Monitor (warship)

A monitor was a relatively small warship which was neither fast nor strongly armoured but carried disproportionately large guns. They were used by some navies from the 1860s, during the First World War and with limited use in the Second World War. During the Vietnam War they were used by the United States Navy.[1] The Brazilian Navy's Parnaíba is the last monitor in service.

The original monitor was designed in 1861 by John Ericsson, who named it USS Monitor. They were designed for shallow waters and served as coastal ships. The term "monitor" also encompassed more flexible breastwork monitors, and was sometimes used as a generic term for any turreted ship.

The term "monitor" also encompasses the strongest of riverine warcraft, known as river monitors. In the early 20th century, the term "monitor" was revived for shallow-draught armoured shore bombardment vessels, particularly those of the Royal Navy: the Lord Clive-class monitors carried guns firing heavier shells than any other warship ever has, seeing action (albeit briefly) against German targets during World War I. The Lord Clive vessels were scrapped in the 1920s.

Monitor officers2
Officers of a Union monitor, probably USS Patapsco, photographed during the American Civil War
Monitor model
USS Monitor, the first monitor (1861)
HMS Marshal Ney. The large gun turret is typical of a monitor type warship.

Nineteenth century

Battle of Mobile Bay
U.S.Navy monitors forcing the surrender of the casemate ironclad CSS Tennessee during the Battle of Mobile Bay

American Civil War

In Latin, a monitor is someone who admonishes:that is, reminds others of their duties—which is how USS Monitor was given its name. She was designed by John Ericsson for emergency service in the Federal navy during the American Civil War (1861–65) to blockade the Confederate States from supply at sea. Ericsson designed her to operate in shallow water and to present as small a target as possible, the water around her acting as protection.

Nathaniel Hawthorne described Monitor thus:

At no great distance from the Minnesota lay the strangest-looking craft I ever saw. It was a platform of iron, so nearly on a level with the water that the swash of the waves broke over it, under the impulse of a very moderate breeze; and on this platform was raised a circular structure, likewise of iron, and rather broad and capacious, but of no great height. It could not be called a vessel at all; it was a machine—and I have seen one of somewhat similar appearance employed in cleaning out the docks; or, for lack of a better similitude, it looked like a gigantic rat-trap. It was ugly, questionable, suspicious, evidently mischievous—nay, I will allow myself to call it devilish; for this was the new war-fiend, destined, along with others of the same breed, to annihilate whole navies and batter down old supremacies. The wooden walls of Old England cease to exist, and a whole history of naval renown reaches its period, now that the Monitor comes smoking into view; while the billows dash over what seems her deck, and storms bury even her turret in green water, as she burrows and snorts along, oftener under the surface than above. The singularity of the object has betrayed me into a more ambitious vein of description than I often indulge; and, after all, I might as well have contented myself with simply saying that she looked very queer.

Going on board, we were surprised at the extent and convenience of her interior accommodations. There is a spacious ward-room, nine or ten feet in height, besides a private cabin for the commander, and sleeping accommodations on an ample scale; the whole well lighted and ventilated, though beneath the surface of the water. Forward, or aft (for it is impossible to tell stem from stern), the crew are relatively quite as well provided for as the officers. It was like finding a palace, with all its conveniences, under the sea. The inaccessibility, the apparent impregnability, of this submerged iron fortress are most satisfactory; the officers and crew get down through a little hole in the deck, hermetically seal themselves, and go below; and until they see fit to reappear, there would seem to be no power given to man whereby they can be brought to light. A storm of cannon-shot damages them no more than a handful of dried peas. We saw the shot-marks made by the great artillery of the Merrimack on the outer casing of the iron tower; they were about the breadth and depth of shallow saucers, almost imperceptible dents, with no corresponding bulge on the interior surface. In fact, the thing looked altogether too safe; though it may not prove quite an agreeable predicament to be thus boxed up in impenetrable iron, with the possibility, one would imagine, of being sent to the bottom of the sea, and, even there, not drowned, but stifled. Nothing, however, can exceed the confidence of the officers in this new craft. It was pleasant to see their benign exultation in her powers of mischief, and the delight with which they exhibited the circumvolutory movement of the tower, the quick thrusting forth of the immense guns to deliver their ponderous missiles, and then the immediate recoil, and the security behind the closed port-holes. Yet even this will not long be the last and most terrible improvement in the science of war. Already we hear of vessels the armament of which is to act entirely beneath the surface of the water; so that, with no other external symptoms than a great bubbling and foaming, and gush of smoke, and belch of smothered thunder out of the yeasty waves, there shall be a deadly fight going on below—and, by and by, a sucking whirlpool, as one of the ships goes down.[2]

