At 00.08 hours on 2 July 1943 the unescorted Bloody Marsh (Master Albert Harrison Barnes) was on her maiden voyage, when the ship´s torpedo indicator sounded after detecting the approach of a torpedo from U-66. The master ordered a course change to hard left, but 30 seconds later the torpedo struck the port side at the engine room, destroying the room completely, flooding the compartment and killing one officer and two men on watch below. The hull was ruptured on the port side from midship to the engine room. As the tanker settled slowly by the stern, gradually losing headway, the after gun crew reported a conning tower but could not open fire because the explosion had jammed the gun. The forward gun did not get into action because it could not be brought to bear.

Most of the ten officers, 40 men and 27 armed guards (the ship was armed with one 5in, one 3in and eight 20mm guns) left the ship in four lifeboats and three rafts, with the exception of the armed guard commander and three of his men. 20 minutes after the attack, a second torpedo struck the port side amidships, broke the ship in two and immediately sank the tanker about 75 miles east of Savannah, Georgia. The four armed guards jumped overboard as the water reached the after gun platform. At 06.00 hours, a Navy blimp sighted the survivors and signaled that help was on the way. USS SC-1048 picked them up at 09.00 hours and landed them at Charleston, South Carolina.