At 06.20 hours on 30 Sep 1942 the unescorted Kumsang (Master William J. Lawrence) was hit on the port side amidships in the engine room by one stern torpedo from U-125 while steaming on a non-evasive course at 10.5 knots about 300 miles south of Freetown. When the ship settled on an even keel, the crew and eight gunners (the ship was armed with one 12pdr and four machine guns) began to abandon ship in eleven of twelve lifeboats because the port boat amidships had been blown away by the explosion. Only four actually got clear as the water rushing into the engine room prevented the men on watch below to secure the engines and the vessel was still making headway of about 4 knots when the boats were launched, capsizing some of them. Distress signals were sent six times, but no answer received. Many survivors had to jump overboard and swam to several rafts that were released. About 15 minutes after being torpedoed, the ship sank rapidly after breaking in two with the forward part raising up before sinking. Four crew members were lost. The U-boat surfaced after the ship sank and the Germans questioned the survivors in the boat in charge of the third officer before leaving the area.

At daylight, the survivors bailed out a waterlogged lifeboat that was put in charge of the fourth officer who eventually picked up all men from the various rafts drifting around. The five lifeboats were then tied together in a line ahead with the two leading boats hosting sails, but they made little progress in the next five days as the weather was calm with very little wind. The master then ordered all boats to proceeded independently as they could sail faster alone. On 6 October, the two boats in charge of the third and fourth officer landed at Roberts Port, Cape Mount, Liberia. They were joined the next day by the boats of the master and the staff captain, which were towed in by a barge after being sighted by a flying boat. These survivors were brought to Freetown by the British motor launches HMS ML-302 and HMS ML-2771. The occupants in the boat of the chief officer made landfall further north after 10 days at sea and were eventually taken to Freetown by a passenger vessel.