# Stokes mortar > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Stokes_mortar > Markdown URL: https://mediated.wiki/source/Stokes_mortar.md > Source: https://en.wikipedia.org/wiki/Stokes_mortar > Source revision: 1352398903 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{About|the World War I Stokes 3-inch mortar|the World War II mortar|Ordnance ML 3 inch mortar}} {{Use British English|date=November 2025}} {{Use dmy dates|date=November 2025}} {{Infobox weapon | name = 3 inch Stokes mortar | origin = United Kingdom | type = [Light mortar](/source/Mortar_(weapon)) | image = Image:WilfredStokeswithMortar.jpg | caption = Sir [Wilfred Stokes](/source/Wilfred_Stokes) with example of his mortar and bombs. Typical 3-inch bombs used are 2nd and 6th from left | is_ranged = yes | is_explosive = yes | is_artillery = yes | is_UK = yes | service = | used_by = {{ubl|[British Empire](/source/British_Empire)|[Belgium](/source/Belgium)|[French Third Republic](/source/French_Third_Republic)|[Kingdom of Greece](/source/Kingdom_of_Greece)|[Kingdom of Italy](/source/Kingdom_of_Italy)|[Paraguay](/source/Paraguay)The Military Evolution. CLAUDIO VELAZQUEZ PLAIN. EDITORIAL GOYA. Pags 82-83.|[Netherlands](/source/Netherlands){{Cite web|url=http://generalyegros.com/index.php/guerra-del-chaco/41-blog/80-mortero-stokes-brandt-de-81mm-el-mortero-del-chaco |title=Mortero Stokes Brandt de 81mm - El mortero del Chaco |lang=es|trans-title=81mm Stokes Brandt Mortar - The Chaco Mortar |url-status=usurped |date=May 2025}}{{Cite book|last1=Boselli Cantero |first1=Cristina |last2=Casabianca |first2=Ange-Francois |year=2000 |title=Una guerra desconocida: la campaña del Chaco Boreal, 1932–1935 |trans-title=An Unknown War: The Chaco Boreal Campaign, 1932-1935 |volume=4 & 5 |publisher=Lector |p=176 |isbn=99925-51-91-7 |lang=es}}|[Second Polish Republic](/source/Second_Polish_Republic)|[Portugal](/source/Portugal)|[Commonwealth of the Philippines](/source/Commonwealth_of_the_Philippines)|[United States](/source/United_States)}} | wars = {{ubl|[World War I](/source/World_War_I)|[World War II](/source/World_War_II)|[Banana Wars](/source/Banana_Wars)|[Chaco War](/source/Chaco_War)}} | designer = [Sir Wilfred Stokes](/source/Wilfred_Stokes) [KBE](/source/Order_of_the_British_Empire) | design_date = 1915 | manufacturer = | production_date = | number = | weight = {{cvt|104|lb|1}} total"Appendix D. Details of Trench Mortars" in "Field Artillery Notes No. 7". Mortar=48 lb; Elevating Stand=28 lb; Base Plate=28 lb; Total Weight for Transport = 104 lbs | length = | width = | height = | part_length = | diameter = | crew = 2 | cartridge = [HE](/source/Shell_(projectile)) {{cvt|10|lb|11|oz|2}}"Appendix E. Details of Ammunition" in "Field Artillery Notes No. 7". This figure is for the unstabilised cylindrical bomb used in World War I. | caliber = {{cvt|3.2|in}}War Dept. Technical Manual TM9-2005, Volume 3, Ordnance Materiel - General, p. 17, December 1942 | action = Trip | rate = 25 rpm (maximum)"Appendix D. Details of Trench Mortars" in "Field Artillery Notes No. 7"
6–8 rpm (sustained) | velocity = | range = {{cvt|750|yds|0}} | max_range = {{cvt|800|yds|0}}{{sfn|Range Table For 3-Inch Stokes Mortar|1917|loc=A|ps=: "At 45° using 4 Rings of propellant. This figure is for the unstabilised cylindrical bomb used in World War I."}} | feed = | sights = | breech = | recoil = | carriage = | elevation = 45–75°{{sfn|Range Table For 3-Inch Stokes Mortar|1917|loc=B|ps=: "45° gave maximum range with any particular propellant amount e.g. {{cvt|420|yds}} with 1 ring. 75° gave the most vertical descent for the shell and the shortest range with any particular propellant amount e.g. {{cvt|197|yds}} with 1 ring."}} | traverse = | filling = [Amatol](/source/Amatol) | filling_weight = {{cvt|2|lb|4|oz|0}}"Appendix E. Details of Ammunition" in "Field Artillery Notes No. 7" | detonation = | yield = }} The '''Stokes mortar''' was a British [trench mortar](/source/mortar_(weapon)) designed by [Sir Wilfred Stokes](/source/Wilfred_Stokes) [KBE](/source/Order_of_the_British_Empire) that was issued to the [British](/source/British_Army) and [U.S. armies](/source/American_Expeditionary_Forces), as well as the [Portuguese Expeditionary Corps](/source/Portuguese_Expeditionary_Corps), during the latter half of the [First World War](/source/First_World_War). The 3-inch trench mortar was a smooth-bore, muzzle-loading weapon for high angles of fire. Although it was called a 3-inch mortar, its bore was actually 3.2 inches or 81 mm. ==Design== The Stokes mortar was a simple weapon, consisting of a [smoothbore](/source/smoothbore) metal tube fixed to a base plate (to absorb recoil) with a lightweight [bipod](/source/bipod) mount. When a mortar bomb was dropped into the tube, an impact sensitive [primer](/source/Percussion_cap) in the base of the bomb would make contact with a firing pin at the base of the tube, and ignite the propellant charge in the base, launching the bomb towards the target. The warhead itself was detonated by an impact fuse on reaching the target. The barrel was a seamless drawn-steel tube necked down at the breech or base end. A base cap was fitted to the breech end, within which a firing pin was secured, protruding into the barrel. The caps at each end of the bomb cylinder were 81 mm diameter. The bomb was fitted with a modified [hand grenade](/source/hand_grenade) [fuse](/source/fuze) on the front, with a perforated tube containing a propellant charge and an impact-sensitive cap at the rear. Range was determined by the amount of propellant charge used and the angle of the barrel. A basic propellant cartridge was used for all firing, and covered short ranges. Up to four additional "rings" of propellant were used for incrementally greater ranges. The four rings were supplied with the cartridge and gunners discarded the rings that were not needed. One potential problem was the recoil, which was "exceptionally severe, because the barrel is only about 3 times the weight of the projectile, instead of about one hundred times the weight as in artillery. Unless the legs are properly set up they are liable to injury".Stokes's Trench Howitzer 3" Mark I, page 15 A modified version of the mortar, which fired a modern fin-stabilised streamlined projectile and had a booster charge for longer range, was developed after World War I;{{sfn|Ruffell}} this was in effect a new weapon. == History == Light mortars portable by one man had already been in use centuries earlier, but had fallen out of general usage since the [Napoleonic era](/source/Napoleonic_era). With the many changes to battlefield doctrine during the First World War, the concept gained interest again. At first the British and French resorted to re-issuing these obsolete mortars;{{cite web |url=https://www.longlongtrail.co.uk/the-british-trench-mortar-batteries-in-the-first-world-war/|title=The British Trench Mortar Batteries in the First World War|last=Baker|first=Chris|date=24 July 2015 |via=The long, long trail|access-date=26 February 2023 |quote=Forty ancient [Coehorn](/source/Coehorn) mortars, firing spherical ammunition using black powder charges,were obtained from the French, and were actually fired at the battles at Neuve Chapelle and Aubers Ridge. }} after modernised designs became available, the Stokes mortar in particular gained popularity. Frederick Wilfred Scott Stokes designed the mortar in January 1915. The British Army was at the time trying to develop a weapon that would be a match for the [Imperial German Army's](/source/German_Army_(German_Empire)) [Minenwerfer](/source/Minenwerfer) mortar, which was in use on the [Western Front](/source/Western_Front_(World_War_I)). Stokes's design was initially rejected in June 1915 because it was unable to use existing stocks of British mortar ammunition. It took the intervention of [David Lloyd George](/source/David_Lloyd_George) (at that time [Minister of Munitions](/source/Minister_of_Munitions)) and Lieutenant-Colonel J. C. Matheson of the Trench Warfare Supply Department (who reported to Lloyd George) to expedite manufacture of the Stokes mortar. In the last quarter of 1915, 304 Stokes mortars were produced. Only 104 of these reached the front, however, the remainder being sent to training schools.{{sfn|Saunders|2008|p=110}} The subcontracting-out of manufacture of the mortar mounting was undertaken in February 1916.{{sfn|Saunders|2008|p=103}} In March 1916, it was announced the light trench mortars would be controlled by Infantry Brigades. The handbook for the Stokes trench mortar was issued to the infantry in April 1916.{{sfn|Saunders|2008|p=224}} In total, 11,331 3-inch Stokes mortars were manufactured in Britain.{{sfn|Saunders|2008|p=111}} It remained in service into the Second World War, when it was superseded by the [Ordnance ML 3 inch mortar](/source/Ordnance_ML_3_inch_mortar), and some remained in use by New Zealand forces until after the [Second World War](/source/Second_World_War). Stokes was [knighted](/source/knighted) as a [Knight of the British Empire](/source/Order_of_the_British_Empire) in 1917 for inventing the mortar.{{London Gazette|issue=30250 |supp=y| date=24 August 1917|page=8795}} He was also given several forms of monetary reward by the [Ministry of Munitions](/source/Ministry_of_Munitions).{{citation needed|date=July 2015}} The French developed an improved version of the Stokes mortar as the [Brandt Mle 27](/source/Brandt_Mle_27%2F31), further refined as the [Brandt Mle 31](/source/Brandt_Mle_27%2F31); this design was widely copied with and without licence.{{cite book|author=Chris Bishop|title=The Encyclopedia of Weapons of World War II |url=https://books.google.com/books?id=MuGsf0psjvcC&pg=PA202 |year=2002 |publisher=Sterling Publishing Company|isbn=978-1-58663-762-0|page=202}}{{Cite web|url=https://www.militaryfactory.com/smallarms/detail.php?smallarms_id=483|title=Brandt mle 27 (Mortier Brandt de 81mm modele 27) Infantry Mortar|website=www.militaryfactory.com}} Despite their indigenous production, out of 8,000 81 mm mortars in service with the French in 1939, 2,000 were of the original Mk. I build purchased from Great Britain.{{cite book |author=John Norris |title=Infantry Mortars of World War II |series=No. 54 (New Vanguard) |year=2002 |publisher=Osprey Publishing |isbn=978-1-84176-414-6 |pages=42–43}} ==Usage== [[File:PortugueseLoadingStokesMortarWesternFront.jpg|thumb|[Portuguese Expeditionary Corps](/source/Portuguese_Expeditionary_Corps) soldiers loading a Stokes mortar, on the Western Front during World War I.]] In World War I, the Stokes mortar could fire as many as 25 bombs per minute and had a maximum range of {{convert|800|yd|m|0}} firing the original cylindrical un-stabilised projectile. British Empire units had 1,636 Stokes mortars in service on the [Western Front](/source/Western_Front_(World_War_I)) at the Armistice.{{sfn|Farndale |1986 |page=342}} ===American usage=== After [American entry into World War I](/source/American_entry_into_World_War_I), the Stokes mortar was standardised as the "Mortar, Trench, 3", Mk. I" and "Mortar, Trench, 3", Mk. IA2." Although production of the weapon was started in the United States before the end of the war, few American-built weapons reached France and most of those actually used in combat were of British manufacture. It was used in the [Banana Wars](/source/Banana_Wars) and helped American forces defeat [Sandinista](/source/Sandinista) rebels during the [Second Battle of Las Cruces](/source/Battle_of_Las_Cruces_(1928)) on 1 January 1928.{{cite web |url=http://www.sandinorebellion.com/PCDocs/1928a/PC280104b-Brown.html|title=The Sandino Rebellion, 1927–1934 |website=www.sandinorebellion.com}} Refinements of the British Stokes mortar were made by French weapons designer [Edgar Brandt](/source/Edgar_Brandt) in the [interwar period](/source/interwar_period), resulting in the [Brandt mortar](/source/Brandt_Mle_27%2F31). The new weapon, which was adopted by the Americans as the [M1 mortar](/source/M1_mortar) and put into limited production starting in 1935, had a heavier barrel, cross-leveling device on the bipod, and a new base plate. By 1942, the Mk. I and Mk. IA2 had been fully supplanted by the M1 and reclassified as "limited standard." ===Other usage=== The [Paraguayan Army](/source/Paraguayan_army) made extensive use of the Stokes mortar during the [Chaco War](/source/Chaco_War), especially as a [siege weapon](/source/Siege_warfare) in the [Battle of Boquerón](/source/Battle_of_Boquer%C3%B3n) in September 1932. Stokes mortars were widely used by the [Republican Army](/source/Spanish_Republican_Army) during the [Spanish Civil War](/source/Spanish_Civil_War), [sold mostly by Poland](/source/Polish_arms_sales_to_Republican_Spain). In September 1936, 44,000 Stokes rounds arrived in Spain.{{Cite book|last=Howson |first=Gerald |year=2000 |title=Armas para España: la historia no contada de la Guerra Civil Española |lang=es|trans-title=Weapons for Spain: The Untold Story of the Spanish Civil War |publisher=Península |location=Madrid |p=394 |isbn=9788483073049}} ===South Persia Rifles usage=== *{{flag|Qajar Iran}} – [South Persia Rifles](/source/South_Persia_Rifles) received 4 [Stokes mortars](/source/Stokes_mortar) and 1,000 rounds of ammunition to complete its artillery complement.{{Cite web |title=Despatch on Minor Operations in Southern Persia, 7 November 1917 to 31 March 1918 |author=Percy Molesworth Sykes |publisher=Qatar Digital Library |date=1918 |url=https://www.qdl.qa/en/archive/81055/vdc_100000000239.0x000143 |page=8 |quote=4 trench mortars (Stokes) and 1,000 rounds obtained to complete South Persia Rifles Artillery... |access-date=27 April 2026 }} ==4-inch variant== A {{convert|4|in|mm|0|adj=on}} calibre version of the Stokes design was used to fire smoke, poison gas, and [thermite](/source/thermite) (incendiary) rounds. A quantity of just under thirty were first used at the Battle of Loos in September 1915. Up to the end of 1918, a total of 1,123 were manufactured.{{Cite report |title=Report on work of Trench Warfare Supplies Department |publisher=Ministry of Munitions, Munitions Council: Historical Records Branch |subject=The 4-inch Stokes mortar |id=MUN 5/195/1600 |via=The National Archives UK reading room }} This weapon, used solely by the Special Brigade of the [Royal Engineers](/source/Royal_Engineers),{{cite web |title=Surviving 4-in. Stokes trench mortar at Rovereto |last=Plumier|first=Bernard |url=http://www.passioncompassion1418.com/Canons/Eng_AfficheCanonGET.php?IdCanonAffiche=732 |via=Passion & Compassion 1914–1918 |date=20 August 2008 |access-date=1 March 2023}} should be considered a separate weapon from the standard "3-inch" {{convert|81|mm|in|0|adj=on}} version used by the infantry.{{cite web |title=Surviving Stokes mortar at Les Invalides |last=Jalabert |first=Jean-Luc |url=http://www.passioncompassion1418.com/Canons/Eng_AfficheCanonGET.php?IdCanonAffiche=552 |via=Passion & Compassion 1914–1918 |date=14 August 2008 |access-date=26 February 2023}} ==Image gallery== Image:3inchStokesHERound.JPG|{{center|High explosive bomb}} Image:No145MkIPercussionFuzeDiagram.jpg|{{center|No. 145 percussion fuze}} Image:The Battle of Passchendaele, July-november 1917 Q6025.jpg|{{center|Men of the [KOYLI](/source/KOYLI) fusing Stokes shells near Wieltje, 1 October 1917}} File:World-war-one-belgium-iron-harvest-telegraphpole.redvers.jpg|An intact Stokes shell found during the [iron harvest](/source/iron_harvest) in 2004 near [Ypres](/source/Ypres) and placed on a telegraph pole for collection and disposal ==Surviving examples== *Australian War Memorial, Canberra{{Cite web | title=Australian War Memorial» Blog Archive » Trench Mortar | url=http://blog.awm.gov.au/awm/2008/04/01/trench-mortar/ | archive-url=https://web.archive.org/web/20080723035912/http://blog.awm.gov.au/awm/2008/04/01/trench-mortar/ | access-date=2024-12-15 | archive-date=2008-07-23}} *An example with bombs is displayed at l'hotel de ville d'Arras, France.[http://canonspgmww1guns.canalblog.com/archives/03__lance_mines_allies__allied_mine_throwers_/p60-0.html Bernard Plumier : his web page], [http://canonspgmww1guns.canalblog.com/images/canon05.jpg photograph] ==See also== * [List of infantry mortars](/source/List_of_infantry_mortars) * [7.58 cm Minenwerfer](/source/7.58_cm_Minenwerfer)—Approximate German equivalent ==Notes== {{notelist}} {{reflist}} ==Bibliography== * {{cite report |ref={{sfnref|Range Table For 3-Inch Stokes Mortar|1917}} |title=Range Table For 3-Inch Stokes Mortar |date=September 1917 |publisher=United Kingdom War Office}} * [http://cgsc.cdmhost.com/cdm4/item_viewer.php?CISOROOT=/p4013coll9&CISOPTR=198&CISOBOX=1&REC=1 "Stokes' trench howitzer, 3", mark I". US Army War College, January 1918.] {{Webarchive|url=https://web.archive.org/web/20080409133659/http://cgsc.cdmhost.com/cdm4/item_viewer.php?CISOROOT=%2Fp4013coll9&CISOPTR=198&CISOBOX=1&REC=1 |date=2008-04-09 }} via Combined Arms Research Library * [http://cgsc.cdmhost.com/u?/p4013coll9,89 Field Artillery Notes No. 7. US Army War College August 1917.] {{Webarchive|url=https://web.archive.org/web/20080409133721/http://cgsc.cdmhost.com/u/?%2Fp4013coll9%2C89 |date=2008-04-09 }} via Combined Arms Research Library * {{cite book |first=Bruce N. |last=Canfield |chapter-url=http://www.worldwar1.com/dbc/smortar.htm |chapter=The Three Inch Stokes Mortar |title=U.S. Infantry Weapons of the First World War |date=2000 |publisher=Andrew Mowbray Pub. |isbn=978-0917218903}} * {{cite book |series=History of the Royal Regiment of Artillery |title=Western Front 1914–18 |last=Farndale |first=M. |author-link=Martin Farndale |year=1986 |publisher=Royal Artillery Institution |location=London |isbn=978-1-870114-00-4}} * {{cite book |first=W. L. |last=Ruffell |chapter-url=https://web.archive.org/web/20150115122833/http://www.riv.co.nz/rnza/hist/mortar/mort7.htm |chapter=The Stokes Mortar |url=http://www.riv.co.nz/rnza/hist/mortar/index.htm |archive-url=https://web.archive.org/web/20150114075938/http://www.riv.co.nz/rnza/hist/mortar/index.htm |url-status=dead |archive-date=2015-01-14 |title=The Mortar}} * {{cite thesis |type=PhD |first=Anthony |last=Saunders |year=2008 |title=A MUSE OF FIRE; British Trench Warfare Munitions, their Invention, Manufacture and Tactical Employment on the Western Front, 1914–18 |publisher=University of Exeter |url=https://ore.exeter.ac.uk/repository/bitstream/handle/10036/69476/SaundersA.pdf?sequence=2&isAllowed=y |access-date=27 February 2023}} ==External links== {{Commons category|3 inch Stokes Mortar}} * [http://www.lexpev.nl/downloads/handbook3instokesmortar1919.pdf "Handbook of the M.L. Stokes 3-Inch Trench Mortar Equipments. 1919."] Published by His Majesty's Stationery Office, London, 1920. * [http://cgsc.cdmhost.com/cdm4/item_viewer.php?CISOROOT=/p4013coll9&CISOPTR=1&CISOBOX=1&REC=8 "Basic Field Manual. Volume III, Basic Weapons. Part Four, Howitzer Company. 3-inch Trench Mortar"] {{Webarchive|url=https://web.archive.org/web/20070807014350/http://cgsc.cdmhost.com/cdm4/item_viewer.php?CISOROOT=/p4013coll9&CISOPTR=1&CISOBOX=1&REC=8 |date=2007-08-07 }}. United States War Department, 1932. via Combined Arms Research Library] {{WWI British Empire small arms}} {{GreatWarBritishWeapons}} Category:World War I British infantry weapons Category:World War I mortars of the United Kingdom Category:World War II infantry mortars of the United Kingdom Category:World War I infantry weapons of Australia Category:World War II infantry weapons of Australia Category:81mm mortars Category:Weapons of the Philippine Army --- Adapted from the Wikipedia article [Stokes mortar](https://en.wikipedia.org/wiki/Stokes_mortar) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Stokes_mortar?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.