Also 5 boats of the wolfpack Haudegen : U-438 (Kptlt. Franzius), U-613 (Kptlt. Köppe), U-624 (Kptlt. Graf von Soden-Fraunhofen), U-704 (Kptlt. Kessler), U-752 (Kptlt. Schroeter)

Coming from the HX-224 operations : U-456 (Kptlt. Teichert), U-614 (Kptlt. Sträter) *

* U-boats that fired torpedo or used the deck gun

Taking in account the B-Dienst report, the U-632 rapport and the fact that the convoy will probably avoid the HX-224 battle grounds, Dönitz forms the patrol line Pfeil. Indeed the convoys steams right on to the centre of the patrol line but it passes the line unnoticed on the 3rd Feb.

Unfortunately a merchant ship fires accidentally a snow flake and gives the position of the convoy away to U-187. The sighting report of the boat is detected by the HF/DF of the Toward. She sends immediately the Beverly and Vimy out on the bearing and they manage to sink U-187.

On the sighting report, Dönitz orders also 5 boats from the Haudegen gruppe and U-456 and U-614 to the scene. The boats concentrate around the convoy and attack during the night of the 4th. But the boats continually transmit contact and sighting reports, giving excellent occasion to the escort to charge on the HF/DF bearings. The escort manages to keep the situation under control and drives off U-267, U-402, U-608 (twice) and U-609.

But the convoy is again short on good luck: when it changes course in an effort to shake of the U-boats, the 3 left columns do not follow and romp from the convoy. Most of the U-boats in contact follow the smaller section, but are unable to exploit the confusing situation. U-609 gets a thorough plastering from the Lobelia but continues the operation and remains the contact keeper.

In the morning of the 5th the two sections of the convoy join. The U-boats have lost contact due to the offensive actions of the escort and the increasingly bad weather. U-413 sinks a straggler. Three American escorts (the destroyers Babbitt and Schenk and the cutter Ingham) coming from Iceland reinforce the escort in the night.

During the next day, the U-boats manage to concentrate again around the convoy, lead by U-609. U-465 is heavily damaged by a liberator guided by the signals of its contact report. U-266 sinks a straggler which has had machine trouble, and picks up the captain and chief engineer. U-262 and U-456 come up and U-454, U-438, U-135 and U-267 make attacks in the evening but are driven off. U-267 is severly damaged by the Vimy and must return to port.

Finally U-262 gets through the escort screen on the port side of the convoy, while all escorts on this side are busy dealing with other U-boats. She moves in between two columns in the convoy, fires all 5 torpedo tubes but misses all her targets around her. But the 2 torpedoes of her second spread who have missed a large ship, continue to run and they blaze a small ship out of the water. This ship perishes with all hands, so quickly no one, not even U-262 has noticed it. U-262 is then detected by Bibb, and the Lobelia damages her with depth charges. U-262 must also return to port.

Until this point the escort is well in control of the situation, but things change when U-402 enters the battle scene. When the starboard side of the convoy is left uncovered shortly after midnight, U-402 moves in quickly and sinks 2 ships. U-402 retires to reload the tubes.

The loss of one of these 2 ships is to have big consequences, for it was the rescue ship. A dangerous situation is developing, in which the escorts have now the responsibility to rescue survivors. In doing so, they have to leave their position in the screen and weaken the defence of the convoy, making it easier for the U-boats to sink other ships, for which again escorts must provide help.

U-614 sinks a straggler on the other side of the convoy. The escorts loose control of the situation and leave wide gaps in the screen, through which U-402 attacks again and damages a large tanker, who is later finished off by U-608.

The Lobelia who is searching for survivors astern, runs into the U-609 and damages her with canon fire. U-609 dives and is finished off with depth charges. U-402 attacks again and sinks a freighter. She falls astern of the convoy and sinks 2 stragglers, one of them a troop ship that perishes with heavy loss of live.

When dawn comes, most U-boats have lost contact and air patrols prevent any boat to come up. U-624 is sunk by a B-17 of 220 Sqdn. Only U-402 and U-456 make contact. U-456 is driven off by the Beverley but U-402 sinks its seventh victim with its last torpedo in the night of the 7th and is lucky to escape from a counterattack from the Bibb and Ingham. U-608 makes also an attack on the escort and a straggler but has no success. The other boats cannot approach the convoy. Both U-135 and U-614 are damaged by aircraft trying so. Still the convoy loses again one of its number in a collision.

The battle around SC-118 was by no means the biggest convoy battle, but 'it was perhaps the hardest convoy battle of the war' as Dönitz wrote after the war. Indeed the Pfeil gruppe has been thoroughly worked over by the escorts, sending many to the dockyard for extensive repairs. Three boats have been destroyed. The escorts did not get away unharmed too: the Lobelia arrives back in port on the end of a towing line after her machines had broken down and all ships have suffered a lot from the heavy weather conditions. Still, the U-boats were lucky that the experienced commander of the escort group, McIntyre was left behind in port where his ship, the Harvester was undergoing repairs after ramming an U-boat in the previous convoy escort trip.

With 12 ships against 3 U-boats, the balance wasn't quite in favour of the Germans and even more alarming was that 4 of them were stragglers and only 2 U-boats managed to penetrate the escort screen. The correct, offensive use of the HF/DF and radar made attacks on the surface difficult and this would soon lead to a change in tactics: instead of making night attacks on the surface and submerged attacks during day as has been done in the past three years, they are ordered to keep as far as possible away from the convoy perimeter during day, making their way to the front for a submerged attack at night.