Early in the Seventeenth Century, while confined to the Tower of London, Sir Walter Raleigh wrote: ‘There are two ways in which England may be afflicted. The one by invasion ... the other by impeachment of our Trades’. On this Sir Julian Corbett has commented: ‘Herein lies the raison d’être for British sea power throughout the ages. Trade protection and security from invasion both depended on sea power’. As will become apparent in the ensuing account, in the last two World Wars, through insufficient attention to trade protection, Britain was nearly defeated even though she was the dominant naval power and under no serious risk of invasion.
From the beginning of the Thirteenth Century until the end of the wars with France in 1815, the standard method of protecting Britain’s seaborne trade was by sailing ships in convoy, first groups of armed merchantmen which could support each other, later, from the beginning of the Eighteenth Century by which time the distinction between merchantmen and warships had become well defined, by providing convoys of merchant ships with an armed escort of frigates and sloops, supported where necessary by ships of the line.
By the end of the Seven Years’ War of 1756-63 the Admiralty had developed a finely-tuned system of convoys across the Atlantic to and from North America, Canada and the West Indies; into the Baltic; and to and from the Mediterranean and India. In the Napoleonic Wars the system was further sophisticated. Convoy was made compulsory in wartime from 1798.
It is only if one remembers the importance of this defence of trade through convoy that one can fully appreciate the dispositions of fleets and squadrons made by such great First Lords of the Admiralty as Lord Howe, Lord St. Vincent and Lord Barham, or the work of Nelson when Commander-in-Chief in the Mediterranean or when acting in that capacity. In their eyes, protection of Britain’s overseas trade was an integral part of the naval offensive against France and her allies and satellites.
In the middle of August 1805, when Napoleon was at Boulogne and the Grand Army and its transports were poised for the invasion of England, when it was not known whether Admiral Villeneuve, with the Combined Fleet at Ferrol, would move north to effect a massive concentration with the French Brest Squadron or south to Cadiz and thus threaten England’s grip on the Mediterranean, there was still present in the mind of Lord Barham, the First Lord, the need to protect the great homeward-bound convoys. ‘Ferrol,’ he wrote to Admiral Cornwallis, commanding the blockade off Brest, ‘is the great object until our East India and West India fleets are arrived, and which may be in the course of a fortnight. The heavy frigates, as far as you can spare them, cannot be employed better than meeting them towards the coast of Ireland.’
An additional worry and uncertainty at this time was the whereabouts of Commodore Allemand’s squadron of five ships of the line (one three decker of 120 guns and four 74s), three 40-gun frigates and two brig-corvettes, which had slipped out of Rochefort on 17 July 1805, was reported off Cape Finisterre by 28 July, but subsequently could not be accounted for. The convoy of fifty transports carrying 6 700 troops under the command of Major-General David Baird, which had sailed from Cork on 28 August to recapture the Cape of Good Hope from the Dutch, narrowly escaped running into this well-armed, well-led squadron on 12 September. The convoy’s own escort, under the command of Commodore Sir Home Popham, was markedly inferior in numbers and weight of metal: three 64s, one 50- and two 32-gun frigates.
A popular view of Nelson is that he was a young officer constantly seeking battle with the enemy but with little or no regard for such mundane matters as the protection of seaborne commerce or trade. Nothing could be further from the truth. His letters and despatches when commanding the detached squadron in the Mediterranean and later when Commander-in-Chief show a constant and active concern for the protection of the trade and convoys to and from Malta, the Adriatic and the Levant, and to and from England. Convoys needed strong escorts past the coasts of Tunis and Algeria and through the Gut between 20 leagues (60 miles) west of Cape Spartel and Gibraltar if they were not to fall into the hands of well-armed privateers or enemy frigates. His constant ‘distress for lack of frigates’ was not only because these were ‘the eyes of the fleet’, but because they were needed for trade protection.
On 7 October 1805, a fortnight before the Battle of Trafalgar, Lord Nelson wrote to the Secretary of the Admiralty, pointing out that his needs for the Mediterranean station were 22 frigates and 16 sloops, of which 8 frigates and 2 sloops should be constantly with the fleet off Cadiz, the bulk of the remainder being for trade protection and observation. At the time he wrote, his actual effective strength was 14 frigates and 8 sloops. His concern for trade protection is shown by the fact that at the Battle of Trafalgar the fleet had with it only 4 frigates, 1 schooner and a cutter.
