BdU-German U-Boat Command and Admiral Doenitz were intending to continue U-Boat offensive with whatever long range submarines left in autumn of 1941. However now things were much harder for them since British Admiralty reading German Naval Enigma messages , learned that two Type IX long range U-boats sailed in last week of September to these waters and they would replenish their saupplies en rouyte from German U-Boat supply shi Kota Pinang which also sailed from Bordeux at the end of September.
British Admiralty alerted to this scheme thaqnks to Enigma decrypts , ordered Force H cruisers HMS Sheffield and HMS Kenya to intercept Kota Pinang and sink her. HMS Kenya found Kota Pinang 700 miles west of Spain on the 4th October and sunk German U-Boat supply ship with gunfire. This was first devestating blow to German U-Boat operations in South Atlantic during fall 1941. As a result only U-124 made a sortie into South Atlantic , off South West Africa and South Afrian shores , sinking 8.100 ton British tanker Darkdale off Saint Helena and two 10.000 ton British freightters off Walvis Bay , South Africa and three lone sailing merchant ships off Freetown , West Africa , before directed by BdU to rendezvous with homebound merchant ship turned to supply ship Atlantis to replenish her supplies
HMS Kenya , Colony Crown class cruiser
Next victim of British Amiralty’s “cleaning” operations of German supply vessels was famous German merchant raider auxiliary cruiser Atlantis which sunk 22 Allied merchant ships over 145.000 tons in high seas since 1939. (she was the most successful of her class) Atlantis was serving as a U-Boat supply ship since 1941 summer and after destruction of Kota Pinang , BdU directed all four long range U-boat in dire need of suppy at South Atlantic to her. As a result , BdU painted a perfect bulls eye on Atlantis. With aid of British Admiralty’s decryption of German naval Enigma messages , Royal Navy decided this troublesome raider once and for all. British heavy cruisers HMS Devonshire , HMS Dorsetshire and HMS Dunedin all sailed independently to intercept Atlantis and another German U-Boat supply vessel (last one) Python , in first week of November.
On 22 November 1941 , Atlantis met with homebound German submarine returning to France to replenish supplies of U-boat. While captain of U-126 and his senior officers were aboard Atlantis for a breakfast (captain of U-126 was actually taking a bath aboard Atlantis before that) , Royal Navy 8 inc heavy cruiser HMS Devonshire appeared on the horizon (her catapult scout plane actually pinpointed location of Atlantis a few hours ago) and opened fire. U-126 quickly cast off from Atlantis and crash dived but there was no hope for Atlantis. Under shellfire from 8 inc guns HMS Devonshire , Atlantis was wrecked and sunk. Most of her 350 man crew was picked up by U-126. Aware that there is a U-Boat in the area HMS Devonshire quickly left off after making sure Atlantis was destroyed.
U-124 then transferred survivors of Atlantis to another (and last) U-Boat supply ship Python on 24th November but reporting these events to BdU command in Kerneval France , Germans unknowingly also revealed the location of Python to British Admiralty thanks to Enigma decrypts. British Admiralty quickly set up another trap.
On 24th November 1941 , Germans struck back and U-124 returning from South African waters intercepted , torpedoed and sunk aging Royal Navy light cruiser HMS Dunedin (she sunk with heavy loss of life) And finally on 1st December 1941 , last German U-Boat supply ship Python was also intercepted by Royal Navy heavy cruiser HMS Dorsetshire at South Atlantic. Python was in process of resupplying U-68 when HMS Dorsetshire opened fire with 8 inc guns. U-68 crash dived while by using her guns HMS Dorsetshire damaged Python heavily which was then scuttled by her crew. After HMS Dorsetshire left the area , survivors of Python was picked up by U-68.
Loss of all remaining supply vessels and chain was a terrible shock to German Navy. Donitz and BdU reluctantly had to abandon all patrols off South Atlantic and off South Africa from now on till 1942 spring when “Milk Cow” type supply submarines became operational.