Pará class monitor
Encyclopedia
The Pará class monitors
were a group of six wooden-hulled ironclads named after Brazilian states and built in Brazil for the Brazilian Navy
during the War of the Triple Alliance
in the late 1860s. The first three ships finished, , and , participated in the Passagem de Humaitá
in February 1868. Afterwards the remaining ships joined the first three and they all provided fire support for the army for the rest of the war. The ships were split between the newly formed Upper Uruguay and Mato Grosso
Flotilla
s after the war. Alagoas was transferred to Rio de Janeiro
in the 1890s and participated in the Fleet Revolt
of 1893–94.
s were designed to meet the need of the Brazilian Navy for small, shallow-draft armored ships capable of withstanding heavy fire during the War of the Triple Alliance
, which saw Argentina
and Brazil allied against Paraguay
. The two foreign-built river monitors already in service drew enough water that they could not operate on the shallower rivers in Paraguay. The monitor configuration was chosen as a turreted design did not have the same problems engaging enemy ships and fortifications as did the casemate ironclad
s already in Brazilian service. The oblong gun turret
sat on a circular platform that had a central pivot. It was rotated by four men via a system of gears; 2.25 minutes were required for a full 360° rotation. A bronze ram
was fitted to these ships as well. The hull was sheathed with Muntz metal
to reduce biofouling
.
The ships measured 39 metre long overall, with a beam
of 8.54 metre. They had a draft between of 1.51 metre and displaced 500 tonnes (492.1 LT). With only 0.3 metre of freeboard
they had to be towed between Rio de Janeiro and their area of operations. Their crew numbered 43 officers and men.
, each driving a single 1.3 metre propeller. Their engines were powered by two tubular boiler
s at a working pressure of 59 pound per square inch. The engines produced a total of 180 ihp which gave the monitors a maximum speed of 8 knots (4.4 m/s) in calm waters. The ships carried enough coal for one day's steaming.
rifled muzzle loader (RML) in their gun turret, but the last three ships substituted a 120-pounder Whitworth
RML. The 70-pdr gun had a maximum elevation of 15°, but the larger gun's elevation was reduced because of its longer barrel. Both guns had a similar maximum range of 5540 metres (6,058.6 yd). The 70-pdr gun weighed 8582 pounds (3,892.7 kg) and fired a 5.5 inches (139.7 mm) shell that weighed 81 pounds (36.7 kg). The 7 inches (177.8 mm) shell of the 120-pdr gun weighed 151 pounds (68.5 kg) while the gun itself weighed 16660 pounds (7,556.8 kg). Most unusually the guns' Brazilian-designed iron carriage was designed to pivot vertically at the muzzle; this was done to minimize the size of the gunport through which splinters and shells could enter.
. The ships had a complete wrought iron
waterline belt
, 0.91 metres (3 ft) high. It had a maximum thickness of 102 millimeters amidships, decreasing to 76 millimetres (3 in) and 51 millimetres (2 in) at the ship's ends. The curved deck
was armored with 12.7 millimetre (0.5 in) of wrought iron.
The gun turret was shaped like a rectangle
with rounded corners. It was built much like the hull, but the front of the turret was protected by 152 millimetres (6 in) of armor, the sides by 102 millimeters and the rear by 76 millimeters. Its roof and the exposed portions of the platform it rested upon were protected by 12.7 millimeters of armor. The armored pilothouse
was positioned ahead of the turret.
on 19 February 1868. For the engagement the three river monitors were lashed to the larger ironclads in case any engines were disabled by the Paraguayan guns. led with Rio Grande, followed by with Alagoas and with Pará. Both Alagoas, which had taken an estimated 200 hits, and Pará had to be beached after passing the fortress to prevent them from sinking. Alagoas was under repair at São José do Cerrito
until mid-March, although Pará joined a squadron
to capture the town of Laureles
on 27 February. Rio Grande continued upstream with the other undamaged ships and they bombarded Asunción
on 24 February with little effect. On 23 March Rio Grande and Barroso sank the Parguayan steamer Igurey and both ships were boarded
by Paraguayan soldiers on the evening of 9 July, although they managed to repel the boarders.
For the rest of the war the river monitors bombarded Paraguayan positions and artillery batteries in support of the army, notably at Angostura, Timbó and along the Tebicuary
and Manduvirá River
s. After the war the ships were divided between the newly formed Upper Uruguay and Mato Grosso Flotillas. Alagoas was transferred to Rio de Janeiro in the 1890s and participated in the Fleet Revolt
of 1893–94. The ships were disposed of during the last two decades of the 19th century, although Rio Grande was docked for reconstruction in 1899. However, the work was never completed and she was eventually scrapped in 1907.