The Battle of Hampton Roads (March 1862), between Monitor and CSS Virginia, was the first engagement between ironclad vessels. Several such battles took place during the course of the American Civil War, and the dozens of monitors built for the United States Navy reflected a ship-to-ship combat role in their designs. However, fortification bombardment was another critical role that the early monitors played, though one that these early designs were much less capable in performing.

Three months after the Battle of Hampton Roads, John Ericsson took his design to his native Sweden, and in 1865 the first Swedish monitor was built at Motala Warf in Norrköping, taking the engineer's name. She was followed by 14 more monitors. One of them, Kanonbåten Sölve, served until 1922 and is today preserved at the Maritiman marine museum in Gothenburg.

Ericsson and others experimented greatly during the years of the American Civil War. Vessels constructed included a triple-turreted monitor, a class of paddlewheel-propelled monitors, a class of semi-submersible monitors, and a class of monitors armed with spar torpedoes.

1866 to 1878

In the 1860s and 1870s several nations built monitors that were used for coastal defense and took the name monitor as a type of ship. Those that were directly modelled on Monitor were low-freeboard, mastless, steam-powered vessels with one or two rotating, armoured turrets. The low freeboard meant that these ships were unsuitable for ocean-going duties and were always at risk of swamping, flooding and possible loss. However, it greatly reduced the cost and weight of the armour required for protection, and in heavy weather the sea could wash over the deck rather than heeling the ship over.

Attempts were made to fit monitors with sails, but the provision of masts interfered with the turrets' ability to operate in a 360-degree arc of fire and the weight of masts and sails aloft made the ships less stable. One ship, HMS Captain, which combined turret and sails with a low freeboard, was lost in heavy weather.

War of the Pacific

Huáscar anchored in the harbour at Talcahuano

A late example of a vessel modeled on Monitor was BAP Huáscar, designed by Captain Cowper P. Coles, the advocate and developer of turret ships for the Royal Navy. Huáscar was one of many monitor designs to be equipped with a ram. She was built and launched in 1865 for the Peruvian Navy at Birkenhead, England, and attained fame in the Battle of Pacocha during the Peruvian Civil War of 1877.

BAP Huáscar, under the command of Rear Admiral Miguel Grau, fought with distinction during the War of the Pacific. Huáscar successfully raided enemy sea lanes for several months and delayed an invasion of the Chilean Army into Peruvian territory until she was captured by the Chilean Navy at the Battle of Angamos in 1879. Once in Chilean hands, Huáscar fought a small battle with the Peruvian monitor Manco Capac, during the bombardment of Arica, where she was damaged; after the land battle was lost, the crew scuttled BAP Manco Capac to prevent capture.

Over the years, both Chile and Peru came to venerate the ship and the officers from both sides that died on her deck, either commanding her or boarding her, as national heroes. Huáscar is currently commissioned in the Chilean Navy, has been restored to a near-original condition and, as a museum ship, is open to visitors at its berth in Talcahuano.

Monitor monterrey
USS Monterey, a breastwork monitor, at Mare Island Naval Shipyard, c.1896. The older Ericsson-designed monitor USS Camanche is visible in the background.


In an effort to produce a more seaworthy vessel that was more capable in ship-to-shore combat, a type called the breastwork monitor became more common in the later nineteenth century. These ships had raised turrets and a heavier superstructure on a platform above the hull. They were still not particularly successful as seagoing ships, because of their short sailing range and the poor reliability of their steam engines. The first of these ships was HMVS Cerberus, built between 1868 and 1870. She was later sunk and used as a breakwater near Melbourne, Australia and is still visible there, as her upper works project from the water.

