At 02.19 hours on 25 Feb 1942 the unescorted La Carriere (Master Robert Hyde Cairns) was hit on the starboard side amidships and further aft by two G7a torpedoes from U-156 while steaming on a non-evasive course at 12 knots about 75 miles south by west of Guanica, Puerto Rico. The tanker stopped and blew off steam while the crew examined the damage. They discovered that the explosions smashed in 20 to 30 feet of the side plates just forward of the engine room, blew the lids off the tanks #3 and #4, opened a hole in the deck near the pump room, put the telemotor gear out of action and moved the bridge back about 7 feet. However, the engines were soon restarted and after 10 minutes the ship was able to proceed on a zigzag course at 9 knots with the intention to beach her on the south coast of Puerto Rico. Attempts were made to send distress signals after a temporary aerial was rigged because the main aerials had been carried away, but no answer could be heard as the receiver was broken. In the meantime the U-boat surfaced to get into a favorable attack position again, dived at 05.19 hours and fired a spread of two G7a torpedoes from a distance of 1000 meters. A torpedo track was spotted by the gunners on the starboard beam in the bright moonlight and evaded by turning away hard, it was seen to pass about 40 feet astern. They believed to have seen the dim outline of a conning tower and fired one round from the 4in stern gun (the ship was also armed with four machine guns) at a range of 800 yards in the direction the torpedo came from. Shortly afterwards, five to seven crew members and one gunner attempted to lower the port aft lifeboat without orders, but the forward fall broke and capsized the boat. Most occupants were thrown out and drowned, except the carpenter who clung to the upturned boat and eventually drifted ashore two days later.

It seems the master believed to have escaped the attacker after one hour and decided to change course in order to wait until daylight before beaching the vessel. However, after surfacing and overtaking the vessel again, U-156 waited until moonset before firing its last torpedo on the surface at 08.39 hours. The G7e torpedo struck La Carriere forward on the starboard side and blew off the bow which disappeared quickly. A huge column of water hit the bridge and the order to abandon ship was given immediately. While the chief and second officer lowered both lifeboats amidships, the tanker settled fast by the head with the stern raising out of the water and developed a list to port, then righted herself and continued to go over to starboard until she finally keeled over and sank vertically in less than three minutes about 17 miles south-southwest of Guanica in position 17°42N, 67°00W. Despite the rapid sinking the crew managed to launch the port forward boat and the jolly boat. Due to the proximity of the coast the Germans did not question the survivors and left the area.

The second officer took charge of the lifeboat with 20 occupants and they reached Guanica about eleven hours after the ship sank, followed one hour later by four men in the jolly boat commanded by the third officer. There had been five men in the smaller boat, however the chief engineer died of heart failure from shock and exhaustion before reaching Puerto Rico. The master had been on the bridge and went down with the ship, but came to the surface and clung to a piece of floating wreckage for about four hours until daylight. He then swam to a damaged life raft and the next night observed two submarines and tried to attract their attention by making noise and smoke but they disappeared. During the afternoon of 27 February, he was spotted by an American patrol aircraft that dropped a flare and was eventually picked up the next morning after being on it for 73 hours without food and water by USCGC Unalga (WPG 53) (LtCdr E.B. Smith, USCG) which landed him at Ponce later that day. The starboard aft lifeboat was found adrift with no one in it. In all, eleven crew members and all four gunners were lost. The second officer and five survivors returned to New York aboard Cherokee, arriving on 12 March, while 19 survivors decided to accompany the master to Trinidad.