Coastal Command Requirements

‘Caught on the Surface’.  The sinking of U-461 by RAAF Sunderland “U” of 461 Squadron RAAF, in the Bay of Biscay in July 1943.  [As depicted by aviation artist Robert Taylor.]


At the outbreak of war in September 1939 Air Marshal Sir Frederick Bowhill, the Air Officer-in-Chief of Coastal Command, had forces of ten Anson squadrons, including four Auxiliaries, one Hudson squadron, and two strike squadrons of Vildebeests. The flying-boat units were two squadrons of Sunderlands, three with Saro Londons, and one equipped with Supermarine Stranraers. The Vildebeest strike-aircraft and the London and Stranraer flying-boats were all obsolescent.

The Ansons represented the equipment for more than half his total force, but with insufficient range to undertake the reconnaissance required, and four out of the six flying-boat squadrons were equipped with obsolescent aircraft. Sir Frederick was thus left with just three squadrons with modern aircraft, namely Hudsons and Sunderlands, that were considered able to operate effectively.

In the early months of 1939 supplies of engines for the Avro Anson aircraft were limited, and there was a need to restrict the flying of Ansons on that account. It was necessary also to conserve even the outdated Vildebeests, as there were only six in store to supply both home and abroad. At that time the Command had ten Stranraers, seventeen Londons, four Short Singapore flying-boats, and two Sunderlands. Deliveries of the latter to the Command were given as only two per month.

The Director of Organisation at the Air Ministry, then Charles Portal, following the Munich crisis, foresaw what was to be a problem in respect of the availability of aircraft throughout the war. That was that aircraft could be weather-bound for days at various places round the coast. Coastal Command was required to operate throughout the twenty-four hours, and to do that bases were required for both take-off and landing with some degree of safety. This applied particularly to flying-boats. The new twin-engined flying-boat, the Saro Lerwick, had not been expected to be delivered before April 1939, and therefore was unlikely to be operational before the end of the year, but then it was to be found unsuitable for operations.

There was a need, therefore, for land-based aircraft to cover the South-Western Approaches, and significantly, in the same memo of 25 October 1938, Portal refers to having Newquay (St Eval) laid out to take two squadrons.

Between December 1939 and August 1940 the following reinforcements were received by Coastal Command: No. 10 Squadron RAAF Sunderlands in December 1939, four Blenheim squadrons on loan from Fighter Command in February 1940 (Nos 235, 236, 248 and 254); in June 1940 Nos 53 and 59 Squadrons with Blenheims on loan from Bomber Command, and in August 1940, No. 98 Squadron’s Fairey Battles, also on loan from Bomber Command, the latter to be based in Iceland.

These additions had followed an agreement by the Air Ministry with the Admiralty for Coastal Command to have an additional fifteen squadrons by June 1941. By 15 June, that had only been achieved by the loan of seven squadrons from other Commands, with aircraft unsuited to the maritime role, and with a daily average availability of 298 aircraft.

Just a month later, the Command had 612 aircraft with thirty-nine squadrons, but by then it was estimated that future requirements would be sixty-three and a half squadrons with 838 aircraft. The 612 aircraft then available included eleven types, and that would have produced problems in training for aircrew when they converted to a different type of aircraft. At Air Chief Marshal Sir Philip Joubert de la Ferté’s first staff meeting on 30 June as Air Officer Commanding-in-Chief Coastal Command, the number of aircraft available was not stated, but rather that there were only four strike squadrons.

By 1 December 1941 reconnaissance aircraft available to Coastal Command included eighteen Catalina flying-boats, nine Sunderlands, twenty Whitleys and 170 Hudsons. The Command’s strike aircraft comprised sixty Beaufort torpedo-bombers, twenty Beaufort bombers and forty Beaufighters. Additionally, Coastal had sixty of the Blenheim fighter version. The total of 397 aircraft was available to equip eighteen squadrons.

The total number of aircraft available to Coastal Command in June 1942 was 496, and would have included aircraft of four squadrons on loan from Bomber Command, but for Sir Philip, there was a shortage of three landplane squadrons, and ten flying-boat squadrons; and in his report to the Air Ministry he added: ‘I therefore cannot accept your view that we are comparatively well off, nor do I feel that we have sufficient strength to carry out our job.’

Although, in November 1942, Coastal had 259 Hudsons, Sir Philip was concerned about their availability, due to ten squadrons plus other units still operating them, and stated that with the ‘present Hudson commitment … continuance of the present numbers of squadrons is impossible’.