Spanish–American War

Monitors were used frequently during the Spanish–American War in 1898. Notable United States Navy monitors which fought in the war were USS Amphitrite, USS Puritan, USS Monterey, and USS Terror. These four monitors fought at battles or campaigns such as the Bombardment of San Juan, the Battle of Fajardo, and the Philippines Campaign. Other monitors also participated in the conflict.

Twentieth century

World War I

Uss Florida BM9
USS Tallahassee, formerly USS Florida, tending to submarines K-5 and K-6 in Hampton Roads, 1919

During World War I, the Royal Navy developed several classes of ships which were designed to give close support to troops ashore. Termed "monitors", they owed little to the monitors of the 19th century, though they shared the characteristics of poor seaworthiness, shallow draft and heavy armament in turrets.

The first class, the Humber class, had been laid down as large river gunboats for the Brazilian navy. Later monitor classes were equally makeshift; they were often designed for carrying whatever spare guns were available from ships scrapped or never built, with the hulls quickly designed and built in "cheap and cheerful" fashion. They were broad beamed for stability (beam was about 1/3 of the overall length) which together with a lack of emphasis on speed made them extremely slow, and they were not suitable for naval combat or any sort of work on the high seas. Monitors of the Royal Navy played a part in consolidating the left wing of the Western Front during the Race to the Sea in 1914.

In addition to these ships, several monitors were built during the course of the war. Their armament typically consisted of a turret taken from a de-commissioned pre-dreadnought battleship. These monitors were designed to be resilient against torpedo attacks—waterline bulges were incorporated into the Abercrombie class of 1915.[3] As the war settled to its longer course, these heavier monitors formed patrols along with destroyers on either side of the Straits of Dover to exclude enemy surface vessels from the English Channel and keep the enemy in port. The monitors could also operate into the river mouths. HMS General Wolfe, one of the Lord Clive-class monitors, which had a single 18-inch (457 mm) gun added in 1918, was able to shell a bridge 20 miles (30 km) away near Ostend. Other RN monitors served in the Mediterranean.

The dimensions of the several classes of monitor varied greatly. Those of the Abercrombie class were 320 feet (98 m) by 90 feet (27 m) in the beam and drew 9 feet (2.7 m) compared to the M29-class monitors of 1915 that were only 170 feet (52 m) long. and the Erebus class of 1916 were 405 feet (123 m) long. The largest monitors carried the heaviest guns.

By this point the United States Navy had largely stopped using monitors. Only a few still existed, and only seven were still in service, all of which had been relegated to being submarine tenders. This would be the last war in which United States monitor-type vessels would see commissioned service. The last original American monitor, USS Wyoming, renamed USS Cheyenne in 1908, was stricken from the Navy List in 1937.[4]

The Austro-Hungarian Navy had also invested heavily in the construction of river monitors to patrol its internal river systems such as the Danube and its tributaries. These vessels were among the first to fire on Serbian territory at the start of the First World War, and took part in the bombardment of Belgrade, as well as other Balkan campaigns against Serbia and Romania. At the end of the war, the surviving vessels were parceled out to the navies of the new state of Yugoslavia and Romania as war prizes. Several would see action in World War II as well.

World War II

The smaller Royal Navy monitors were mostly scrapped following World War I, though Erebus and Terror survived to fight in World War II. When the requirement for shore support returned, two large new Roberts-class monitors, Roberts and Abercrombie, were constructed and fitted with 15-inch (380 mm) guns from older battleships.

HMS Erebus I02
HMS Erebus during World War II

Allied monitors saw service in the Mediterranean in support of the British Eighth Army's desert and Italian campaigns. They were part of the offshore bombardment for the Invasion of Normandy in 1944. They were also used to clear the German-mined River Scheldt by the British to utilize the port of Antwerp.

The former Italian WW1 monitor Faa di Bruno had been redesignated as floating battery by the beginning of WW2, in which role she continued to play until the capitulation of Italy. She was then captured by the Germans and served as monitor Biber in Genoa, until German surrender. She was scrapped after the war.

The German, Yugoslav, Croatian and Romanian navies all operated river monitors on the Danube, which saw various combats during WW2.

Soviet river monitors

The Soviets built many monitors before World War II, and used them mostly on rivers and lakes. After experiences during WWI, the Russian Civil War and the Manchukuo Imperial Navy raids in the Far East, the Soviets developed a new monitor class for their river flotillas. The lead ship of the new series was Zheleznyakov, laid down in the Kiev factory "Lenin's Smithy" in the fall of 1934. Currently, Zheleznyakov is preserved as a museum and monument on the Dnieper.


