The Development of Sea-Air Co-operation
'Wide eyes that weary never
And wings that search the sea'
Swinburne. To a Seamew. 1866.
THE year 1937 saw two important decisions governing sea-air warfare. Between them they resolved the disagreements which had continued ever since the transfer of some 2,500 aircraft and 55,000 men from the Navy to the newly-formed Royal Air Force in 1918. They also formed the basis from which sea-air co-operation developed from small beginnings to great dimensions during the Second World War.
The first of those two decisions ended the compromise which had governed the control, administration and operation of the Fleet Air Arm since 1924 and which, though acceptable to the Air Ministry, had been a constant source of dissatisfaction and anxiety to the Admiralty. Under the 1924 agreement the Air Ministry remained responsible for the provision of naval aircraft, though the Admiralty specified the types and numbers required and provided funds to cover the cost of the Fleet Air Arm; the Admiralty provided the ships in which they were embarked and their specialised equipment; the Fleet Air Arm pilots (of whom more than half were naval officers) held Air Force rank, but the rest of the aircrews were all naval; the Air Force provided the skilled maintenance staff of the aircraft carriers; and when disembarked the Fleet Air Arm crews came under Air Force jurisdiction, whereas when embarked they were subject to naval discipline. These and other provisions of a complicated arrangement were greatly altered in 1937 when the naval air branch was reborn, though in a different form to that which it had possessed during the 1914-18 war. With the termination of the Air Force partnership in the Fleet Air Arm and the return to the Admiralty of responsibility for the Navy's shipborne aircraft and their crews the title of the Fleet Air Arm, which had been used to describe the Air Force units which worked with the Navy, became obsolete. Thenceforth naval aircraft became as much a part of the Navy as its destroyers, submarines and torpedo-boats. In these volumes, therefore, the Navy's aircraft and crews are, except
when dealing with the period prior to 1937, referred to only as such.1
The second of the two decisions taken in 1937 was contained in a directive issued by the Air Ministry on the 1st of December stating that the primary rôle of the Coastal Command of the R.A.F. in war would be trade protection, reconnaissance and co-operation with the Royal Navy. It guaranteed that the aircraft belonging to Coastal Command would only be employed on other duties when the threat to our sea communications was insignificant, and thus not only met the Admiralty's views regarding the function of aircraft allocated to naval co-operation but eliminated its apprehensions regarding the diversion of Coastal Command aircraft.
The first of these two decisions put a term to the controversy which had marred relationships between the two services; and the second assisted the development of the intimate co-operation between the Navy and Coastal Command which was to contribute so greatly to the success of the nation's maritime strategy. Only one change was made to the 1937 arrangements during the last war, and that was the transfer to the Admiralty of the operational control of Coastal Command aircraft in April 1941. This, however, did not alter the status of Coastal Command as an integral part of the R.A.F.
It is outside the scope of the present volume to trace the various, and often painful steps along the road which led to the 1937 agreements. But the late hour at which those decisions were taken and the controversies which had prevailed during the previous two decades contributed so greatly to the weakness of the Navy's air strength and of the R.A.F.'s Coastal Command when war broke out that some knowledge of the background must be given.
In the Navy itself a division of opinion regarding the functions and importance of shipborne aircraft existed well into the nineteen- thirties. The conventional view then was that aircraft would, in a future war, prove valuable in assisting to bring about a decision by gun power with the enemy's fleet, but that they were not, of themselves, likely to strike decisive blows, or to act as substitutes for the big guns of the heavy ships, or to defend the fleets against air attack as the flotilla vessels defended them against shipborne torpedo attack. The conventional view prevailed, though with gradually lessened assurance, until late in 1931 when the appointment of Rear-Admiral R. G. Henderson as the first Rear-Admiral, Aircraft Carriers, led to the principles involved in the use of the new weapon being radically reconsidered, and to a more just position being allotted to the aircraft in the tactics and employment of the fleets. But throughout the
nineteen-twenties, when all the service departments were labouring under the acute difficulties caused by the Cabinet ruling that no war was to be expected for ten years‹which date was constantly being moved forward‹the section of the R.A.F. to which the Fleet Air Arm belonged, then known as Coastal Area, was the least-favoured part of that service. And from the beginning of 1929 until the end of 1932 the funds provided by the Admiralty were so small that only eighteen aircraft were added to the Fleet Air Arm. Not until 1936, by which time the R.A.F.'s two first expansion schemes had been approved, was Coastal Area placed under its own Commander-in-Chief with the title of Coastal Command.