Sir Philip was still concerned about the two types from Bomber Command, such as the Whitley, ‘… on the whole, given unsatisfactory service’ and the Hampden, which was ‘incapable of operating in daylight … off the enemy coast … without a very strong escort of long-range fighters’.

There were no Beaufort-equipped squadrons left with Coastal Command (they were posted overseas), and no trained Beaufighter squadron, and it was known that German Fw190 fighters were 50 mph faster than the Beaufighter, which was therefore hardly suitable as escort to the Hampdens even if available.26 De Havilland Mosquitoes had been made available for Photo-Reconnaissance in 1942, but for the Mosquito Mark VI fighter-bomber priority was given to Fighter Command.

When Air Marshal John Slessor assumed command of Coastal Command in February 1943, the strength was sixty squadrons with ‘some 850 aircraft’. Although he appeared largely content with the aircraft available to him, in respect of both quantity and quality, he wrote to the Air Ministry in September stating, ‘I now find that there are 120 first line Mosquitoes going into photo-reconnaissance in this country, and over 200 first line Mosquitoes going to the Army support in the Tactical Air Force’.

Thus, despite the need for reconnaissance, priority was given to the TAF. He refers, however, to the ‘unforeseen requirement for modification of certain four-engined types to Very Long Range [VLR]’ coinciding with the introduction of a system of ‘planned flying and maintenance … in what was a “difficult period of availability”’.

Air Chief Marshal Sir Sholto Douglas succeeded Air Marshal Slessor in January 1944, when, in respect of numbers of aircraft, equilibrium had obviously been reached. The Command’s records written during his tenure refer to equipment of aircraft such as ASV, and modifications to aircraft rather than the need for more aircraft. Forces for Sholto Douglas included (again, as was the case for Slessor) 430 aircraft for anti-submarine operations.

The 430 aircraft, however, were the equipment for ten squadrons of Liberators, including three of the United States Navy; five Leigh-Light Wellington squadrons, and two squadrons each equipped with Halifaxes, Hudsons and Fortresses. There were also seven Sunderland and two Catalina squadrons. The heavy four-engined aircraft that Sir Sholto then had available did, however, raise another requirement–the need for runways of sufficient length to take such as the Liberator, Fortress and Halifax.

Thus, on 7 February 1944, the Air Ministry was asked to approve the lengthening of the runways at Brawdy, Chivenor, Aldergrove and Leuchars. Although Sholto Douglas expressed no need for more aircraft, he referred to the ‘Bomber Baron’s decision finding the Liberator unsuitable for night operations’, such that Coastal Command’s near starvation came to an end’. He added, ‘By the time that I became C-in-C of Coastal we were using twelve squadrons of them.’

However, by 27 April the Command was obviously preparing for Operation Overlord–the invasion of Europe, and a signal was sent to No. 19 Group regarding the necessity for ‘reducing wastage to conserve aircraft for forthcoming operations’. Specifically mentioned were Mosquitoes and Liberators.

In November the re-equipment of Halifax squadrons with Liberators was again mooted, although these were all bombers that had to be modified for Coastal Command.

In 1945 the Air Ministry agreed to thirty Mark V Sunderlands (those with Pratt & Whitney Wasp engines), which had been intended for overseas service, to be allocated to Coastal Command. This was in sharp contrast to Sir Philip Joubert’s experience three years earlier, when he was losing both aircraft and crews to overseas. During Sir Sholto’s final meetings, a whole spectrum of aircraft types had to be considered. Thus, during the 4 May meeting he asked the Senior Air Staff Officer to find from the Air Ministry what the Command’s commitments might be for modifying fifty Gloster Meteor jet aircraft for photo-reconnaissance, and those required for the Supermarine Sea Otter.


Until the outbreak of the Second World War the number of aircraft considered necessary for Coastal Command to provide trade protection in Home Waters was 281. This number assumed a war by Britain alone against Germany. The prime duty was then to cover the exits from the North Sea.

The capitulation of France, the over-running of the Low Countries and the occupation of Norway and Denmark resulted in a vast coastline from the French Biscay ports to North Cape to be covered. The entry of Italy into the war in addition to a possible hostile French fleet made further demands on Coastal Command. Thus, in addition to covering the North Sea exits, three additional flying-boat squadrons were considered to be immediate requirements to cover the Irish Sea, Faeroes areas, and Western Approaches, plus an additional general reconnaissance landplane squadron and two long-range fighter squadrons–say, another 100 aircraft.