The Royal Navy still had HMS Abercrombie (completed 1943) and HMS Roberts (1941) in reserve in 1953. They were typical monitors, trunk-decked vessels, some 373 feet (114 m) long overall, 90-foot (27 m) in the beam and with an 11-foot (3 m) mean draught carrying two 15-inch (381 mm) guns.

The Brazilian Navy presently operates the last true "monitor" as part of their inland waterway force, Parnaíba.

Vietnam War

The Vietnam War was the U.S. Navy's second riverine war, after the American Civil War. On 18 December 1965, the U.S. Navy, for the second time in a hundred years, authorized the reactivation of a brown-water navy, this time in the Republic of Vietnam (South Vietnam). After studies were conducted, plans were drawn up by the U.S. Naval Advisory Group in February 1966, and by the summer of 1966 Secretary of Defense Robert S. McNamara authorized the U.S. Navy a Mobile Riverine Force (MRF).[5]

Although U.S. Navy Patrol Craft Fast (Swift Boats), Patrol Boat River (PBRs), and assorted gunboats had been performing counter-insurgency operations in country prior to 1966, the allies were not gaining success in the Mekong Delta regions of the Republic of Vietnam. A stronger naval force was needed, one that was heavily armored, and heavily gunned.

The U.S. Navy's MRF initially consisted of River Assault Flotilla One, under Program 4 in 1967, and consisted of four River Assault Divisions: RAD-91 which contained 3 monitors; RAD-92 contained 2 monitors; RAD-111 had 3 monitors; and RAD-112 operated 2 monitors. These "river battleships",[6] as they were known by the men, operated in conjunction with the CCB (Command Control Boat—also a monitor), ATCs (Armored Transport Carriers), and the ASPBs (Assault Support Patrol Boats) which were also assigned to each RAD.[7]

Vietnam monitors were originally converted from World War II 56-foot (17 m) long all-steel Landing Craft Mechanized (LCM) Mark 6s. They were constructed under two phases: Programs 4 and 5. Under Program 4, 10 monitors were armed with one 40 mm cannon and then fielded. Program 5 monitors would correct any deficiencies from the previous vessels, and were fielded as the Monitor (H) 105 mm (Howitzer) and the Monitor (F) (Flamethrower).[8] The Program 4 monitors mounted their single barrel 40 mm cannon in a Mk 52 turret; while the Program 5 monitors mounted their 105 mm cannon in a T172 turret, and the six flamethrowers were mounted in M8 cupola turrets (one on each side of the vessel's 40 mm turret).[9] Because the U.S. Marine Corps was also using the M49 105 mm howitzer, there was a shortage, and only 8 Monitor (H) versions could be procured for the brown-water navy.

As fielded, the 24 monitors of the U.S. Navy in Vietnam averaged about 10 tons of armor, were about 60 feet (18 m) long, had two screws, were powered by two 64NH9 diesel engines, 8.5 knots (15.7 km/h; 9.8 mph) (maximum speed), 17.5 feet (5.3 m) wide, 3.5 feet (1.1 m) draft, and were normally manned by 11 crewmen. When South Vietnam fell on 30 April 1975, all monitors fell into the enemy's hands; leaving only one survivor, a training monitor, that never left the US. "Training" monitor #C-18 is on display, along with one Swift Boat and one PBR at the U.S. Naval Amphibious Base in Coronado, California.

Similar vessels

River monitors

The monitor, by proving the efficacy of turrets over fixed guns, played a part in development of the dreadnought battleship from the ironclad. As a shallow draft vessel it also led to the river gunboats which were used by imperial powers to police their colonial possessions; indeed the largest and most heavily armed river gunboats became known as river monitors. They were used by several navies, including those of the United Kingdom, the United States and Japan.

Submarine gunboats

USS Monitor had had very little freeboard so as to bring the mass of the gun turret down, thereby increasing stability and making the boat a smaller and therefore harder target for gunfire. At the end of the American Civil War, the U.S. Navy Casco-class monitors had large ballast tanks that allowed the vessels to partially submerge during battle. This idea was carried further with the concept of the Royal Navy's R class of submarine gunboats.