Monitor (warship)
A monitor was a class of relatively small warship which was neither fast nor strongly armoured but carried disproportionately large guns. They were used by some navies from the 1860s until the end of World War II, and saw their final use by the United States Navy during the Vietnam War.The monitors...
were a group of six wooden-hulled ironclads named after Brazilian states and built in Brazil for the Brazilian Navy
Brazilian Navy
The Brazilian Navy is a branch of the Brazilian Armed Forces responsible for conducting naval operations. It is the largest navy in Latin America...
during the War of the Triple Alliance
War of the Triple Alliance
The Paraguayan War , also known as War of the Triple Alliance , was a military conflict in South America fought from 1864 to 1870 between Paraguay and the Triple Alliance of Argentina, Brazil, and Uruguay...
in the late 1860s. The first three ships finished, , and , participated in the Passagem de Humaitá
Passagem de Humaitá
The Siege of Humaitá was a naval battle and later siege which occurred at the fortress of Humaitá, on the Paraguay River beginning on February 19, 1867, as a part of the War of the Triple Alliance, and ending on July 25, 1868....
in February 1868. Afterwards the remaining ships joined the first three and they all provided fire support for the army for the rest of the war. The ships were split between the newly formed Upper Uruguay and Mato Grosso
Mato Grosso
Mato Grosso is one of the states of Brazil, the third largest in area, located in the western part of the country.Neighboring states are Rondônia, Amazonas, Pará, Tocantins, Goiás and Mato Grosso do Sul. It also borders Bolivia to the southwest...
Flotilla
Flotilla
A flotilla , or naval flotilla, is a formation of small warships that may be part of a larger fleet. A flotilla is usually composed of a homogeneous group of the same class of warship, such as frigates, destroyers, torpedo boats, submarines, gunboats, or minesweepers...
s after the war. Alagoas was transferred to Rio de Janeiro
Rio de Janeiro
Rio de Janeiro , commonly referred to simply as Rio, is the capital city of the State of Rio de Janeiro, the second largest city of Brazil, and the third largest metropolitan area and agglomeration in South America, boasting approximately 6.3 million people within the city proper, making it the 6th...
in the 1890s and participated in the Fleet Revolt
Revolta da Armada
Brazilian Naval Revolts, or the Revoltas da Armada , were armed mutinies promoted mainly by Admirals Custodio de Mello and Saldanha da Gama and their fleet of Brazilian Navy ships against unconstitucional attitudes of the then the central government in Rio de Janeiro.-First revolt:In November 1891,...
of 1893–94.
Design and description
The Pará-class river monitorRiver monitor
River monitors were heavily armored, and normally mounted the largest guns of all riverine warships. The name originated from the US Navy's Brown Water Navy's USS Monitor, which made her first appearance in the American Civil War, and being distinguished by a single revolving turret.On 18 December...
s were designed to meet the need of the Brazilian Navy for small, shallow-draft armored ships capable of withstanding heavy fire during the War of the Triple Alliance
War of the Triple Alliance
The Paraguayan War , also known as War of the Triple Alliance , was a military conflict in South America fought from 1864 to 1870 between Paraguay and the Triple Alliance of Argentina, Brazil, and Uruguay...
, which saw Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
and Brazil allied against Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...
. The two foreign-built river monitors already in service drew enough water that they could not operate on the shallower rivers in Paraguay. The monitor configuration was chosen as a turreted design did not have the same problems engaging enemy ships and fortifications as did the casemate ironclad
Casemate ironclad
The casemate ironclad is a type of iron or iron-armored gunboat briefly used in the American Civil War. Compared to the traditional ironclad warship, the casemate ironclad does not have its cannons in an armored gun deck, but instead has a casemate structure on the main deck housing the guns...
s already in Brazilian service. The oblong gun turret
Gun turret
A gun turret is a weapon mount that protects the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in many directions.The turret is also a rotating weapon platform...
sat on a circular platform that had a central pivot. It was rotated by four men via a system of gears; 2.25 minutes were required for a full 360° rotation. A bronze ram
Naval ram
A naval ram was a weapon carried by varied types of ships, dating back to antiquity. The weapon consisted of an underwater prolongation of the bow of the ship to form an armoured beak, usually between six and twelve feet in length...
was fitted to these ships as well. The hull was sheathed with Muntz metal
Muntz metal
Muntz metal is a form of alpha-beta brass with about 60% copper, 40% zinc and a trace of iron. It is named after George Fredrick Muntz, a metal-roller of Birmingham, England who commercialised the alloy following his patent of 1832....
to reduce biofouling
Biofouling
Biofouling or biological fouling is the undesirable accumulation of microorganisms, plants, algae, or animals on wetted structures.-Impact:...