For overseas, an additional five flying-boat squadrons and one landplane squadron were specified; thus, for additional home and overseas commitments, possibly 200 aircraft above the 281 already stated were needed. This assumed that other forces would cover the Caribbean and Newfoundland areas. In December 1939, however, the Command was concerned with close escort of coastal convoys and the chain of patrols to the Norwegian coast.

For those duties reference was made specifically to two types of aircraft, the Avro Anson and the Lockheed Hudson, the reconnaissance landplanes then available. With those two types, a total of 273 aircraft was anticipated, following an agreement to increase the requirements of each squadron to twenty-one aircraft. Other landplanes for reconnaissance then being considered about that time were the Blackburn Botha, the Bristol Blenheim and Bristol Beaufort, with the comments that the Botha was ‘specially designed for reconnaissance’, but that the Blenheim was ‘adversely reported’. It was hoped that twenty Bothas would be delivered to the Command by the end of 1939, and twelve Beauforts were expected in October/November.

The Bothas, however, were found unsuitable for operations, and no more of the Mark IV Blenheims were being allocated to Coastal Command.

In October 1941 the Prime Minister became aware of U-boats operating further afield, and suggested to the First Lord of the Admiralty that it was probably due to our air operations. Following this, Coastal Command’s requirement programme was considered to be 150 Catalinas and seventy-two Sunderlands for twenty-six flying-boat squadrons; thirty-two Liberators and thirty-two Wellingtons or Whitleys to equip four long-range GR squadrons; sixty-four Mosquitoes and 180 GR Hudsons for fifteen and a half medium- and short-range squadrons; 128 Beauforts for eight torpedo-bomber squadrons; and 160 Beaufighters for ten long-range fighter squadrons. However, four flying-boat and two GR short-range squadrons were to be earmarked for West Africa, and three flying-boat squadrons for Gibraltar.

By December 1941 the types of aircraft required were stated as a long-range flying-boat, a long-range landplane, a medium-range landplane, a high-speed reconnaissance landplane, a long-range fighter, and a torpedo- bomber. Changes had been made to requirements following the previous three months’ experience and an analysis of U-boat attacks. At that time it was considered that extra-long-range aircraft should have a range of 2,000 miles because some U-boat attacks had been 700 miles from British bases, and if air patrols were deployed 350–600 miles, the enemy would move to the 600–700-mile area (600 miles from a United Kingdom base would be up to 20’E 15’W; from Iceland, up to 40’E 12’W).

Reconnaissance aircraft were then expected to have ASV (Aircraft-to-Surface Vessel) radar for homing; long-range planes were to be able to operate in all weathers and have a short take-off and landing distance. For high-speed reconnaissance aircraft the Air Ministry suggested the Mosquito, but other services were given priority in their supply.

Three types were suggested to undertake the task of a torpedo bomber: the Handley-Page Hampden, the Bristol Beaufort and the Vickers Wellington III.

All three were to operate as such, despite the lack of forward armament in the Hampden and Beaufort, and the Wellington and Hampden had not been designed for maritime work.

In early 1942 the functions of the Command’s operational aircraft were clearly stated in six categories. Anti-submarine warfare was first in order of importance, covering reconnaissance, depth-charging and bombing. Second and fifth were torpedo warfare (reconnaissance and the attack on large merchant vessels and enemy naval forces) and anti-shipping warfare (reconnaissance and bombing). Third, fourth and sixth in order of importance were photo-reconnaissance, meteorological reconnaissance and coastal fighter warfare.

Coastal fighter and anti-shipping warfare were rated former RAF peacetime functions; anti-submarine warfare had become a highly specialised category, as also torpedo warfare. Little consideration had been given to the latter, as it was ‘uneconomical to have torpedo squadrons locked up for a target which may never materialise so may find ourselves making more use of the GR/TB squadrons for GR work’, as was the case with Beauforts.

At the time of Air Marshal John Slessor assuming command of Coastal in February 1943, the trend (which is reflected in the Command’s records) was concerned about the equipment then being added to aircraft, rather than the aircraft itself. This was resulting in an effect on the aircraft’s range due to the additional loads–a matter of concern throughout the war. Slessor addressed this matter in a letter to all his Group’s headquarters in May 1943.