The British M-class submarines were initially designed for shore bombardment, but their purpose was changed to attacking enemy merchant vessels as their 12-inch (305 mm) gun would be more effective at long range than a torpedo against a moving target. Only one, HMS M1, entered service before the end of World War 1; she was lost in the English Channel after the war in 1925 after being accidentally rammed while submerged: her gun came free of its mount and she was completely flooded.

USS Casco
USS Casco in the James River, 1865

Derivative uses of the name

To overcome the stability problems arising from the heavy turret mounted high in monitors, their hulls were designed to reduce other top weight. After Ericsson's ships, monitors developed the trunk deck design as the upper deck had to be heavily armoured against plunging shells. Because of the weight high in the hull, its breadth was minimized, giving rise to a vessel broad-beamed at the waterline, but with a narrow upper deck. The term for this sort of construction was tumblehome. Ships which were far narrower at the deck than the waterline were said to have a "pronounced tumblehome".

By analogy, nineteenth century railway coaches with clerestory roofs to accommodate ventilators and lamps above the heads of standing passengers in the centre while lower to the sides where passengers were seated were called monitors or monitor cars in the U.S.; the raised part of the roof was known as a turret. In ship design of around 1900, a turret deck was a more austere version of the trunk deck.

Surviving vessels

  • The Peruvian Huáscar is a monitor built in England originally for Peru in 1865, which is still afloat in original condition in Talcahuano, Chile.
  • HMS M33 is an M29-class monitor of the Royal Navy built in 1915; she is preserved at Portsmouth Historic Dockyard in the United Kingdom.
  • HMVS Cerberus, launched in 1868, was scuttled as a breakwater off the Australian coast in 1926. Work for her preservation is proceeding.
  • Parnaíba is a river monitor currently in service with the Brazilian navy.
  • HSwMS Sölve is a Swedish monitor built in 1875 and designed by John Ericsson the "father" of all monitors. Currently in a Maritime Museum in Gothenburg, Sweden
  • SMS Leitha (now "Lajta Monitor Múzeumhajó") which is an Austro-Hungarian monitor built in 1871. Currently a museum ship.
  • SMS Bodrog which is an Austro-Hungarian monitor built 1904, said to have fired the very first shots of the First World War. Currently a landing stage in Beograd.
  • HNLMS Schorpioen (1868) and HNLMS Buffel (1868) are Dutch ramming ship monitors preserved as museum ships.

See also


  1. ^ Carrico p. 10, 11
  2. ^ Hawthorne, Nathaniel (1883). The complete works of Nathaniel Hawthorne. XII. Riverside Press Cambridge. pp. 336–338.
  3. ^ Abercrombie Class Monitors
  4. ^ "USS Wyoming (Monitor # 10, later BM-10 and IX-4), 1902-1939". Washington DC: Department of the Navy; Naval Historical Center. Retrieved August 20, 2013.
  5. ^ Carrico p. 10, 11
  6. ^ Carrico p. 20, 21, 63
  7. ^ Carrico P. 12
  8. ^ Carrico p. 63
  9. ^ Carrico p. 27


  • Anon. Jane's Fighting Ships 1953-54 (1953)
  • Carrico, John M. Vietnam Ironclads, A Pictorial History of U.S. Navy River Assault Craft, 1966–1970. (2007) Brown Water Enterprises. ISBN 978-0-9794231-0-9.
  • Churchill, W.S. The World Crisis 1911–1918 (1938) Chapter XVI
  • Oxford English Dictionary
  • Friedman, Norman. U.S. Small Combatants: An Illustrated Design History. (1987) U.S. Naval Institute Press. ISBN 0-87021-713-5.
  • Konstam, Angus The Duel of the Ironclads (2003) ISBN 1-84176-721-2

External links

Anti-Invasion Floating Mortar

Also known as Naysmyth's Submarine Mortar and the Steam Ram, the Anti-Invasion Floating Hammer was a semi-submerged naval ship design conceived and published by inventor James Nasmyth in 1853. The mortar had a length of 80 feet (24 m) and a beam of 30 feet (9.1 m) and was equipped with a small steam engine that drove a single propeller. The walls of the mortar were 10 feet (3.0 m) thick, protecting it against potential enemy gunfire of that period. At the front of the boat was a hollow brass cap shaped like a ram that was 9 feet thick. Inside the ram was a case filled with a heavy charge of explosive powder. With only the funnel and a domed structure covering the pilot being visible above water, the mortar sought to attack enemy ships by ramming the hull with the explosive-filled ram at speeds of over 10 knots (19 km/h; 12 mph). Because of potential dangers associated with its means of attack, the Anti-Invasion Floating Mortar was never built.