Few of the lessons from these earlier wars were remembered in 1914; most had been forgotten and had to be learnt afresh or were deemed to be irrelevant under new conditions.
World War I
At the outbreak of World War I the Admiralty was prompt to introduce the convoy system for troop transports. But while convoys were instituted for troop transports, storeships and other special ships, and while the Grand Fleet never left harbour without an extensive anti-submarine, anti-torpedo-boat screen of escorting destroyers, not until May 1917 was any attempt made to protect the bulk of Britain’s extensive ocean-going merchant shipping through the traditional means of convoy and escort. How does one explain this curious paradox in the light of past history?
It stemmed from three misconceptions at the Admiralty which were shared to a greater or lesser extent by the Government of the day at the outbreak of the war.
Firstly, there was an obsession with the ‘decisive battle’ concept, the conviction that the main function of the Navy was not home defence or trade protection (which were essentially ‘defensive’ measures), but to seek out and destroy the enemy’s fleet (which was ‘offensive’). This thinking persisted right through into 1918 even though as early as 23 September 1916 the Admiralty was writing to the Commander-in-Chief of the Grand Fleet: ‘The British Fleet is vital to the success of the Allied cause. The German Fleet is of secondary importance; its loss would not vitally affect the cause of the Central Powers ...’
Secondly, there was the notion that as the dominant naval power Britain had nothing to fear from a weaker naval power which resorted to the guerre de course, or commerce raiding. But there was a fallacy in this argument. The guerre de course had never been attempted against a power so vulnerable to it as Britain now was. Britain imported nearly two-thirds of her food supplies, all her oil, most of her iron ore and other minerals and metals except coal.
Thirdly, while it was generally recognised in 1914 that the submarine posed a distinct threat to warships, with the notable exception of Admiral of the Fleet Lord Fisher, a former First Sea Lord, there was a complete failure to recognize its possibilities as a commerce raider. Here Admiralty thinking was in accord with that of the German Secretary of State for the Navy, Admiral von Tirpitz. He saw the submarine only as a defensive weapon for German harbours and their approaches. The early war successes of the U-boats surprised him.
The possibility of German submarines sinking merchantmen without warning was discarded in the pre-war Royal Navy as ‘impossible and unthinkable’. Churchill, on 1 January 1914, stated that he did not believe ‘this would ever be done by a civilised Power’. He was not alone in this error.
On the other hand, Lord Fisher, in a memorandum to Churchill in January 1914, was remarkably prescient. He pointed out that the submarine ‘cannot capture the merchant ship; she has no spare hands to put a prize crew on board; little or nothing would be gained by disabling her engines or propeller; she cannot convoy her into harbour; and, in fact, it is impossible for the submarine to deal with commerce in the light and provisions of international law ... There is nothing else the submarine can do except sink her capture’.
In 1915 British and Allied losses of merchant shipping totalled 1,3 million tons of which nearly 400 ships of over 1 million tons were sunk by U-boats. Worse was to follow in 1916: total losses were 2,3 million tons of which U-boats accounted for 964 ships of nearly 2 million tons. What was particularly worrying to the Admiralty and the Government was the marked increase in losses from October onwards.
By the latter part of October 1916, not quite five months after the Battle of Jutland, the Commander-in-Chief, Grand Fleet, Admiral Sir John Jellicoe, realised that what mattered was no longer victory over the German High Seas Fleet, but over the submarine menace. In a memorandum of 29 October to Lord Balfour, the then First Lord of the Admiralty, he wrote: ‘There appears to be a serious danger that our losses in merchant ships, combined with the losses in neutral merchant ships, may by the early summer of 1917 have such a serious effect upon the import of food and other necessaries into allied countries as to force us into accepting peace terms, which the military position on the Continent would not justify and which would fall far short of our desires.’
On 2 November Jellicoe attended a meeting of the Government’s War Committee together with Admiral Sir Henry Jackson, the First Sea Lord, and Vice-Admiral Sir Henry Oliver, Chief of the War Staff and later Deputy Chief of the Naval Staff. Professor Temple Patterson, one of Jellicoe’s biographers, records that at this meeting ‘anti-submarine measures were discussed, including the convoy system, which all three admirals regarded as impracticable’.
