Republic of Korea Navy
The Republic of Korea Navy known as the ROK Navy, is the naval warfare service branch of the South Korean armed forces, responsible for naval and amphibious operations. The ROK Navy includes the Republic of Korea Marine Corps. Established in 1945, the ROK Navy is the oldest branch of the South Korean armed forces. Since the end of the Korean War, the South Korean navy had concentrated its efforts on building naval forces to counteract the North Korean navy, which has littoral naval capabilities; as South Korea's economy grew, the ROK Navy was able to locally build larger and better equipped fleets to deter aggression, to protect the sea lines of communication, to support the nation's foreign policy. As part of its mission, the ROK Navy has engaged in several peacekeeping operations since the turn of the 21st century; the ROK Navy has about 70,000 regular personnel including 29,000 Republic of Korea Marines. There are about 150 commissioned ships with the ROK Navy; the naval aviation force consists of about 70 rotary-wing aircraft.
The ROK Marine Corps has about 300 tracked vehicles including assault amphibious vehicles. The ROK Navy aims to become a blue-water navy in 2020s; the main duties of the Navy shall be operations on the sea, including landing operations, the main duties of the Marine Corps shall be landing operations, the Navy and Marine Corps shall be formed and equipped for that purpose and shall provide education and training necessary therefor. The objectives of the ROK Navy as core strength for the National Security are: Establishing self-reliant naval forces to deter war Securing maritime superiority to gain victory Promoting national interests through protection of maritime activities Enhancing the national prestige through naval presence Korea has a long history of naval activity. In the late 4th century during the Three Kingdoms Period, Goguryeo defeated Baekje, fielding amphibious forces of 40,000 men in the process. In the 9th century, Commissioner Chang Bogo of Unified Silla established a maritime base called Cheonghaejin on an island to foster trading with China and Japan, to eradicate pirates.
In 1380, naval forces of the Goryeo Dynasty defeated 500 invading Japanese pirate vessels by deploying shipboard guns, devised by Choi Moosun. This is the first use of shipboard guns in naval history. In 1389 and 1419, Korean naval forces invaded Tsushima Island to suppress Japanese piracy. In the early years of the Joseon Dynasty, the naval force reached its peak of 50,000 personnel, in order to combat the ongoing piracy issue. During the Japanese invasions of Korea, the Korean naval force commanded by Admiral Yi Sunshin, who became the head of the Navy, cut off the invaders' naval lifeline and defeated the Japanese fleet, reversing the war in favor of Joseon. Admiral Yi is credited with the creation of the Turtle Ship. By the end of 19th century, the Joseon Navy had no significant naval force other than coastal defense fortresses. Although there was an attempt to modernize the navy by establishing a royal naval school, the Joseon Navy was brought to an end in 1895. In 1903, the government of the Korean Empire purchased the Yangmu.
Korean naval tradition was disrupted after Korea was annexed by the Empire of Japan in 1910. During the Japanese occupation period, the Imperial Japanese Navy built a naval base - Chinkai Guard District in southern Korea. Shortly after Korea was liberated from the Empire of Japan on August 15, 1945, Sohn Won-yil, a former merchant mariner and son of the methodist minister and independence activist Sohn Jung-do, led the Maritime Affairs Association; the Association evolved into the Marine Defense Group on November 11, 1945, the Group became the Korean Coast Guard, formed at Jinhae in June 1946. After the new Republic of Korea government was established on August 15, 1948, the Korean Coast Guard was formally renamed the Republic of Korea Navy, Sohn became the first Chief of Naval Operations of the ROK Navy on September 5, 1948. On April 15, 1949, the Republic of Korea Marine Corps was founded in Jinhae. In October 1949, the ROK Navy purchased a 600-ton submarine chaser, the former USS PC-823 with funds raised among its personnel.
She was renamed ROKS Baekdusan after Paektu Mountain, became "the first significant warship of the newly independent nation". The Korean War started with the North Korean army's surprise attack on Sunday, June 25, 1950; the ROK Navy confronted threats from the North Korean navy: "Perhaps the most aggressive and effective, if smallest, member of the South Korean armed services during the first year of the Korean War was the Republic of Korea Navy. At the outset of the conflict, the 6,956-man ROKN, with naval vessels of various types, was outnumbered by the 13,700 men and 110 naval vessels of the North Korean navy." With its UN allies, dominated by U. S. forces, the ROK Navy was able to gain control in the seas surrounding the country. On July 27, 1953, the three-year-long war was brought to an end when an armistice agreement was signed. During the war, Canada, Philippines, the Netherlands, New Zealand, the United Kingdom, the United States contributed naval vessels as UN allies; the Commander-in-Chief Republic of Korea Fleet, the highest operational command, was established in September 1953.
