At the Symbol Conference in Casablanca between January 14–24, 1943, with both Churchill and Roosevelt present, it was decided that the absolute first priority of the Allies was defeating the German U-Boats in the Battle of the Atlantic. But if it was the first priority, not many commanders seemed to pay any attention since they didn’t change allocations of men and material and ships and planes very quickly. All of this took time, I know. Immense forces were involved and just because a conference had been held and FDR and Churchill had agreed on something, it took the Allied military secretariat known as COSSAC, (Combined Chiefs of Staff), with its headquarters in Washington, to translate strategic decisions into specific orders for specific commands.
It wasn’t that the Allies lacked the equipment. It was prying it away from the different services and different commands. Sir Max Horton, Commander in Chief, Western Approaches, the largest operational command in the Royal Navy which was responsible for escorting North Atlantic convoys, repeatedly asked the Admiralty and the War Cabinet for some of the larger and newer destroyers assigned to the Home Fleet. Occasionally the fleet loaned him a few but not often. This could have changed with one order. Home Fleet had a lot of destroyers. And they spent a fair amount of time in port since Home Fleet was the last line of defense for Great Britain and it didn’t put to sea unless there was a specific reason, such as the breakout of the Bismarck. But Home Fleet didn’t like to let them go. This resulted in North Atlantic escorts often spending less than a day or two in port before being turned around and sent back out no matter if all their equipment was working or not. And usually it was not because of the storm damage caused to the ships in the Winter North Atlantic.
But it wasn’t just the Royal Navy which held back equipment from the U-Boat war. The US Navy had a large number of the specially built Very Long Range (VLR) four engine Liberator patrol bombers because of the extremely long distances planes had to fly in the Pacific Theater where the US Navy was primarily engaged. Yet statistics at that time showed that very few merchant ships were sunk in convoys with continuous air cover. But prying some of these VLR Liberators away from Ernie King finally took a direct order from Roosevelt at the Quadrant Conference in Quebec between August 17–24, 1943. Once these aircraft were made available, the “air gap” in the Atlantic was closed and German U-Boats no longer had any respite.
It is also worth noting that neither RAF Bomber Command under Arthur Harris or the USAAF Bomber under Hap Arnold, showed any interest in providing long range aircraft to either Western Approaches Command (although technically air units would actually be under 15 Group RAF Coastal Command) or US Navy 10th Fleet which was an administrative command coordinating all US anti-submarine efforts outside the Pacific theater.
There is no reason this did not happen excepting sheer inter-service rivalry and intense rivalry between commands in the same services. The very sad result of this squabbling was the needless deaths of thousands of men.