 2 SG put in a determined attack on a U-boat, (thought to be ), but was unsuccessful, though the battle for SL 140/MKS 31 saw the destruction of a U-boat, without loss of ships.In January 1944 2 SG sailed on its most famous exploit, accounting for six U-boats in one patrol, three of them in one 15-hour period.On 31 January 1944 Walker's group gained their first kill of the year when they sank .