DEPARTMENT OF THE NAVY -- NAVAL
HISTORICAL CENTER
805 KIDDER BREESE SE -- WASHINGTON NAVY YARD
WASHINGTON DC 20374-5060
CHAPTER VIII
BOMBARDMENT AND OTHER DEFENSIVE OPERATIONS AGAINST ENEMY LAND FORCES
PART 1
GENERAL BOMBARDMENT PLANS
A. Coordination of Naval and Air Bombardment
-
The various measures taken to protect NEPTUNE from
German Naval and Air counter action have been described
in the preceding chapter. Comparable measures were
taken to protect NEPTUNE from the hazards of the German shore
defenses. The principal means employed was bombardment.1
Other measures employed included Diversions, Radar Counter
Measures and the use of smoke.
-
The primary object of the bombardment program was to
prevent German coastal batteries, in the vicinity of the
assault area, from interfering with the safety of allied
ships and forces. The Germans had installed some 25
major batteries, composed of heavy and medium guns, in
various casemated emplacements covering the sea approaches
and anchorages to the assault area. If these batteries
had been allowed an uninterrupted opportunity they would
have been able to defeat the NEPTUNE assault before it
reached the beaches. The locations of these batteries
and their area of fire, in relation to the positions of
allied assault forces, are shown in the accompanying sketch.2
In addition to fixed coastal artillery, the Germans had an
indeterminate quantity of mobile heavy artillery, which
might be rapidly brought into the Seine Bay area to reinforce
these fixed batteries.
--458--
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A secondary object of the bombardment program was
to support the assault and subsequent operations ashore,
by neutralizing or destroying beach defenses, enemy concentrations
and other targets impeding the army's advance.
In this role, bombardment was employed to flatten beach
obstacles, to explode beach mines, to neutralize infantry
positions and batteries shelling the beach, and to engage
counter attacking formations.
-
The bombardment policies followed were those developed
in the Graham Report on "Fire Support of Sea-Borne landings
against a Heavily Defended Coast". This report laid down
two basic principles:
-
Casemated batteries probably could not be destroyed
by bombardment, but could be sufficiently neutralized
to render them acceptably ineffective until the army
could capture them. The report also calculated in
detail the weight of fire required to do this.
-
Beach defenses could best be neutralized by "beach
drenching," which would force the defender underground
and numbs his mind and nerves. Aimed fire in the
dust and smoke of battle would be less likely to
accomplish this. Bombardment was recognized to be
a combined naval, air, and army task, but until the
army was well established ashore the job had to be
done principally by air and naval forces. The NEPTUNE
bombardment plan was prepared by the joint action of
the three Service Commanders, under the general supervision
of SCAEF.1
-
The broad outlines of the Joint Fire Plan were:-
-
Coordination of the Bombardment effort, final selection
of targets, and the assignment of priorities was
assured by the three C's-in-C;
-
The targets for air and naval bombardment were so
selected that priority could be given to those targets
which would interfere most with the approach of the
Naval Forces;
--459--
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NEPTUNE targets were to be bombed from the air
prior to D-day, at least once and oftener if possible,
but the air effort allotted to the task was limited
by:
-
The necessity of bombing batteries in other
areas to prevent the Germans from ascertaining
the intended point of invasion; and
-
By air operations, immediately prior to D-day,
designed to distract attention from the assault
area.
-
During the night preceding H-hour, the heavy night
bomber effort was to be concentrated on ten selected
batteries in the assault area, this number being the
limit of availability of night bombing aids.1
-
During the first light of D-day (that is during the
30 to 60 minutes before H-hour a proportion of the
medium (day) bombers were to concentrate on 6 particularly
dangerous German batteries.
-
During the last 40 minutes before H-hour, Naval
Bombarding forces were to engage all of the German
batteries in the area with maximum fire.
-
During the balance of the assault, these batteries
were to be engaged with further counter battery
naval fire to the extent required to keep them
silenced.
-
Fighter bombers were also to be employed in post
H-hour counter battery bombardment.
-
Commencing at about 40 minutes before H-hour (that
is during the final approach of the landing forces)
the entire available heavy and medium day bomber
effort was to be concentrated on the neutralization
and destruction of beach defenses (beach drenching).2
--460--
[page 461 missing]
--461--
B. Air Bombardment Program
-
The Allied air forces, operating in accordance with this general plan,
for putting dangerous batteries out of action before allied ships
came within their ranges,executed a long series of bomber attacks
for many months preceding the invasion.1
The primary object of these operations, the obstruction of the enemy's program of
building concrete emplacements for his coastal field batteries,
was only partially achieved. On D-day, there were more concreted emplacements than
could be dealt with by available battle ships and
monitors.2
This program of air bombardment of the Seine Bay batteries was a part of
the larger air forces offensive, POINTBLANK. An exclusive
concentration on Seine Bay targets would have indicated to
the Germans the intended assault area. In order therefore to preserve
that secret, pre D-Day aerial bombardment of
coastal battery targets was uniformly dispersed over the
entire northern coasts of France and the Low Countries.
The air forces had, however, succeeded, before D day, in
bombing the most dangerous batteries in the Bay of the
Seine at least once.3
During the night preceding D-day, 1,136 heavy bombers
of R.A.F. Bomber Command dropped 5,853 tons of bombs on
the 10 most dangerous batteries in the NEPTUNE
area.4
--462--
As daylight came 1,365 heavy bombers of the 8th U.S.