After the Korean War, the ROK Navy built up its surface fleet with World War II-era warships loaned from the United States Navy. In May 1963, the ROK Navy acquired its first destroyer, ROKS Chungmu, a Fletcher-class destroyer
Pounds per square inch
The pound per square inch or, more pound-force per square inch is a unit of pressure or of stress based on avoirdupois units. It is the pressure resulting from a force of one pound-force applied to an area of one square inch. In SI units, 1 psi is equal to 6895 N/m2. Pounds per square inch absolute is used to make it clear that the pressure is relative to a vacuum rather than the ambient atmospheric pressure. Since atmospheric pressure at sea level is around 14.7 psi, this will be added to any pressure reading made in air at sea level. The converse is pounds per square inch gauge, indicating that the pressure is relative to atmospheric pressure. For example, a bicycle tire pumped up to 65 psig in a local atmospheric pressure at sea level will have a pressure of 79.7 psia. When gauge pressure is referenced to something other than ambient atmospheric pressure the units would be pounds per square inch differential; the kilopound per square inch is a scaled unit derived from psi, equivalent to a thousand psi. ksi are not used for gas pressures.
They are used in materials science, where the tensile strength of a material is measured as a large number of psi. The conversion in SI Units is 1 MPa = 0.145 ksi. The megapound per square inch is another multiple equal to a million psi, it is used in mechanics for the elastic modulus of materials for metals. The conversion in SI Units is 1 GPa = 0.145 Mpsi. Inch of water: 0.036 psid Blood pressure – clinically normal human blood pressure: 2.32 psig/1.55 psig Natural gas residential piped in for consumer appliance. Boost pressure provided by an automotive turbocharger: 6–15 psig NFL football: 12.5–13.5 psig Atmospheric pressure at sea level: 14.7 psia Automobile tire overpressure: 32 psig Bicycle tire overpressure: 65 psig Workshop or garage air tools: 90 psig Air brake or air brake reservoir overpressure: 90–120 psig Road racing bicycle tire overpressure: 120 psig Steam locomotive fire tube boiler: 150–280 psig Union Pacific Big Boy steam locomotive boiler: 300 psig US Navy steam boiler pressure 800 psi Natural gas pipelines: 800–1000 psig Full SCBA for IDLH atmospheres: 2216 psig nuclear reactor primary loop 2300 psi Full SCUBA tank overpressure: 3000 psig Full SCBA for interior firefighting operations: 4500 psig Airbus A380 hydraulic system: 5000 psig Ultimate strength of ASTM A36 steel: 58,000 psi Water jet cutter: 40,000–100,000 psig The exact conversions to and from SI are, by definition: 1 psi = Pa 1 Pa = psi As the pascal is small unit, relative to industrial pressures, the kilopascal is used.
1000 kPa = 147 psi. Approximate conversions are shown in the following table. Conversion of units: Pressure or mechanical stress Pressure: Units Pressure measurement primer Online pressure conversions ksi to psi conversions
The tonne referred to as the metric ton in the United States and Canada, is a non-SI metric unit of mass equal to 1,000 kilograms or one megagram. It is equivalent to 2,204.6 pounds, 1.102 short tons or 0.984 long tons. Although not part of the SI, the tonne is accepted for use with SI units and prefixes by the International Committee for Weights and Measures; the tonne is derived from the weight of 1 cubic metre of pure water. The SI symbol for the tonne is't', adopted at the same time as the unit in 1879, its use is official for the metric ton in the United States, having been adopted by the United States National Institute of Standards and Technology. It is a symbol, not an abbreviation, should not be followed by a period. Use of upper and lower case is significant, use of other letter combinations is not permitted and would lead to ambiguity. For example,'T','MT','Mt','mt' are the SI symbols for the tesla, megatesla and millitonne respectively. If describing TNT equivalent units of energy, this is equivalent to 4.184 petajoules.