But during the years when responsibility for the Fleet Air Arm was divided between the Admiralty and the Air Ministry there was one branch of naval aviation in which steady progress was made ‹and that was in the design and construction of aircraft carriers. Here there was no division of responsibility, the experiences of the 1914-18 war could be carried on into the ensuing period of peace and continued experiment and development were possible. The table below gives particulars of the ships of that class which were in service on, or shortly after, the outbreak of war and of the aircraft embarked in them at that time.
Table 1. Royal Navy--Aircraft Carriers in Service, 1939
Remarks 1920 Eagle 18 Swordfish Converted ex-Chilean battleship 1923 Hermes 9 Swordfish First ship to be designed and built as an aircraft carrier 1925 (reconstructed) Furious 18
Converted from mammoth cruiser of the 1914-18 war 1928 (reconstructed) Courageous 24 Swordfish Ditto 1930 (reconstructed) Glorious 36
Ditto 1938 Ark Royal 42
The first new Fleet aircraft carrier [1917 Argus Non-operational Converted merchant ship]
[Notes on Aircraft Types
Swordfish Torpedo-bomber/spotter/reconnaissance Skua Two-seater fighter/dive bomber Roc Two-seater fighter Sea Gladiato Single-seater fighter]
In addition to the completed ships tabulated above six new fleet carriers of the Illustrious and Implacable classes were authorised in the naval programmes for 1936 to 1939. That such a substantial proportion of the available funds was devoted to building new aircraft
carriers should dispel any idea that, after 1935, the Navy was any longer in doubt regarding the contribution of shipborne aircraft to maritime control.
In the equipment of the carriers with aircraft and trained crews our position, compared with the United States and Japan, was not so favourable. In September 1939 the Navy's strength was 232 first-line aircraft, over half of which were Swordfish, while 191 more were employed on training work. During the war it increased to 1,336 first-line aircraft organised in twenty-three 'Strike' and fifty fighter squadrons, and the number of naval air stations grew from four to forty-five. But we could not replace the obsolescent types of aircraft during the first two years of the war and even after that time we had to rely to a considerable extent on American production.
The doctrine current in 1939, based on peace-time training and development, summarised the duties of naval aircraft under the following headings:
- Reconnaissance for the fleet to extend the vision of the surface ships and so enable the enemy to be first sighted by us and, after first sighting, to shadow and keep touch with the enemy.
- Attack by striking forces on a faster enemy attempting to escape battle, thus reducing his speed to enable our surface ships to come into action.
- To assist in protecting the fleet against submarine and air attacks and, in particular, to defend the carriers themselves.
- Spotting for the fleet's gunfire in surface actions or shore bombardments.
Though the use of aircraft for protecting merchant shipping was reviewed before the war, and the value of the small aircraft carrier to work on the trade routes had been stressed in authoritative naval circles, little progress in that important development was accomplished until after war had broken out.
Once the decision that the Navy was to resume responsibility for the Fleet Air Arm had been taken in 1937, the Admiralty strenuously set about building the necessary organisation. A 'Fifth Sea Lord and Chief of the Naval Air Services' was added to the Board of Admiralty, and the departments necessary to handle naval air material and personnel were created. The entry of short-service officers and the training of ratings as pilots, which measures the Admiralty had previously opposed, were started early in 1938 and the Royal Naval Volunteer Reserve Air Branch, which was to supply a great proportion of the naval pilots and observers who fought at sea from 1939 to 1945, was formed in the autumn of the same year. But these measures had not borne fruit before war broke out.
