At 08.01 hours on 13 Nov, 1942, the unescorted Excello (Master Maurice Almond Kent) was hit by one torpedo from U-181 about 50 miles south of Port St.John, South Africa, while proceeding on a nonevasive course at 9 knots. The torpedo struck on the port side at the #5 hold, blew the hatch covers off the #4 and #5 holds, brought down the main mast, unseated the winches and threw wreckage all over the boat deck. The engine room began to flood within three minutes and the engines were secured. The eight officers, 30 men and 13 armed guards (the ship was armed with one 4in, four 20mm and two .30cal guns) abandoned ship in three lifeboats. The falls of the first boat jammed, forcing several men to jump overboard and climb on board rafts. The ship sank stern first in less then 20 minutes. The explosion had killed one armed guard and the first engineer died later in the third lifeboat from shock and suffocation after swallowing fuel oil. The U-boat surfaced and questioned the survivors before leaving.
On 14 November, one boat with 19 survivors made landfall at Port St.John, South Africa and another with 18 survivors landed the following day. The ten crewmen and two armed guards in the third boat were picked up after seven days at sea by the British hospital ship HMHS Atlantis and landed at Capetown on 22 November.

U-181 was informed of the sailing times of the Alcoa Pathfinder, East Indian and Excello from a secret transmitter located aboard the German motor merchant Ehrenfels which was interned along with the German motor merchants Braunfels and Drachenfels and the Italian steam merchant Anfora in the Portuguese Mormugao Harbor. The information was given to the ship by a German spy living in Goa. On 9 Mar, 1943, the Ehrenfels was scuttled by the own crew to prevent seizure by Portuguese.