Army Air Force took over. In the 30 minutes preceding
H-hour, they were scheduled to drop 4,200 tons of bombs
in a "beach drenching effort" on the beach defenses of
all beaches, although, when the time came, no bombs at
all were dropped on Omaha beach. Their total effort
was 1,365 bombers, with 2,796 tons of bombs. The
failure of the U.S. Army Air Force to carry out its
assigned task at Omaha beach made the assault there
much more difficult and costly than at the other beaches.1
-
Medium and light bombers, just before H-hour, delivered
their bombs on the six selected targets. These, and
fighter bombers, continued throughout the day to attack
special inland and coastal defense targets with light
bombs, rockets and gunfire. Later in the day the U.S.
8th Air Force came over with 2,627 heavy bombers and
1,347 escorts with which it dropped 1,746 tons of bombs
at targets requested by the army.2
--463--
PART 2
GENERAL BOMBARDMENT PLANS
A. Naval Bombarding Forces
-
Naval Bombardment was designed to accomplish the
following tasks:
-
Neutralization of German coastal defense and
inland batteries capable of bringing fire to
bear on NEPTUNE sea approaches, anchorages or
beaches until each battery was captured or
destroyed;
-
Neutralization or destruction of beach defenses
during the final approach and assault, and
-
Support of the army after the assault by engaging
mobile batteries, counter attacking formations,
defended areas, etc., particularly during that
period when the army artillery was not fully
deployed.1
-
Naval bombardment was carried out by the following
heavy forces: 7 Battle Ships,2
2 Monitors, 23 Cruisers,
2 Gun Boats and 74 Destroyers.3
In addition, a wide variety of special amphibious fire support craft were
provided, to give close support by firing onto the beaches
from inshore waters. This force consisted of 25 LCG (L's)
36 LCT (R's), 24 LCS (M's), 29 LCF's, 45 LCA (HR's),
5 LCT (CB's), 48 LCT (A's), and 16 LCT (HE's).4
--464--
-
ANCXF allocated firing ships and craft between the
--465--
Western and Eastern Task Forces partly on the basis of
nationality and partly on the basis of requirements.1
The Task Force Commanders allocated Bombarding Forces
within each Task Force to meet special requirements.
The entire force of close support craft were allotted
to assault forces and all were employed in the barrage
of drenching fire laid down just before the landing
began. About nine tenths of the heavy ships were also
allotted to the assault forces. The remainder were
held in reserve to relieve ships which sustained severe
battle damage or had depleted their ammunition. The
allocation of firing ships to these various purposes is
shown in Chapter IV section 5-E-(2). In general, the
two wings were allotted a heavier proportion of naval
bombarding forces, to keep the batteries on the flanks
of the land front neutralized.
--466--
-
Command of Bombarding Forces in the Eastern Task
Force was exercised by a Commander, (Bombardment).
Direct Control of Bombardment Forces was retained by the
Assault Force Commander and was not delegated to the
Assault Group Commanders. In the Western Task Force,
the bombarding forces were assigned to independent task
groups in each assault force, and the management of the
firing ships was left to the task group commander.1
Command of fire support craft, in each assault force,
was exercised by a separate task group Commander.
-
The heavier bombarding ships were assembled for the
most part in the Clyde (British Forces) and at Belfast
(U.S. Forces).2
They were sailed in 5 convoys so as to
rendezvous in the assault area with the appropriate
assault forces. They made the cross channel passage
and approach in the fast convoys lanes of each assault
force.3
-
Bombarding destroyers were used as escorts during
the passage and approach and were assigned to escort
convoys whose destination and scheduled time of arrival
corresponded with their bombardment tasks. Fire support
craft were sailed in convoy with the assault groups
with which they were scheduled to operate. In order to
protect bombarding ships from the danger of enemy mines
inside German Mine Barriers, special minesweepers were
ordered to sweep the flanks and clear the bombarding
positions.4
--467--
B. Pre-Arranged Bombardment Schedule
-
There were 25 heavy and medium batteries situated
in the Bay of the Seine, capable of bringing fire to
bear on Allied ships in the assault area and on troops
and boats near or along the beach.1
In addition, there
were 2 batteries within range of naval firing ships
capable of harassing airborne troops landing near Isigny.2
By the pre-arranged plan, these batteries were apportioned
out among the bombarding ships who were to begin fire at
the pre-arranged time.3
-
In order to ensure accuracy in the naval bombardment
of pre-arranged targets, Spotting Aircraft were detailed
to arrive before sunrise and to observe the fire from all
heavy ships. In the Eastern Task Force, bombardment was
begun 40 minutes before sunrise and continued until H-hour.
This allowed 130 minutes of fire. In the Western Task
Force, fire was opened at H minus 40 minutes and directed
against beach targets until H-hour and then against inland
targets for another 20 minutes.4
Fire was continued after
H-hour against batteries and strong points on the flanks
for varying periods, based on the time it was expected
troops would reach the various phase lines.
--468--
-
In order to assist in blasting a path through the
beach obstacles and to neutralize local beach defense
strong points, all fire support craft and all heavy ships,
not engaging enemy batteries, opened up at H minus 40
minutes with all the fire power at their disposal, to
drench the beach until H-hour with the maximum weight of
naval bombardment.1
The object of Beach Drenching was to
put down as heavy a barrage as possible with the object of
numbing and demoralizing the defenders. Except in special
cases, aimed fire, with the object of destroying specific
enemy positions, was impracticable at that stage because
the smoke and dust of war made accurate observation impossible.
C. Post H-Hour Aimed Bombardment
-
On completion of the initial barrage bombardment,
naval bombarding forces stood by in the assault area to
deliver aimed fire on special targets. These targets
included:
-
Re-bombardment of coastal batteries when and if they
returned to action
-
Special strong points or obstacles impeding the
advance of the army and enemy emplacements, and
-
Strong points inland for which the army required
artillery support.
-
As this fire had to be delivered in close support of
the army and would fall very close to positions occupied
by allied forces, careful arrangements were required to
observe targets and the fall of shot. Three types of
spotters were used; (1) Shore Fire Control Parties (SFCP);2
(2) Air Spotters; (3) Air Observation Posts (Air OP).