Admiral of the Fleet Sir Charles M. Forbes, Commander-in-Chief Home Fleet 12th April 1938--2nd December 1940.
Admiral Sir John C. Tovey, Commander-in-Chief Home Fleet 2nd December 1940--8th May 1943.
Air Chief Marshal Sir F. W. Bowhill, Commander-in-Chief Coastal Command 18th August 1937--14th June 1941.
Air Chief Marshal Sir P. B. Joubert de la Ferté, Commander-in-Chief Coastal Command, 1st September 1936--16th August 1937 and 14th June 1941--5th February 1943.
During the period of transition the assistance of the Royal Air Force was indispensable and was freely given. As late as December 1940 some 2,000 R.A.F. officers and men were still serving in the Navy. The Air Ministry also undertook the training of naval maintenance crews, and allowed some of its own men to transfer to the sister service. In fact once the decision, which the Air Ministry had strenuously resisted, had been taken by the Government everything possible was done to ensure its loyal fulfilment.
From 1939 to 1945 much assistance was afforded to the Navy by the R.A.F. Commands at home. Fighter Command protected naval bases and installations against air attack, escorted coastal convoys, carried out tactical reconnaissance work and made attacks on enemy shipping in the narrow seas. Bomber Command provided striking forces against enemy warships and submarines, made many attacks on building yards or on factories engaged in producing submarine parts and deployed a considerable proportion of its effort against targets affecting the maritime war. But it was Coastal Command which, after the issue of the directive quoted at the beginning of this chapter, was charged with the specialised duty of co-operating with the Navy. This command had grown out of the old Coastal Area organisation already mentioned, and in July 1936 its Commander (Air Marshal Sir Arthur Longmore) thus became the first Air Officer Commander-in-Chief of Coastal Command. On the 1st of September he was succeeded by Air Marshal Sir Philip Joubert de la Ferté, whose first period of command, lasting until 16th August 1937, saw the foundation of the joint Naval--R.A.F. system of controlling maritime air operations, to be discussed more fully later.
Concurrently with these administrative changes the Chiefs of Staff had ordered an investigation into the protection of seaborne trade, and as it was in this field that Coastal Command finally achieved its full stature, the progress of the investigation will be followed in some detail. The questions asked by the Chiefs of Staff of their Planning Sub-Committee were as follows:
- How far they regarded air attack as a menace to our supplies of food and raw materials in time of war?
- How such attack should be countered?
- What part the R.A.F. should play in the protection of trade?
It was from the extensive deliberations which followed on the asking of these questions, and from the determination of the Chiefs of Staff that an agreed solution should be achieved, that the duties allocated to Coastal Command before the outbreak of war, and so the disposition of its strength, stemmed. Nor was agreement easily reached. The Naval Staff considered that the early establishment of the convoy system would reduce the air threat to merchant shipping to 'manageable proportions' and that surface escorts, suitably armed,
would 'prove the answer' to air attacks as well as to the submarine menace. But they qualified their advocacy of convoy by agreeing that if, in the light of experience, the system proved expensive in shipping losses from air attack, the matter would have to be reconsidered. Because the enemy, remembering the lessons of 1917, would not again risk alienating neutral opinion the Naval Staff considered that unrestricted air or submarine attacks were unlikely. The Air Staff, on the other hand, considered that our dependence on seaborne trade positively invited unrestricted attacks, and that to mass ships in convoy would result in heavier losses from air attack because it would bring large numbers of vulnerable targets close together. This was actually one of the arguments which had been used against introducing convoy to counter the U-boat menace in the 1914-18 war.2
The Naval Staff was confident of the great value of the new 'Asdic' anti-submarine detecting device.3 In 1937 they reported to the Shipping Defence Advisory Committee that 'the submarine should never again be able to present us with the problem we were faced with in 1917'. There were, indeed, good grounds for confidence in the asdic, provided that the operators were thoroughly trained and the submarine target remained submerged. In such circumstances it could and did produce excellent results. But it was difficult to provide skilled asdic operators quickly to all the ships which needed them in war and, as will be told later, the asdic was almost useless against a surfaced submarine.4 The Naval Staff also considered that anti-aircraft gunfire from the escort vessels would adequately protect the convoys against air attack. On both issues the Air Staff was sceptical. Another stumbling block on the road to agreement was the desire of the Air Ministry to use Coastal Command aircraft as part of its offensive striking force--a diversion from their proper function which the Admiralty could not accept.