In French and most varieties of English, tonne is the correct spelling. It is pronounced the same as ton, but when it is important to clarify that the metric term is meant, rather than short ton, the final "e" can be pronounced, i.e. "tonny". In Australia, it is pronounced. Before metrication in the UK the unit used for most purposes was the Imperial ton of 2,240 pounds avoirdupois or 20 hundredweight, equivalent to 1,016 kg, differing by just 1.6% from the tonne. The UK Weights and Measures Act 1985 explicitly excluded from use for trade certain imperial units, including the ton, unless the item being sold or the weighing equipment being used was weighed or certified prior to 1 December 1980, then only if the buyer was made aware that the weight of the item was measured in imperial units. In the United States metric ton is the name for this unit used and recommended by NIST. Both spellings are acceptable in Canadian usage. Ton and tonne are both derived from a Germanic word in general use in the North Sea area since the Middle Ages to designate a large cask, or tun.
A full tun, standing about a metre high, could weigh a tonne. An English tun of wine weighs a tonne, 954 kg if full of water, a little less for wine; the spelling tonne pre-dates the introduction of the SI in 1960. In the United States, the unit was referred to using the French words millier or tonneau, but these terms are now obsolete; the Imperial and US customary units comparable to the tonne are both spelled ton in English, though they differ in mass. One tonne is equivalent to: Metric/SI: 1 megagram. Equal to 1000000 grams or 1000 kilograms. Megagram, Mg, is the official SI unit. Mg is distinct from milligram. Pounds: Exactly 1000/0.453 592 37 lb, or 2204.622622 lb. US/Short tons: Exactly 1/0.907 184 74 short tons, or 1.102311311 ST. One short ton is 0.90718474 t. Imperial/Long tons: Exactly 1/1.016 046 9088 long tons, or 0.9842065276 LT. One long ton is 1.0160469088 t. For multiples of the tonne, it is more usual to speak of millions of tonnes. Kilotonne and gigatonne are more used for the energy of nuclear explosions and other events in equivalent mass of TNT loosely as approximate figures.
When used in this context, there is little need to distinguish between metric and other tons, the unit is spelt either as ton or tonne with the relevant prefix attached. *The equivalent units columns use the short scale large-number naming system used in most English-language countries, e.g. 1 billion = 1,000 million = 1,000,000,000.†Values in the equivalent short and long tons columns are rounded to five significant figures, see Conversions for exact values.ǂThough non-standard, the symbol "kt" is used for knot, a unit of speed for aircraft and sea-going vessels, should not be confused with kilotonne. A metric ton unit can mean 10 kilograms within metal trading within the US, it traditionally referred to a metric ton of ore containing 1% of metal. The following excerpt from a mining geology textbook describes its usage in the particular case of tungsten: "Tungsten concentrates are traded in metric tonne units (originally designating one tonne of ore containing 1% of WO3, today used to measure WO3 quantities in 10 kg units.
One metric tonne unit of tungsten contains 7.93 kilograms of tungsten." Note that tungsten is known as wolfram and has the atomic symbol W. In the case of uranium, the acronym MTU is sometimes considered to be metric ton of uranium, meaning 1,000 kg. A gigatonne of carbon dioxide equivalent is a unit used by the UN climate change panel, IPCC, to measure the effect of a technolo
A drive shaft, driving shaft, propeller shaft, or Cardan shaft is a mechanical component for transmitting torque and rotation used to connect other components of a drive train that cannot be connected directly because of distance or the need to allow for relative movement between them. As torque carriers, drive shafts are subject to torsion and shear stress, equivalent to the difference between the input torque and the load, they must therefore be strong enough to bear the stress, while avoiding too much additional weight as that would in turn increase their inertia. To allow for variations in the alignment and distance between the driving and driven components, drive shafts incorporate one or more universal joints, jaw couplings, or rag joints, sometimes a splined joint or prismatic joint; the term drive shaft first appeared during the mid 19th century. In Stover's 1861 patent reissue for a planing and matching machine, the term is used to refer to the belt-driven shaft by which the machine is driven.
