At 23.10 hours on 26 Sep 1941 the unescorted and unarmed I.C. White (Master William Mello) was hit by one of two torpedoes from U-66, while proceeding fully lighted and neutrally marked. The U-boat had spotted the tanker already on the morning of 24 September and observed her since then. Zapp asked the BdU for advice after seeing the Panamanian flag and got the answer that it is only allowed to sink the vessel outside of the Pan-American security zone. He attacked the I.C. White after she left the zone because they were transporting oil to a British port. The torpedo struck on the starboard side between #7 and #8 tanks. The explosion threw flaming oil up over the boat deck aft. The ship stopped but continued after about 15 minutes and two more torpedoes had to be fired at 04.04 hours on 27 September which both hit and caused her to break in two, so that water ran across the deck amidships. At 05.30 hours, a coup de grâce missed but the tanker sank anyway at 07.40 hours about 500 miles off Recife.

The survivors abandoned ship in three lifeboats and some rafts. Later the survivors were evenly distributed between two of the lifeboats, which then headed for Brazil. The occupants of one boat were picked up on 3 October after sailing 470 miles by the American steam merchant Delnorte (Master C.A. Hoehn) about 40 miles off Porto de Maceio, Brazil in position 10°16S/35°23W. The remaining survivors in the other boat were also picked up on 3 October after sailing 500 miles by the American steam merchant West Nilus (Master John Stern). All survivors landed four days later in Rio de Janeiro from which they were repatriated aboard the American steam passenger ship Brazil, arriving at New York on 20 October.