In the agreement finally reached between the Joint Staffs the probability of unrestricted submarine and air attacks was accepted by the Navy, the introduction of convoy was accepted by the R.A.F.,
and the Air Ministry abandoned the proposal to divert Coastal Command aircraft at will to other duties. Concessions were thus made by both sides and the agreement which, as the Secretary of State for Air remarked, constituted 'an admirable piece of combined staff work' was approved by the Committee of Imperial Defence on the 2nd of December 1937.
The next, and most important, stage--that of defining the duties which Coastal Command aircraft should carry out--had now been reached. Until this issue had been clarified plans and dispositions could not be made, nor specialised training started, nor the most suitable types of aircraft ordered.
The Admiralty was, at this time, chiefly anxious about the powerful German surface warships which might be sent out to attack our sea communications. As the First Sea Lord put it to his colleagues on the Chiefs of Staff Committee, 'nothing would paralyse our supply system and seaborne trade so certainly and immediately as successful attack by surface [i.e. warship] raiders'. The submarine menace, on the other hand, was considered unlikely to prove serious, at any rate during the opening phase of a war with Germany. In consequence the Admiralty felt that the chief contribution which Coastal Command could make to the maritime war was constantly to watch the exits from the North Sea, and this became its primary responsibility. Anti-submarine co-operation, the precise form of which would have to be decided when it was known whether the enemy would or would not wage unrestricted warfare, was placed next, and co-operation with the Northern Patrol, which the Navy intended to establish on the outbreak of war to watch the passages to the Atlantic between the north of Scotland and Greenland, came third in order of priority.
The number of aircraft to be provided in the event of war with Germany, and their allocation were as follows:
(I) Home Waters: For convoy escort duties 165 For the North Sea reconnaissance 84 In the northern area of the North Sea 24 For the Northern Patrol 18 (2) Abroad: At Atlantic Convoy assembly ports 48 TOTAL 339
The above total was provided for in the current R.A.F. expansion scheme, but it was made clear that, by the 1st of April 1939, only 194. (or under two-thirds of the required total) would actually be available. This number was so disposed as to give priority to the North Sea reconnaissance. Unhappily not only were the necessary numbers of aircraft not available before the outbreak of war, but the
performance of the aircraft with which the General Reconnaissance squadrons were then equipped--the Anson--was inadequate to the efficient execution of its function. More will be said on that score shortly.
The Munich crisis found Coastal Command far from fully prepared for war. The organisation into three groups (Nos. 15, 16 and 18) to cover all the waters surrounding these islands was incomplete and only No. 16 Group had been formed.5 Of the fifteen squadrons comprising the Command only twelve could, because of shortage of men, be mobilised; and of those twelve squadrons eight had to move from their peace to their war stations. Less than a year of peace remained to improve matters.