Jellicoe relieved Sir Henry Jackson as First Sea Lord on 4 December 1916. On 16 December he established an Anti-Submarine Division of the Staff at the Admiralty with Rear-Admiral A.L. Duff as its Director.
Well into 1917 the Admiralty remained opposed to the introduction of an extensive convoy system as a means of ocean trade protection. In January of that year, the Admiralty War Staff issued a revised handbook on trade defence that condemned convoy in explicit terms. It stated: ‘The system of several ships sailing in company, as a convoy, is not recommended in any area where submarine attack is a possibility. It is evident that the larger the number of ships forming the convoy, the greater the chance of a submarine being enabled to attack successfully, and the greater the difficulty of the escort in preventing such an attack.’ In passing, it is worth pointing out that experience in the latter years of World War I showed that the last statement was a complete inversion of the truth and this was confirmed again in World War II by the operational research studies of Professor P.M.S. Blackett and others and proved by actual experience in the Battle of the Atlantic.
The arguments against introducing a general system of ocean convoy were lack of escorts; the fact that, unlike the convoys of the old wars, vessels were now proceeding in many different directions; the delays and loss of tonnage consequent on assembling vessels for convoy; the alternating slack times and congestion at the ports of loading and discharge; the variation in the speeds of merchant ships (as though in the days of sail all ships were of the same speed!); the inability of merchantmen to zigzag or keep proper station together (though presumably the troop transports had learnt this art). Other arguments, or excuses, were the danger of a convoy running into a minefield and the difficulties of assembling convoys in neutral countries such as the U.S.A. The truth of the matter was that naval thought was focussed too exclusively on battle and too little on the protection of shipping. In spite of Jellicoe’s memorandum to Balfour of 29 October 1916, it was still not appreciated that lack of shipping could lose the war without a single major engagement at sea.
Not that the Admiralty was backward in pursuing a number of anti-submarine measures, particularly after Jellicoe became First Sea Lord. Mine and net barrages were laid at vast expense; patrols and coastal air patrols were increased; merchantmen continued to be armed and were evasively routed; auxiliary patrols were established to hunt U-boats in focal areas near the coast. At a number of bases the Admiralty established special ‘hunting patrols’ for hunting U-boats on the approach routes, and in March of 1917 there were detailed and definite systems of varying approach routes for homeward-bound ships where protection could be provided by patrol craft. None of these measures achieved much success either in protecting shipping or in destroying U-boats. Indeed, the approach route system and patrols did more harm than good because the U-boats were able to locate the traffic routes by the mere presence of the patrolling vessels. They could sight the patrols before they themselves were sighted; all they had to do was to dive until the patrol had passed, and then resume their lookout for merchantmen.
A change of strategy was forced upon the Admiralty by the resumption of unrestricted U-boat warfare by Germany on 1 February 1917 which lead to a drastic increase in shipping losses. In his memorandum of 22 December 1916, urging the opening of an unrestricted submarine warfare campaign, the German Chief of the Naval Staff, Admiral von Holtzendorff, estimated that Britain was fed and supplied by some 10 750 000 tons of shipping of which 3 000 000 tons was from neutrals. Judging from experience gained in 1915 and 1916, he believed that unrestricted U-boat warfare should account for 600 000 tons of British and Allied shipping each month and that at least 1 200 000 tons of neutral shipping would be frightened away. After five months shipping to and from Great Britain would have been reduced by some 39 per cent. He concluded: ‘England would not be able to stand that ... I do not hesitate to assert that, as matters now stand, we can force England to make peace in five months by means of an unrestricted U-boat campaign.’
Admiral von Holtzendorff’s forecast of the results of unrestricted U-boat warfare proved uncomfortably accurate. In February 1917 the U-boats sank 464 599 tons of British, Allied and neutral shipping; in March 507 001 tons; in April 834 549 (an average for the three months of just over 602 000 tons per month). These sinkings were achieved by the Germans at a cost to themselves of only ten U-boats of which certainly two, and perhaps three, were lost by accident. In fact the situation was far more perilous for Britain than even these figures suggest, for they do not include the many ships damaged and laid up for repair, or the disruption to movements of shipping caused by the mere threat of the U-boats. At the end of February over 600 neutral vessels in Allied ports had refused to sail. Worst of all was the continuing steep rise in the curve of tonnage losses. British ocean-going vessels (1 600 tons gross and upwards), which were vital for the North Atlantic trade, were the principal victims of the holocaust: 120 were lost during April, over 90 per cent of the British losses by tonnage. Professor A.J. Marder sums it up bluntly: ‘The chance of an ocean-going steamer leaving the United Kingdom and returning safely was but one in four’.