.
The ships measured 39 metre long overall, with a beam
Beam (nautical)
The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...
of 8.54 metre. They had a draft between of 1.51 metre and displaced 500 tonnes (492.1 LT). With only 0.3 metre of freeboard
Freeboard (nautical)
In sailing and boating, freeboardmeans the distance from the waterline to the upper deck level, measured at the lowest point of sheer where water can enter the boat or ship...
they had to be towed between Rio de Janeiro and their area of operations. Their crew numbered 43 officers and men.
Propulsion
The Pará-class ships had two direct-acting steam enginesMarine steam engine
A marine steam engine is a reciprocating steam engine that is used to power a ship or boat. Steam turbines and diesel engines largely replaced reciprocating steam engines in marine applications during the 20th century, so this article describes the more common types of marine steam engine in use...
, each driving a single 1.3 metre propeller. Their engines were powered by two tubular boiler
Boiler (steam generator)
A boiler or steam generator is a device used to create steam by applying heat energy to water. Although the definitions are somewhat flexible, it can be said that older steam generators were commonly termed boilers and worked at low to medium pressure but, at pressures above this, it is more...
s at a working pressure of 59 pound per square inch. The engines produced a total of 180 ihp which gave the monitors a maximum speed of 8 knots (4.4 m/s) in calm waters. The ships carried enough coal for one day's steaming.
Armament
The first three ships carried a single 70-pounder Whitworth70-pounder Whitworth naval gun
The 70-pounder Whitworth naval gun was designed by Joseph Whitworth during the 1860s. It was a rifled muzzle loader and used his hexagonal rifled bore design.-Service:...
rifled muzzle loader (RML) in their gun turret, but the last three ships substituted a 120-pounder Whitworth
120-pounder Whitworth naval gun
The 120-pounder Whitworth naval gun was designed by Joseph Whitworth during the 1860s. It was a rifled muzzle loader and used his hexagonal rifled bore design.-Service:...
RML. The 70-pdr gun had a maximum elevation of 15°, but the larger gun's elevation was reduced because of its longer barrel. Both guns had a similar maximum range of 5540 metres (6,058.6 yd). The 70-pdr gun weighed 8582 pounds (3,892.7 kg) and fired a 5.5 inches (139.7 mm) shell that weighed 81 pounds (36.7 kg). The 7 inches (177.8 mm) shell of the 120-pdr gun weighed 151 pounds (68.5 kg) while the gun itself weighed 16660 pounds (7,556.8 kg). Most unusually the guns' Brazilian-designed iron carriage was designed to pivot vertically at the muzzle; this was done to minimize the size of the gunport through which splinters and shells could enter.
Armor
The hull of the Pará-class ships was made from three layers of wood that alternated in orientation. It was 457 millimetres (18 in) thick and was capped with a 102 millimetres (4 in) layer of peroba hardwoodAspidosperma polyneuron
Aspidosperma polyneuron is a timber tree native to Brazil, Colombia, Peru, Argentina, and Paraguay which is typical of Atlantic Forest vegetation...
. The ships had a complete wrought iron
Wrought iron
thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...
waterline belt
Belt armor
Belt armor is a layer of heavy metal armor plated on to or within outer hulls of warships, typically on battleships, battlecruisers and cruisers, and on aircraft carriers converted from those types of ships....
, 0.91 metres (3 ft) high. It had a maximum thickness of 102 millimeters amidships, decreasing to 76 millimetres (3 in) and 51 millimetres (2 in) at the ship's ends. The curved deck
Deck (ship)
A deck is a permanent covering over a compartment or a hull of a ship. On a boat or ship, the primary deck is the horizontal structure which forms the 'roof' for the hull, which both strengthens the hull and serves as the primary working surface...
was armored with 12.7 millimetre (0.5 in) of wrought iron.
The gun turret was shaped like a rectangle
Rectangle
In Euclidean plane geometry, a rectangle is any quadrilateral with four right angles. The term "oblong" is occasionally used to refer to a non-square rectangle...
with rounded corners. It was built much like the hull, but the front of the turret was protected by 152 millimetres (6 in) of armor, the sides by 102 millimeters and the rear by 76 millimeters. Its roof and the exposed portions of the platform it rested upon were protected by 12.7 millimeters of armor. The armored pilothouse
Pilothouse
A pilothouse or pilot-house is a glass-enclosed room from which a ship is controlled by the ship's pilot. The pilothouse also is known as the wheelhouse....
was positioned ahead of the turret.