Battle of Hampton Roads

The Battle of Hampton Roads, often referred to as either the Battle of the Monitor and Merrimack (or Virginia) or the Battle of Ironclads, was the most noted and arguably most important naval battle of the American Civil War from the standpoint of the development of navies. It was fought over two days, March 8–9, 1862, in Hampton Roads, a roadstead in Virginia where the Elizabeth and Nansemond rivers meet the James River just before it enters Chesapeake Bay adjacent to the city of Norfolk. The battle was a part of the effort of the Confederacy to break the Union blockade, which had cut off Virginia's largest cities and major industrial centers, Norfolk and Richmond from international trade.The major significance of the battle is that it was the first meeting in combat of ironclad warships, i.e., the USS Monitor and the CSS Virginia. The Confederate fleet consisted of the ironclad ram Virginia (built from the remnants of the under construction steam frigate USS Merrimack, newest warship for the United States Navy / Union Navy) and several supporting vessels. On the first day of battle, they were opposed by several conventional, wooden-hulled ships of the Union Navy. On that day, Virginia was able to destroy two ships of the Federal flotilla, USS Congress and USS Cumberland, and was about to attack a third, USS Minnesota, which had run aground. However, the action was halted by darkness and falling tide, so Virginia retired to take care of her few wounded—which included her captain, Flag Officer Franklin Buchanan—and repair her minimal battle damage.Determined to complete the destruction of Minnesota, Catesby ap Roger Jones, acting as captain in Buchanan's absence, returned the ship to the fray the next morning, March 9. During the night, however, the ironclad Monitor had arrived and had taken a position to defend Minnesota. When Virginia approached, Monitor intercepted her. The two ironclads fought for about three hours, with neither being able to inflict significant damage on the other. The duel ended indecisively, Virginia returning to her home at the Gosport Navy Yard for repairs and strengthening, and Monitor to her station defending Minnesota. The ships did not fight again, and the blockade remained in place.The battle received worldwide attention, and it had immediate effects on navies around the world. The preeminent naval powers, Great Britain and France, halted further construction of wooden-hulled ships, and others followed suit. Although Britain and France had been engaged in an iron clad arms race since the 1830s, The Battle of Hampton Roads signalled a new age of naval warfare had arrived for the whole world. A new type of warship, monitor, was produced based on the principle of the original. The use of a small number of very heavy guns, mounted so that they could fire in all directions was first demonstrated by Monitor but soon became standard in warships of all types. Shipbuilders also incorporated rams into the designs of warship hulls for the rest of the century.

Gun turret

A gun turret (or turret) is a location from which weapons can be fired that affords protection, visibility, and some cone of fire. A modern gun turret is generally a weapon mount that houses the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in some degree of azimuth and elevation (cone of fire).


A gunboat is a naval watercraft designed for the express purpose of carrying one or more guns to bombard coastal targets, as opposed to those military craft designed for naval warfare, or for ferrying troops or supplies.

Half Moon Bay (Victoria)

The Half Moon Bay is a bay and neighbourhood on Port Phillip, south east of Melbourne. Located in the suburb of Black Rock, it is home to the Black Rock Yacht Club, the Half Moon Bay Lifesaving Club and the Cerberus Beach House Restaurant and Beach Kiosk. This bay also gets a mention in the Cat Empire song, "The Wine Song". Half Moon Bay is also home to HMVS Cerberus, the last surviving monitor warship in the world, which acts as a breakwater. Half Moon Bay has a lifesaving club and a pier and has the Red Bluff Cliffs just along the beach. The cliffs were briefly featured in the movie "Mad Max'" as well as the 90's children's television series "Round The Twist". Half Moon Bay also has aquatic life which makes good snorkelling.

