The training required by the naval personnel before the invasion of Normandy was most comprehensive and dealt with all sorts of questions which would not occur to the layman. One obvious need was combined training in communications, particularly as all three arms of two nations and the Dominions were to be used in the Invasion, while French, Polish, Dutch and Norwegian ships would take part. No possible chance of breakdown, confusion or delay in communications could be accepted, for any one of these might lead to chaos and the loss of men, ships and material.
The guarantee against such disaster lay in good combined training and in the closest possible integration of all the communications staffs. These were very numerous. Apart altogether from thousands of visual signalling links between ships, between ship and shore, and between shore stations, arrangements had to be made for communications with aircraft in the air and between the numerous headquarters, some of them in England and some of them afloat in ships during the assault stage of the invasion. Some idea of the magnitude of the problem is conveyed by the fact that nearly eighty wireless wavelengths had to be allocated.
Another matter where training was necessary, although the need for it was less obvious, was in the provision in all infantry landing ships of naval personnel who were familiar with the ships, with the assault boat stations of the troops, and trained to help the troops to get to their stations with all their equipment in the dark. It is no disparagement of the army to say that the fully equipped soldier is a peculiarly helpless individual when he gets to sea. Consider the things with which he has to contend. He is not familiar by long habit with ships or with the motion of ships. If he is about to embark upon a hazardous amphibious operation he is necessarily equipped for the fighting which he will have to do as soon as he regains his rightful and accustomed element. He wears heavy “ammunition boots” and his equipment is heavy and bulky. His equipment makes him apt to lose his balance if a ship lurches. His boots are not made for decks, many of them steel and many of them often wet. Nor do they make it easier for him to climb steep ladders or negotiate high coamings. The bulk of his equipment makes it extremely difficult for him to negotiate narrow gangways, the sides of which are fitted with many steel protuberances, designed apparently for the sole purpose of catching in his equipment. Add to these difficulties pitch darkness and a desire to avoid all unnecessary noise, and one marvels that the troops manage so well, and appreciates the need of trained sailors to help and to act as guides. In order to train the sailors and the soldiers together in the landing ships there were frequent occasions on which this so-called “LSI Drill” was carried out at Inveraray.
Yet another form of special training which had to be given was that for the officers and men who were to take charge of the organisation of the beaches during invasion. The responsibility of the navy technically ends at high-water mark, but this was a rule of thumb which could only have led to chaos in a large scale amphibious operation. There had to be a beach organisation to control the assault craft, landing craft, coasters, and ferry craft as they came ashore to discharge their men and cargoes, and to see that they vacated their berths at the earliest possible moment to make way for other vessels. At the same time, there had to be a rigid control of traffic on and off the beaches, for any large accumulation of stores or equipment would quickly grow into a beach dump which would not only be obvious and vulnerable to enemy attack but would also greatly impede the work of unloading the ships and landing craft as they came in.
Thus there came into being the “Naval Beach Commandos,” composed of selected officers and men specially trained in the complicated technique of organising a beach during the apparent confusion of a great landing, and in close co-operation with the military beach control organisation.
One form of training which was very closely linked with development and had been in progress since before the Allied invasion of French North and West Africa was that concerned with the control and direction of naval bombardment in support of the land forces. One of the lessons which had been learnt at the Dieppe raid had been that heavy casualties would inevitably be suffered by the assault troops while landing over the beaches unless enemy batteries, mortar batteries and machine-gun posts could be silenced, or the men manning these defences forced to abandon their weapons and take cover during the crucial minutes of the “touch down” of the assault. At Dieppe air bombardment and “ground strafing” by fighter aircraft had not proved sufficient to do this. It had, therefore, been appreciated that for invasion a very much greater weight of naval bombardment would have to be provided than had been the case at Dieppe. The decision to provide a very greatly increased naval bombarding force was facilitated by another lesson learnt at Dieppe. During that operation events had proved that with air cover on the scale even then possible naval squadrons could operate close off a hostile shore in clear weather without risk of incurring crippling casualties. At Dieppe we lost one destroyer—HMS Berkeley—which was hit by bombs jettisoned by a Ju 88 trying to escape from a pursuing Spitfire. We had gone a long way since the Battle of Crete.
Close study of the requirements of naval bombardment and supporting fire during an amphibious operation, coupled with experience gained in the Pacific as well as in Europe and North Africa, had led to the conclusion that the naval bombardment and supporting fire would have to be of three distinct types.
First, heavy guns firing armour-piercing shells would be required to deal with the fixed batteries and strong concrete defences. Then bombardment from lighter guns capable of greater rapidity of fire would be needed to deal with mortar batteries and machine-gun posts, and also to lay a barrage on the beach just before the “touch down” of the first wave of the assault. This barrage would be lifted to the shoreward edges and approaches to the beach as the assault troops dashed ashore. This barrage fire came to be known as “drenching fire,” and was designed not only to knock out the enemy’s lighter defences, but to force him to abandon his weapons and “keep his head down” during the vital minutes of the assault. The third type of naval bombardment which would be required would be the provision of controlled supporting fire for the troops as they advanced inland, and on their flanks. This might be barrage fire on a certain limited area or accurate bombardment of specified targets such as strong points or concentrations of enemy armour or troops massing for a counter-attack.
