At 04.22 hours on 11 April 1942 the unescorted Gulfamerica (Master Oscar Anderson) on her maiden voyage was hit by one G7e torpedo from U-123 about five miles off Jacksonville, Florida. Illuminated by the lights of the Jacksonville Beach resort, the tanker had stopped steaming a zigzag course only 20 minutes before the attack. The torpedo struck at the #7 tank on the starboard side and caused a tremendous explosion and fire. The master ordered the engines stopped and the ship abandoned as the radio operator sent distress calls. The armed guards manned the 4in after gun (the ship was also armed with two .50cal guns), but did not fire on the U-boat. The eight officers, 33 crewmen and seven armed guards began abandon ship in an orderly manner, but then U-123 tried to bring down the radio antenna with the AA gun and fired about 12 shells from the deck gun into the engine room on the port side.
In the resulting confusion, a lifeboat capsized, while another with the master and ten crewmen got away in ten minutes. Ten minutes later another boat with only three men left and three others abandoned ship on a liferaft, later they picked up two men from the water. Five men had been killed by the torpedo blast or the machine gun fire and 14 men drowned after jumping overboard. A total of two officers, two armed guards and 15 crewmen perished. The survivors were all rescued by US Coast Guard patrol boats and taken to Mayport, Florida. The tanker settled by the stern with about a 40° list to starboard but did not sink until 16 April.