It features many coastal processes.

The first Black Rock Post Office opened here on 23 April 1902, was renamed Half Moon Bay in 1922 and closed in 1968.

Imperial Brazilian Navy

The Imperial Brazilian Navy (Portuguese: Armada Nacional, commonly known as Armada Imperial) was the navy created at the time of the independence of the Empire of Brazil from the United Kingdom of Portugal, Brazil and the Algarves. It existed between 1822 and 1889 during the vigency of the constitutional monarchy. The Navy was formed almost entirely by ships, staff, organizations and doctrines proceeding from the transference of the Portuguese Royal Family in 1808. Some of its members were native-born Brazilians, who under Portugal had been forbidden to serve. Other members were Portuguese who adhered to the cause of separation and German and Irish mercenaries. Some establishments created by King João VI were used and incorporated. Under the reign of Emperor Pedro II the Navy was greatly expanded to become the fifth most powerful navy in the world and the armed force more popular and loyal to the Brazilian monarchy. The republican coup d'état in 1889, led by army men, put an end to the Imperial Navy that fell into decay until the new century.

Khasan-class monitor

The Khasan-class (Project 1190) were a class of three sea-going river monitors built between 1936 and 1942 for the Soviet Navy, the Khasan, Perekop and Sivash. All three ships served with the Amur Flotilla of the Pacific Fleet throughout the Soviet invasion of Manchuria (but did not participate). The Khasan class were notable for being the largest river-going monitors ever built. All three ships survived the war and served in the Soviet Navy until the early 1960s.

List of ships named USS Monitor

Two ships of the United States Navy have been named USS Monitor. The name means "a person or thing that warns or instructs"; it was suggested by the engineer John Ericsson who hoped that his warship — the first Monitor — would admonish the Confederate States of America and the United Kingdom which was then sympathetic to the Confederacy.

USS Monitor, launched in 1862, was a revolutionary ironclad warship that gave its name to the monitor warship type. She served in the American Civil War and fought in the battle of Hampton Roads on 1862-03-09. She was lost at sea on 1862-12-31.

USS Monitor (LSV-5), launched in 1941, was a landing ship that served in World War II, landing troops and equipment on Luzon and Okinawa.

List of ships of the Brazilian Navy

This is a list of active ships of the Brazilian Navy, complete and correct as of 2018.

The Navy has approximately 112 ships in commission, including 39 auxiliary vessels. 9 of the commissioned vessels are frigates of British origin and 5 are conventional attack submarines of German origin. Recently the Brazilian Navy has sought modernization through the acquisition of 4 submarines of French manufacture, class Scorpéne, and of the own construction of a nuclear submarine, besides 4 corvettes class Tamandaré and 4 patrol ship of 500 ton.

List of types of naval vessels

This is a list of types of watercraft which have seen naval use.


M32 may refer to:

M32 (catamaran), a lightweight, high-performance, multihull sailing vessel

Messier 32, an elliptical galaxy in the constellation Andromeda

M32 motorway, a motorway in Bristol, England

M-32 (Michigan highway), a state highway traversing northern lower Michigan from the town of East Jordan to the city of Alpena

M32 MGL, a multiple grenade launcher

M32 Tank Recovery Vehicle, a variant of the M4 Sherman tank

HMS M32, an M29-class monitor warship of the Royal Navy


M33, M-33, or M.33 may refer to:

M-33 (Michigan highway), a state highway in Michigan

M33 cluster bomb, a Cold War-era U.S. biological cluster bomb

HMS M33, an M29-class monitor warship of the Royal Navy

M33 helmet, used by the Italian Army in World War II

Macchi M.33, an Italian racing flying boat of 1925

Miles M.33 Monitor, a 1944 twin engined British target tug aircraft

Mike Tempesta (aka M.33), a rock guitarist

Messier 33, or Triangulum Galaxy, a galaxy in the Local Group of galaxies

M33 (gene)

M33, US Army rocket launcher for the Honest John rocket

M33, the postcode district of Sale, a town in Greater Manchester, England

National Museum of the Royal Navy, Portsmouth

The National Museum of the Royal Navy, Portsmouth, formerly known as the Royal Naval Museum, is a museum of the history of the Royal Navy located in the Portsmouth Historic Dockyard section of HMNB Portsmouth, Portsmouth, Hampshire, England. The museum is part of the National Museum of the Royal Navy, a non-departmental public body sponsored by the Ministry of Defence. It received 1,081,909 visitors in 2017.


