HMS M21
Encyclopedia
HMS M21 was a First World War
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
M15-class
M15 class monitor
The M15-class comprised fourteen monitors of the Royal Navy, all built and launched during 1915.- Design :The ships of this class were ordered in March, 1915, as part of the Emergency War Programme of ship construction...
monitor. After service in the Mediterranean and the Dover Patrol
Dover Patrol
The Dover Patrol was a Royal Navy command of the First World War, notable for its involvement in the Zeebrugge Raid on 22 April 1918. The Dover Patrol formed a discrete unit of the Royal Navy based at Dover and Dunkirk for the duration of the First World War...
, she struck a mine off Ostend
Ostend
Ostend is a Belgian city and municipality located in the Flemish province of West Flanders. It comprises the boroughs of Mariakerke , Stene and Zandvoorde, and the city of Ostend proper – the largest on the Belgian coast....
in January 1918 and sank off Dover
Dover
Dover is a town and major ferry port in the home county of Kent, in South East England. It faces France across the narrowest part of the English Channel, and lies south-east of Canterbury; east of Kent's administrative capital Maidstone; and north-east along the coastline from Dungeness and Hastings...
.
Design
Intended as a shore bombardment vessel, M21s primary armament was a single 9.2 inch Mk VI gunBL 9.2 inch gun Mk I - VII
The BL 9.2 inch guns Mk I - Mk VII were a family of early British heavy breechloading naval and coast defence guns in service from 1881 to the end of World War I...
removed from the HMS Theseus
HMS Theseus (1892)
HMS Theseus was an Edgar-class protected cruiser of the Royal Navy. The Edgars were basically smaller versions of the Blake class. Theseus was launched at Leamouth, London in 1892 and commissioned on 14 January 1896....
. In addition to her 9.2 inch gun,she also possessed one 12 pounder
QF 12 pounder 12 cwt naval gun
The QF 12 pounder 12 cwt gun was a common calibre naval gun introduced in 1894 and used until the middle of the 20th century. It was produced by Armstrong Whitworth, Elswick and used on Royal Navy warships, and exported to allied countries...
and one six pound anti-aircraft gun
QF 6 pounder Hotchkiss
The QF 6 pounder Hotchkiss was a light 57 mm naval gun and coast defence gun of the late 19th century used by many countries, and was adapted for use in the early British tanks in World War I.- Canada History :...
. Due to the shortage of Bolinder diesel engines that equippped her sisters, she was fitted with 2 shaft triple expansion steam engines that allowed a top speed of eleven knots. The monitor's crew consisted of sixty nine officers and men.
Construction
HMS M21 ordered in March, 1915, as part of the Emergency War Programme of ship construction. She was laid down at the Sir Raylton Dixon & Co.Sir Raylton Dixon
Sir Raylton Dixon , was a shipbuilder at Middlesbrough on the River Tees. He was one of the seven children of Jeremiah Dixon and Mary Frank of Cockfield, County Durham who were married on 21 July 1833 in St. Cuthberts, Darlington...
Ltd shipyard at Govan
Govan
Govan is a district and former burgh now part of southwest City of Glasgow, Scotland. It is situated west of Glasgow city centre, on the south bank of the River Clyde, opposite the mouth of the River Kelvin and the district of Partick....
in March 1915, launched on 27 May 1915, and completed in July 1915.
World War 1
M21 served initially in the Mediterranean from September 1915. On her return from the Mediterranean in September 1917, M21 had her main 9.2in gun removed, as it was required for artillery use on the Western FrontWestern Front
Western Front was a term used during the First and Second World Wars to describe the contested armed frontier between lands controlled by Germany to the east and the Allies to the west...
, and a BL 7.5 inches (190.5 mm) Mk III 50-caliber gun
BL 7.5 inch Mk II - V naval gun
The BL 7.5 inch guns Mk II - Mk V were a variety of 50 calibres naval guns used by Britain in World War I. They all had similar performance and fired the same shells.-Mark II:...
was fitted in lieu.
M21 then served with the Dover Patrol
Dover Patrol
The Dover Patrol was a Royal Navy command of the First World War, notable for its involvement in the Zeebrugge Raid on 22 April 1918. The Dover Patrol formed a discrete unit of the Royal Navy based at Dover and Dunkirk for the duration of the First World War...
from October 1917.