At 23.15 hours on 4 March 1943 the unescorted California Star (Master Sydney Foulkes) was hit on the starboard side in #3 hold and the engine room by two torpedoes from U-515 about 335 miles northwest of Flores, Azores. All lights went out and the ship stopped. Because both starboard lifeboats were destroyed the crew began to abandon ship on the port side, but when the second port boat was being launched a coup de grâce hit on the port side at 23.34 hours and the explosion destroyed the boat and killed all occupants. The remaining crew members had to abandon ship on rafts. The vessel sank by the bow a few minutes after being hit on the port side by a second coup de grâce at 23.52 hours. The U-boat surfaced to question the survivors and took the Second Officer George Cameron Smart as prisoner aboard.

At daybreak the survivors decided that the master should sail the only lifeboat to the nearest land to get help for the survivors left behind drifting on rafts. One boy died and was buried at sea before the boat with the master 19 crew members and three passengers reached Flores after 11 days. A subsequent search for the rafts was unsuccessful, they were never seen again. 41 crew members, eight gunners and one passenger were lost.