Patapsco may refer to:

Patapsco River, a large river on the western shore of the Chesapeake Bay, in Maryland, United States, forming the Helen Delich Bentley Port of Baltimore

Patapsco, Maryland (disambiguation), two unincorporated communities in Maryland, one in Anne Arundel County and the other in Carroll County

Patapsco Street, a small residential street in old South Baltimore, near Federal Hill neighborhood of Baltimore

Patapsco Avenue, (Maryland Route 173), a major business/commercial/residential thoroughfare in the Brooklyn section in the southern part of Baltimore, Maryland, laid out in 1853. Divided into East and West Patapsco Avenues at the mid-way point of South Hanover Street (Maryland Route 2) - formerly First Street

Patapsco (Baltimore Light Rail station), one of 33 stops at Patapsco Avenue, west of Brooklyn along the Baltimore Light Rail central line, running north and south through the metro area

Patapsco Female Institute, a former girls boarding school in Ellicott City, Maryland, the ruins of which now form a background for a performing arts venue

Patapsco Freeway, a southeastern portion of the Baltimore Beltway, Interstate 695

Patapsco High School and Center for the Arts, a public high school of suburban Baltimore County in Dundalk, Maryland

Patapsco Valley State Park, the first state park designated in Maryland stretching along the upper Western Branch of the Patapsco River, forming the border between Howard County and Baltimore County

Patapsco Swinging Bridge, a pedestrian "swinging bridge" across the upper Western Branch of the Patapsco River in the "Avalon" and "Orange Grove" areas of Patapsco Valley State Park, west of BaltimoreVesselsU.S.S. Patapsco (1799), a sloop-of-war built in June 1799 on behalf of subscribing Baltimore merchants/citizens during the naval Quasi-War with the revolutionary French Republic at De Rochbroom's Shipyard, in Fells Point. Originally named the "U.S.S. Chesapeake", later sold after hostilities ceased in 1801.

Patapsco-class gasoline tanker, a class of U.S. Navy tankers

"U.S.S. Patapsco" (1862), a Passaic-class "ironclad" "Monitor" warship during the American Civil War in the United States Navy / Union Navy

"U.S.S. Patapsco" (AOG-1), a World War II oil tanker

River 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 turrets.

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 South Vietnam. In July 1966, Secretary of Defense Robert S. McNamara authorized the formation of a Mobile Riverine Force (MRF); a force that would bring back the heavily armored single-turret river monitor.

River monitors were used on inland waterways such as rivers, estuaries, deltas and lakes. Usually they had a shallow 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 Lord Clive-class monitors, 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 mm) in size. Typically, however, river monitors displayed a mixture of gun sizes from 3-inch (75 mm) to 6-inch (152 mm), plus machine guns. This type of vessel overlaps with the river gunboat.

Turret ship

Turret ships were a 19th-century type of warship, the earliest to have their guns mounted in a revolving gun turret, instead of a broadside arrangement.

USS Galena (1862)

USS Galena was a wooden-hulled broadside ironclad built for the United States Navy during the American Civil War. The ship was initially assigned to the North Atlantic Blockading Squadron and supported Union forces during the Peninsula Campaign in 1862. She was damaged during the Battle of Drewry's Bluff because her armor was too thin to prevent Confederate shots from penetrating. Widely regarded as a failure, Galena was reconstructed without most of her armor in 1863 and transferred to the West Gulf Blockading Squadron in 1864. The ship participated in the Battle of Mobile Bay and the subsequent Siege of Fort Morgan in August. She was briefly transferred to the East Gulf Blockading Squadron in September before she was sent to Philadelphia, Pennsylvania for repairs in November.

Repairs were completed in March 1865 and Galena rejoined the North Atlantic Blockading Squadron in Hampton Roads the following month. After the end of the war, the ship was decommissioned at Portsmouth, New Hampshire in June. She was transferred to Hampton Roads in 1869, condemned in 1870, and broken up for scrap in 1872.

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