It was clear that what Admiral Doenitz was later to describe as ‘the tonnage war’ was running heavily against Britain. It would soon be impossible to supply the needs of both the civilian population and of the armies in France and elsewhere.
On 26 April 1917, Rear-Admiral Duff submitted an important memorandum to the First Sea Lord which opened with the surprising statement: ‘It seems to me evident that the time has arrived when we must be ready to introduce a comprehensive scheme of convoy at any moment’. He proposed convoy of all vessels under 15 knots (later changed to 12 knots), British Allied and neutral, in the North and South Atlantic. On 30 April Jellicoe informed Admiral Sims of the U.S. Navy that ‘the Admiralty had not definitely decided that the convoy system should be adopted, but there was every intention of giving it a fair trial’.
What brought about this sudden change in attitude was, first of all, the appalling rate of sinkings. As Doctor Johnson once put it, ‘Depend upon it, when a man knows he is about to be hanged, it concentrates his mind wonderfully’. That was the Admiralty’s position. All other methods having failed, there was no alternative but to give the despised convoy system a trial, especially as there were strong indications that the Prime Minister, Lloyd George, was going to press for this. Also, America’s entry into the war on 6 April gave hope that the shortage of escorts might be eased and resolved the doubts about being able to assemble convoys in U.S. ports. Furthermore, early in April, Commander R.G.H. Henderson in Admiral Duff’s Division had established that the number of ships requiring ocean convoy was far less than the Admiralty had hitherto, mistakenly, believed. Not more than 280 vessels a week would require ocean convoy, whether homeward- or outward-bound.
Finally, there was what Admiral Duff described in his memorandum as the ‘unexpected immunity from successful submarine attack ... of the French Coal Trade’. French industry was heavily dependent on coal supplies from Britain. There had been heavy losses of the colliers engaged in this trade during the last quarter of 1916 and French factories were shutting down through lack of coal. As a result of representations by the French, a system of ‘controlled sailings’, mainly with trawler escorts, was brought into force in February 1917. It was an immediate success. Between then and the end of April the U-boats sank a mere 5 of the nearly 2 600 such ships sailed in convoy (or a loss rate of 0,19 per cent). For the whole war 37 927 ships were convoyed for the loss of only 53 (or 0,14 per cent).
On 10 May a trial convoy of 17 merchant vessels (6 1/2 knots average speed) left Gibraltar, escorted through the danger zone as far as 11° West by three armed yachts, and two Q-ships as ocean escorts. They were met outside the submarine danger zone, some 200 miles from the English Channel, by eight destroyers from Devonport and later given a flying boat from the Scillies as air escort. The experiment was a complete success. Not a ship was lost, station-keeping was quite good, and the convoy made the voyage in two days less than would have been the case had the ships come home independently on the various devious routes which were then prescribed. In May and June five homeward-bound Atlantic convoys were run from Hampton Roads, Virginia, again with considerable success. Out of a total of seventy-three ships in these convoys only one, a straggler, was torpedoed and sunk.
However, it was only slowly that the convoy system was extended and not until the end of the year that the complete system was in operation. The Admiralty were still inclined to drag their feet about convoy and there was difficulty in providing the necessary escorts, largely because the Admiralty still clung to its system of patrols and hunting groups, and the Grand Fleet still believed that its destroyer/capital ship ratio must be of the order of 2:1.
Nevertheless, from August onwards the rate of shipping losses declined significantly. By the end of October 1917, to quote Professor Marder again, ‘it was apparent that the convoy system was a success - that an effective reply to the U-boats had been found, even if the merchant tonnage loss rate was still uncomfortably high ... By the end of the year the last doubts about the efficacy of convoy had been removed.’
Convoy proved far less wasteful in carrying capacity of ships than its original opponents had claimed. For one thing, convoys were not held up in harbours or the approaches to them through threats of mines or U-boats as happened to single ships. The minesweepers would sweep a channel and the convoy with its escort would proceed on its way. Furthermore, direct routing, as opposed to evasive routing, could save substantial time on passage as we saw in the case of the first trial convoy from Gibraltar.
