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.
German Type IIB submarines were enlarged versions of the original Type IIs. U-18 had a displacement of when at the surface and while submerged. Officially, the standard tonnage was , however. 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 MWM RS 127 S four-stroke, six-cylinder diesel engines of for cruising, two Siemens-Schuckert PG VV 322/36 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-18 was fitted with three torpedo tubes at the bow, five torpedoes or up to twelve Type A torpedo mines, and a anti-aircraft gun. The boat had a complement of twenty-five.
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 SÃÂp, 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 GalaÃÂi. She was then re-assembled by the Romanians at the GalaÃÂi shipyard and sent to the Black Sea.
On 20 August 1944, in a Soviet air raid on the Romanian harbor of Constanà £a 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 on 26 May 1947 off Sevastopol (also sunk that day was the former ).