Each of these three types of naval gunfire supporting an invasion require different weapons, different technique, and different training. All of them present problems with which the average naval officer, trained to use his weapons against other ships, was to some extent unfamiliar.
There still persisted in the Royal Navy a considerable body of opinion which was opposed to the use of orthodox warships for bombardment. The belief had persisted for decades that naval gunfire was useless against shore targets; that bombardment of shore positions was wasteful of guns as well as of ammunition and likely to bring ships into dangers which they had not been designed to meet. It was not until it was appreciated that the key to victory lay in combined operations that naval bombardment of shore positions and in support of troops came to be regarded as an essential science for which naval weapons are eminently suitable if properly handled and directed.
Curiously enough, the first nation to use large naval forces, including battleships, in this war for the bombardment of shore positions were the Japanese. This was when they made their determined attempt to re-take Henderson Airfield on Guadalcanal Island in the Solomons. The United States Marines held on to Henderson Field with the gallantry for which they are justly famous—but they only just succeeded in doing so, and their reports on the devastating nature of the heavy naval gunfire led the United States to adopt a policy of preceding any landing on a Japanese-held island by a naval bombardment of terrific weight. Sometimes it has seemed from a safe distance that the Americans were using sledge-hammers to crack nuts—in the Marshall Islands, for instance, the Americans used fifteen battleships and some twenty-five aircraft carrier
s for sea and air bombardment as well as a great many cruisers and destroyers. There is not the slightest doubt, however, that the policy enormously reduced casualties among the landing troops and precluded any failure to secure a footing with the first assault. In Normandy all arms of the Allied forces, and thousands of dazed German prisoners, have testified to its efficacy.
The first phase of naval bombardment in support of an assault on a fortified enemy coast must take place before H-hour. Its first duty is to neutralise the enemy shore batteries commanding the sea approaches to the beaches on which it is intended to land. Were this not done there would certainly be heavy casualties, particularly among the landing ships and transports during the highly dangerous period when they are lying stopped and lowering their assault craft and disembarking troops and equipment. The whole of this work, however, does not devolve upon naval bombardment from heavy ships. The air forces play an important part, and the silencing of certain enemy batteries is usually confided in Commando troops specially landed for the purpose. To achieve the maximum effect the three arms must co-operate as closely as possible.
It was known that most of the German batteries and gun emplacements along the Normandy coast were built of reinforced concrete, in some cases eight or twelve feet thick. This applied particularly to the heavy batteries at Le Havre and on the Cotentin Peninsula which, if they were not knocked out, would be able to enfilade from both east and west the sea approaches to the Bay of the Seine beaches. It would have been foolish to imagine that bombardment could actually destroy the enemy’s heavy guns. To do so would require a direct hit on the gun itself or on the embrasure through which it projects, and this at any reasonable range could only be a fluke. Nevertheless, it was calculated that accurate bombardment using heavy armour-piercing shells would result in a sufficient breaking up of concrete seriously to interfere with the working of the guns and with their ammunition supply. It was, moreover, considered in the light of experience that such heavy bombardment would force the Germans to abandon their weapons for a short time and seek shelter underground.
For this reason, as well as to avoid giving the enemy premature warning of the sector of coast chosen for the assault, the timing of this first phase of naval bombardment had to be very carefully worked out. If it were too early it would give the enemy valuable information and allow him to recover before the “touch down” of the assault; if it were too late the vulnerable landing ships would inevitably suffer before the enemy batteries were silenced.
This first phase of naval bombardment in support of the invasion would be carried out partly with direct observation from the bombarding ships, and partly with aircraft spotting.
The second phase of the naval bombardment would follow immediately, the warships closing in to turn their attention on redoubts, pillboxes, the smaller batteries, mortar batteries and machine-gun posts, and concrete anti-tank defences. Most of this work would fall to the cruisers. Their work would be far more extempore than that of the heavy ships in the first phase. They would have to be here, there and everywhere, acting at a moment’s notice on calls for counter-battery or supporting fire. They would be close enough to the shore to rely entirely on direct observation.
Then, as the assault forces approached the beaches, the “drenching fire” proper would commence. For this destroyers, special “landing craft, gun” (the modern equivalent of the floating batteries of past centuries) and other craft would literally “drench” every yard of the beaches with high explosive, laying a dense barrage behind which the assault troops would be approaching the beaches.
