Liveblogging World War II: March 15, 1943
Convoy UGS 6 came under attack by wolf packs Unverzagt, Wohlgemut, and Tummler…. U-524 torpedoed the freighter Wyoming on 15 March 1943…
B-Dienst had given notice of an east-bound convoy and by 8pm on the 13th had a location for SC122; Grand Admiral Karl Dönitz directed Raubgraf to intercept, forming a new rake to the west. However a westerly gale gave speed to SC122, which passed through Raubgrafs patrol area on the morning of the 15th just 24 hours before the patrol line was formed. The Enigma intelligence which had helped the Admiralty to divert convoys away from wolf packs, had been "blinded" on March 10, 1943 by the result of the Germans bringing in a new short weather report. This resulted in the English codebreakers being starved of the cribs necessary to break "Shark". The Admiralty OIC U-Boat tracking room was therefore unable to divert convoys around the U-Boat packs. Fortunately a message from a U-Boat gave away its position once that position had been fixed by DF and the convoy SC122 was diverted around the estimated danger area. The Allied Cipher Number 3 used by the convoy escorts had been broken by the Germans. This allowed them to position wolfpacks in the way of HX229, which was following a similar course.
HX 228 was an east bound convoy of 60 ships, plus local contingents, which sailed from New York on 28 February 1943 bound for Liverpool and carrying war materials. Mid-Ocean Escort Force group B3 joined the convoy from St Johns… led by Cdr AA Tait of HMS Harvester…. Arrayed against them in the North Atlantic were patrol lines, Wildfang, Burggraf and Neuland, although in the event only a re-configured Neuland, comprising 13 U-boats, engaged HX 228…. HX 228 arrived safely at Liverpool on 15 March 1943…. HX 228 cannot be seen as a victory for either side; HX 228 had lost 4 ships and a warship, with the loss also of Cdr Tait, an effective and well-respected Escort Group commander; while Neuland had lost 2 boats, a potentially ruinous rate of exchange.
The Battle of the Atlantic was won by the Allies in two months. There was no single reason for this, but what had changed was a sudden convergence of technologies, combined with an increase in Allied resources…. [A]ir cover was provided by the introduction of merchant aircraft carriers or MAC ships and later the growing numbers of American-built escort carriers. Flying primarily Grumman F4F/FM Wildcats and Grumman TBF/TBM Avengers, they sailed with the convoys and provided much needed air cover and patrols all the way across the Atlantic.
Larger numbers of escorts became available, both as a result of American building programmes and the release of escorts committed to the North African landings during November and December 1942. In particular, destroyer escorts (similar British ships were known as frigates) were designed, which could be built more economically than expensive fleet destroyers and were more seaworthy than corvettes. There would not only be sufficient numbers of escorts to securely protect convoys, they could also form hunter-killer groups (often centred around escort carriers) to aggressively hunt U-boats.
By spring 1943, the British had developed an effective sea-scanning radar small enough to be carried in patrol aircraft armed with airborne depth charges. Centimetric radar greatly improved interception and was undetectable by Metox…