Range of aircraft for a given design is affected by many factors, such as the all-up weight, the quantity of fuel carried and the type of engine(s). When airborne, other factors include the height at which the aircraft is flown (this because the engines would be designed for an optimum height for greatest efficiency).

Other factors for Coastal Command’s aircrew to consider were whether they should deploy side guns in, for example, Wellingtons or Hudsons; and in the case of the Sunderland flying-boats, whether they should run out their depth charges onto the wings from the bomb-bay.

These were continuing tactical problems in addition to the reduction of speed and range. All four of Coastal Command’s Air Officers Commanding-in-Chief show their awareness of the importance of range for aircraft in the Second World War–notably Sir Philip Joubert –who imposed a limit on the endurance for crews of eighteen hours; and even that figure was to be under exceptional circumstances. At RAF Waddington in April 1998, it was understood that the endurance of aircrew is still the deciding factor in maritime operations, albeit due to toilet facilities.

Although given as having an endurance of 5½ hours at 103 knots, the Anson represented the operational equipment for Coastal Command’s land-based reconnaissance squadrons at the outbreak of war, excluding No. 224, which had just rearmed with Hudsons. The Anson’s lack of range precluded it being effectively used, even for the Command’s prime task on the outset of war, reconnaissance from Britain to Norway. As Capt T. Dorling, RN, stated: ‘Ansons were unable to reach Norway and blockade the North Sea. Only flying-boats and Hudson squadrons were able to do so.’

The Air Ministry, when writing to the C-inC of Coastal Command in September 1941, stated that a limit should not be set on the range of reconnaissance aircraft, but that the matter would be pursued with the Admiralty with a view to limiting the maximum operating distance from base of 600 miles, as convoy escorts beyond that would be uneconomical. Range was necessary to cover, in particular, convoy routes, notably out into the North Atlantic as far as the ‘prudent limit of endurance’, or ‘PLE’.

If on a ‘sweep’, that would have sufficed; but if a convoy was to be escorted, say, at 12°W, it was essential also to have some hours in that area circling the convoy; endurance was therefore also required. Opinions vary in what was considered a useful time with a convoy, but typically two to three hours. In a letter dated 28 July 1941, however, from Air Commodore Lloyd, the Deputy SASO, it was recommended that at least one-third of sorties should be with the convoy.

In Coastal Command, it was decided that the limit of long-range aircraft should be the endurance of the crew rather than the fuel supply. This was decided at a Command meeting on 7 January 1942, when Catalinas were considered able to have a radius of 600 nautical miles, ‘on the fringe of the U-boat area’, with a sortie of eighteen hours’ duration.

Sir Philip Joubert decided that routine patrols should not exceed fourteen hours, but in cases of emergency could be extended up to eighteen hours due to ‘conditions of cold and cramp in which the crews are called upon to operate, and the need for sparing their endurance and not stretching it to the limit unless an emergency arises’.

As an economy measure in Coastal Command’s use of Catalinas in respect of long-range work, it was suggested by the Deputy Senior Air Staff Officer (D/SASO) that Sunderlands could be used for sorties between 250 and 440 nautical miles along convoy routes. It is not clear, however, if that idea was followed.

Range was considered so important that the question of Liberators with or without self-sealing fuel tanks was raised, as without them there would be a reduction of unladen weight but an increase in fuel capacity. In January 1942, however, the Mark I Liberator’s maximum range is stated as 2,720 miles, but with the crew’s endurance limiting it to 2,240 miles.

When the Liberator was just coming into service with Coastal in June 1941 for antisubmarine warfare, the C-in-C wrote to the Air Ministry:

For duties of this nature, which involve flying for long periods by day and night, out of sight of land in all conditions of weather, the Long Range bombers do not provide the same amenities and freedom of movement to the crew as a flying-boat. The Liberator, which is being provided for one squadron, meets these requirements to a greater extent than any existing British bomber ….

He added, however, that more attention should be given to their layout for reconnaissance rather than bomb load.

The long range of 2,240 miles enabled the Liberator in Coastal Command to help close the ‘Mid-Atlantic Gap’ south of Cape Farewell with such as a shuttle service between Newfoundland and Iceland.

Sir Philip Joubert stated that his first problem when he succeeded Sir Frederick Bowhill in 1941 was ‘the need to fill the Gap’, and here the only land-based aircraft that could do the job was the American B24, the Liberator. The C-in-C Coastal Command in a review of the Command’s expansion and re-equipment programme dated 12 June 1941 wrote: ‘The extension of unrestricted U-boat warfare against shipping in the Atlantic to areas outside the range of MR [medium-range] aircraft has necessitated the use of LR


bombers such as the Whitley and Wellington as anti-submarine aircraft.’