--469--
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Shore Fire Control Parties were allotted on the
basis of one party per assault battalion. In the
U.S. Sector 27 Shore Fire Control Parties were organized,
of which nine were assigned to each assault infantry
division. In addition, nine naval gun fire spotting
teams, consisting of one Army Paratroop Officer and two
enlisted men, were dropped by parachute with the 101st
Airborne Division. The personnel of each shore fire
control party was one Army Officer, one Naval Officer,
and twelve enlisted men. Each party was supplied with
a Jeep, an M.14 Half-track, and had both a frequency
modulated and an amplitude modulated radio transmitter-receiver.
In the British Sector, 39 F.O.B. Parties were
provided, one accompanying each British Army battalion.
In both Sectors, a Naval gun fire liaison officer was
attached to each regimental fire control center in order
to direct the activities of the three shore fire control
parties in his section. In addition, a Naval gunfire
officer was attached to each divisional headquarters in
charge of all shore fire parties in his division.
-
Every firing ship was provided with an army artillery
officer, charged with maintaining up-to-date information
about the position of allied troops and with determining
the desirability of firing at any given target. The
organization worked as follows:
-
The Shore Fire Control Party made contact with his
firing ship by radio link and designated a target
by reference to a grid;
-
The Army liaison officer decided whether it was
safe to fire at that target;
-
The ship itself controlled the fire.
-
The Shore Fire Control Party observed the fall of
shot and corrected fire by a means of a clock code.
-
Shore Fire Control Parties were sent on to the beaches
as early as H plus 30 minutes. As a result of landing so
early, their equipment suffered considerable damage. It
was not until Regimental Headquarters were established
ashore and the early confusion and fluid conditions on the
beaches had been stabilized, that their parties were able
to do their job effectively. Even then they were subject
to interruption. The Germans possessed and used extremely
--470--
effective D/F equipment. They were able to locate key
radios, particularly in the medium frequency band, and
take then under fire in a matter of seconds.1
-
The second form of bombardment spotting was by
aircraft. Spotting was carried out by 104 single seater
aircraft operated by the R.A.F., Royal Navy, Fleet Air
Arm, and U.S. Naval pilots in British planes. Single
seaters were used because it was believed by the A.E.A.F.
that high casualties would result if aircraft of low
speed were employed. The ordinary two seater observation
plane was so slow that it was easily put out of action by
enemy anti-aircraft guns or fighters.2
Spotting by single seater aircraft had never before been undertaken on
a large scale, but none the less, it was very successful.
These spotting aircraft operated in pairs, one plane
acting as a spotter and one as escort. Planes were
capable of doing either job interchangeably. Both planes
operated on the same radio frequency and in contact with
the same ships. Spotting aircraft were formed into a
pool which was situated at Lee-on-Solent. No attempt
was made to attach individual pilots to individual ships,
because of the limited availability of both pilots and
ships for training, and because of the much larger number
of aircraft which would have been required.
-
The organization employed was changed during the
course of the Operation. It was originally intended
that spotting aircraft would be retained on call at Lee-on-Solent
and that the pilots should be briefed before
taking off on two targets. The initial targets were
those laid down in the fire plan, and at a later date
those specially requested by the Army. In practice,
it was found, after the pre-arranged targets had been
dealt with, that most shots were impromptu. Pilots were
briefed in the air on the way to the assault area.
Even when pilots were briefed on specific targets before
they left the ground, it was found that they were required
afterwards to observe on different targets. The policy
was therefore adopted of reducing delay by maintaining a
few aircraft continuously in the air over the assault
area, instead of keeping them on call at Lee-on-Solent.
--471--
[map missing]
--472--
This required that every ship should be capable of working
with any aircraft, and radio crystals for all bombarding
frequencies were provided to each vessel. When a ship
required air spot, it made radio contact with a plane in
the area. The plane then located the target and gave the
exact location to the ship by means of a grid reference,
on a pre-arranged gridded map, from which the ship directed
its own fire. The plane then observed the fall of shot and
gave corrections as required on the basis of the clock code.
Owing to the shortage of aircraft, one plane was often
employed to spot for two or more ships.
-
The third method of observing fire was by the employment
of Army Air Observation posts. These were small
light aircraft, usually Piper Cubs or Austers, which
spotted for the shore fire control party, which in turn
relayed the information back to the ships. In all cases,
it was the responsibility of the ship to determine whether
any given shoot would endanger allied personnel or positions.
To enable the ship to do this, each ship was
provided with an Army officer who was kept up to date on
the positions of allied forces ashore.
D. Ammunition Supplies
-
A comprehensive program for replenishing stores of
ammunition in all firing ships had been carefully worked
out prior to the operation. These arrangements provided
for holding certain ships in reserve, so as to take over
bombarding duties when the initial ships had expended
their outfit, and also for the employment of destroyers
and other ships in dual roles of bombardment, escort and
screen.
-
The Admiralty provided stowage afloat in lighters and
ammunition ships for the majority of large calibre ammunition
to permit rapid reammunitioning. One refill of main
battery ammunition for U.S. Battleships and Destroyers and
two refills for U.S. Cruisers was available. 14", 12", 8"
and 5" ammunition was held in Plymouth, and 8" and 5" ammunition
in Portland and Southhampton. U.S.S. Nitro carried
the majority of ammunition for U.S. ships in Plymouth.
Quick ammunitioning was accomplished in all cases. In
one particular case, the U.S.S. Nevada main battery was
replenished in 20 hours.