Another useful lesson which was learnt in this war but which, unfortunately, had to be learnt all over again in World War II, was the value of combining air and surface escorts for convoys where U-boats were likely. Aerial patrols by themselves proved of as little value as hunting patrols by surface vessels. But an aircraft or airship proved a valuable adjunct to the surface escort of a convoy. For one thing, when the air escort preceded the convoy at a distance it caused U-boats to submerge, which reduced their power of manoeuvering into a good attack position. During the whole war only five ships were sunk in convoy when an air escort was present as well as a surface anti-submarine escort and this in spite of the fact that, owing to the lack of any weapon with which to attack a submerged submarine, aircraft sank none.
World War II
When war was declared on 3 September 1939 the Admiralty was confident of beng able to deal with the German U-boats; they were much more concerned about the threat to British shipping posed by surface raiders, especially the heavily armed, so-called ‘pocket battleships’, Deutschland (later renamed Lutzow), Admiral Graf Spee and Admiral Scheer. As late as 1937 the Naval Staff reported that in their opinion ‘the submarine would never again be able to present us with the problem we were faced with in 1917’. They based this view on the belief that in the Asdic the Navy had developed a successful device for detecting submerged U-boats and in the depth charge an effective means of destroying them. They were also influenced by the mistaken belief, which was widely held at the outbreak of the war, that Hitler would not resort to unrestricted U-boat warfare because this would alienate the Americans.
However, experience soon showed that the performance of the Asdic in peace-time exercises, in calm to moderate weather and in daylight, handled by highly-trained and well-practised operators, was hard to match in war-time in the wild weather of the North Atlantic when, as likely as not, the operator would be a ‘Hostilities Only’ rating who had undergone a crash course of training and who might be miserably cold and wet, desperately tired, and perhaps sea-sick as well.
Fortunately, even before the outbreak of war, the Admiralty had decided that the convoy system should be applied to the defence of merchant shipping to the maximum possible extent, and had set in train an extensive organisation of Naval Control Service Officers and Sea Transport Officers at the main convoy assembly ports at home and abroad.
Unfortunately, the Navy was woefully short of fast, long-range vessels suitable for anti-submarine convoy escort work, due partly to the Admiralty under-estimating the U-boat menace, but mainly to the Treasury’s clamp of financial stringency on the Navy estimates for most of the 1930s. At the outbreak of war, the Royal Navy’s Asdic-fitted force consisted of some 150 destroyers, half of which were veterans of the First World War and, having been designed for work in the North Sea, of only short range; some coastal vessels; and twenty-four sloops. The sloops had a good range but their speed was two knots less than a surfaced U-boat. Most of the newer, faster and larger destroyers were required to screen the Home and Mediterranean Fleets or to escort troop transports across the Channel to France. Many of the others were needed to protect the large volume of shipping moving up and down the vulnerable east coast of Britain. The few remaining surface escorts could take the outward-bound Atlantic convoys only as far as 12 1/2° West Longitude - some 100 miles west of Ireland. There the merchant ships would continue in company for two more days before dispersing to sail independently to their destinations. At the point of dispersal they were still well within the operating range of the German U-boats.
Coastal Command, which was the orphan child of the R.A.F., was in no position to help. At the outbreak of the war it was woefully under strength, most of its aircraft were obsolescent, none of its aircrews had received any training in anti-submarine warfare and its only anti-submarine weapon was a bomb which mistaken attacks on British submarines soon showed to be quite ineffective.
To make matters worse, the old heresy of hunting patrols reared its ugly head again, supported by pressure from the First Lord of the Admiralty, Mr Winston Churchill, to take the ‘offensive’ against the U-boats. The extreme folly was at the outbreak of the war when fleet aircraft carriers, each with a small destroyer screen, were formed into hunting groups. Ark Royal narrowly escaped being torpedoed on 14 September 1939 and three days later H.M.S. Courageous was torpedoed and sunk with the loss of 518 highly trained officers and men. Right into 1941 there was a tendency to order convoy escorts to leave their charges to search for U-boats in waters quite remote from the convoys which they were supposed to be protecting. Such searches were uniformly unsuccessful and while they were in progress the convoys themselves were left in great peril.
