First patrol

U-568 departed Trondheim on 3 August 1941 and was assigned to U-boat Wolfpack Grönland in the North Atlantic Ocean, arriving there a week later.^[4][5] On 12 August, the submarine attacked Convoy ON 4, firing two torpedoes at a "tanker"^{[lower-alpha 1]} and convoy escort Flower-class corvette Picotee (925 tons).^[6] The torpedo fired at the "tanker" went wide, but Preuss observed how the corvette "sinks immediately as her depth charges detonate (five or six of them)".^[6][1] All hands on board Picobee were killed in action. Other escorts stopped and held the U-boat down while the rest of the convoy escaped.^[7] Afterwards, U-568 had short stints with Woflpacks Kurfürst (23 August – 2 September 1941^[8]) and Seewolf (2 – 8 September 1941^[9]), arriving at homeport Saint-Nazaire on 10 September 1941.^[4]

Second patrol

U-568 embarked on her second patrol on 9 October 1941. On her way west into the Atlantic, she attacked Convoy SC 48 on 16 October 1941, sinking the steam merchant ship Empire Heron (6,023 GRT) with two torpedoes and killing forty-two on board. The next day, she fired a spread of four torpedoes at the United States Navy destroyer Kearny (1,630 tons) having been repeatedly depth-charged by her the previous night. One torpedo hit the ship starboard, killing 11 sailors.^{[10][lower-alpha 2]} Sighted by HMCS Pictou, U-568 attempted to escape the escorts by sailing under cover of a rain squall, but was pursued. The submarine attempted to sink Pictou with a torpedo, but it passed 15 ft (4.6 metres) to port and missed. Afterwards, the U-boat retreated.^[1] The Kearny incident was cited by Adolf Hitler as being reasoning for Nazi Germany declaring war against the United States, with Hitler presenting the action as starting with the Kearny attacking U-568 with depth charges.^[11]

Between 21 and 31 October 1941, U-568 was part of Wolfpack Reissewolf.^[12] After her attack on Convoy SC 48, the remainder of her patrol was routine, and she arrived at Saint-Nazaire on 7 November 1941.^[13]

Wolfpacks

She took part in four wolfpacks, namely:

• Grönland (10 – 23 August 1941)
• Kurfürst (23 August – 2 September 1941)
• Seewolf (2 – 8 September 1941)
• Reissewolf (21 – 31 October 1941)

Fate

U-568 was sunk on 28 May 1942 in the Mediterranean Sea NE of Tobruk in position 32°42′N 24°53′E, by Royal Navy vessels, the destroyer HMS Hero, and escort destroyers HMS Eridge and HMS Hurworth. All 47 hands survived.^[14]