--473--
-
For British ships, there was average of two
outfits, per bombarding ship, held in reserve afloat
in the Isle of Wight area and in other southern English
ports. Small calibre ammunition was available for all
Landing Craft and other smaller vessels at all south
coast English ports. Five British Ammunition Store
Issuing Ships (ASIS) were stationed in the assault area
to replenish small ammunition for Landing Craft, Gun
Support Craft and light vessels which remained on the far
shore. Ammunition carriers were also provided for the
purpose of replenishing the stores of the issuing ships.
The entire program of reammunitioning worked admirably
and the bombarding forces never were in a position in
which they did not have sufficient ammunition in hand to
meet all demands.
E. Results of Naval Bombardment
-
A generalized tabulation of the results of Naval
bombardment is hard to give.1
Prisoners reports indicated that the terror of the gun fire from ships at sea was a
major factor in driving the Germans from their positions.
Subsequent to the assault, considerable trouble was
experienced on both flanks from enemy guns which shelled
the beaches and anchorages. Although doubtless new guns
were rushed up by the enemy to replace those made unserviceable,
there is no evidence that naval gun fire caused
great destruction to enemy guns.
-
Naval gunfire neutralized rather than destroyed enemy
batteries. The long periods of silence of flanking batteries,
which often followed bombardment, was considered to
be the result of the moral effect of H.E. on the defenders
rather than of its destructive effect. In the rapid
advance along the Cotentin Peninsula, hostile batteries
which could fire on the Western beaches were captured at
an early date. On the Eastern static flank, an enemy
battery east of the River Orne and another at Le Havre made
it necessary to discontinue unloading on Sword Beach. All
Navy and Army reports covering the subject are agreed that
the close supporting fire delivered by small ships,
immediately preceding H-hour, was of the greatest assistance
in enabling the Infantry to make the first break across the
open beaches.
--474--
-
German reports on the effect of Naval bombardment
are equally eloquent concerning the damage which it did
to the German defenders. The following extract from
the German Military Journal was broadcast over the German
telegraph service:
"Militarische Correspondenz aus Deutschland" depicts
the part played by the guns of the Navy at the invasion coast.
"The fire curtain provided by the guns of the Navy
proved to be one of the best trump cards of the Anglo-U.S.
invasion Armies. It may be that the part played by the
Fleet was more decisive than that of the air forces because
its fire was better aimed and unlike the bomber formations
it had not to confine itself to short "Bursts of Fire".
"Fire power of warships must not be under-estimated:-
While the first troop landings were in progress and no
bridgehead existed the invasion forces had only little
artillery at their disposal. It was, however provided
to very high degree by the combined Anglo-U.S. Fleet. It
would be utterly wrong to under-estimate the fire-power of
warships even of smaller vessels. A Torpedo Boat for
instance had the fire power of approximately a Howitzer
Battery, a destroyer that of a Battery of Artillery.
"Equivalent to an unusually heavy artillery barrage:-
With regard to its armament a cruiser may be compared with
a regiment of artillery. Battleships carrying 38 cm. or
40 cm. guns have a fire-power which to achieve in land
warfare is difficult and only possible by an unusual
concentration of very heavy batteries.
"Great mobility of these "Floating Batteries":- Of
particular advantage to the invasion troops which employed
strong formations of warships as floating batteries was
the great mobility of the vessels by which artillery
concentrations could be achieved at any point of the coast
and to change the place according to the exigencies of the
fighting situation. The attackers have made the best
possible use of this opportunity."
"An umbrella of fire:- Repeated strong formation of
warships and cruisers were used against single coastal
batteries thus bringing a quite extraordinary superior
fire-power to bear on them. Moreover time and again he
put an umbrella of fire (Feuerglocks) over the defenders
at the focal points of the fighting compared with which
incessant heavy air attacks have only a modest effect."1
--475--
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The following extracts which are from a report on
the Invasion of France by Field-Marshall von Rundstedt,
likewise shows the great advantage which the Allies
derived from Naval Fire Support.
"Facts must be emphasized
-
"The enemy's complete mastery of the air.
-
"The skilful and large scale employment of
enemy parachute and airborne troops.
-
"The flexible and well directed support of the
land troops by ships' artillery of strong
English naval units ranging from battleship
to gun boat ......"
...... The enemy had deployed very strong naval
forces off the shores of the bridgehead. These can be
used as quickly mobile, constantly available artillery,
at points where they are necessary as defence against
our attacks or as support for enemy attacks. During
the day their fire is skillfully directed by . . . . . .
plane observers, and by advanced ground fire spotters.
Because of the high rapid-fire capacity of naval guns
they play an important part in the battle within their
range. The movement of tanks by day, in open country,
within the range of these naval guns is hardly possible".1
--476--
PART 3
GENERAL BOMBARDMENT PLANS
A. Bombardment of Cherbourg1
-
The initial plan provided bombardment at 28,000
yards, to neutralize or destroy long range batteries,
after which, ships were to close in to a position roughly
14,000 yards north of Cherbourg. The long range bombardment
was, however, cancelled shortly before the
commencement of the operation. This was considered
necessary by the U.S. Army Commanders to avoid any danger
that U.S. troops, who were already close to Cherbourg
defences, might advance into the firing zone. Bombarding
ships, therefore, proceeded into close range position
before opening fire. A congested situation developed at
the southern end of the approach channel, where the Nevada,
Quincy, Tuscaloosa, Glasgow and Enterprise were forced to
reduce speed to keep clear of the minesweepers when the
whole force was turning eight points, from the approach
channel, into the fire support area.2
-
Support of the advance of the VIIth U.S. Army Corps
up the Cotentin Peninsula, and of its capture of Cherbourg,
was organized at the request of the Commanding General,
1st U.S. Army by CTF 122. A Bombarding Force (Task Force
129), was organized which on June 25, 1944, bombarded
enemy batteries and shore defenses guarding the approaches
to Cherbourg. Task Force 129 was under the Command of
Rear-Admiral Deyo, USN, (CTF 129) flying his flag in the U.S.S.