Not the least important deficiency was the lack of an organisation for combined operational control of Coastal Command aircraft. This problem was tackled energetically and was solved by establishing an Area Combined Headquarters (A.C.H.Q.) to control the operations of each group. Within these A.C.H.Q.'s each service had its representative, who enjoyed full executive authority to act for it. At the end of 1938 sites were chosen at Plymouth (for No. 15 Group), Chatham (for No. 16 Group) and Rosyth (for No. 18 Group), and the all-important communications requirements were agreed. But only the Rosyth A.C.H.Q. was properly installed by the time war broke out. In the summer of 1939 the headquarters of the Commander-in-Chief, Coastal Command (Air Marshal Sir F. W. Bowhill), moved from Lee-on-Solent, where it was unsuitably sited, to Eastbury Park, Northwood, where the Commander-in-Chief was in close touch with the Admiralty and whence his own forces could be efficiently controlled.5
The duties allocated to the various squadrons of Coastal Command were promulgated on the last day of March 1939 and were little altered between that date and the outbreak of war. The majority of the squadrons was based in the north-east of these islands to carry out the North Sea reconnaissance work required by the Admiralty. No. 233 General Reconnaissance (G.R.) squadron was to carry out an 'endless chain patrol' during daylight between Montrose and the nearest point on the Norwegian coast (Obrestadt).6 To guard against the possibility of raiders passing through this patrol line unobserved at night the three flying boat squadrons (Nos. 201, 209 and 228) were to search from Invergordon to the north of No. 233 Squadron's patrol as far as a line drawn from the Shetland Islands to the Norwegian coast near Stadtlandet, while two other G.R. squadrons (Nos. 224 and 269) were to search to the south of the Montrose-Obrestadt line from Flamborough Head. A gap which this left off
Map 1: Naval Command Areas at Home 1939 and Associated Maritime RAF Commands
the Danish coast was to be covered by north-south searches by the flying boats of No. 210 Squadron.7 It was calculated that a ship which entered the area covered by the southern patrols at dusk would not steam far enough during darkness to escape the northern patrol at dawn next day. If bad weather dislocated the routine patrols and a raider might have escaped through all their lines, then the flying boats would search, as soon as weather conditions permitted, to the north-west of the Orkneys in the hope of locating the enemy ship after it had left the North Sea.
Though these patrols and searches appeared, on paper, to meet the Admiralty's requirements as far as was possible at the time, there were two factors which substantially reduced their effectiveness. The first was the bad weather which, for prolonged periods--especially in winter--prevails in the North Sea. That the Navy, with its long experience of the vagaries of the North Sea weather, doubted the reliability of the air patrols is shown by a letter written by the First Sea Lord (Admiral Sir Roger Backhouse) to the Commander-in-Chief, Home Fleet, in October 1938, when the plans referred to above were being framed. Admiral Backhouse wrote:'In particular I am not at all sure that the arrangement for a continuous air patrol across the North Sea is workable all the year round. You know as well as I do what the North Sea is like in the winter months. I cannot believe that aircraft could maintain a daily reconnaissance under bad weather conditions. As ships are not stopped by bad weather or long nights to anything like the extent that aircraft are [stopped] we could never be sure that some would not get through unsighted.'
War experience was to show at an early stage that the First Sea Lord's doubts were well founded. Unfortunately time did not permit the effectiveness of the reconnaissance patrols during the winter months to be tested by exercises before war broke out.
The second factor limiting the effectiveness of the patrols was the low performance of the Anson, which had a range of only 510 miles and a speed of 144 knots. It could not even reach to the Norwegian coast at Obrestadt. The last sixty miles of the patrol line from Montrose had therefore to be covered by five or six of the Home Fleet's submarines, stationed at twelve-mile intervals, and carrying out diving patrols. This was rapidly proved to be an unsatisfactory arrangement.
As early as 1937 the Air Ministry had desired to replace the Ansons, but neither of the new types intended for that purpose could be available until later in 1938. As an emergency measure the purchase of Lockheed Hudsons from America was investigated, and orders for
250 aircraft of this type were placed. The Hudson possessed double the range and could carry five times the bomb load of the Anson, and the intention was to equip five reconnaissance squadrons with them. Only No. 224 Squadron had, however, received its Hudsons when war broke out.
Our weakness in flying boats was even greater, since only two squadrons had received the modern Sunderland, and the Lerwick, which was intended as the replacement aircraft for the other three squadrons, had proved a complete failure. As with the Hudsons, an endeavour was made, later, to obtain more modern types from America.