The term is not used in his original patent. Another early use of the term occurs in the 1861 patent reissue for the Watkins and Bryson horse-drawn mowing machine. Here, the term refers to the shaft transmitting power from the machine's wheels to the gear train that works the cutting mechanism. In the 1890s, the term began to be used in a manner closer to the modern sense. In 1891, for example, Battles referred to the shaft between the transmission and driving trucks of his Climax locomotive as the drive shaft, Stillman referred to the shaft linking the crankshaft to the rear axle of his shaft-driven bicycle as a drive shaft. In 1899, Bukey used the term to describe the shaft transmitting power from the wheel to the driven machinery by a universal joint in his Horse-Power. In the same year, Clark described his Marine Velocipede using the term to refer to the gear-driven shaft transmitting power through a universal joint to the propeller shaft. Crompton used the term to refer to the shaft between the transmission of his steam-powered Motor Vehicle of 1903 and the driven axle.
The pioneering automobile industry company, was the first to use a drive shaft in a gasoline-powered car. Built in 1901, today this vehicle is in the collection of the Smithsonian Institution. An automobile may use a longitudinal shaft to deliver power from an engine/transmission to the other end of the vehicle before it goes to the wheels. A pair of short drive shafts is used to send power from a central differential, transmission, or transaxle to the wheels. In front-engined, rear-drive vehicles, a longer drive shaft is required to send power the length of the vehicle. Two forms dominate: The torque tube with a single universal joint and the more common Hotchkiss drive with two or more joints; this system became known as Système Panhard after the automobile company Panhard et Levassor patented it. Most of these vehicles have a clutch and gearbox mounted directly on the engine, with a drive shaft leading to a final drive in the rear axle; when the vehicle is stationary, the drive shaft does not rotate.
Some vehicles, seeking improved weight balance between rear, use a rear-mounted transaxle. In some non-Porsche models, this places the clutch and transmission at the rear of the car and the drive shaft between them and the engine. In this case the drive shaft rotates continuously with the engine when the car is stationary and out of gear. However, the Porsche 924/944/928 models have the clutch mounted to the back of the engine in a bell housing and the drive shaft from the clutch output, located inside of a hollow protective torque tube, transfers power to the rear mounted transaxle, thus the Porsche driveshaft only rotates when the rear wheels are turning as the engine-mounted clutch can decouple engine crankshaft rotation from the driveshaft. So for Porsche, when the driver is using the clutch while briskly shifting up or down, the engine can rev with the driver's accelerator pedal input, since with the clutch disengaged, the engine and flywheel inertia is low and is not burdened with the added rotational inertia of the driveshaft.
The Porsche torque tube is solidly fastened to both the engine's bell housing and to the transaxle case, fixing the length and alignment between the bell housing and the transaxle and minimizing rear wheel drive reaction torque from twisting the transaxle in any plane. A drive shaft connecting a rear differential to a rear wheel may be called a half-shaft; the name derives from the fact. Early automobiles used chain drive or belt drive mechanisms rather than a drive shaft; some used electrical motors to transmit power to the wheels. In British English, the term "drive shaft" is restricted to a transverse shaft that transmits power to the wheels the front wheels. A drive shaft connecting the gearbox to a rear differential is called a propeller shaft, or prop-shaft. A prop-shaft assembly consists of a slip joint and one or more universal joints. Where the engine and axles are separated from each other, as on four-wheel drive and rear-wheel drive vehicles, it is the propeller shaft that serves to transmit the drive force generated by the engine to the axles.
Several different types of drive shaft are used in the automotive industry: One-piece drive shaft Two-piece drive shaft Slip-in-tube drive shaftThe slip-in-tube drive shaft is a new type that improves crash safety. It can be compressed to absorb energy in the event of a crash, so is known as a collapsible drive shaft
The Soviet Navy was the naval arm of the Soviet Armed Forces. Referred to as the Red Fleet, the Soviet Navy was a large part of the Soviet Union's strategic plan in the event of a conflict with opposing super power, the United States, the North Atlantic Treaty Organization, or another conflict related to the Warsaw Pact of Eastern Europe; the influence of the Soviet Navy played a large role in the Cold War, as the majority of conflicts centered on naval forces. The Soviet Navy was divided into four major fleets: the Northern, Black Sea, Baltic Fleets; the Caspian Flotilla was a smaller force operating in the land-locked Caspian Sea. Main components of the Soviet Navy included Soviet Naval Aviation, Naval Infantry, Coastal Artillery. After the dissolution of the Soviet Union in 1991, Russia inherited the largest part of the Soviet Navy and reformed it into the Russian Navy, with smaller parts becoming the basis for navies of the newly independent post-Soviet states; the Soviet Navy was based on a republican naval force formed from the remnants of the Imperial Russian Navy, completely destroyed in the two Revolutions of 1917 during World War I, the following Russian Civil War, the Kronstadt rebellion in 1921.
