(Group Polar Bear) was a force of German U-boats that operated from 23 August 1942 in the South Atlantic during the Second World War. The group was to operate off Cape Town, which was considered to be vulnerable. Some of the most experienced U-boat commanders including Harald Gelhaus, Werner Hartenstein and Carl Emmermann participated in the operation.
During the voyage south, the group temporarily was diverted to attack Convoy SL 119 that had been attacked by . sank (5,941 GRT) on 27 August and sank the liner on 12 September, which began the Laconia Incident. U-156 was replaced in by and the group was redirected to the waters around South Africa.
The Allies were preoccupied with Operation Torch and the campaign in north-west Africa, giving priority to the protection of troop convoys that left the Allied navies with few escort vessels to reinforce the South Atlantic Station. Merchant ships were sent to Durban instead of Cape Town and routed far to the south, across the South Atlantic to South America, thence to sail up the east coast, crossing the Atlantic from the US to Britain.
sank 23 ships (155,335 GRT) off Cape Town and Durban along and eleven ships (60,829 GRT) in transit, for the loss of . The 34 ships sunk (216,164 GRT) averaged 8.5 ships (54,041 GRT) per boat, one of the most successful U-boat operations of the war. The U-cruisers sank 27 ships of 161,407 GRT, an average of 6.75 ships per U-boat (40,350 GRT). Ammiraglio Cagni sank one ship making 28 ships and 163,400 GRT. About 2,690 crew, passengers, Italian internees and military personnel on the ships were killed.
Background
From mid-July 1942, to tie down Allied convoy escorts and to sink more ships in distant waters, four to six U-boats and a U-tanker operated in the middle-Atlantic, west of Freetown in Sierra Leone. On 7 August, a U-boat was allowed freedom of manoeuvre to commit reprisals against Brazil for its support of the Allied naval war, despite its neutral status but this gave Brazil a pretext to declare war on 28 August. As in 1941, an extension of operations to the South Atlantic was planned by the Naval War Staff (, SKL) for the summer of 1942, to exert strategic pressure.
The sudden appearance of a U-boat group off South Africa was to inhibit the transport of Allied reinforcements to the Middle East and interrupt trade with India. To deny the Allies time for counter-measures, SKL wanted to conceal the voyage of the boats to the south for as long as possible. The U-boat commanders received orders to avoid contact with all merchant ships south of the Equator and only to attack valuable targets such as big warships.
Rear-Admiral () Karl Dönitz the commander, U-boats ( BdU) disagreed with SKL because the strategic pressure that could be exerted was insufficient justification for a long-range operation. Dönitz wanted priority to remain with the tonnage war, with sinkings as the measure of success. The southern voyage of the boat should be used offensively, as far as 15° South. SKL, basing its strategic calculations on the widening war, refuse to relent until 6 September, when received freedom of action against merchant shipping as far as 5° South.
At a review of naval operations in September 1942, Dönitz described to Hitler the declining prospects for U-boat operations off the east coast of the US, due to the introduction of convoys and increased air reconnaissance. The U-boats were to return to the North Atlantic, the coast of West Africa and to Cape Town in the South Atlantic. In 1941 the Germans had attempted to attack ships around South Africa but were defeated by the interception of German U-boat supply ships. For operations in 1942, Dönitz had available long-range Type IX submarines and supply boats to substitute for commerce raiders used earlier in the war. In mid-August the four Type IXC U-boats of had sailed from France, followed at intervals by a second wave of four of the new and larger Type IXD2 submarines.
German plan
Dönitz and the commanders due to operate in intended that around 5 October 1942, (Karl-Friedrich Merten) and (Carl Emmermann) would conduct a reconnaissance of Table Bay near Cape Town, getting past the minefield sown by the German commerce raider Doggerbank () earlier in the year and the defensive minefields laid by the British, using captured charts. In the early hours of 8 October, during the new moon, an attack on the expected 50 ships anchored there would be made. Outside the bay, , and would lie in ambush for fleeing ships. The boats might then raid the Indian Ocean, depending on circumstances.
Royal Navy Submarine Tracking Room At the tracking room at the Admiralty, Commander Rodger Winn, kept watch over the deployment of U-boats and on 2 August, before the departure of the four Type IXC U-boats of , Winn speculated that the U-boats off Freetown and a possible move to Ascension Island might foreshadow a move further south. Winn thought that the departure of and its Milch Cow support boat, was for operations in far waters; Winn guessed that they were bound for the waters off South Africa. The departure of in mid-August and the sailing at intervals of four of the new and larger U-cruisers of the Type IXD2 class from 21 September, bore out Winn's analysis when was sunk on 12 September and U-156 began signalling for assistance on the international frequency. Survivors rescued by U-boats were transferred to Vichy rescue ships; Winn thought that the attack on Laconia was not conclusive but on 21 September, he warned the Commander-in-Chief South Atlantic, that the arrival of U-boats in the south 'seemed imminent'. On 28 September Winn reported that the whereabouts of the U-boats was unknown but that two fishermen had reported seeing the landing of men from a U-boat about north of Cape Town.
