At 03.07 hours on 6 June 1942 the unescorted C.O. Stillman (Master Daniel H. Larsen) was struck by one torpedo from U-68 on the starboard side abaft the midship house setting the after end of the house on fire. The engines were secured and the most of the 47 crewmen, eight armed guards and three workaways from other tankers aboard abandoned ship in two lifeboats and four rafts. 20 minutes later another torpedo hit the ship on the starboard side forward of the engine room, showering the deck with fuel oil and debris. The remaining men aboard jumped overboard and swam to the rafts, while the tanker sank within two minutes 60 miles southwest of Puerto Rico. Three crew members were lost.
Just before dark on 7 June, the 22 crewmen and three armed guards on the four rafts were picked up by the US Coast Guard patrol boat #83310 after she was notified by an Army aircraft, which had spotted the rafts. On 8 June, they were landed at Ponce, Puerto Rico and were repatriated on the American steam passenger ship Seminole. The two lifeboats drifted until the dawn on 6 June and then set sail for the Dominican Republic. One boat with 17 survivors landed at the Bay of Yuma and the other with 13 survivors at La Romana.