During the revolutionary period, Russian sailors deserted their ships at will and neglected their duties. The officers were dispersed and most of the sailors walked off and left their ships. Work stopped in the shipyards; the Black Sea Fleet fared no better than the Baltic. The Bolshevik revolution disrupted its personnel, with mass murders of officers. At the end of April 1918, Imperial German troops moved along the Black Sea coast and entered Crimea and started to advance towards the Sevastopol naval base; the more effective ships were moved from Sevastopol to Novorossiysk where, after an ultimatum from Germany, they were scuttled by Vladimir Lenin's order. The ships remaining in Sevastopol were captured by the Germans and after the Armistice of 11 November 1918 on the Western Front which ended the War, additional Russian ships were confiscated by the British. On 1 April 1919, during the ensuing Russian Civil War when Red Army forces captured Crimea, the British Royal Navy squadron had to withdraw, but before leaving they damaged all the remaining battleships and sank thirteen new submarines.
When the opposing Czarist White Army captured Crimea in 1919, it rescued and reconditioned a few units. At the end of the civil war, Wrangel's fleet, a White flotilla, moved south through the Black Sea, Dardanelles straits and the Aegean Sea to the Mediterranean Sea to Bizerta in French Tunisia on the North Africa coast, where it was interned; the first ship of the revolutionary navy could be considered the rebellious Imperial Russian cruiser Aurora, built 1900, whose crew joined the communist Bolsheviks. Sailors of the Baltic fleet supplied the fighting force of the Bolsheviks led by Vladimir Lenin and Leon Trotsky during the October Revolution of November 1917 against the democratic provisional government of Alexander Kerensky established after the earlier first revolution of February against the Czar; some imperial vessels continued to serve after the revolution, albeit with different names. The Soviet Navy, established as the "Workers' and Peasants' Red Fleet" by a 1918 decree of the new Council of People's Commissars, installed as a temporary Russian revolutionary government, was less than service-ready during the interwar years of 1918 to 1941.
As the country's attentions were directed internally, the Navy did not have much funding or training. An indicator of its reputation was that the Soviets were not invited to participate in negotiations for the Washington Naval Treaty of 1921–1922, which limited the size and capabilities of the most powerful navies - British, Japanese, Italian; the greater part of the old fleet was sold by the Soviet government to post-war Germany for scrap. In the Baltic Sea there remained only three much-neglected battleships, two cruisers, some ten destroyers, a few submarines. Despite this state of affairs, the Baltic Fleet remained a significant naval formation, the Black Sea Fleet provided a basis for expansion. There existed some thirty minor-waterways combat flotillas. During the 1930s, as the industrialization of the Soviet Union proceeded, plans were made to expand the Soviet Navy into one of the most powerful in the world. Approved by the Labour and Defence Council in 1926, the Naval Shipbuilding Program included plans to construct twelve submarines.
Beginning 4 November 1926, Technical Bureau Nº 4, under the leadership of B. M. Malinin, managed the submarine construction works at the Baltic Shipyard. In subsequent years, 133 submarines were built to designs developed during Malinin's management. Additional developments included the formation of the Pacific Fleet in 1932 and the Northern Fleet in 1933; the forces were to be built around a core of powerful Sovetsky Soyuz-class battleships. This building program was only in its initial stages by the time the German invasion forced its suspension in 1941; the Soviet Navy had some minor action
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. It is the largest and most capable navy in the world and it has been estimated that in terms of tonnage of its active battle fleet alone, it is larger than the next 13 navies combined, which includes 11 U. S. allies or partner nations. With the highest combined battle fleet tonnage and the world's largest aircraft carrier fleet, with eleven in service, two new carriers under construction. With 319,421 personnel on active duty and 99,616 in the Ready Reserve, the Navy is the third largest of the service branches, it has 282 deployable combat vessels and more than 3,700 operational aircraft as of March 2018, making it the second-largest air force in the world, after the United States Air Force. The U. S. Navy traces its origins to the Continental Navy, established during the American Revolutionary War and was disbanded as a separate entity shortly thereafter.