Tuscaloosa. Second in command was Rear-Admiral Bryant,
USN, flying his flag in U.S.S. Texas. In addition to
these two ships, the force comprised: U.S. Ships, Arkansas,
Quincy, Nevada, Laffey, Barton, O'Brien, and H.M. Ships:
Glasgow and Enterprise. The British 9th and 159th
minesweeping flotillas and U.S. 7th M/S Squadron, provided
minesweeping protection, and an anti-submarine screen to
the force was provided by H.M. Ships, Onslow, Offa, Onslaught,
Oribi, Melbreak and Brissenden.
--477--
-
While the ships were in this awkward position,
turning at slow speed, the enemy opened fire at 1206
with initial accuracy. Destroyers made smoke, bombarding
ships increased speed and, in some cases, had
to proceed into unswept waters to obtain manoeuvering
room. By 1212 all ships had opened fire by air spot
on Army designated targets, but fire was soon shifted
in many cases, to batteries which were straddling ships.
The batteries, whose accurate fire gave most trouble, were
chiefly those which, under the original plan, would have
been destroyed at long range.
-
The Nevada was straddled on 23 occasions, and several
near misses covered her decks with water and splinters,
but she was not hit. However, frequent use of helm and
drastic alterations in speed while shell dodging was thought
to have diminished the accuracy of her own fire. When she
ceased fire at 1525 she had expended 112 round of 14"
and 167 round of 5". The Texas received a direct hit on top
of her conning tower which wrecked the navigational bridge
and facilities. Glasgow, O'Brien, Laffey and Barton also
sustained hits and damage varying in degrees. Casualties
to personnel in all ships were reported as 13 killed, 86
wounded. Bombarding forces withdrew at 1530 when it was
reported that all but possibly two batteries been
silenced.
--478--
PART 4
RADAR COUNTER MEASURES
A. Radar Countermeasures1
-
The enemy was known to have an effective and well
integrated chain of radar sweeping and gun control stations
along the invasion coast.2
With these he could provide himself with:
-
Early warning of the approach of allied invasion forces;
-
Radar plots of the movement of allied vessels; and
-
Accurate ranges and bearings for the control of his coastal guns.
One of the tasks which the navy, in conjunction
with the air force, was required to accomplish was that
of neutralizing enemy radar. This presented a problem
of considerable magnitude, especially as it was essential
that some 80 minesweepers should approach within detection
range of enemy radar ten hours before the assault.
The first step was to acquire detailed intelligence concerning:
-
The location and interconnection of enemy radar stations
and networks, and
-
Technical details of the types, frequencies,
characteristics and capabilities of his various instruments.
-
A COSSAC committee, made up of representatives of
all the services, began the accumulation of the necessary
information at an early date. After SCAEF assumed
the direction of the operation, this committee was carried
on as a department of his staff. In the end detailed and
accurate intelligence became available, derived from air
reconnaissance, from radar monitors and from other sources.
ANCXF was given responsibility for operational policy and
general orders, governing the use of R.C.M.3
In November
1943 a joint Navy-Air R.C.M. Plan was evolved. This plan
provided for the following measures to be taken to counter
enemy radar.
--479--
-
-
Bombardment (Air and Naval) of enemy radar
stations and networks was the first and principle
means of neutralizing enemy radar. The effect
of bombardment was to destroy many stations and
unnerve the operators at others, thus making them
less critical of the jamming and deception being
used. Over 1,400 air sorties were flown against
suitably random sites. In the area effecting the
main assault, which for Radar purposes was between
Cap d'Antifer and Cap Levi, the principle twelve
sites containing 44 sets were rendered inoperative,
at least temporarily. Allowing for repair of minor
damage and subsequent attacks, it was estimated that
about 20 out of the original 44 sets were operative
on the night of 5/6th June. The heavy air and naval
bombardment preceeding the assault further reduced
this figure. Only eight enemy radar stations were
definitely heard transmitting during the night of
the assault.
-
The second method of neutralizing enemy radar was
by interposing an R.C.M. screen between enemy radar
sites and approaching assault forces. This was
done in part by routing diversionary forces so as to
pass in a westerly direction along a route to the
shoreward of the convoy route. Full particulars of
this operation are given in the next section of this
chapter.
-
Further support by the Air Force was obtained by
"Window" laid on the East Flank of the main assault
to add to the confusion of the enemy. Special
window filled rockets and shells were carried by
bombing ships to supplement their electronic R.C.M.
in case of need. They were also accompanied by
M.M.S. towing reflector balloons in order to multiply
echoes and confuse the enemy's point of aim.
-
In order to interpose an anti radar screen, between
enemy shore radar stations and the assault area, the
following measures were planned and executed:-
--480--
-
An inshore screen was provided by installing
some 240 low power sweeping and locking
jammings in LCT(A)s and LCG(L)s. These
vessels were selected to carry the inshore
jammers because their primary mission, which
was to sail up to the beach, concurrently
with the assault landings, in order to deliver
close fire support, would site them in a favorable
position to interpose an R.C.M. screen.
-
An offshore screen was established by installing
some 60 medium power sweeping and locking jammers
in certain minesweepers and destroyers.
Vessels were chosen for this job from those
whose primary mission would keep them in or
near the assault area during the critical period.
-
Certain individual ships, in general bombarding
ships, carried R.C.M. as a part of their standard
equipment, and an additional 120 high powered
hand tuned jammers were fitted in these ships.
This equipment was intended primarily for the
protection of the individual ships, but every
ship was also expected to augment the offshore
R.C.M. screen when required.
-
Balloons fitted with radar reflectors, capable
of making an impression on enemy radar similar
to that made by a ship of a certain size, were
towed into the assault and bombardment areas to
confuse the range and point of aim of coastal batteries.