And what was happening ‘on the other side of the hill’, i.e. in German Naval circles? They were completely unprepared for war with Britain in September 1939, largely because they had been misled by their Fuehrer. At the end of May 1938 Hitler told the Commander-in-Chief, German Naval Forces, that Britain too must now be regarded as a possible adversary, but that there was no immediate prospect of a conflict with her. In June 1939, Commodore Karl Doenitz, head of U-boat command, expressed anxiety about the possibility of an early war with Britain in view of the numerically weak strength of his fleet. Hitler’s reply, through the Commander-in-Chief, was that, ‘he would ensure that in no circumstances would war with Britain come about. For that would mean finis Germaniae.’
Doenitz believed that to operate successfully against Britain he should have at least 100 U-boats always operational, which presupposed a total strength of at least 300. When war was declared he had 56 U-boats in commission of which 46 were operational. But of these 46 only 22 were suitable for service in the Atlantic, the remaining 24 being small, 250-ton boats, whose short radius confined their area of operation to the North Sea. He did the best he could with the resources at his command. By the end of August he had 19 of his Atlantic U-boats on station in the Western Approaches.
The backbone of his Atlantic force, then and later, was the Type VII U-boat of a little over 750 tons displacement when surfaced, about 220 feet in length, and with a complement of about 40 officers and men, all highly trained, proud of their service and the elite of the German Navy. Right to the bitter end Doenitz’s crews maintained a very high morale in the face of heavy losses. The maximum speed on surface of the Type VII was 17 1/2 knots and the maximum submerged speed, for short bursts, was 7 knots. They had good endurance and could remain at sea on a normal patrol for seven or eight weeks without refuelling. They carried one 88mm gun for use against ships and one 20mm against aircraft, but the main armament was, of course, the torpedo. There were four torpedo tubes in the bows and one in the stern, and nine spare torpedoes were carried, making 14 in all. The firing control gear was well designed and efficient and they were fitted with excellent hydrophones which, when the boat was dived to about 100 feet in reasonable weather conditions, could detect convoys and large warships at ranges of up to 50 miles.
Vice-Admiral Sir Peter Gretton, who in World War II was a distinguished Escort Group Commander, said of the Type VII U-boats: ‘All in all, the U-boats were well designed and built. They handled well and dived quickly. They were planned to withstand the pressures at a depth of 600 feet and several had dived even deeper without damage. With their low silhouettes, they were ideally suited to their task.’
The Battle of the Atlantic began on 3 September 1939, the day war was declared, with the sinking of the liner Athenia by U.30, with heavy loss of life. It ended on 8 May 1945 when Germany surrendered. However, the turning point, when it was clear that the escorts had secured a victory over the U-boats, took place in May of 1943. On the 22nd of that month Doenitz decided to withdraw his U-boats from the North Atlantic in the face of insupportable losses.
Captain Stephen Roskill, the official British historian of the war at sea, points out that ‘the broad trend of the first seven months of the campaign (September 1939 to March 1940) was by no means unfavourable to the Allies. Merchant ship losses totalled 222 ships of 746 766 tons - little more than 100 000 tons per month - and no less than 18 U-boats - more than a third of the entire operational strength available at the beginning - were destroyed by one means or another. Furthermore new U-boats were still only completing very slowly, because Hitler had not yet given their construction high priority. Thus with only eleven new boats commissioned in those seven months Doenitz had not even replaced his losses’.
But the invasion of Norway, Denmark, Holland, Belgum and France swung the balance sharply in Germany’s favour. The fighting off Norway cost the Royal Navy 9 destroyers sunk and 12 damaged and the evacuation from Dunkirk a further 6 sunk and 19 seriously damaged. Thereafter, because of the fears of invasion, escorts had to be withdrawn from the Western Approaches to strengthen the south-east coast and Channel ports, and shipping losses rose alarmingly.
An even more serious consequence of these German successes on land was that Doenitz promptly moved his U-boats to bases in France on the Bay of Biscay coast. In July 1940 the first Atlantic U-boat base was brought into service at Lorient, followed a month later by bases at Brest and La Pallice (near La Rochelle). The passage of U-boats from these French bases to the main shipping routes was some 450 miles shorter than from their home ports in Germany and this gave them a correspondingly greater reach into the Atlantic. The Type VII U-boats could now cruise as far out as 250 West, far beyond the then range of British surface and air escorts. Furthermore, the small 250-ton coastal U-boats could now also be used on the ocean routes. The whole German U-boat strength was concentrated on the Atlantic routes, attacks on British east coast and Channel convoys being left to aircraft and E-boats.
