U-159's keel was laid down on 11 November 1940 at the DeSchiMAG AG Weser shipyard in Bremen, one of dozens of long-range Type IXC boats designed to carry the war far from European waters. At 76.76 meters long with a surface displacement of 1,120 tons, she was larger than the more common Type VII boats, built for endurance rather than coastal patrols. Her twin MAN diesel engines could push her 13,450 nautical miles at ten knots on the surface -- enough range to reach the coast of South America or southern Africa and return. She carried 22 torpedoes, a 10.5 cm deck gun, and a crew of forty-eight. Launched on 1 July 1941 and commissioned on 4 October under Kapitanleutnant Helmut Witte, a Knight's Cross recipient, U-159 completed her training with the 4th U-boat Flotilla before transferring to the 10th Flotilla for combat operations in May 1942.

Her first patrol was a transit run -- Kiel to Lorient through the gap between the Faroe and Shetland Islands, arriving at the French Atlantic port on 3 May 1942. Lorient would be her home for the rest of her career. The second sortie drew blood immediately. On 21 May, U-159 sank the tanker Montenol 140 nautical miles east-southeast of Santa Maria in the Azores. She caught the ore carrier Illinois loaded with 8,000 tons of manganese; the ship went down in forty seconds. The deck gun saw heavy use, sinking the Sally on 5 June and Flora on the 18th. Against the Brazilian sailing vessel Paracury, rough seas made the deck gun impractical, so the crew used the 20mm anti-aircraft gun instead, punching holes at the waterline until the ship capsized. But the hunters could become the hunted: on 13 July, a Leigh Light-equipped Wellington bomber from No. 172 Squadron RAF caught U-159 on the surface and severely damaged her. She barely limped back to Lorient.

U-159's third patrol was her longest and most destructive -- 135 days prowling the South Atlantic from the Azores to the waters off South Africa. She sank the Boringia, the Empire Nomad, and the Ross among others. A South African Air Force Lockheed Ventura attacked her on 10 October 1942, but inflicted only minor damage. Then came La Salle and her earth-shaking ammunition explosion. Among U-159's other victims was the Star of Scotland, a steel-hulled American sailing ship attacked with the deck gun roughly 900 nautical miles west of Luderitz Bay, South Africa. When Witte's crew attempted to take the ship's master prisoner, the captain talked his way free by pointing out that he was the only man aboard who could navigate -- without him, his crew would be lost at sea. He was returned to his men. After sinking the Star of Suez, the crew fished an unusual haul from the floating debris: 45 aircraft tires, a 20-horsepower electric motor, and 120 grapefruits. Another nearby U-boat, frustrated at having missed the attack, salvaged tires and car parts of its own.

By early 1943, the tide of the Battle of the Atlantic was turning against the U-boats. Allied air cover expanded, radar improved, and convoy escorts grew more effective. U-159's fourth patrol reflected this shift. She sank the Silverbeech on 28 March 1943 south of the Canary Islands from convoy RS 3, but found herself under repeated air attack off the coast of what was then Spanish Sahara -- one of eight U-boats targeted in the same sweep. She participated in two wolfpacks during this period: Wohlgemut from 12 to 22 March and Seerauber from 25 to 30 March. The era of the lone raider roaming unchallenged was ending. The Atlantic had become a killing ground for submarines as much as for merchant ships.

U-159 departed Lorient for the last time on 12 June 1943. By then, the Kriegsmarine was losing U-boats faster than it could replace them -- May 1943 alone had seen 43 boats destroyed, a catastrophe the Germans called Black May. On 28 July 1943, a U.S. Navy Martin PBM Mariner flying boat from patrol squadron VP-32 found U-159 in the Caribbean, near coordinates 15.95 degrees north, 68.50 degrees west. The aircraft attacked and sank her. All forty-eight crew members died. In her fifteen months of combat, U-159 had sunk 23 ships. She now rests somewhere on the floor of the Caribbean, one of roughly 780 U-boats lost during the war -- each one a steel tomb holding the remains of young men sent to fight a campaign that, by mid-1943, their own commanders knew was failing.