-
In order to control the propagation of the R.C.M.
jamming screen, 12 monitoring receivers were
installed on headquarters ships. These were
tuned to the frequencies which the enemy used
for radar emission, and, when an enemy radar
was detected, the force commander directed
R.C.M. screening vessels to close the gap by
suitable jamming.
-
Careful coordination in the use of R.C.M. was essential,
especially in the early stages of the operation,
as it was necessary that the enemy should not detect
the allied approach, either by the direct use of radar
or by monitoring R.C.M. emissions. If R.C.M. were
turned on too soon, enemy R.C.M. monitors would be
alerted; if it were turned on too late, enemy radar
--481--
would pick up the movement of assault forces.
There was no precedent to act upon, but a plan was
adopted by which transmissions were to be begun by
loading units at a specified time, and by the
remainder, on crossing a certain latitude. Flexibility
was provided, to allow last minute adjustment
by ANCXF, in case propagation conditions might be
expected to deviate from normal. Transmissions
were actually begun at 2130 on D-minus-1, by minesweepers
which were at that time fifteen miles off
Cap Barfleur. Other ships switched on when south
of latitude 50° 05' N.
-
Another R.C.M. requirement was to screen convoys,
including a build-up force, while passing through
the straits of Dover. This involved enlargement
of an existing chain of shore stations, and the
intensive use of smoke. As a result only six of
the 2,127 ships that passed through the Strait were
damaged by fire from enemy shore batteries.
-
Production of much of the equipment required for
this program had never before been undertaken. The
question of supply and production had therefore to be
solved. It was agreed that the U.S. Navy would supply
250 sets and the Royal Navy 350 sets. Production requirements
were substantially met. A total of 603
electronic radar jammers were employed, of which 371
were of American manufacture and 232 British. 351
of the 371 American equipments were of a design originally
intended for aircraft. 207 of the 232 British
equipments were also types designed for aircraft. 64
guided missile jammers were employed, 28 of American
manufacture and 36 of British, 16 of the 28 American
equipments were converted aircraft jammers, 36 balloon
reflectors and 18 Moonshine equipments, all British were
employed.
-
Frequencies were allocated on the basis of the radio-radar
spectrum allocation promulgated by the SHAEF Signal
Board, the intended disposition of forces and the known
location and ranges of enemy equipment. Several large
scale trials were held to assure that the completed plan
would function as intended. Fitting and tuning of sets
proved a problem because of the late date at which the
equipment was available. About 85% of the intended program
was completed before sailing. To provide operators
to man the new equipment employed, a special school was
constituted at which 86 radar and radio men were given a
5 day course of instruction.
--482--
PART 5
NAVAL DIVERSIONS1
-
One of the defensive tasks undertaken by the Navy
was to execute diversionary operations. These diversions,
which were supported by air operations but which
did not involve the landing of troops, were carried out
more or less concurrently with the actual landings.
Light naval forces, fitted with special equipment,
approached certain beaches outside the assault area
shortly prior to H-hour to simulate the threat of landings.
The simulation was largely effected by the use
of radio deception, radar, radar counter measures, sonic
devices and the use of smoke. The object of these
diversions was primarily to cause the enemy to delay the
movement of his military reserves to meet the real
invading forces. Secondary objects were to provoke a
naval engagement which would draw enemy naval opposition
away from the assault forces. The general plan was to
make several feints at the enemy shore at approximately
the same time as the real assault forces approached the
beaches.2
The feints were made as follows:
-
Operation GLIMMER was a feint in the direction of
Pas de Calais designed to simulate an amphibious
attack by one infantry division and a naval force
equivalent to that of one assault force. The
operation was carried out by a force of six
M.D.M.L's (70 foot motor launches) which were
placed under the orders of Vice Admiral Dover,
who was responsible for the execution of the
operation in accordance with the detailed plan and
technical instructions of ANCXF.
--483--
-
Operation TAXABLE was a feint in the direction of
Cap d'Antifer, designed to simulate a landing by
one infantry division and one naval assault force.
It was carried out by a force of eight H.D.M.L's
operating under the direction of Vice Admiral
Dover, in accordance with detailed ANCXF instructions.
It was sailed with Force S and its radio
deception was arranged to as to give the appearance
that Force S and the 50th division were actually
preparing to land near Cap d'Antifer.
-
Operation BIGDRUM was carried out by a force of
four H.D.M.L's under the command of the Naval
Commander, Force U. It was routed so as to pass
in a westerly direction along a route to the
shoreward of the approach route of Force U. It
would thus screen the movement of Force U from enemy
radar located in the vicinity of Barfleur, and would
so occupy the attention of enemy radar during the
passage of the assault forces as to confuse him as
to the progress of the main force.
-
Operation ACCUMULATOR was a small diversion executed
in the Channel Islands area by two destroyers, H.M.S.
Haida and H.M.S. Hurron1
on the 12th and 13th of June,
several days after the assault. This diversion
was intended to give the Germans the impression that
a landing was to be carried out in the vicinity of
Granville on the west coast of the Cotentin Peninsula.
The object, which appears to have been achieved, was
to hold enemy troops in the neck of the Peninsula
while the U.S. Army was in the process of cutting
across its base.
-
The effective simulation of real operations in these
diversions, was achieved by the following means:
-
"Window"2
were dropped from aircraft. These had
been specially designed to create the illusion of
enemy radar of ships of various sizes lying to seaward.
--484--
-
"Moonshine", produced by hand turned transmitter
receivers, giving the same effect on enemy radar
monitors as if radar search were being conducted,
was disposed in imitation of amphibious force
approaching an assault area.
-
Balloons, mounting radar reflectors, designed to
give a response on enemy radar equivalent to that
of 5,000 ton ship, were flown from vessels and tows.
