At 06.16 hours on 24 Oct 1939, U-37 torpedoed and sank Menin Ridge about 98 miles west of Gibraltar and shortly afterwards spotted the unescorted and unarmed Ledbury (Master Norman Rice) approaching the sinking position from the east. The ship had spotted wreckage with survivors clinging to it and changed course to rescue them. The U-boat then fired two torpedoes at her but missed because the ship was constantly changing courses during a careful approach at 7 knots. However, her lookouts failed to notice the attack, so the ship first picked up one survivor by means of a line and then launched her starboard lifeboat manned by the chief officer and four crewmen to search the wreckage. They picked up four more survivors and returned to the ship after half an hour, but before they could be taken aboard U-37 surfaced off the starboard quarter in a distance of a quarter of a mile and fired a shot across the bow of Ledbury at 09.18 hours. The master ordered the lifeboat alongside to cast off, turned the stern towards the U-boat and sent a distress signal that was received by Gibraltar and other stations. The use of the radio forced Hartmann to immediately open fire with the deck gun on the steamer. The steering gear was smashed by the first round, two others struck the bridge and set it on fire and two more hit the engine room, but the most of the 34 rounds fired during the attack were aimed at the waterline on the starboard side and caused the ship to sink after about 15 minutes. The master threw the confidential books overboard and was almost trapped when a shell wrecked his cabin when he tried to get the ship’s papers from there. He then abandoned ship in the port lifeboat together with 25 crew members and the survivor who had been picked up earlier. Despite the continuous shelling none reported any injures, except one man with a lacerated wrist. Subsequently the Germans questioned the occupants of the starboard lifeboat and when the chief officer told them that the master was in the other boat, he was asked by Hartmann to deliver the following message: Tell the Captain I am sorry to shell him but he used his wireless and that is forbidden. It is the fault of Winston Churchill and the money grabbers in London. We don’t want war.

The presence of U-37 was now known to the enemy due to the distress signal of Ledbury and Hartmann decided to left the area to the southwest. Doing so he first spotted a tanker heading for Gibraltar, but the ship suddenly reversed course, presumably after receiving a U-boat warning. The U-boat soon had to give up the chase of the tanker and dived because four or more aircraft arrived in the area. At 10.30 hours, the Germans sighted the Tafna which had observed the shelling from a distance of 10 miles and unsuccessfully tried to avoid the U-boat, but was eventually torpedoed and sunk at 11.19 hours. The torpedo explosion was heard by the survivors of Leadgate and Menin Ridge shortly before they were rescued by the American motor merchant Crown City (Master W.E. Carley) which had received the distress signal and was led to the boats by a French aircraft. The ship hurriedly picked them up and left the empty lifeboats adrift in order to get to the torpedoed ship as soon as possible, but she then just proceeded to Gibraltar to land the survivors after two destroyers were observed in the area.