German submarine U-18 was a Type IIB U-boat of Nazi Germany's Kriegsmarine during World War II. It was laid down 10 July 1935 and commissioned on 4 January 1936. It served in many U-boat flotillas during its service.

Design

German Type IIB submarines were enlarged versions of the original Type IIs. U-18 had a displacement of 279 tonnes (275 long tons) when at the surface and 328 tonnes (323 long tons) while submerged. Officially, the standard tonnage was 250 long tons (254 t), however. The U-boat had a total length of 42.70 m (140 ft 1 in), a pressure hull length of 28.20 m (92 ft 6 in), a beam of 4.08 m (13 ft 5 in), a height of 8.60 m (28 ft 3 in), and a draught of 3.90 m (12 ft 10 in). The submarine was powered by two MWM RS 127 S four-stroke, six-cylinder diesel engines of 700 metric horsepower (510 kW; 690 shp) for cruising, two Siemens-Schuckert PG VV 322/36 double-acting electric motors producing a total of 460 metric horsepower (340 kW; 450 shp) for use while submerged. She had two shafts and two 0.85 m (3 ft) propellers. The boat was capable of operating at depths of up to 80–150 metres (260–490 ft).

The submarine had a maximum surface speed of 12 knots (22 km/h; 14 mph) and a maximum submerged speed of 7 knots (13 km/h; 8.1 mph). When submerged, the boat could operate for 35–42 nautical miles (65–78 km; 40–48 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 3,800 nautical miles (7,000 km; 4,400 mi) at 8 knots (15 km/h; 9.2 mph). U-18 was fitted with three 53.3 cm (21 in) torpedo tubes at the bow, five torpedoes or up to twelve Type A torpedo mines, and a 2 cm (0.79 in) anti-aircraft gun. The boat had a complement of twenty-five.

Fate

While a training boat, U-18 sank at 0954 hrs on 20 November 1936 in Lübeck Bay, after a collision with T-156. Eight men died and 12 survived. It was raised on 28 November 1936. It returned to service on 30 September 1937. On 3 September 1939 it attacked a Polish submarine, most probably ORP_Sęp, but missed. Starting late 1942 she served in the 30th U-boat Flotilla, after being transported in sections along the Danube to the Romanian port of Galați. She was then re-assembled by the Romanians at the Galați shipyard and sent to the Black Sea.

On 20 August 1944, in a Soviet air raid on the Romanian harbor of Constanţa in the Black Sea, U-18 was damaged and as a result was deemed not seaworthy and was scuttled on the 25th.

The boat was raised by the USSR in late 1944. It was sunk for target practice by the Soviet submarine M-120 on 26 May 1947 off Sevastopol (also sunk that day was the former U-24).

Summary of raiding history

Date	Name	Nationality	Tonnage	Fate
18 November 1939	Parkhill	United Kingdom	500	Sunk
24 January 1940	Bisp	Norway	1,000	Sunk
29 August 1943	TSC-11 Dzhalita	Soviet Navy	400	Sunk
30 August 1943	SKA-0132	Soviet Navy	56	Damaged
18 November 1943	Josif Stalin	Soviet Union	7,745	Damaged