So far only the steps taken to meet the Admiralty's first requirement have been considered. For the second priority, that of antisubmarine duty, three G.R. squadrons (Nos. 224, 217 and 204) were allocated to the Thames estuary, the Channel and the Lizard areas respectively until such time as the convoy system was introduced. If and when that occurred, escorts for the convoys were to be provided by six squadrons. The Coastal Command aircraft thus allocated to anti-submarine duties were, from the beginning, given freedom to carry out attacks in all areas except those in which our own submarines were patrolling; but Bomber Command aircraft were forbidden to attack submarines during the first weeks of the war because it was considered that bomb loads might thus be wasted on targets of secondary importance, the bombs carried would probably be unsuitable for such attacks and the bombers' navigation might be insufficiently accurate to determine the limits of our own submarines' patrol areas. This order was, however, modified after three U-boats had been sighted in the Heligoland Bight but not attacked.
Yet another deficiency in the strength and equipment of Coastal Command remains to be recounted. It possessed very little striking power of its own wherewith to attack such enemy warships as might be sighted. Only one torpedo-bomber squadron (No. 42) was available for that duty, though another was held in reserve. And No. 42 Squadron was equipped with the obsolete Vildebeeste. This lack of striking power made Coastal Command largely dependent on Bomber Command to inflict damage on enemy warships; and the latter had received no training in attacking such targets.
The final version of Coastal Command's war plans was issued at the end of June 1939. Between the 15th and 21st of August the arrangements were tested in an exercise designed to deal with surface raiders breaking out from the North Sea. On conclusion of this rehearsal most of the squadrons moved to their war stations, and the war-time reconnaissance patrols were started almost immediately.
The reader will have remarked that the plans discussed above made no special provision for the protection of the great flow of
shipping which must, in war as in peace, flow along the route off the east coast of these islands and which, in the event of war with Germany, was plainly very exposed to air attack. Not until early in 1939, and then only through the agency of a committee appointed to investigate other subjects, was this important matter forced into the foreground. To divert all the shipping from the east to the west coast ports was not practicable, because the handling facilities at the latter were inadequate and the strain on the inland transport system would have been intolerable. The Air Defence of Great Britain (A.D.G.B.) organisation was responsible for the defence of our cities and industries, and also for the defence of the ports themselves; but the ships which entered and left the ports would, if in convoy, be protected only by the escort vessels' guns and, if sailing independently, be quite unprotected. The short-range single-seater aircraft of Fighter Command included in the A.D.G.B. organisation were operated on the principle of control from the ground. Such control could not be extended more than a few miles from our shores and, moreover, the pilots were untrained in sea-air co-operation, which was not within the responsibilities of Fighter Command. But the need to introduce some measure of air protection for the east coast shipping could not be ignored and, in consequence, it was decided in the summer of 1939 to form four Trade Protection Squadrons of Blenheim fighters. They were allocated to Fighter Command. None was, however, brought into being until after the outbreak of war, when the start of enemy air attacks had rendered it imperative. Though the need for special protection for the east coast shipping was now recognised many months were to elapse, and serious losses were to be suffered from air attack, before it was properly organised.
Looking back to-day over the period prior to the outbreak of war, it cannot but be concluded that the slow progress made in the development of sea-air co-operation until 1937, when it was almost too late, was brought about, firstly, by the Cabinet's 'ten-year rule' regarding the possibility of war breaking out and, secondly, by the inter-service controversies which bedevilled all impartial discussion of the fundamental issues involved. Though it may be considered that this contributed to bringing us, for the second time in the present century, to the very edge of the abyss of defeat at sea, it must be recognised that, in the enemy's camp, the same problems were never satisfactorily resolved. Controversy and jealousy between the German Navy and the Luftwaffe continued throughout the war. They prevented the former from developing the use of air power at sea and greatly restricted the effectiveness of the latter when operating in a maritime rôle. It was, indeed, fortunate that the British Navy and Air Force abandoned such controversies and joined hands in a spirit which, as the war progressed, grew more and more
comradely--and that they did so just in time. Nor should it be forgotten that if the Germans had, some years prior to 1939, found a solution to the problems outlined in this chapter and then concentrated even a reasonable proportion of their great energies on the maritime use of air power--as did the Japanese and the Americans --then the survival of Britain would indeed have been problematical.
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