The twin-engined medium bombers that came from Bomber Command, the Wellington 1C and Whitley V, were both serving in Coastal by late 1940. Although they helped to fill a gap in the Command’s general reconnaissance requirements, Air Commodore I.T. Lloyd, the D/SASO, wrote to the C-in-C Coastal Command on 28 July 1941: ‘Whitleys and Wellingtons are uneconomical at their speed and with only nine-hour sorties; we require a replacement for these types to give range up to 600 miles … or at least 440 miles.’

Four-engined bombers that were loaned or allocated to Coastal Command included the British Handley-Page Halifax and the Avro Lancaster, but the Halifax when used for meteorological flights was provided with drop tanks to increase the range.

By 30 November 1944 Coastal Command was due to receive Pathfinder-type Mk III Halifaxes from Bomber Command’s production, but it was considered necessary for the first one to be examined and modified at Gosport to bring it up to the Command’s standard. When No. 502 Squadron was due to re-equip with Halifaxes they were to be fitted with long-range tanks, compensated, apparently, in respect of all-up weight, by having the front turret removed.

This was despite the fact that when considering the provision of Halifaxes for No. 58 Squadron, it was stated that for operations in the Bay of Biscay front turrets were needed, largely against enemy fighters.

These essentially bomber aircraft were nevertheless operated by Coastal Command in anti-submarine warfare, and for meteorological flights and anti-shipping sorties. The Avro Lancaster, another four-engined bomber, was only on brief loan to Coastal Command during the war, and does not feature in the RAF’s official history as a Coastal Command aircraft. With a range of 2,350 miles it could have been invaluable, but the Chief of Air Staff was strongly opposed to Lancasters being transferred to Coastal Command, as it was the only aircraft able to take an 8,000 lb bomb to Berlin.

The American-built B17 Flying Fortress was rated a long-range aircraft, but was selected for Coastal Command because it was considered unfit for Bomber Command’s night operations. The Fortress served as a useful reconnaissance aircraft with such as Nos 59, 206 and 220 Squadrons; fortunately it was not required by Bomber Command, and it was reported on 27 January 1942 that all Fortress aircraft from America would go to Coastal Command.

The C-in-C Coastal Command, Air Chief Marshal Sir Philip Joubert, wrote to the Air Ministry on 7 January 1942 of his concern that his long-range aircraft, ‘except the Liberator, fall far short of Coastal Command’s needs … when U-boat attacks on shipping were about 700 miles westwards with Catalinas at 600 miles only on the fringe of the U-boats’ area’. In that same letter, Sir Philip referred to the medium-range Hudson as a ‘stop gap’ with the Ventura [a development of the Hudson] of lesser range; that a medium-range aircraft should have a range of 1,200 nautical miles, while the Wellington and Whitley ‘more nearly meet requirements’. The Air Ministry’s ultimate response was in a letter dated 7 March 1942, which stated:

It would be uneconomical to divert a successful heavy bomber type to a Coastal Command role particularly if … a less successful type of heavy bomber is available … the Fortress … is unfit for night bomber operations and weather conditions strictly limit its employment … in high altitude bombing … for these reasons it was selected for … Coastal Command.

The Air Ministry did show some appreciation of Coastal Command’s requirements, but indicated the priority given to Bomber Command with:

We should hamper the normal evolution of GR [general reconnaissance] aircraft by setting a limit to their range. It is now apparent that our requirements for heavy bomber types are unlikely to be realised in full for a very long time. It will therefore be impracticable to provide many squadrons equipped with this type for general reconnaissance work. Consequently this role will have to be fulfilled by normal GR landplanes for some time to come.

The Air Ministry added that the matter would be pursued with the Admiralty, with Coastal Command aircraft limited to a radius of 600 miles; greater distances ‘should be the responsibility of surface forces’.

At Sir Philip Joubert’s fifth staff meeting, photo-reconnaissance aircraft were said to be Coastal’s ‘weak point’, and he stated, ‘We must have long-range Spitfires.’ For both the Beaufighter, and later the Mosquito, attempts were made to increase their endurance and range by the addition of drop tanks. For the Mosquito, modifications are recorded from November 1941 until towards the end of the war.


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