At 03.02 and 03.03 hours on 5 May 1943, U-264 fired two spread of two torpedoes at convoy ONS-5 about 500 miles south of Cape Farewell and observed the sinking of two ships with two hits each. The ships sunk were the West Maximus and Harperley. At 03.05 hours, Looks fired a single torpedo and observed a hit on another ship, but this is not confirmed by Allied sources.

However, the West Maximus (Master Earl Elmo Brooks) in station #22 was struck by one torpedo on the port side in the after peak tank and lost a large part of the stern. Due to a misunderstanding some of the eight officers, 31 crewmen, 21 armed guards (the ship was armed with one 5in and six 20mm guns) and two passengers (US Army personnel) abandoned ship in two lifeboats, but were ordered by the master to remain alongside. She became unmaneuverable as the ship settled, so the engines were secured and they waited for assistance, but after some hours another torpedo hit on the port side at #3 hatch, destroying the after bulkhead and steam lines, blowing off the hatch covers, spreading fuel oil over the deck and flooding the fireroom. A few minutes after the remaining crew members abandoned ship in two more lifeboats a third torpedo struck on the port side at the #2 hold and caused the ship to sink by the bow within ten minutes. It is likely that she was finished off by the same U-boat that had torpedoed her initially. One officer and four crewmen were lost and one armed guard drowned while trying to jump from a raft to a lifeboat. The survivors were picked up at 11.00 hours by HMS Northern Spray (FY 129) (Lt F.A.J. Downer) and landed at St. Johns on 8 May.

At 02.51 hours on 5 May 1943, U-952 (Curio) had attacked convoy ONS-5 and reported one hit with a T-3 magnetic pistol on a steamer of 5000 grt, but the torpedo apparently detonated near West Maximus without damaging the ship.