Naval Guns at Normandy (navy.mil)Our large ships would be forced to remain outside the shoals, much further than we wished them to be, but there was no help for it. They too would be confined to swept channels with consequent loss of their mobility when engaged by the heavily protected defense guns.
Our advance knowledge of the general characteristics and exact location of the batteries was of tremendous importance. For we could plan the arrangement of our ships so that the toughest batteries would be engaged by our most powerful ships.
The NEPTUNE Plan called for an approach to the Normandy coast during darkness. It seemed too optimistic to expect the enemy to be caught napping. Our spotting aircraft would not arrive until about daylight and we believed the Allied ships would be under heavy fire long before that.
To meet this contingency, we prepared a plan called "ZEBRA." Modern radar and navigational equipment had made it possible for the captains to know, within acceptable limits, the exact positions of their ships at any instant. This greatly simplified the gunnery problem and permitted us to shoot "blind" with considerable accuracy. When signal was made our bombardment group would open fire, each upon its own designated target. Unaware of which batteries were shooting, we would take all the important ones under simultaneous fire. There is something very disturbing to the receiver in the deafening violence of close bursting high power shells. At night its effect is enhanced. It would be our business to see to it that the enemy batteries were too occupied with us to turn their attention to the troop laden boats as they approached the shore. Whether we destroyed them or not we must prevent them from doing what Rommel expected them to do.
We had no illusions, however, that blind firing, day or night, no matterhow good, would destroy or permanently disable such well designed and protected batteries. No artillery, afloat or ashore, could do so without expert spotting. The spotter is the "eyes of the ship." He is in a place overlooking the target where he can report precisely where the shells are falling and their effect, This does by special radio to the ship.Spotting is a highly specialized task for a man who must be cool and steady. He may be on the ground, near the target; afloat, where he had a close view; or in the air. Naval spotters, in sea battles or in the early phases of amphibious assault must, of course, be in aircraft.
Since the 1920s, air spotting and scouting had been an important factor in the U.S. Navy, Highly efficient seaplane units were a part of each larger ship. Far reaching were their effects on the growth of U.S. naval aviation and its acceptance by our Navy as a whole back in the 1920s and 30s.
But Normandy differed from previous amphibious objectives in the Pacific and Mediterranean in the strength of enemy anti-aircraft preparation. The Cotentin was studded with "flak towers" and all the defense positions were supplemented with AA guns. Slow seaplanes such as we normally used would not long survive over that country.
The Allies possessed no fast two-seater planes. The British offered perhaps the only solution by providing a spotting "pool" of fast fighters. In it were: four squadrons of R.N. Seafires (Naval Spitfires), five squadrons of RAF Spitfires and Mustangs (many of these would be withdrawn after noon of D-day), added to these were 17 USN pilots taken from our ships, who quickly learned to fly Spitfires. They were expert spotters.
Most of the RAF pilots had no previous experience in spotting, a function which differed greatly from their normal tasks, The training they received was good, but very brief.