The U. S. Navy played a major role in the American Civil War by blockading the Confederacy and seizing control of its rivers, it played the central role in the World War II defeat of Imperial Japan. The US Navy emerged from World War II as the most powerful navy in the world; the 21st century U. S. Navy maintains a sizable global presence, deploying in strength in such areas as the Western Pacific, the Mediterranean, the Indian Ocean, it is a blue-water navy with the ability to project force onto the littoral regions of the world, engage in forward deployments during peacetime and respond to regional crises, making it a frequent actor in U. S. foreign and military policy. The Navy is administratively managed by the Department of the Navy, headed by the civilian Secretary of the Navy; the Department of the Navy is itself a division of the Department of Defense, headed by the Secretary of Defense. The Chief of Naval Operations is the most senior naval officer serving in the Department of the Navy.
The mission of the Navy is to maintain and equip combat-ready Naval forces capable of winning wars, deterring aggression and maintaining freedom of the seas. The U. S. Navy is a seaborne branch of the military of the United States; the Navy's three primary areas of responsibility: The preparation of naval forces necessary for the effective prosecution of war. The maintenance of naval aviation, including land-based naval aviation, air transport essential for naval operations, all air weapons and air techniques involved in the operations and activities of the Navy; the development of aircraft, tactics, technique and equipment of naval combat and service elements. U. S. Navy training manuals state that the mission of the U. S. Armed Forces is "to be prepared to conduct prompt and sustained combat operations in support of the national interest." As part of that establishment, the U. S. Navy's functions comprise sea control, power projection and nuclear deterrence, in addition to "sealift" duties, it follows as certain as that night succeeds the day, that without a decisive naval force we can do nothing definitive, with it, everything honorable and glorious.
Naval power... is the natural defense of the United States The Navy was rooted in the colonial seafaring tradition, which produced a large community of sailors and shipbuilders. In the early stages of the American Revolutionary War, Massachusetts had its own Massachusetts Naval Militia; the rationale for establishing a national navy was debated in the Second Continental Congress. Supporters argued that a navy would protect shipping, defend the coast, make it easier to seek out support from foreign countries. Detractors countered that challenging the British Royal Navy the world's preeminent naval power, was a foolish undertaking. Commander in Chief George Washington resolved the debate when he commissioned the ocean-going schooner USS Hannah to interdict British merchant ships and reported the captures to the Congress. On 13 October 1775, the Continental Congress authorized the purchase of two vessels to be armed for a cruise against British merchant ships. S. Navy; the Continental Navy achieved mixed results.
In August 1785, after the Revolutionary War had drawn to a close, Congress had sold Alliance, the last ship remaining in the Continental Navy due to a lack of funds to maintain the ship or support a navy. In 1972, the Chief of Naval Operations, Admiral Elmo Zumwalt, authorized the Navy to celebrate its birthday on 13 October to honor the establishment of the Continental Navy in 1775; the United States was without a navy for nearly a decade, a state of affairs that exposed U. S. maritime merchant ships to a series of attacks by the Barbary pirates. The sole armed maritime presence between 1790 and the launching of the U. S. Navy's first warships in 1797 was the U. S. Revenue-Marine, the primary predecessor of the U. S. Coast Guard. Although the USRCS conducted operations against the pirates, their depredations far outstripped its abilities and Congress passed the Naval Act of 1794 that established a permanent standing navy on 27 March 1794; the Naval Act ordered the construction and manning of six frigates and, by October 1797, the first three were brought into service: USS United States, USS Constellation, USS Constitution.
Due to his strong posture on having a strong standing Navy during this period, John Adams is "often called the father of the American Navy". In 1798–99 the Navy was involved in an undeclared Quasi-War with France. From 18
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. In the age of sail, a gunboat was a small undecked vessel carrying a single smoothbore cannon in the bow, or just two or three such cannons. A gunboat could carry one or two masts or be oar-powered only, but the single-masted version of about 15 m length was most typical; some types of gunboat else mounted a number of swivel guns on the railings. The small gunboat had advantages: if it only carried a single cannon, the boat could manoeuvre in shallow or restricted areas – such as rivers or lakes – where larger ships could sail only with difficulty; the gun that such boats carried could be quite heavy. As such boats were cheap and quick to build, naval forces favoured swarm tactics: while a single hit from a frigate's broadside would destroy a gunboat, a frigate facing a large squadron of gunboats could suffer serious damage before it could manage to sink them all.
