On Oct. 7, 1942 the U-172 torpedoed and sank two ships off the coast of South Africa. The first to be hit was the Chickasaw City, a cargo ship owned by the Isthmian Steamship Company of New York. The two torpedoes sent the ship to the bottom in three minuets taking nine men with her. The survivors were questioned by the U-boat and were released. Chickasaw City won the distinction of being the first ship sunk by a German submarine off of the South African coast.

A few hours later U-172 struck again sinking the Firethorn, an ex Danish cargo ship seized by the U.S. Government in 1941. In the two minuets it took for her to sink twelve men died. By October 9 all the survivors from both ships had been picked up by HMS Rockrose K-51 and they were landed at Cape Town.

The survivors from both of these ships and Coloradan, Examelia and Swiftsure were again subjected to the terror of a torpedo attack when the passenger ship Zaandam was sunk by U-174 on Nov. 2, 1942 off the Brazilian coast, many of them did not live through the second attack. One man from Firethorn along with two of the crewmen from Zaandam spent 84 days on a liferaft being picked up Jan. 24, 1943 by USS PC-576.