On departure from the area, those balloons were
moored to give the impressions, both visually and
by radar, that assaulting forces were lying off the
beach.
-
Standard obstruction and jamming devices were also
used, to lead the enemy to believe that an amphibious
force was trying to conceal its presence and
strength from radar ashore, and also to prevent
enemy radar from learning the true composition of
the diversionary force.
-
Smoke was laid between the balloons and the shore
to further the impression of an enemy force lying
to seaward.
-
Sonic effects, in imitation of the noises made by
naval forces assaulting a beach, were produced, but
it is probable that the effect of these was lost in
the sound of the surf which was running very high
that night.
-
Radio deception was staged. Several additional
radio transmitters and receivers, installed aboard
the diversionary forces, put out a radio program
closely approximating the emissions of an assault
force just breaking radio silence and carrying out
the early tasks of an assault.
-
The entire diversion was coordinated with the large
scale radio deception operations, carried out on
the east coast, so that enemy could not discern
the deception by observing the fact that no such
forces had been previously reported as being available
to carry out such an assault as that simulated.
--485--
Table of Contents
Previous Section **
Next Section
Footnotes:
p.458 #1
The role played by bombardment was partly defensive and
partly offensive. It contributed to the defense of
NEPTUNE, in that it was employed in the neutralization of
shore batteries whose fire endangered ships approaching
or in the assault area. It was offensive, in that it was
employed to blast a path for assaulting troops through the
enemy beach defenses and coastal fortifications.
p.458 #2
For details of the German coastal batteries see Chapter IV,
section 1-e.
The fire of these batteries had been "gridded"
in advance so that they would be able to shoot with a high
degree of accuracy.
p.459 #1
Serial 5 to NJC 1004 of 1 February 1944.
p.460 #1
This was to be a R.A.F. bomber command effort as the U.S.
heavys did not employ the appropriate bombing aids.
p.460 #2
4,200 tons were to be dropped by air forces.
p.462 #1
See Chapter II, Part IV Section ___.
p.462 #2
ANCXF report Vol I, Page 64.
p.462 #3
These were: (a) Le Grand Clos (Le Havre) (b) Fontenay Sur Mer
(c) Benerville (d) Houlgate (e) Points du Hoe (f) Riva Bella
(g) La Pernelle (h) Sallenelles (i) Morsalines (h)Villerville. (See ON-8).
p.462 #4
This night effort was accomplished by "instrument"
aiming - R.A.F. did the job because the U.S.A.A.F. was
not fitted with the necessary instruments. The batteries
bombed were: Points du Hoe, La Fenelle, Fontenay Sur Mer,
Morsalines, St. Martin de Vaueville, Sallenelles, Houlgat,
Benerville, Barfleur, Riva Bella. (See report of C-inC AEAF).
p.463 #1
See Report of NC Force O as reprinted ANCXF Report Vol
III Page 6.
p.463 #2
For air bombardment figures generally see NEPTUNE report
of C in C AEAF.
p.464 #1
See ON-8
p.464 #2
Including one in reserve
p.464 #3
See Chapter IV Section 5-E-2
for the names and organization of bombarding forces.
p.464 #4
An LCG(L), Landing Craft Gun (Large) was a converted
LCT(3) or (4) mounting two 4.7" guns on a false deck built
over the hold. It was designed to provide close supporting
fire during the assault and subsequent advance. It was
approximately 187 feet long, had a speed of 7 knots and
used diesel fuel.
LCT(R), Landing Craft Tank (Rocket), was a normal
LCT(3) fitted with 5" rockets projectors. It was capable
of firing 800 to 1,000 rockets, so as to provide high
explosive drenching fire on an area target prior to touch
down of the first landing craft. She had an overall
length of 160', a speed of 8 knots and used diesel fuel.
LCS(L), Landing Craft Support (Large) was an early
model LCT converted so as to mount one two pounder gun,
two .5 oerlicons, one 4" mortar and 2 small oerlicons.
It was used to support the assaulting forces by light
artillery fire from close inshore. She was a 104' vessel
capable of 11½ knots speed, using gasoline for fuel.
LCS(M), landing Craft Support (Medium), was an LCA
converted so as to mount one 4" mortar, two .5" guns and
other miscellaneous anti-aircraft guns. It was used to
provide close support for landing parties by means of military
gun fire and smoke cover. It was capable of being
hoisted fully loaded, having a length of 40', a speed of 7
knots and using gasoline.
LCF, Landing Craft Flack, was a converted LCT(3) or
(4), equipped with eight 2 lb. guns and 4 - oerlicons or
four 2 lb. guns and eight oerlicons. It was used to provide
protection for assault forces against close range air
or E-boat attack. It was capable of being used in a secondary
role as close support. It had a maximum speed of 7
knots and used diesel fuel.
LCA(HR), Landing Craft Assault (Hedge Row) was an LCA
capable of projecting 24 H.R.'s (60 lb. bombs) the blast
from which was capable of blasting a path through wire and
anti-personnel mines. Length approximately 45 feet.
LCT(CB), Landing Craft Tank (Concrete Buster), was an
LCT rigged to carry two or three tanks each mounting 17 lb.
guns capable of being fired from the vessel, in order to
provide a high velocity fire for attacking concrete.
LCT(A), Landing Craft Tank (Armoured), was a converted
LCT(5) specially armoured and carrying two or three tanks
mounting 95mm guns, two of which were capable of being
fired from the ship. It was used to provide close support
for the assault, using high explosive shells.
