25 Aug 1942
While picking up the survivors of Trolla in thick fog astern of convoy ONS-122, HNoMS Potentilla obtained a radar contact approaching her in this vulnerable situation. Hurrying up the rescue work, the corvette turned towards the contact and engaged the U-boat with all weapons from a distance of less than 300 meters at 05.21 hours. One of the five rounds from the 4in gun was observed to hit the base of the conning tower and several hits from the AA guns were seen. She had completely surprised U-174 but missed to ram by a few meters, turning astern of the boat and coming up along her port side, dropping five depth charges so close that the charge from the starboard thrower was fired over the crash-diving U-boat and detonated on her starboard side while the others detonated on port. Shortly afterwards HNoMS Potentilla dropped four depth charges ahead of the swirl and then circled the area for one hour without obtaining an Asdic contact, the area was littered with wreckage and oil from ships sunk from the convoy so no traces could be attributed to the U-boat. U-174 surfaced more than 5 hours later and examined the damage, several hits were found in the upper deck and the conning tower with a leak in the galley and an untraceable damage that left a trail of oil behind the boat, forcing the commander to abort the patrol. (Sources: ADM reports, KTB U-174)

15 Dec 1942
An American Catalina aircraft from squadron VP 83 at Natal, piloted by Wall, found and attacked the boat without any damage as the boat crash dived. (Sources: Blair, vol 2, page 55)

15 Dec 1942
Later in the day another Catalina from VP 83, this time piloted by Bertram J. Prueher, attacked the a U-boat, probably the U-174. U-174 left the area shortly afterwards due to lack of fuel (Sources: Blair, vol 2, page 55)

3 recorded attacks on this boat.