For example: in the Battle of Alvøen during the Gunboat War of 1807–1814, five Dano-Norwegian gunboats defeated the lone frigate HMS Tartar. Gunboats used in the Battle of Valcour Island on Lake Champlain during the American Revolutionary War were built on the spot, attesting to the speed of their construction. All navies of the sailing era kept a number of gunboats on hand. Gunboats saw extensive use in the Baltic Sea during the late 18th century as they were well-suited for the extensive coastal skerries and archipelagoes of Sweden and Russia; the rivalry between Sweden and Russia in particular led to an intense expansion of gunboat fleets and the development of new gunboat types. The two countries clashed during the Russo-Swedish war of 1788–90, a conflict that culminated in the massive Battle of Svensksund in 1790, in which over 30,000 men and hundreds of gunboats and other oared craft took part; the majority of these were vessels developed from the 1770s and onwards by the naval architect Fredrik Henrik af Chapman for the Swedish archipelago fleet.
The designs and refined by the rival Danish and Russian navies, spread to the Mediterranean and to the Black Sea. Two variants occurred most commonly: a larger 20 m "gun sloop" with two 24-pounders, one in the stern and one in the bow a smaller 15 m "gun yawl" with a single 24-pounderMany of the Baltic navies kept gunboats in service well into the second half of the 19th century. British ships engaged larger 22 m Russian gunboats off Turku in southeast Finland in 1854 during the Crimean War; the Russian vessels had the distinction of being the last oared vessels of war in history to fire their guns in anger. Gunboats played a key role in Napoleon Bonaparte's plan for the invasion of England in 1804. Denmark-Norway used them in the Gunboat War. Between 1803 and 1812 the United States Navy had a policy of basing its navy on coastal gunboats, experimenting with a variety of designs. President Thomas Jefferson and his Democratic-Republican Party opposed a strong navy, regarding gunboats as adequate to defend the United States' major harbors.
They proved useless against the British blockade during the War of 1812. With the introduction of steam power in the early 19th century, the Royal Navy and other navies built considerable numbers of small vessels propelled by side paddles and by screws; these vessels retained full sailing rigs and used steam engines for auxiliary propulsion. The British Royal Navy deployed two wooden paddle-gunboats in the Lower Great Lakes and St. Lawrence River during the Rebellions of 1837 in Upper and Lower Canada; the United States Navy deployed an iron-hulled paddle gunboat, USS Michigan, to the Great Lakes in 1844. Von der Tann became the first propeller-driven gunboat in the world. Conradi shipyards in Kiel built the steam-powered 120 long tons gunboat in 1849 for the small navy of Schleswig-Holstein. Called "Gunboat No. 1", Von der Tann was the most modern ship in the navy. She participated in the First Schleswig War of 1848–1851. Britain built a large number of wooden screw-gunboats during the 1850s, some of which participated in the Crimean War, Second Opium War and Indian Mutiny.
The requirement for gunboats in the Crimean War was formulated in 1854 to allow the Royal Navy to bombard shore facilities in the Baltic. The first ships the Royal Navy built. In mid-1854 the Royal Navy ordered six Gleaner-class gunboats followed in the year by an order for 20 Dapper-class gunboats. In May 1855 the Royal Navy deployed six Dapper-class gunboats in the Sea of Azov, where they raided and destroyed stores around its coast. In June 1855 the Royal Navy reentered the Baltic with a total of 18 gunboats as part of a larger fleet; the gunboats attacked various coastal facilities, operating alongside larger British warships from which they drew supplies such as coal. Gunboats experienced a revival during the American Civil War. Union and Confederate forces converted existing passenger-carrying boats into armed sidewheel steamers; some purpose-built boats, such as USS Miami, joined the fray. They mounted 12 or more guns, sometimes of rather large caliber, carried some armor. At the same time, Britain's gunboats from the Crimean War period were starting to wear out, so a new series of classes was ordered.
Construction shifted from a purely wooden hull to an iron–teak composite. In the 19th century and early 20th century, "gunboat" w