The months of July to October 1940 were later called by the German U-boat commanders ‘the happy time’. Attacks were generally made on ships sailing independently, on inadequately defended convoys, or on stragglers from convoys. Plenty of these targets could then be found, since outward bound convoys from the U.K. dispersed between 15° and 17° West, nearly all were weakly escorted and many ships still had to be sailed independently. In these four months 144 unescorted and seventy-two escorted ships totalling over 1 100 000 tons were sunk by U-boats, and by way of return only six U-boats were destroyed.
British deficiencies at this stage were lack of surface escorts of sufficient speed and range; lack of suitable aircraft for convoy escort; ineffective Radar in ships and aircraft; lack of an effective airborne depth-charge; and the need for reliable radio telephony for rapid communication between surface escorts and with aircraft. Wolf-pack night attacks by groups of U-boats on the surface, which Doenitz gradually introduced between October 1940 and March 1941, reinforced the need for better Radar because the Asdic was almost useless against a surfaced U-boat. These attacks also brought home the need to provide the surface escorts with a suitable High-Frequency Direction-Finding Wireless Set (later known as HUFF-DUFF) which could detect shadowing or waiting U-boats on surface at a distance and to improve the means of visually sighting a surfaced U-boat by night. (Star-shell was not entirely effective and was frequently counter-productive because the flash from the gun firing it frequently caused temporary night-blindness in the watchkeepers and look-outs on the bridge. The ‘Snowflake’ rocket, which turned night into day, proved successful.) Finally, it was soon recognised that if they were to be fully effective the escorts must be formed into Escort Groups which would train and operate together under the same Group Commander, thereby greatly improving their mutual understanding and tactical handling in the inevitable confusion of a night attack by a pack of U-boats on a convoy of perhaps forty ships.
But all these and other measures took time. It was only towards the end of 1940 that the first of the 1 000 ton ‘Flower Class’ corvettes came into service. They were good sea boats with a reasonably long range, but they were too slow (maximum speed 15 1/2 knots) to catch a surfaced U-boat, and were extremely lively and uncomfortable ships in any kind of a sea-way. They were followed in 1942 by the ‘River Class’ frigates, 1 445 tons, with a top speed of 20 knots and with better endurance. The ‘Modified Black Swan Class’ sloops, with six 4 inch dual purpose guns, good endurance and a speed of 19 3/4 knots, started coming forward in the following year. Moreover from the latter part of 1940 onwards there was a steady flow of new destroyers from the shipyards.
As a result of the improved escort situation and the development of new bases at St. John’s, Newfoundland, and in Iceland, from 27 May 1941 it was possible to introduce continuous surface escort across the North Atlantic for homeward-bound convoys. In July similar arrangements were made on the Sierra Leone route and for westbound North Atlantic convoys. Unfortunately, through lack of suitable long-range aircraft, there was still an 800 mile mid-ocean gap between Iceland and Newfoundland where air escort could not be provided, and this was the area where the U-boats soon concentrated. From the beginning of 1941 the new 10 cm wavelength, Radar sets, capable of detecting the presence of a surfaced U-boat, but which the U-boats’ search-receivers could not pick up, were being fitted to the surface escorts. But not until 1943 was RAF Command prepared to release any such sets to Coastal Command. The development of HUFF-DUFF was slower, but by the latter part of 1942 it had become a normal part of the armoury of British anti-submarine vessels.
Nevertheless, the balance in 1941 and 1942 was by no means in the Allies’ favour. In 1941, losses of British, Allied and Neutral shipping amounted to 1 299 ships of over 4,3 million tons, of which the U-boats accounted for 2 171 754 tons and aircraft - mainly the Focke-Wulf ‘Kondors’ working from bases near Bordeaux in France and Stavanger in Norway - for over 1 million tons. Worse was to follow in 1942 when shipping losses totalled just under 7,8 million tons of which the U-boats accounted for 6 266 000 tons. Imports into Britain that year fell to one-third less than they had been in 1939 and stocks of oil fuel at the year-end were little more than two months’ consumption. What was particularly worrying to the Admiralty was that the enemy’s U-boat strength was still steadily increasing. Thus between July and October 1942, 61 new U-boats had been commissioned, bringing the total to 365, whereas only 32 had been destroyed.