LCT(HE), Landing Craft Tank (High Explosive), was the
same thing as an LCT(A) but unarmed.
p.466 #1
As originally planned, the Royal Navy was to supply the
entire bombardment commitment. As the scale of the
operation gradually expanded, and as the Germans in 1943
and 1944 rapidly transformed their batteries from open
gun positions to heavily concreted emplacements, the
requirements for Naval Bombardment mounted steadily. As
the Royal Navy did not have the resources to meet the
entire added requirement, the U.S. Navy was called on to
make up the difference. In the end the U.S. Navy provided
a good third of the Bombardment commitment. The
way in which the bombardment commitment grew may be seen
by comparing Admiral Ramsay's estimates of requirements
(a) for ROUND-UP (b) initial OVERLORD estimate made in
November 1944 and (c) final allocation to OVERLORD,
|
Round-Up Estimates |
First Overlord Estimate (Nov. '43) |
Final Provision |
Battleships |
0 |
2 |
7 |
Monitors |
0 |
3 |
2 |
Cruisers |
6 |
15 |
23 |
Gunboats |
1 |
2 |
2 |
Destroyers |
25 |
60 (approx.) |
74 |
Close Support Craft |
48 |
200 (approx.) |
242 |
See Operation Round-up 1943 Provisional Assessment of Naval
Implication Admiralty 051404/42 of 16/7/42; Appendix H to
COSSAC Plan; ANCXF Report Vol. 1b. 25 and b.29.
p.467 #1
In Force O, the bombarding ships were TG 124.9 under
command of Admiral Bryant USN, in USS Texas. In Force
U, the bombarding ships were TG 125.8 under command of
Rear Admiral M.L. Deyo USN in USS Tuscaloosa.
p.467 #2
Augusta, Scylla and Destroyers required for escort were
assembled with the assault forces on the South Coast.
p.467 #3
They crossed the channel closely behind the minesweepers
so as to be able to afford the minesweepers protective
fire in case German Batteries opened fire. (See ON - [text missing]
p.467 #4
In 1917 the British lost 3 Battleships in 20 minutes to
enemy mines while they were trying to blast a path on the
assault on Gallipoli. For special minesweeping arrangements
for bombarding ships - see Chapter VII Section 7.
p.468 #1
These batteries were:- Barfleur, La Pernelle, Morsalines,
Ozeville, Chateau De Courcy, Fontenay Sur Mer, Emondville,
Maisy II, Maisy I, Pointe Du Hoc, Villerville, Beneville,
Houlgate, Riva Bella, Oistreham, Colleville Sur Orne,
Moulineaux, Mont Fleury, Ver Sur Mer, Arromanches I,
Arromanches II, Longues, Vaux-Sur-Aure, and Le Grand Cloche,
Le Havre.
p.468 #2
These were:- St. Martin De Varreville and Sallenelles.
p.468 #3
The pre-arranged time for opening fire was to be at first
light on D-day, if Allied ships were within range of German
batteries; if they were not yet within range, it was to be
when the first ships came under fire of the German batteries.
At night, ships within range of German batteries were not in
great danger because; (1) The Germans could not aim visually
in the darkness; (2) An elaborate Radar counter-measures
plan was being executed which prevented German Radar from
locating Allied vessels, see Chapter VIII, Sec.4 for details.
p.468 #4
See Reports of N.C.E.T.F. (Page 26) Vol.II ANCXF Report and
N.C.W.T.F. (Page 68) Vol.III ANCXF Report.
p.469 #1
It will be recalled that the air force was simultaneously
doing the same thing at every beach except Omaha.
p.469 #2
The British called these Forward Observers Bombardment (FOB).
p.471 #1
Report of NC Force 'O' contained in the ANCXF report Volume
3 Page 57.
p.471 #2
Experience in Sicily and Italy had indicated that the
Germans paid particular attention to destroying spotting
aircraft which were the highest of their list of priorities
for counter action.
p.474 #1
In the Western Task Force Bombarding ships exclusive of
craft standing off the beaches delivered the following
quantity of naval fire, 15-in. 101 HC, 14-in. 508 A.P.
1490 H.C., 12-in. 163 A.P., 7.5-in. 1,200 H.C., 5.25 in. 65 A.P.
1,473 H.C., 5.38-in. 25,707 5.25-in. 118, 5.51-in. 376,
4-in. 3000, 656 H.C. 8-in. 168 A.P. 2,862 H.C. 6-in.
1,064 A.P. 5,414 H.C.
p.475 #1
Reference Admiralty Publications C.B. 3148 (Feb. '45)
Gunnery Review - Normandy Bombardment Experience (June/Sept.,
1944, Page 29).
p.476 #1
Reference Ibid, Page 28.
p.477 #1
For details of the bombardment of Cherbourg, see Reports
of CTF 129 contained in Vol. III of ANCXF Report and also
ANCXF War Diary for June 25, 1944.
p.477 #2
A misunderstanding arose regarding procedure in the mine
clearance operation ahead of the bombarding force through
the last minute change in plan of which the S.O. Minesweepers
had not been informed.
p.479 #1
All materials in this section have been taken from the
ANCXF (US) report on Naval Communications, Operation NEPTUNE.
p.479 #2
The location of enemy radar sites in the assault area as
shown on sketch -.
p.479 #3
ONCO, Section XV.
p.483 #1
Except where otherwise noted the materials in this
section were taken from the ANCXF (US) report on Naval
Communications operation NEPTUNE. See Chapter II section
5 for the relation between these diversions and the
General Cover Plan.
p.483 #2
See sketch - for the approximate position of diversionary
forces at H minus 6 hours.
p.484 #1
Report of C in C Plymouth on Operation NEPTUNE Section II Page 30.
p.484 #2
"Window" are bits of metal foil, which are cut to a size
"tuned" to the frequency of the Radar station being jammed,
and which are dropped like confetti from an airplane or
from a rocket projectile. They flutter earthward intercepting
radar emissions and screen objects behind them.
6 July 2005