This is a very narrow bit of ‘data’.Richard Anderson wrote: ↑23 Jun 2020 02:13...
It's an interesting sidelight to NEPTUNE, the German analysis of the effectiveness of the building program. The most interesting finding was that adding the overhead cover to the coast artillery batteries may have been counterproductive. The problem was the "protected" emplacements were more easily disabled than the older open emplacements because the embrasure tended to "funnel" naval counterbattery rounds into the gun house where they exploded with devastating effect. Marcouf was an example, but apparently others suffered similarly. Since the gun crews tended to remain in the gun house, they were killed or injured, and the concentration of the blast and fragments did more damage to the guns and accessories, but in the open emplacements the crew shelters were separate, protecting the crews and only a direct hit on the gun itself tended to damage it.Can you elaborate on that one? There was a large amount of concrete poured in the latter 1943, then winter & spring of 1944, not just along the possible landing sites , but around the ports as well. What specifically are you looking at that cancels the difference is the quantity of concrete protecting the defenders? Beyond that this seems to strongly connect to the difference in defense strategy & expected operational & tactical methods between 1943 & 1944 and the changes in personalities at several levels of command.
There would not be the flanking beach casemates, but I suspect that field fortifications in enfilade would have been as effective.
Funneling naval cannon shots into embrasures, or of any cannon, is a long and tedious thing. Unless you are at very close range & have precise identification of the target that sort of accuracy is problematic. Very close range would be under 1200 meters for lighter cannon like a tank gun, a bit more for a 5” naval gun, or maybe between 1500 & 2000 for larger naval cannon. Thats great when your tank, or destroyer playing chicken with the surf is supporting a assault team, but for general fire support the odds of hitting a embrasure is too small to consider. It happens, but never count on it.
In this larger context the concrete has the advantage over the sandbag and log structure in that the steel reinforced concrete is far more resistant to the hit on the other 90%of the structure other than the embrasure. I can spend several days digging out the data of shot vs assorted protective cover, but I suspect you have some of that near your comfy chair, so I dont need t reproduce your data. Effects on target can be displayed as a spectrum across scale of protection. The harder the material the more ammunition it takes to gain effect. Or for a practical quantity of ammunition it moves the lesser effect along the scale. For the duration of the sort of preparatory fires there were on the Normandy beaches concrete moved the effects to the far end of the scale to Suppresive. Against lght entrenchemnts the effct vs infantry and cannon defense would have been near the Destructive end of the scale. Log or steel & sandbag structures turn identical fires to the Nuetralizing & Suppresive portion of the scale. Concrete & steel shifts the effect firmly into the Suppresive zone.
Beyond that theres the many other details differing between the two years, the quantity of mines, wire, AT ditches, communications trenches, MG, AT guns, field artillery, men, buried telephone wire, ect... ect... Through the advent of Rommel the German strategy was to not defend the beaches. It was to defend the ports, denying those to the enemy & defeat the enemy force by concentrating substantial reserves for a counter attack. Most folks have at least a cursory understanding of this. What they miss is the relatively thin line of outposts that covered the beaches & lack of local reserves. Before Rommel think of Nettuno Italy covered by a company deployed in a observation role, and a couple battalions within six to twelve hours march.
I could go on at length but need to get to work. I think that any more than a cursory glance at the German ground force shows just how weak it was man for man vs what Rundstead had in May 1944.