Source: Historical Section, COMNAVEU. "Administrative History of U.S. Naval Forces in Europe, 1940-1946." vol. 5. (London, 1946): 301-337 [This manuscript, identified as United States Naval Administrative History of World War II #147-E, is located in the Navy Department Library's Rare Book Room.]

Part III
NAVAL COVER FOR NEPTUNE

A. Countering the German Heavy Fleet.

10. The major distant naval threat was from the German heavy fleet and associated units stationed in Norwegian and Baltic Waters. In November 1943, these forces consisted of two Battleships (one seriously damaged), two Pocket Battleships, one unfinished Carrier, two Heavy Cruisers, 4 Light Cruisers, from 16 to 25 Destroyers, and miscellaneous lighter vessels.¹ Between November and invasion day, these forces were further reduced by constant air and naval attacks.

11. The allied force charged with the responsibility of guarding NEPTUNE from these forces, was the British Home Fleet stationed at Scapa Flow and operating in the North Sea and North Atlantic. Between 5 - 9 June 1944, the Home Fleet in Scapa Flow consisted of three Battleships, three Fleet Carriers, seven Heavy Cruisers, 12 Destroyers, and numerous miscellaneous light forces.² With it were associated Number 18 Group Coastal Command (R.A.F.), and various long distant heavy bombing formations of Bomber Command.

12. This force was obviously adequate to deal with any movement of the German heavy forces of the north. Indeed, it had stood guard against them throughout the war. Little, if any, coordination with ANCXF and SCAEF was required, and control of the distant naval cover against this threat was

retained by Admiralty working through the normal command channels of the Home Fleet. Throughout the critical first days of the invasion, the German heavy forces in the north failed to react, and the Home Fleet did not even have the opportunity to repel an attempted "rush" toward the channel area.¹

B. Countering U-Boat Movements From the North.

13. Another threat from distant enemy naval forces was that, when the invasion began, U-boats stationed in the north might be transferred to the Channel. Admiralty assigned CinC Western Approaches responsibility for guarding against this threat.² He (CinC Western Approaches) provided a force consisting of three escort carriers³ with associated aircraft, and six groups of naval escort, stationed some 130 miles westward of Land's End.⁴ This force, operating in conjunction with Coastal Command, maintained a constant surveillance over the U-Boat transit area. In the event, few contacts were obtained, and by 10 June, four of the escort groups were transferred for use inside the Channel.⁵

C. Sealing the Western Channel.

14. The task of sealing off the western channel approaches from U-Boat or other penetration, was assigned to CinC Plymouth, who was to operate under the general direction of ANCXF.¹ The strength of enemy forces based in the Brittany and Biscay area, which were available to be sent against NEPTUNE via the western approach, was estimated to be five destroyers, five torpedo boats, 80 to 90 miscellaneous light war vessels and 130 U-Boats. It was thought that the enemy might be able to reinforce his U-Boats to about 200.²

15. In order to prevent these forces from penetrating into the Channel, where they could menace the flanks of the convoy routes, CinC Plymouth organised a sea barrier, known as the "CORK", in the western reaches of the channel.³ ANCXF, allotted to CinC Plymouth the following forces with which to seal the CORK: 12 fleet destroyers,⁴ four MTB flotillas,

comprising 34 craft plus 3 U.S.N. P.T's. and 4 anti-submarine support groups. In addition to this, Coastal Command, aircraft of Number 19 Group, with its attached R.N. and U.S.N. formations, operated to CinC Plymouth's requirements.
16. The first step taken to seal the CORK was the laying of extensive minefields along the west coast of Brittany astride the enemy's coastal route. The object of this mine barrier was to compel enemy U-Boats and other vessels to detour sufficiently to seaward to be outside the range of German fighter cover. In order to allow allied air and naval forces an unmolested opportunity to attack them.¹

17. On the night before D-Day, the general disposition of these forces was as follows:

    1. One Destroyer Division carried out a constant patrol in the Hurd Deep² in order to arrest any possible attempt by the enemy to rush a strong U-Boat pack up the middle of the Channel;

