HMS M21
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{{Use British English|date=December 2016}}
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{{Infobox ship image |Ship image=HMS M21 WWI IWM SP 2030.jpg |Ship caption= }} {{Infobox ship career |Hide header= |Ship country=United Kingdom |Ship flag={{shipboxflag|United Kingdom|naval}} |Ship name=HMS M21 |Ship namesake= |Ship ordered= |Ship builder=Sir Raylton Dixon & Co. |Ship laid down=1 March 1915 |Ship launched=27 May 1915 |Ship acquired= |Ship commissioned= |Ship decommissioned= |Ship in service= |Ship out of service= |Ship struck= |Ship reinstated= |Ship honours= |Ship fate=Sunk 20 October 1918 off Dover |Ship notes= }} {{Infobox ship characteristics |Hide header= |Header caption= |Ship tonnage= |Ship displacement=540 tons |Ship length={{convert|177|ft|3|in|m|abbr=on}} |Ship beam={{convert|31|ft|m|abbr=on}} |Ship height= |Ship draught={{convert|6|ft|9|in|m|abbr=on}} |Ship depth= |Ship power= |Ship propulsion=*2 shaft
|Ship sail plan= |Ship speed=11 knots |Ship range= |Ship endurance= |Ship boats= |Ship capacity= |Ship troops= |Ship complement=69 |Ship crew= |Ship time to activate= |Ship sensors= |Ship EW= |Ship armament=
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HMS M21 was a First World War Royal Navy M15-class monitor. After service in the Mediterranean and the Dover Patrol, she struck a mine off Ostend in January 1918 and sank off Dover.
Design
Intended as a shore bombardment vessel, M21{{'}}s primary armament was a single 9.2 inch Mk VI gun removed from the {{sclass|Edgar|cruiser}} HMS Theseus.{{cite book | title = Conway's All the World's Fighting Ships 1906-1921 | editor = Randal Gray | year = 1985 | isbn = 0-85177-245-5 | publisher= Conway Maritime Press | page = 48}} In addition to her 9.2 inch gun, she also possessed one 12 pounder and one six pound anti-aircraft gun. Due to the shortage of Bolinder diesel engines that equipped 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 War Emergency Programme of ship construction. She was laid down at the Sir Raylton Dixon & Co. Ltd shipyard at Govan in March 1915, launched on 27 May 1915, and completed in July 1915.
World War I
M21 served initially in the Mediterranean from September 1915. On her return from the Mediterranean in September 1917, M21 had her main 9.2 in gun removed, as it was required for artillery use on the Western Front, and a BL 7.5 inch Mk II - V naval gun was fitted in lieu.
M21 then served with the Dover Patrol from October 1917.
Loss
M21 struck a mine off Ostend on 20 October 1918. She was taken in tow to Dover, but sank off West Pier.
Citations
{{Reflist}}
References
- {{Cite Colledge2006}}
- Dittmar, F. J. & Colledge, J. J., "British Warships 1914-1919", (Ian Allan, London, 1972), {{ISBN|0-7110-0380-7}}
{{M15 class monitors}}
{{October 1918 shipwrecks}}
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{{coord missing|English Channel}}
{{DEFAULTSORT:M21}}
Category:World War I monitors of the United Kingdom
Category:Maritime incidents in 1918