German minesweeper M18 (1939)

The German minesweeper M18 was a M1935 type minesweeper of the Nazi German Kriegsmarine. Built under the 1937 construction programme by Oderwerke, Stettin, M18 was launched in 1939 and entered service in 1940. She was sunk in an air raid on Kiel on 20 March 1945.

Design and construction
The M1935 type minesweeper was a development of Germany's successful minesweepers of the First World War, but with a longer hull and using oil fuel rather than coal. A first order for twelve ships (M1–M12) was placed in 1935, as part of the first shipbuilding programme for the German Navy since the Anglo-German Naval Agreement signalled an expansion of the German Navy past the constrictions of the Treaty of Versailles. Six more minesweepers of the same design (M13–M18) were ordered as part of the 1937 construction programme.

M18 was 68.40 m long overall and 66.60 m at the waterline, with a beam of 8.50 m and a draught of 2.65 m. Displacement was 772 LT standard and 874 LT full load. Two Wagner oil-fired water-tube boilers fed steam to reciprocating steam engines, rated at 3500 ihp which drove two propeller shafts, giving a speed of 18.3 kn. 143 tons of oil were carried giving a range of 5000 nmi at 10 kn and 1000 nmi at 17 kn.

As built, M18 had a main gun armament of two 10.5 cm (4.1 in) SK C/32 naval guns, two 3.7 cm SK C/30 and two 2 cm Flak 30 anti-aircraft guns. 30 mines could be carried. The ship's anti-aircraft armament was increased during the Second World War, with several (4–6) more 2 cm cannon added. The ship had a complement of 95–113 men.

M18 was laid down as Yard number 804 at the Oderwerke shipyard in Stettin (now Szczecin in Poland. She was launched on 16 September 1939 and entered service on 19 March 1940.

Service
M18 served with the 1st and 3rd Minesweeper Flotillas. On the night of 7/8 July 1942, Soviet forces launched an amphibious attack with light forces against the Finnish island of Someri. M18, together with several other German and Finnish ships, provided artillery support to a Finnish counter-attack, and helped to prevent Soviet naval forces from interfering. The Soviet force was defeated on 9 July.

On 4 November 1943, Soviet ground attack aircraft attacked German minesweepers in the Gulf of Finland, slightly damaging M18 and the minesweepers GERMAN MINESWEEPER M30, GERMAN MINESWEEPER M459 and GERMAN MINESWEEPER M460 and badly damaging the minesweeper GERMAN MINESWEEPER M16.

On 3 February 1944, M18 and sister ship GERMAN MINESWEEPER M29 were badly damaged in an American air raid on Wilhelmshaven. When repaired, she returned to service with the 3rd Minesweeper Flotilla, and on 22 June supported (together with the rest of her flotilla (GERMAN MINESWEEPER M15, GERMAN MINESWEEPER M19, GERMAN MINESWEEPER M22 and M30) and the 2nd Torpedoboat Flotilla (GERMAN TORPEDO BOAT T8, GERMAN TORPEDO BOAT T10 and GERMAN TORPEDO BOAT T30)) an unsuccessful attempt to land Finnish forces on the island of Narvi (island). By late September 1944, the advance of the Soviet armies into Estonia prompted an evacuation of German troops and refugees from Tallinn, with the last convoy leaving on 23 September. M18 helped to lay minefields to protect this evacuation and block routes out of the Gulf of Finland. Minelaying operations to cover the German retreat continued, with M18 taking part in Operation Krokodil Süd, to mine the southern exits to Moon Sound on 4–6 October.

Loss
On 20 March 1945, M18, along with sister ships M15, M16, M19 and the old minesweeper M522, was sunk in an air raid at Kiel and later scrapped.