Another matter of great concern to the Admiralty was that the ongoing struggle in Whitehall to obtain an increased allocation to Coastal Command of four-engined bombers, particularly the very long range Liberators, was making little or no progress. In spite of all that Mr Winston Churchill subsequently wrote about his continuing concern about the Battle of the Atlantic, one of the mysteries of World War II is the prolonged blindness of the British to the relative strategic importance of devoting more four-engined, long-range aircraft, with suitable anti-submarine weapons, to the Battle of the Atlantic instead of concentrating all such resources on the blanket bombing of German cities.
When the much publicised ‘thousand bomber raids’ were started with the attack on Cologne at the end of May 1942, 100 of Coastal Command’s maritime aircraft were lent to Bomber Command and similar loans took place on later occasions. Yet Bomber Command always strenuously resisted any transfer of any of its aircraft to Coastal Command to increase, even temporarily, the meagre strength allocated to the maritime war.
In December 1942 it was clearly demonstrated by 120 Squadron of Coastal Command, operating twelve to eighteen Liberators out of Northern Ireland and Iceland, at what a great distance air escort could be provided for Atlantic convoys and with what good effect. Thus, as in 1917 and 1918, it was very rare for a merchantmen to be sunk in a convoy which had both sea and air escorts. Moreover, these Liberators, while admirably suited for convoy escort and anti-submarine work, were not particularly successful as night bombers over Germany, being too lightly armed and armoured. Yet it was not until April 1943 that Coastal Command was able to start forming a second Liberator Squadron, and not until the end of May that ten aircraft could be found to be transferred to the Royal Canadian Air Force in Newfoundland which finally and fully closed the ‘air gap’ south of Greenland.
By then the Battle of the Atlantic had nearly been lost. You may recall the Duke of Wellington’s comment to his friend Thomas Creevey the day after the Battle of Waterloo: ‘It has been a damned nice thing - the nearest run thing you ever saw in your life’. The same was true of the Battle of the Atlantic. In March 1943, in all theatres of war, the U-boats sank 108 ships totalling 627 000 tons, and the proportion of these losses suffered by the North Atlantic convoys was so high that the British naval staff later recorded that the enemy then came ‘very near to disrupting communications between the New World and the Old’. It was clear that the Western Approaches Command’s escort strength had to be increased at once, and this could only be done at the expense of the Home Fleet. Accordingly Mr Churchill firmly declared that until a satisfactory balance had been restored in the Atlantic no more convoys could be sent to Russia, and neither the pleadings of President Roosevelt nor the inevitable recriminations from Stalin could budge him from that decision.
These and other measures, notably the operation of five ‘Support Groups’ to reinforce the escorts of convoys under attack or threat of attack by wolf-packs and the inclusion of escort carriers in convoy escorts, soon bore fruit. * In May, sinkings dropped to 50 ships of 265 000 tons and in all theatres 41 U-boats were destroyed. Such a rate of loss was more than Admiral Doenitz could endure. On 22 May he recalled his U-boats from the North Atlantic. He subsequently declared: ‘Wolf-pack operations against convoys in the North Atlantic, the main theatre of operations and at the same time the theatre in which air cover was strongest, were no longer possible ... We had lost the Battle of the Atlantic.’
Captain Stephen Roskill in his work ‘The Navy at War’, published in 1960 provides an apt conclusion: ‘Remembering how black the prospects had appeared only a few weeks earlier, we found it hard to believe that the tables had really been turned so quickly. Perhaps because convoy battles are marked only by latitude and longitude, and have no names that ring in the memory like Matapan, the victory of May 1943, is scarcely remembered. Yet it was in its own way as decisive as the Battle of Britain in the summer of 1940; for never again was the German Navy able seriously to threaten our life-line - let alone come within measurable distance of severing it.’
* This article has concentrated on the part played by the Royal Navy and the Royal Air Force in the Battle of the Atlantic, 1939-1945. Credit must also be given to intelligence successes, prominent among which was ‘the Ultra secret’. This refers to British code-breaking activities which enabled them to read most of the signals sent to and from U-boats for much of the war. While counter-measures had to be carefully controlled to safeguard Ultra, information gained in this way was vital to the successful direction of this battle.
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