were slightly larger than the original Type IXBs. U-158 had a displacement of when at the surface and while submerged. The U-boat had a total length of, a pressure hull length of, a beam of, a height of, and a draught of. The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to. The submarine had a maximum surface speed of and a maximum submerged speed of. When submerged, the boat could operate for at ; when surfaced, she could travel at. U-158 was fitted with six torpedo tubes, 22 torpedoes, one SK C/32 naval gun, 180 rounds, and a SK C/30 as well as a C/30 anti-aircraft gun. The boat had a complement of forty-eight.
Service history
U-158 conducted only two combat patrols, sinking 17 ships totalling and damaging two others totalling 15,264 tons.
1st patrol
U-158 departed the German administered island of Helgoland,, for her first patrol on 7 February 1942. Her route took her north of the British Isles, through the gap between Iceland and the Faroe Islands and into the Atlantic Ocean. Her first victim was Empire Celt, sunk about south southeast of St Johns on 24 February. The ship broke in two after being hit and the stern section was last seen on 4 March. In the same attack, the U-boat also damaged Diloma. This tanker was able to proceed under her own power at reduced speed. She was repaired in Baltimore and returned to service in June 1942. The submarine then moved further down the US east coast. She sank another four ships and damaged one more. They were: Finnanger, Caribsea, John D. Gill, Olean and Ario. John D. Gill was another tanker; her cargo did not ignite on being hit by a torpedo. Instead, the surrounding water was turned into a blazing inferno after a seaman threw a life ring overboard and its built-in carbide lamp malfunctioned. Almost half the crew died. Olean was towed to Hampton Roads, rebuilt and renamed Sweep and then returned to service. Having caused so much mayhem, the boat sailed for France, arriving at Lorient on 31 March 1942.
2nd patrol
For her second foray, U-158 moved into the Caribbean and the Gulf of Mexico in May 1942. On the way she sank Darina about east southeast of Bermuda on 4 May and Frank B. Baird on the 22nd. Following the sinking of Knoxville City on 2 June, the survivors in their lifeboats declined an offer of help from Jamaica as they thought the German submarine was still nearby. The Hermis, despite being hit by two torpedoes on the 7th, maintained a speed of eight knots due to the engines still running. The U-boat surfaced and shelled the ship. She was observed some twelve hours later with her stern out of the water; she eventually sank shortly afterward.