In early October, in a blunder by the censor, German news reported that U-boats were operating in the Far East. On 5 October, Winn reported that by mid-October, U-boats might operate in the Mozambique Channel and two days later a ship was sunk off Cape Town. The Admiralty and the Commander-in-Chief South Atlantic had reduced the shipping at Cape Town by making Durban, on the east coast, the last stop for ships bound for Britain from the Indian Ocean. For the duration of Operation Torch (8–12 November), ships were routed far to the south of Cape Town and then north-west to Brazil, Trinidad and the US, to join convoys across the north Atlantic. Unknown to the British, was not going to operate as a (pack) in the South Atlantic but to disperse after the raid on Table Bay.
South Atlantic Station In late 1942, the demands of Operation Torch, especially the duration of the campaign in Algeria and Tunisia, that ended in May 1943 and required more supplies from more convoys, stretched the Allied escort effort. The west Africa–south Africa–east Africa route continued without convoy for much longer; ships were sent on devious courses to evade U-boats but they had eventually to cross the South Atlantic. The naval forces of the Commander-in-Chief, South Atlantic (Vice-Admiral Sir Campbell Tait) were not adequate for an anti-U-boat campaign. Four destroyers and a few corvettes were based at Cape Town on loan from the Eastern Fleet based at Mombasa. There were not enough escorts or aircraft to convoy ships on the Cape to Freetown route up the west coast of Africa or the Cape to Suez route up the east coast. The British and the Americans diverted 12 British anti-submarine warfare (ASW) trawlers from the Western Approaches and 18 from US waters, along with six more destroyers and four corvettes from the Eastern Fleet. Four Catalina flying boats of 209 Squadron were transferred to Cape Town and Durban. The transfers took time and the trawlers from US waters did not arrive until December.
Prelude Convoy SL 119
Convoy SL 119 was found by of (ex-) and directed the rest of the wolfpack, , and , along with the boats in the vicinity, diverted by Dönitz (BdU) from the voyage to the South African coast, comprising the Type IXC U-boats , , U-172 and U-504. U-566 sank two ships with a total of 14,085 GRT on 28 August before being damaged by depth charges; U-107 was forced to retire and on 29 August the other boats were also ended their attacks. U-156 sank (5,941 GRT) on 27 August and on 12 September sank Laconia causing the Laconia incident.
Raeder and SKL Dönitz was overruled by Erich Raeder the and SKL. was redirected southwards to Cape Town, refuelling from the tanker south of Ascension Island. U-68 had sunk the British ship (5,300 GRT) on 12 September and the Dutch ship (6,861 GRT) on 14 September; took over from U-156. A second wave of four long-range Type IXD2 boats, , , U-179, and an Italian U-cruiser, , were close behind. The rest of the boats had not expended any torpedoes, leaving the other Type IXC boats with 22 torpedoes each, the IXD2s with 24 each and Cagni with 42).
Operations Cape Town
On the night of 6/7 October, U-68 had been in position for five days, photographing the bay. Emmermann in U-172 had a Metox radar detector and moved towards Table Bay on the surface, placing most of the crew on the deck, wearing life jackets, in case a mine was set off. Emmermann kept the boat on the surface for several hours so that the crew could take turns on deck to watch the peaceful scene as the other boats lay in wait outside the bay. The bay was seen to be empty and covered by searchlights and radar, precluding the likelihood of the attack achieving surprise. Emmermann submerged U-172 before dawn and watched through the periscope in brilliant sunshine.
Outside the bay, U-159 sank the British . The captains of U-68 and U-172 contacted BdU to request that the plan be abandoned but Dönitz wanted them to continue. At midnight on 8 October when the attack was due to begin, Cape Town had not been blacked out and the authorities were ignorant of the attack on Boringia. Having received a garbled reply, Emmermann 'assumed that BdU had agreed to the cancellation and that he had freedom of action' from on 7 October.
U-172 sank the US ship and then the Panamanian . U-172 sank with a torpedo and U-68 used seven torpedoes to sink the Greek freighter and the Dutch , both of which managed to transmit distress signals. At dawn the destroyers , and and , with the corvette sailed and spent much of the day rescuing survivors. Every aircraft that was airworthy went aloft to reconnoitre. The next morning, when tried to rescue the 28 survivors of Boringia, she was torpedoed, and another seven members of the crew of Boringia were killed along with 53 from Clan Mactavish. Aircraft on anti-submarine patrol guided to the area to rescue survivors who were landed at Cape Town.
Other attacks
U-159 had gone into action off Cape Town on and sank the US ship on 9 October then survived a depth-charge attack by a South African aircraft. U-159 moved to the south-east and sank , and , all British, by the end of the month. On 7 November, the US ship, , to the south-east of the Cape of Good Hope, was destroyed when its cargo of ammunition exploded, the sound being heard away at the Cape Point lighthouse. The next ship sunk was a US schooner, , by gunfire, the survivors making a -voyage to Angola.
By this time, U-159 was on the return leg of its voyage and refuelled from U-461 before sailing for St Paul's Rocks, about to the north-east of Brazil, then raiding along the Brazilian coast. U-159 sank the liner , from which 120 of the 130 crew and passengers survived, 12 of whom were rescued by , which U-159 sank on 15 December. was sunk on 16 December and then U-159 sailed for Lorient in France.