24 Oct 1939

Between 11.47 and 12.12 hrs, the boat was depth charged by several aircraft after attacking Tafna about 100 miles (161km) WSW of Gibraltar. U-37 dived to 105m (345ft) and was not damaged by the depth charges, which exploded far above. Hartmann wisely decided to run silent at a depth of 80m (263ft) and ordered most of the crew to lie down and rest, because shortly afterwards HMS Keppel, HMS Vidette and HMS Watchman arrived from Gibraltar and began an anti-submarine sweep of the area. At 16.45 hrs HMS Keppel dropped a full pattern of five depth charges set for 250ft (76m) after obtaining a good Asdic contact in position 36°03N/07°33,5W, and observed an air bubble and possibly oil rise to the surface afterwards, but failed to regain contact. The Germans had switched off the hydrophones and were caught off guard by the accurate detonations, which were felt as severe blows in the boat, which then dived to 95m (312ft). At 18.20 hrs HMS Watchman dropped a single depth charge set for 150ft (46m) from the port thrower on an Asdic contact in position 36°02N/07°18W, and lost contact after dropping the remaining four depth charges of the pattern in a follow up attack. Hartmann heard these detonate at some distance, but knew that they could not stay submerged all night as the crew had already begun to breathe through potash cartridges, so ordered the boat to be prepared for scuttling before surfacing with all guns manned at 21.45 hrs. However, the destroyers were no longer nearby and the boat was able to leave the area undetected, heading SW with a deck gun out of action due to the breech plug being jammed in place by extreme pressure at depth.

3 Nov 1939
The boat suffered slight damage after an air attack.

2 Aug 1940
15.08 hrs, North Sea SW of Norway: U-37 (Oehrn) and U-38 (Liebe) were sailing together when they were attacked by a Coastal Command Hudson (220 Sqdn RAF), whose pilot thought he had attacked a single submarine. No damage.

16.00 hrs, 56.15N, 02.35E: following an earlier unsuccessful attempt to waylay U-34, Dutch submarine O-22 (J.W. Ort) sighted either U-37 or U-38, and after difficulty getting into a firing position fired two torpedoes from the extreme range of 3600m (3,937 yds) at 16.20. Both missed, and the U-boat remained unaware of the attack.

24 Aug 1940
The boat was hit by both surface escorts and aircraft in mid-Atlantic and forced to abort to France. Date is approximate. (Sources: Blair, vol 1, page 180)

4 recorded attacks on this boat.