Construction
| Ship | Builder | Laid down | Launched | Completed | Fate |
|---|---|---|---|---|---|
| Arsenal de Marinha da Côrte, Rio de Janiero | 8 December 1866 | 21 May 1867 | 15 June 1867 | Discarded Ship decommissioning To decommission a ship is to terminate her career in service in the armed forces of her nation. A somber occasion, it has little of the elaborate ceremony of ship commissioning, but carries significant tradition.... 1884 at Ladário Ladário Ladário is a municipality located in the Brazilian state of Mato Grosso do Sul. The municipality of Ladário is surrounded by the municipality of Corumbá in all directions.... |
|
| 17 August 1867 | 3 September 1867 | Scrapped Ship breaking Ship breaking or ship demolition is a type of ship disposal involving the breaking up of ships for scrap recycling. Most ships have a lifespan of a few decades before there is so much wear that refitting and repair becomes uneconomical. Ship breaking allows materials from the ship, especially... February 1907 |
|||
| 29 October 1867 | November 1867 | Scrapped 1900 | |||
| 8 January 1868 | January 1868 | Scrapped 1893 | |||
| 22 March 1868 | April 1868 | Scrapped 1884 | |||
| 5 May 1868 | June 1868 | Sank 1882 |
Service
The first three ships finished, Pará, Alagoas and Rio Grande, participated in the Passagem de HumaitáPassagem de Humaitá
The Siege of Humaitá was a naval battle and later siege which occurred at the fortress of Humaitá, on the Paraguay River beginning on February 19, 1867, as a part of the War of the Triple Alliance, and ending on July 25, 1868....
on 19 February 1868. For the engagement the three river monitors were lashed to the larger ironclads in case any engines were disabled by the Paraguayan guns. led with Rio Grande, followed by with Alagoas and with Pará. Both Alagoas, which had taken an estimated 200 hits, and Pará had to be beached after passing the fortress to prevent them from sinking. Alagoas was under repair at São José do Cerrito
São José do Cerrito
São José do Cerrito is a town and municipality in the state of Santa Catarina in the South region of Brazil.-References:...
until mid-March, although Pará joined a squadron
Squadron (naval)
A squadron, or naval squadron, is a unit of 3-4 major warships, transport ships, submarines, or sometimes small craft that may be part of a larger task force or a fleet...
to capture the town of Laureles
Laureles
Laureles is a town in the Ñeembucú department of Paraguay.- Sources :* – World-Gazetteer.com...
on 27 February. Rio Grande continued upstream with the other undamaged ships and they bombarded Asunción
Asunción
Asunción is the capital and largest city of Paraguay.The "Ciudad de Asunción" is an autonomous capital district not part of any department. The metropolitan area, called Gran Asunción, includes the cities of San Lorenzo, Fernando de la Mora, Lambaré, Luque, Mariano Roque Alonso, Ñemby, San...
on 24 February with little effect. On 23 March Rio Grande and Barroso sank the Parguayan steamer Igurey and both ships were boarded
Boarding (attack)
Boarding, in its simplest sense, refers to the insertion on to a ship's deck of individuals. However, when it is classified as an attack, in most contexts, it refers to the forcible insertion of personnel that are not members of the crew by another party without the consent of the captain or crew...
by Paraguayan soldiers on the evening of 9 July, although they managed to repel the boarders.
For the rest of the war the river monitors bombarded Paraguayan positions and artillery batteries in support of the army, notably at Angostura, Timbó and along the Tebicuary
Tebicuary River
The Tebicuary River , a tributary of Paraguay River is a river in Paraguay. Located in the southwestern part of that country, it flows eastwards discharging to Paraguay River about 45 km south of Formosa and 30 km north of Pilar....
and Manduvirá River
Manduvirá River
The Manduvirá River is a river of Paraguay. It is a tributary of the Paraguay River.-See also:*List of rivers of Paraguay...
s. After the war the ships were divided between the newly formed Upper Uruguay and Mato Grosso Flotillas. Alagoas was transferred to Rio de Janeiro in the 1890s and participated in the Fleet Revolt
Revolta da Armada
Brazilian Naval Revolts, or the Revoltas da Armada , were armed mutinies promoted mainly by Admirals Custodio de Mello and Saldanha da Gama and their fleet of Brazilian Navy ships against unconstitucional attitudes of the then the central government in Rio de Janeiro.-First revolt:In November 1891,...
of 1893–94. The ships were disposed of during the last two decades of the 19th century, although Rio Grande was docked for reconstruction in 1899. However, the work was never completed and she was eventually scrapped in 1907.