At 08.30 hours on 26 April 1942 the unescorted and unarmed Alcoa Partner (Master Ernest Henke) was hit by a torpedo from U-66 which struck the port side at the #2 hatch of the zigzagging freighter. Immediately after the impact, U-66 fired one shell with the gun, which hit the poop deck. Because of her cargo, the vessel sank in less than three minutes about 80 miles north-northeast of Bonaire. The crew of seven officers, 27 men and one workaway found themselves in the water, never having enough time to launch any of the four lifeboats. But one lifeboat with one man on board floated free and 24 men managed to reach this boat. The survivors searched the vicinity for the missing 10 men (the second engineer, the radio operator, seven others and the workaway) until after dawn. They made landfall in Bonaire 37 hours after the attack.

The master Ernest Henke survived also the sinking of his next ship, the Alcoa Rambler, which was sunk by U-174 (Thilo) on 15 Dec 1942. His next ship, the Alcoa Prospector was also torpedoed but only damaged by a torpedo from the Japanese submarine I-27 in the Gulf of Oman on 5 July 1943 and returned to service.