    2. A second destroyer patrol, known as the "Western Patrol", was organized so as to operate with four destroyers in an area about 50 miles north of Ushant.³ The object of this patrol was to intercept enemy vessels, and, especially, destroyers proceeding from the Gironde toward NEPTUNE;

    3. The U.S. destroyers and, at night, light coastal forces of Plymouth command, were posted to seaward of the exposed western arm of Force U's. convoy route, and were supported by special air patrols;

4. The entire area was patrolled every thirty minutes by aircraft.¹
18. This general plan for sealing the CORK, though modified to fit special requirements, was continued throughout NEPTUNE and afterward.² Enemy destroyers in the Bay of Biscay did not begin to move against NEPTUNE until the evening of June 6 (some 15 hours after the landings). They were brought to action in the early hours of June 9, when four of them departed Brest in the general direction of the Channel. At 0120, they were intercepted 20 miles northwest of the Ilde de Bas, by the 10th RN destroyer Squadron, which sank one, drove another ashore, and damaged a third. The latter, in company with the fourth, escaped to Brest. This action virtually ended the threat to NEPTUNE convoys from attack by enemy destroyers. On the night of 4/5 July destroyer patrols damaged three gun boats in the vicinity of Morlaix. On the night of 12/13 June, they carried out the diversionary operation ACCUMULATOR in the Channel Island area.³ During the first two months of NEPTUNE, constant attacks of opportunity were executed against coastal transport.⁴

19. Anti-U-Boat operations in the CORK were conducted by the combined Air-Navy patrol. The results obtained by naval forces were not spectacular from the point of view of "kills", but they were, none the less, highly successful in that they achieved their principle object of stopping the U-Boats from arriving in the convoy lanes. During the first two months, no NEPTUNE loses were known to have been caused by U-Boats.

D. Sealing the Straits of Dover

20. The task of sealing the eastern end of the Channel was less difficult as the Dover Straits are narrow and do not exceed 20 miles breadth at some points. They are well guarded, not only by numerous British coastal batteries, but also by extensive stretches of unnavigable shoal water. Moreover, German naval forces available to penetrate the eastern barrier were not formidable. The enemy disposed in the southern reaches of the North Sea, southward of the barrier interposed by the Home Fleet, of no more than 30 E-Boats, 65 R-Boats, 40 Minesweepers, and some 45 miscellaneous small vessels. No U-Boats, Torpedo Boats, Destroyers or heavier units were situated in these waters.¹ There was, however, a remote possibility that some six Destroyers and ten Torpedo Boats from the Baltic and the Bight might attempt to elude the patrols of the Home Fleet.²

21. Under the general supervision of ANCXF, the Admiral Commanding Dover was responsible for sealing the eastern Channel.³ His first concern was to ensure that the allied minefields, on the enemy's side of the Straits and elsewhere astride enemy convoy routes, were strengthened and kept up to full effectiveness.⁴ From the forces assigned. him for his various NEPTUNE tasks, he disposed ten squadrons of coastal craft as a constant guard against miscellaneous vessels which might try to penetrate into the Channel. He also ⁵

stationed his four destroyers, whose basic task was to guard the east wall of the SPOUT and the eastern arm of the Force L convoy route, in such a manner that they could be quickly drawn into the Straits in case of an unexpected sortie by German destroyers or torpedo boats. In addition, strong air formations of Number 16 Group, Coastal Command operated to the requirements of A. C. Dover, and maintained constant air surveillance over the entire area of the Dover Straits.¹
22. The enemy's reaction in the Dover area, however, was limited to making preparations to arrest the expected future assault against the Pas de Calais and the Low Countries.² No attempt was made to thrust naval forces through the Straits of Dover.