In order further to increase the density of the “drenching fire,” rockets were to be used. These were to be fired from “landing craft, rocket”—vessels which had been tried out with great effect at Elba. The hull of these vessels is that of an ordinary tank-landing craft, but it is decked in, and along its broadsides it has batteries of rocket tubes. For purposes of short-range “drenching fire” one such craft has a fire-power equivalent to over 80 light cruisers or nearly 200 destroyers. The rocket tubes are fixed and the broadside is “aimed” by steering the vessel towards the target. The rockets generate such heat on discharge that the deck on which they are mounted becomes distorted. Decks are sprayed; but even so, men on deck have anti-flash clothing. The usual practice is for the personnel to go below decks before firing, leaving the commanding officer in a special heat-proof and blast-proof “hut” from which he can con the vessel and control the firing of the rockets. These are not all fired simultaneously as a broadside, but in groups with very short intervals between them. The effect is therefore that of a “ripple salvo.”
Of the effectiveness of the new weapon for “drenching fire” there is no doubt. The rockets devastate whole areas, completely removing woods, villages, and any but the heaviest concrete defences which may have been set up in them.
In the case of the “drenching fire” accurate timing would again be absolutely essential. If it began too early the vessels concerned might well run short of ammunition, so high would be its rate of expenditure. If it began too late our assault troops might suffer at the hands of the enemy during the later stages of the approach to the beaches, and might even run into the “drenching fire” itself.
The third requirement of naval bombardment was that, in effect, the ships would be required to work as mobile artillery for the military forces. This form of bombardment might be expected to continue along the military front until the armies drew out of range of naval gunfire, but might have to continue on the flanks for much longer. It would be of great importance throughout, but it would be absolutely vital during the hours after the initial assault, when the ships’ guns would be virtually the only artillery support available to the troops landed.
It is obvious that many special problems of fire control arise under conditions in which ships’ gunfire must necessarily be under military control—for the guns must shoot when and where required by the military commanders in the field. Yet the mobility of the ships—and therefore the positioning of the guns—must remain under naval control, for this involves navigation, pilotage and other purely naval matters. There is, therefore, absolute necessity for some system approximating to “dual control”; but such a system must be as nearly instantaneous in operation as is humanly and materially possible. If the commander of military forces locked in battle requires an enemy strong point or concentration to be engaged or a barrage to be laid he must have the gunfire at once—not after an indeterminate interval, by which time his troops may have advanced and might therefore come under fire from our own naval guns.
The problem of controlling the fire of ships’ guns firing in support of an army in battle had been studied on both sides of the Atlantic, and both the Americans and the British had evolved systems for such control. The American system consisted of landing a fairly large party of gunnery experts, known as the Shore Fire Control Party, which interpreted the artillery requirements of the military commanders into terms of naval gunnery and gave the orders for bombardment to the ships in naval parlance. The British system, on the other hand, consisted of having with the military commander, or in his immediate vicinity, a bombardment observer officer who was a military officer. This officer used to be known as the FOO—” Forward Observation Officer,” but is now known as the FOB—”Forward Officer, Bombardment.” The FOB relays the requirements of the military commander, as a purely military artillery requirement, to the BLO—“Bombardment Liaison Officer”—who is also a military officer, on board the bombarding ship and in close and direct personal touch with the gunnery officer of the ship. He interprets the military needs to the ship’s fire control organisation.
This system was used very successfully during the invasion of Sicily and at Salerno and Anzio, but many improvements were made in the Organisation as a result of these experiences in the face of the enemy.
As has been said, time is a most important factor in this distant control of naval gunfire in support of troops, and time can
always be saved, as well as mistakes avoided, by good training. To this end the BLO’s and the FOB’s were given special training, both at the Royal Artillery Establishment at Lark Hill on Salisbury Plain and at the Royal Naval Gunnery School at Whale Island, Portsmouth.
It was intended that, with ships engaging specific targets, the observation of the fall of shot and application of the necessary spotting corrections would normally be the duty of the FOB’s. It was realised, however, that there would probably be occasions when he would not be able to do so, and arrangements were therefore made for aircraft to take part.
The spotting aircraft, which were to work during the first phase of preliminary heavy naval bombardment, also had other duties during the third phase of naval gunfire support. It was by no means intended that during this phase the guns of the ships should remain silent until fire was called for by the FOB’s. The spotting aircraft were to search the country ahead of and on the flanks of the Allied military forces for likely targets, report these to the ships, and observe the result of their fire, passing corrections of range and deflection to the ships as might be necessary.
It was realised that to expect air observation and spotting from slow two or three-seater aircraft would be to invite their destruction by “flak” or the Luftwaffe, which would lose valuable lives and probably rob bombardments of their effectiveness at critical moments. It was, therefore, decided that the air spotting, as well as searching areas for likely targets for the ships’ guns, should be done by fast fighter aircraft, and Spitfires and Mustangs were allocated for these duties. A team of fighter pilots was selected to fly these aircraft. There were 180 pilots, of which 15 were Americans and the remainder partly from the Fleet Air Arm and partly from the Royal Air Force.
Operation Neptune Page 11