At 10.00 hours on 14 Sep 1939 the unescorted and unarmed Vancouver City (Master Hugh Charles Egerton) was hit by one torpedo from U-28 while steaming on a zigzag course at 13 knots about 75 miles west-southwest of Milford Haven. The U-boat attacked the ship without warning because she was zigzagging and escorted by an aircraft. The torpedo struck on the starboard side at #4 bulkhead between the engine room and #4 hold and killed the second engineer who was hit by a davit from the destroyed starboard lifeboat. The most crew members abandoned ship in the port lifeboat after distress signals had been sent and acknowledged by Land’s End. The master and five men left in a jolly boat on the starboard side after searching for two missing crewmen who had been on watch below and were presumably killed by the explosion. The ship sank 13 minutes after being hit.

The American steam passenger ship President Roosevelt and the Dutch motor tanker Mamura headed for the sinking position to rescue the survivors of Vancouver City after hearing her distress signals. The aircraft observed by the U-boat was the Sunderland L2167 (210 Sqn RAF) that remained near the lifeboats and dropped smoke floats to attract Mamura, which picked up the survivors at 13.00 hours and landed them at Liverpool later that day. The submerged U-28 tried to get into a favorable attack position on the tanker, but the presence of the flying boat prevented an attack.