E. Patrols Along the Convoy Flanks

23. A system of screening patrols was organised to protect the channel convoy lanes from attack. Enemy naval forces within the Channel consisted of one destroyer, four torpedo boats, seventeen E-Boats, five R-Boats four minesweepers, eighteen light gun craft, some thirty-seven minesweeping trawlers, some thirty-four patrol vessels and seventy-five harbor defense craft.³

24. Under the general direction of ANCXF, CinC Portsmouth was responsible for operating the patrols on the western flank of the SPOUT; the Admiral Commanding Dover, for those on the Eastern flank.⁴ To man the patrols, ANCXF assigned to CinC Portsmouth, four R,N, fleet destroyers,⁵ two frigates

and five flotillas of coastal forces, comprising 39 craft. He assigned to Dover, four R.N. fleet destroyers¹, two frigates, and ten flotillas of Coastal forces, comprising fifty-four craft.² In addition to these naval forces, Number 19 and 16 Groups, Coastal. Command, R.A.F., operated to their general requirements. Bombers carried out several devastating strikes against enemy naval bases and ships in port.³
25. During the course of the war, an elaborate and efficient chain of radar stations had been developed along the entire southern coast of England. Those gave A.C. Dover complete radar coverage of the Channel in his area, while CinC Portsmouth had coverage more than half-way across the Channel. To bring the southern edge of his area of the Channel, which included the assault area, wider radar surveillance, CinC Portsmouth posted four frigates, mounting powerful radar instruments somewhat to the south of mid-Channel. Radar information was fed into central plots, from all shore stations and from the radar frigates. Portsmouth and Dover were thus able to maintain up to the minute locations and movements of all objects in the Channel, and to vector patrols against hostile vessels.⁴

26. The patrols were disposed as follows:

    1. A seven mile gun zone was established on either side of the SPOUT. Any ship found within this zone during darkness was to be presumed hostile. Allied vessels were to enter only in hot pursuit of the enemy;

2. The destroyers were to patrol along the outer edges of the gun zone: these systems of patrols were known as the East and West Walls of the SPOUT;

3. Dover's destroyers patrolled in single units along a line from Dungeness to the east wall to seaward of the coastal channel;¹

4. Coastal forces, which were employed primarily during the night or periods of reduced visibility, were stationed, or carried out patrols as required.

Table of Contents
Previous Section ** Next Section

Footnotes:

p.416 #1 CCS 300/3 of 18 November 1943.

p.416 #2 The balance of the Home Fleet was on duty in the Channel in immediate support of OVERLORD. The ships at or working out of SCAPA were:
2nd Battle Squadron: DUKE OF YORK, ANSON, HOWE.
Fleet Carriers: FURIOUS, INDOMITABLE, VICTORIOUS.
Cruisers: (1) 1st C.S. - KENT, BERWICK, DEVONSHIRE, (2) 10th C.S. - BERMUDA, JAMAICA, SHEFFIELD.
3rd Destroyer Flotilla: MILNE, MARNE, MATCHLESS, METEOR, MUSKETEER, WAGER, WAKEFUL, WESSEX, WHELP, WIZARD, VOLACE, and NUBIAN.

p.417 #1 The quiescence of the German fleet in the north may be explained in part by any or all of the following: (1) Fuel shortage. In 5 June 1944, the allocation of fuel to the German Navy was cut 33%. Fuel issued to submarines was not cut so that the heavier units absorbed a disproportionately larger share of the cut. (2) The battleships were damaged and the cruisers were being used primarily for training. (3) The German High Command expected the main allied landing later and in the Low Countries and gave their orders accordingly. (See Admiralty NID 24/2 65/45, p.45, p.42-43.

p.417 #2 No direct channel of command between ANCXF and SCAEF and CinC Western Approaches was required or provided, in order to achieve the necessary coordination of effort for this task.

p.417 #3 TRACKER, PURSUER AND EMPEROR.

p.417 #4 Approximately 40° 30' North 9° 00' West.

p.417 #5 This operation was known as operation "C A".

p.418 #1 See Chapter III for a detailed account of the relations between the Channel Home C's in C, ANCXF and Admiralty.

