ports such as Royan and La Rochelle holding out until May 1945. To reduce the number of US troops assigned to this siege, in the autumn of 1944 newly raised French units were gradually assigned this mission.
1
For more detail, see Fortress 37: