View source for River monitor

{{Short description|Military warship designed to patrol rivers}}
{{About-distinguish|the military boat type|Water monitor}}
{{Use dmy dates|date=July 2022}}

[[File:Monitor model2.jpg|thumb|upright=1.4|Model of USS ''Monitor'']]
'''River monitors''' are military craft designed to patrol rivers.
They are normally the largest of all riverine [[warships]] in river flotillas, and mount the heaviest weapons. The name originated from the US Navy's {{USS|Monitor}}, which made her first appearance in the [[American Civil War]], and being distinguished by the use of revolving [[gun turret]]s, which were particularly useful in rivers, whose narrow channels could severely limit the directions vessels could face.

River monitors were used on [[inland waterway]]s such as rivers, estuaries, deltas and lakes. Usually they had a shallow [[Draft (hull)|draft]] which was necessary for them to be able to operate in enclosed waters; but their displacement, size and draft varied depending on where they were used.

Most river monitors were lightly armored although this varied, with some carrying more armor. Exceptional examples, however, most notably the [[Royal Navy]]'s {{sclass|Lord Clive|monitor||warship}}s, which could operate in coastal or certain riparian/estuarine situations, bore extra-thick armor plating and heavy shore-bombardment guns, up to a massive 18 inches (457&nbsp;mm) in size. Typically, however, river monitors displayed a mixture of gun sizes from 3-inch (75&nbsp;mm) to 6-inch (152&nbsp;mm), plus [[machine gun]]s. This type of vessel overlaps with the [[river gunboat]] that would be armed with relatively small caliber cannons, or a mix of cannons and machine guns.

==United States==
[[File:USS Neosho (1863-1873) - NH 60617.jpg|thumb|right|The Civil War era river monitor [[USS Neosho (1863)|''Neosho'']]]]
River monitors were used during the [[American Civil War]], playing an important role in the [[Mississippi River campaigns in the American Civil War|Mississippi River Campaigns]]. 
They also played a role in the [[Battle of Mobile Bay]]. The American Civil War river monitors were very large, weighing up to 1,300 tons.

On 18 December 1965, the US Navy, for the second time in one hundred years, authorized the reactivation of a [[brown-water navy]] for riparian operations in [[Vietnam War|South Vietnam]].  In July 1966, Secretary of Defense Robert S. McNamara authorized the formation of a [[Mobile Riverine Force]] (MRF);<ref>Carrico, p. 11</ref> a force that would bring back the  river monitor.

[[File:US riverboat using napalm in Vietnam.jpg|thumb|right|A [[Mobile Riverine Force]] monitor using [[napalm]] in the Vietnam War<ref>Carrico p. 82</ref>]]
The US Navy operated its [[Monitor (Vietnam War)|Monitors]] as part of their River Assault Flotilla One, which initially consisted of four River Assault Divisions (RAD); with RAD 91 containing three monitors, RAD 92 having two monitors, RAD 111 having three monitors, and RAD 112 operating two monitors.<ref>Carrico, p. 12</ref>

The Vietnam monitors were divided into two programs; program 4 would consist of the 40&nbsp;mm gun monitors, while the later program 5 would entail the eight Monitor (H) Howitzer versions, and the six Monitor (F) Flamethrower models.<ref>Carrico p. 63</ref>  All of the monitors were converted from [[World War II]] {{convert|56|ft|m|adj=on}} long [[Landing Craft Mechanized]] (LCMs) Mk 6s.<ref>Carrico, p. 16, 17</ref>  When completed, they were {{convert|60|ft|m}} long, {{convert|17|ft|}} wide, with a [[Draft (hull)|draft]] of {{convert|3+1/2|ft|m}}, had two screws driven by two Gray Marine model 64NH9 [[diesel engine]]s, could do {{convert|8.5|kn|lk=in}} and were manned by usually 11 or more crewmen.<ref>Carrico, p. 63</ref>  They usually carried about ten tons of armor.

{| class="wikitable" style="font-size:97%;"
!colspan="4" | US Navy Brown Water Navy River Monitors (Vietnam)<ref>
Monitor Specifications, U.S. Navy Mobile Riverine Force, {{cite web |url=http://www.mrfa.org/Monitor.specs.htm |title=Monitor - Specifications |access-date=2010-01-25 |url-status=dead |archive-url=https://web.archive.org/web/20100716121341/http://www.mrfa.org/Monitor.specs.htm |archive-date=2010-07-16 }}
</ref>
|-
!
!Generation-One Type
!Generation-Two Type/Flame
!Generation-Two Type/Howitzer
|- align="center"
!Length
|{{cvt|61|ft|0|in|order=flip|1}}
|colspan="2"|{{cvt|60|ft|6|in|order=flip|1}}
|- align="center"
!Width
|colspan="3"|{{cvt|17|ft|6|in|order=flip|1}}
|- align="center"
!Draft
|colspan="3"|{{cvt|3|ft|6|in|order=flip|1}}
|- align="center"
!Engines
|colspan="3"|2 Gray Marine 64HN9 diesels; {{cvt|220|hp|order=flip}} at 2100 rpm
|- align="center"
!Speed
|colspan="3"|{{convert|8.5|kn|kph}}
|- align="center"
!Crew
|colspan="3"|11
|-
!Armament
|valign="top"|
*1 81&nbsp;mm mortar
*1 40&nbsp;mm auto-cannon
*1 20&nbsp;mm cannon
*2 [[Mk 18 Mod 0 grenade launcher|Mk 18 grenade launchers]]
*3 [[M79 grenade launcher]]s
*2 .50 cal. machine guns
*4 7.62&nbsp;mm machine guns
|valign="top"|
*2 20&nbsp;mm cannons
*2 200m range flamethrowers
*3 M79 grenade launchers
*2 .50 cal. machine guns
|valign="top"|
*1 105&nbsp;mm howitzer
*2 20&nbsp;mm cannons
*3 M79 grenade launchers
*2 .50 cal. machine guns
*1 7.62&nbsp;mm machine gun
|}

==Asia==
On Asian rivers, the [[Amur Military Flotilla]] on the [[Amur River|Amur]] used large ''Taifun''-class river monitors of the [[Imperial Russian Navy]] from around 1907; the [[Imperial Japanese Navy]] captured some of these ships in 1918.<ref>See  Warships of World War II. Retrieved 25 August 2015.</ref> They were up to 1,000 tons displacement, armed with 130&nbsp;mm guns. Some of these Russian monitors, such as the recommissioned ''Sverdlov'', were still in use by the [[Soviet Navy]] in the 1945 [[Soviet invasion of Manchuria]].<ref>Glantz, David (2004) [https://books.google.com/books?id=klCQAgAAQBAJ&pg=PA222 Soviet Operational and Tactical Combat in Manchuria, 1945: 'August Storm']. Routledge, p. 222. {{ISBN|9781135774783}}</ref> The most powerful and largest riverine vessels were three [[Khasan-class monitor]]s from 1940s, with 2,400 ton full displacement and limited seagoing capabilities.<ref>{{cite magazine|author=S.V. Patianin|title=Korabli Vtoroi mirovoi voiny. VMF SSSR 1941-1945 gg.|magazine=Morskaya Kampaniya|issue=3(24)/2009|year=2009|lang=ru|pages=54–56}}</ref>

During the [[Vietnam War]], the [[United States Navy]], in conjunction with other riverine craft, commissioned 24 monitors, ten of which mounted a single 40&nbsp;mm cannon in a Mk 52 turret, eight which mounted an M49 105&nbsp;mm [[howitzer]] within a T172 turret,<ref>Carrico, p. 27</ref> and six monitors which mounted two M10-8 flamethrowers from two M8 turrets located on either side of the vessel's 40&nbsp;mm cannon. Referred to as "river battleships"<ref>Carrico, p. 20, 21, 63</ref> by their crews, they provided the firepower of the [[brown-water navy]].

==Europe==
[[File:River monitor Inn.png|thumb|Austro-Hungarian river monitor SMS ''Inn'' (later Romanian ''Basarabia''), the largest Danube warship sunk during World War I]]
On the [[Danube]], river monitors were employed during [[World War I]] by [[Austria-Hungary]] and [[Kingdom of Romania|Romania]]. The Austro-Hungarian river monitor ''[[Yugoslav monitor Sava|Bodrog]]'' fired the first shots of [[World War I]], against the city of [[Belgrade]], and later also fought in the [[Romania during World War I|Romanian Campaign]], notably during the [[Flămânda Offensive]] in October 1916, when she was damaged. Another river monitor, ''[[SMS Körös|Körös]]'', was also heavily damaged by Romanian artillery, taking 12 hits and ran aground after her steam lines were severed.<ref>Michael B. Barrett, Prelude to Blitzkrieg: The 1916 Austro-German Campaign in Romania, p. 140</ref> On 22 September 1917, the [[Enns-class river monitor|''Enns''-class]] river monitor ''[[SMS Inn|Inn]]'' was sunk by a Romanian mine near [[Brăila]].<ref>Angus Konstam, ''Gunboats of World War I'', p. 29</ref><ref>René Greger, ''Austro-Hungarian warships of World War I'', p. 142</ref><ref>Mark Axworthy, Cornel I. Scafeș, Cristian Crăciunoiu, ''Third Axis, Fourth Ally: Romanian Armed Forces in the European War, 1941–1945'', p. 327</ref> She was refloated but her repairs were not completed before the War ended, and she was eventually handed over to Romania as war reparation, being renamed ''Basarabia''.<ref>René Greger, ''Austro-Hungarian Warships of World War I'', p. 142</ref>

[[File:Monitor_Sava_-_05.jpg|thumb|right|220px|The river monitor ''[[Yugoslav monitor Sava|Sava]]'' (formerly ''Bodrog'') fired the first shots of [[World War I]]. She is now a floating museum anchored along the [[Sava]] river in [[Belgrade]], [[Serbia]]]]

During World War I, the Romanian {{sclass|Brătianu|river monitor|4}} were the largest river monitors on the Danube, displacing 680 tons, armed mainly with three 120&nbsp;mm guns and protected by at least 70&nbsp;mm of armor around the belt, turrets and conning tower. They were built in sections at [[Trieste|Triest]] in [[Austria-Hungary]], transported to Romania by rail and assembled by the Romanians at the [[Galați shipyard]] in 1907–1908.<ref>Robert Gardiner, ''Conway's All the World Fighting Ships 1906–1921'', p. 422</ref><ref>Roger Kafka, Roy L. Pepperburg, ''Warships of the World'', p. 881</ref><ref>Frederick Thomas Jane, ''Jane's Fighting Ships'', p. 343</ref> They did not engage enemy ships, however, instead they were used to support ground forces during the [[Battle of Turtucaia]] and the [[First Battle of Cobadin]], and also took part in the [[Romania during World War I#1917 campaign and armistice|1917 campaign]], contributing to the stemming of the enemy advance.<ref>Spencer Tucker, Priscilla Mary Roberts, ''World War I: Encyclopedia, Volume 1'', p. 999</ref> During the Interwar period, the Romanian Danube Flotilla was the most powerful riverine fleet in the world.<ref>Axworthy, p. 327</ref> In 1924, the Romanian river monitors helped suppress the [[Tatarbunary Uprising]], along with the entire Romanian Danube Flotilla. In late 1980s and 1990s Romania commissioned newly built [[Smârdan-class river monitor]]s (classified as large armoured boats), and three big [[Mihail Kogălniceanu-class river monitor]]s, used still in the 21st century.<ref>{{cite magazine|author=Jarosław Malinowski|title=Rumuńska Flotylla Dunajska|magazine=Okręty Wojenne|volume= 2/2006 (76)|date= 2006|place=Tarnowskie Góry|lang=pl}}</ref>

[[File:Hlídková loď President Masaryk (2).jpg|thumb|''President Masaryk'', the flagship of the Czechoslovak River Flotilla]]
Czechoslovakia had one monitor, {{ship||President Masaryk|monitor|2}}, of about 200 tons displacement. She was however classified as a patrol boat (''hlídková loď''). She was captured by the Germans in 1939 and commissioned as ''Bechelaren''. She was extensively rebuilt in 1943 and her armament was also modified in February 1945. She supported German troops during [[Operation Spring Awakening]] and later fought in Austria, sinking two Soviet gunboats.

Yugoslav river monitors were former Austro-Hungarian warships received as reparations. They were renamed {{ship|Yugoslav monitor|Vardar||2}} (ex-''Bosna''), {{ship|Yugoslav monitor|Sava||2}} (ex-''Bodrog''), {{ship|Yugoslav monitor|Drava||2}} (ex-''Enns'') and ''[[SMS Körös#Interwar period and World War II|Morava]]'' (ex-''Körös''). After the [[Invasion of Yugoslavia|fall of Yugoslavia]] in April 1941, ''Morava'' (renamed ''Bosna'') and ''Sava'' were commissioned by the newly created [[Independent State of Croatia]].

Six smaller monitors (70–100 ton displacement) were used by [[Poland]] in 1939 on shallow [[Pripyat River]]. Captured by the [[Soviet Union]], they were used in 1941 by the Soviets on the Pripyat and [[Dnieper|Dnepr]] rivers, along with Soviet riverine ships. The Soviet Union also had five ''Zheleznyakov''-class monitors of 263 tons, which served with the [[Danube Flotilla (Soviet Union)|Danube Flotilla]] and [[Dnieper Flotilla#The Dnieper Flotilla during the Second World War|Dnieper Flotilla]] in World War II.

Hungary also used river monitors, five of them notably taking part during the [[Kozara Offensive]] in 1942.

==South America==
[[File:M_Parnaíba_(U-17).jpg|thumb|Brazilian Navy's river monitor {{ship|Brazilian monitor|Parnaíba|U17|2}}]]
The Brazilian river monitor {{ship|Brazilian monitor|Parnaíba|U17|2}} was built for the navy in [[Rio de Janeiro]] and [[Ship commissioning|commissioned]] on 9 March 1938. It participated in the [[Second World War]] and is currently the world's oldest commissioned warship still in active service.<ref>{{cite web |url=http://warisboring.com/one-of-the-worlds-oldest-military-ships-is-sailing-down-a-river-in-brazil/ |title=One of the World's Oldest Military Ships Is Sailing Down a River in Brazil |last=Beckhusen |first=Robert |date=25 May 2018 |website=warisboring.com |publisher=Bright Mountain Media |access-date=26 May 2018 |quote=In terms of operational and active ships doing military work, perhaps only the Russian salvage ship ''Kommuna'' is older... |archive-date=9 November 2020 |archive-url=https://web.archive.org/web/20201109043620/https://warisboring.com/one-of-the-worlds-oldest-military-ships-is-sailing-down-a-river-in-brazil/ |url-status=live }}</ref> It is assigned to the Brazilian navy's [[Mato Grosso]] Flotilla.

==See also==
* [[Gunboat]]
* [[List of monitors of the United States Navy]]
* [[List of monitors of the Royal Navy]]
* [[List of monitors of the Swedish Navy]]
* [[List of monitors of the Netherlands]]

==References==

{{reflist|30em}}
* Carrico, John M., ''Vietnam Ironclads'', 2007; Brown Water Enterprises.  {{ISBN|978-0-9794231-0-9}}.
* Friedman, Norman, ''U.S. Small Combatants: An Illustrated Design History'', 1987; Annapolis: Naval Institute Press.  {{ISBN|0-87021-713-5}}.
* Kramer, Charles (Illustrator), ''Popular Mechanics'' Magazine, 1967; Charles Kramer of Zik Assoc., Ltd. cutaway view of Vietnam "River Battleship".

{{Warship types of the 19th & 20th centuries}}

{{DEFAULTSORT:River Monitor}}
[[Category:Ship types]]
[[Category:Riverine warfare]]
[[Category:Monitors]]
[[Category:Warships]]
[[Category:Gunboats]]