p.418 #2 See ON I Para. 10; ON I, Appendix VII Annex K; CinC Plymouth NEPTUNE Report, Section 2, Para. 21. There are striking discrepancies in the figures shown in the above sources, especially on the question of U-Boats, CinC Plymouth reckoned that there were no more than 40 odd immediately available on D-day. The balance, perhaps, may be accounted for by the fact that some were on other operations, some never got down from the north, and that a ratio of 60% was the maximum available at any time for sea duty.

p.418 #3 The CORK was bounded on the east by the eastern limit of the Plymouth Command (a line running from Portland Bill, to Cap de le Hague). It was bounded on the north and south by the coasts of Brittany and Cornwall and on the west by a somewhat intermediate line at about 70°00' west longitude.

p.418 #4 These were the 19th R.N. Destroyer Division composed of: TARTAR, ASHANTI, HIADA and HURON; the 20th Destroyer Division composed of BLYSCAIWICA (Polish), ESKIMO, PIORUM (Polish) JAVELIN; and the 18th U.S. Destroyer Division, composed of DAVIS, SOMERS, JOWETT plus EMMONS. See ON 5 & ON I, Appendix II, Section A.

p.419 #1 For details of the minelaying program, See Section 2, Chapter VII.

p.419 #2 The Hard Deep is located in mid-channel, directly south of Devon. The patrol operated been 50° 12' North, 2° 21' West, and 49° 56' North, 3° 16' West.

p.419 #3 Since the main enemy destroyer force was still in the Gironde on the night before D-day, this patrol was not manned until the night of 6 June (night following D-day) when air reconnaissance showed that enemy destroyers were moving northward.

p.420 #1 For details of those air operations, see Chapter VII, Section 8.

p.420 #2 One exception to this, was that the U.S. destroyers were withdrawn after the assault phase. See ON I, Appendix II, Section B.

p.420 #3 See Chapter II, Section 5 and Chapter VIII, Section 9.

p.420 #4 For details of these inconspicuous but, by no means, unprofitable operations, see CinC Plymouth's NEPTUNE Report, Section 2.

p.421 #1 See ON I, Appendix VII, Annex K.

p.421 #2 See ON I, Para.11. Should those forces be so employed, the enemy heavy forces would have no screen in case they put to sea. It was, therefore, considered unlikely that they would be sent to hazard the dangers of the Home Fleet Patrols and to try to penetrate the Channel barrier,

p.421 #3 For details of command arrangements, see Chapter III.

p.421 #4 Details of minelaying operations (MAPLE) are given in Chapter VII, Section 2.

p.421 #5 ON 1, Appendix II, allotted V.A. Dover: (1) 4 destroyers (2) 39 M.T.B's. (3) 10 M/L's. (4) 8 Minelaying M/L's. (5) 4 M/S (6) M/L's.

p.422 #1 See Chapter VII, Section 8 for details of air cover.

p.422 #2 Admiralty N I D 24/T, 65/45.

p.422 #3 See ON I, Appendix VII, Annex K.

p.422 #4 To put this arrangement into effect, the boundary between the Portsmouth and Dover commands was altered on 28 May 1944 for operational purposes from the line Dungeness-Dieppe to a line from Worthing (which is located some 20 miles east of Portsmouth to a position 50°00'N, 0° 15'W, thence to 49° 40'N 0° 00' W, thence due east to the French Coast.

p.422 #5 Onslow, Onslaught, Oribi and Offa.

p.423 #1 Savage, Opportune, Obedient and Orevell.

p.423 #2 For ANCXF's assignment of these vessels, see ON 5, Appendix II, Section A and B. It will be recalled that a part of Dover forces were to enable him to establish the eastern Channel barrier as well as to man the Channel patrols.

p.423 #3 See Chapter VII, Sections 8 and 9 for details on air patrols.

p.423 #4 The Channel in CinC Plymouth area was so wide that he had to rely on air reconnaissance to direct his ships into the vicinity of enemy vessels.

p.424 #1 This was in order to cover the SPOUT, the coastal channel and, at the same time, to be able to cover the Straits.