Coastal command requirements changing controlling over time,and its responses were sometimes routine, sometimes inspired, and sometimes just straight up dumb mistakes. Some of the changes reacted to changing technologies, weaponary, threats operational areas. It is very difficult to succinctly describe in a few words the challenges the command faced.. But the fall of Western Europe and Norway along with the steadily increasing range capabilities of the uboat Arm resulted in a vastly increased zone of conflict for CC to cover. The potential conflict zone stretched from North Cape to Bay of Biscay. The entry of Italy extended CCs responsibilities even further
CC failed to keep pace with its expanded responsibilities. In June 1940, there were about 200 aircraft operational under the control of CC, nostly hudsons and Ansons. There were three squadrons of hudsons, some blenheims, and 4 understrengt squadrons of Sunderlands as well as about the same number of hudsons . There were some coastal squadrons of Stranaer flying boats, I think there were three squadrons of Saro London Flying Boats and Vilderbeetes both types had proven disappointing in service for various reasons. .
The Anson and Hudson were expected to act as interim solutions. The Anson in particular had limited range and did not possess the capacity to carry heavy weaponry needed to sink a submarine.
Towards the autumn of 1941, U-boats began operating further into the Atlantic. Coastal Command's requirement programme was 150 Catalinas and 76 Sunderlands for 26 flying-boat units; 32 Liberators and 32 Wellingtons or Whitleys to equip four long-range GR squadrons; 64 Mosquitoes and 180 GR Hudsons for 15 medium to long-range units; 128 Beauforts for eight torpedo-bomber squadrons; and 160 Beaufighters for 10 long-range fighter squadrons. However, four flying-boats and two GR short-range squadrons were to be sent to West Africa, and another three flying-boat squadrons were for Gibraltar. Operational strengths were at no time anywhere near projected requirements and resistance to pouring more resources into the command were voracious and frankly hysterical..
By December 1941 operational requirements necessitated aircraft with an extra-long-range of 2,000 miles as U-boats were operating 700 miles from the British Isles. If patrols were deployed 350–600 miles covering port approaches, the enemy would move to the 600–700 mile area and out of range. By then ASV (air-to-surface-vessel) radar homing had been developed, and aircraft were being developed with all-weather and short-take off capabilities. Priority went to Coastal Command ASW, units by this time.
In January 1942 it was decided (on very questionable grounds), that the limit of long-range aircraft endurance should be the crew's limits, (due to extreme aircrew fatigue seriously effecting efficiency) not the fuel supply of the aircraft. De la Ferté decided, on 7 January, sorties should not exceed 14 hours, which reduced flying hours by four per mission. This was despite the entry of the very long-range Liberators in June 1941. The Liberator I had a stated Air Ministry range of 2,720 miles, but crew endurance methods now meant it would be airborne for just 2,240. De la Ferté wrote to the Ministry arguing the Liberator should be used for reconnaissance work, rather than bomb load for the solitary squadron being accepted at that time. The Liberator would assist in closing the 'Mid-Atlantic Gap' which U-boats could operate in without worrying about air interdiction. After replacing Bowhill in 1941, de la Ferté had issued a directive on 12 June 1941 to use Wellingtons and Whitleys as an interim solution to unrestricted submarine warfare now practised by the Germans. Their uneconomical operational cost meant immediate replacement of these medium-range machines was pressing. Some Lancasters and Halifaxes were temporarily seconded from Bomber Command for this purpose, again only after the most shrill and quite irrational arguments were mounted about their deployment.
The Lancaster was denied as a large-scale or long-term replacement. The Chief of the Air Staff, Portal, argued it was the only aircraft capable of carrying an 8,000 lb bomb to Berlin and could not be spared. As a result, the RAF official history does not include the Lancaster as a Coastal Command aircraft. With a range of 2,350 miles it could have been invaluable. The American made Fotress was given to the service only because the Air Ministry considered it unfit as a heavy bomber. It issued a directive on 27 January 1942 stating all Fortresses were to given over to Coastal Command for A/S operations. Numbers 59 206 and 220 sqns all used the Fortress as successful reconnaissance aircraft. However, the bulk of the force by early 1942 was still medium-range aircraft, which could now reach only 600 miles into the Atlantic. U-boats were now operating at 700 miles plus.
De la Ferté pushed his case hard to Portal to get the resources needed for the spring, 1942. Portal had accepted that production of Sunderlands was "disappointing" and it had only just met wastage of the existing five squadrons. Portal also admitted a complete "lack of interest on the part of all concerned". Portal insisted he would emphasis the Command's case. But by February 1942, the expected rate of new Catalina aircraft, which the command expected at a rate of three per week, with a final six to complete a batch of 30 before May, were offset by the move of three Catalina squadrons overseas (No. 209, 240 and 413 squadrons).
The situation continued in the same way throughout 1942. By March, the few suitable aircraft in operational service were not serviceable most of the time. By 15 January 1942, de la Ferté knew just one-fifth of his aircraft were operational. The situation slowly improved throughout the year despite mounting convoy losses and voracious resistance from Bomber Command. It has to be said this dogged continued resistance contributed to the tangible possibility of the allies being forced to the surrender table. That and Admiral Kings stupidity made losing a real possibility. By the time Slessor succeeded de la Ferté as AOC-in-C, he identified the need for 60 squadrons with a total of 850 aircraft, of which 34 were A/S squadrons, operating 450 machines. Slessor felt the Catalina was too vulnerable to U-boat flak 9by then more or less standard) and the "prima donnas", namely the Liberator with its long range, were not available in sufficient numbers. On 18 June 1942 the War Cabinet was told that Coastal Command had only 39 Liberators. When it became obvious that the losses to U-boats were becoming unacceptable in March 1943, Coastal Command was finally given sufficient resources it needed. In the latter part of the war it operational responsibilities were again altered, or re-emphasises to include more offensive actions against the DKM convoys operating off the Norwegian coast (mostly)