An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming and recovering aircraft. It is the capital ship of a fleet, as it allows a naval force to project air power worldwide without depending on local bases for staging aircraft operations. Carriers have evolved since their inception in the early twentieth century from wooden vessels used to deploy balloons to nuclear-powered warships that carry numerous fighters, strike aircraft and other types of aircraft. While heavier aircraft such as fixed-wing gunships and bombers have been launched from aircraft carriers, it is not possible to land them. By its diplomatic and tactical power, its mobility, its autonomy and the variety of its means, the aircraft carrier is the centerpiece of modern combat fleets. Tactically or strategically, it replaced the battleship in the role of flagship of a fleet. One of its great advantages is that, by sailing in international waters, it does not interfere with any territorial sovereignty and thus obviates the need for overflight authorizations from third party countries, reduce the times and transit distances of aircraft and therefore increase the time of availability on the combat zone.
There is no single definition of an "aircraft carrier", modern navies use several variants of the type. These variants are sometimes categorized as sub-types of aircraft carriers, sometimes as distinct types of naval aviation-capable ships. Aircraft carriers may be classified according to the type of aircraft they carry and their operational assignments. Admiral Sir Mark Stanhope, RN, former First Sea Lord of the Royal Navy, has said, "To put it countries that aspire to strategic international influence have aircraft carriers." Henry Kissinger, while United States Secretary of State said: "An aircraft carrier is 100,000 tons of diplomacy". As of April 2019, there are 41 active aircraft carriers in the world operated by thirteen navies; the United States Navy has 11 large nuclear-powered fleet carriers—carrying around 80 fighter jets each—the largest carriers in the world. As well as the aircraft carrier fleet, the U. S. Navy has nine amphibious assault ships used for helicopters, although these carry up to 20 vertical or short take-off and landing fighter jets and are similar in size to medium-sized fleet carriers.
China, India and the UK each operate a single large/medium-size carrier, with capacity from 30 to 60 fighter jets. Italy operates two light fleet carriers and Spain operates one. Helicopter carriers are operated by Japan, Australia, Brazil, South Korea, Thailand. Future aircraft carriers are under construction or in planning by Brazil, India, the United Kingdom, the United States. Amphibious assault ship Anti-submarine warfare carrier Balloon carrier and balloon tenders Escort carrier Fleet carrier Flight deck cruiser Helicopter carrier Light aircraft carrier Sea Control Ship Seaplane tender and seaplane carriers Aircraft cruiser A fleet carrier is intended to operate with the main fleet and provides an offensive capability; these are the largest carriers capable of fast speeds. By comparison, escort carriers were developed to provide defense for convoys of ships, they were slower with lower numbers of aircraft carried. Most were built from mercantile hulls or, in the case of merchant aircraft carriers, were bulk cargo ships with a flight deck added on top.
Light aircraft carriers were fast enough to operate with the main fleet but of smaller size with reduced aircraft capacity. The Soviet aircraft carrier Admiral Kusnetsov was termed a heavy aircraft-carrying cruiser; this was a legal construct to avoid the limitations of the Montreux Convention preventing'aircraft carriers' transiting the Turkish Straits between the Soviet Black Sea bases and the Mediterranean. These ships, while sized in the range of large fleet carriers, were designed to deploy alone or with escorts. In addition to supporting fighter aircraft and helicopters, they provide both strong defensive weaponry and heavy offensive missiles equivalent to a guided missile cruiser. Aircraft carriers today are divided into the following four categories based on the way that aircraft take off and land: Catapult-assisted take-off barrier arrested-recovery: these carriers carry the largest and most armed aircraft, although smaller CATOBAR carriers may have other limitations. All CATOBAR carriers in service today are nuclear powered.
Two nations operate carriers of this type: ten Nimitz class and one Gerald R. Ford class fleet carriers by the United States, one medium-sized carrier by France, for a world total of twelve in service. Short take-off but arrested-recovery: these carriers are limited to carrying lighter fixed-wing aircraft with more limited payloads. STOBAR carrier air wings, such as the Sukhoi Su-33 and future Mikoyan MiG-29K wings of Admiral Kuznetsov are geared towards air superiority and fleet defense roles rather than strike/power projection tasks, which require heavier payloads. Today China and Russia each operate one carrier of this type – a total of three in service currently. Short take-off vertical-landing: limited to carrying STOVL aircraft. STOVL aircraft, such as the Harrier Jump Jet family and Yakovlev Yak-38 have limited payloads, lower perfor
Zamorin of Calicut
Samoothiri of Kozhikode is the hereditary title of the Hindu monarch of the kingdom of Kozhikode on Malabar Coast, India. The Samoothiris were based at the city of Kozhikode, one of the important trading ports on the south-western coast of India. At the peak of their reign, the Samoothiri's ruled over a region from Kollam to Panthalayini Kollam, it was after the dissolution of the kingdom of Cheras of Cranganore in the early 12th century, the Samoothiris – autonomous chiefs of Eranadu – demonstrated their political independence. The Samoothiris maintained elaborate trade relations with the Muslim Middle-Eastern sailors in the Indian Ocean, the primary spice traders on the Malabar Coast in the Middle Ages. Kozhikode was an important entrepôt in south-western India where Chinese and West Asian trade met; the Portuguese navigator Vasco da Gama visited the Kozhikode in 1498, opening the sailing route directly from Europe to Asia. The Portuguese efforts to lay the foundations to Estado da Índia, to take complete control over the commerce was hampered by the forces of Samoothiri of Kozhikode.
The Kunjali Marakkars, the famous Muslim warriors, were the naval chiefs of Kozhikode. By the end of the 16th century the Portuguese – now commanding the spice traffic on the Malabar Coast – had succeeded in replacing the Muslim merchants in the Arabian Sea; the Dutch supplanted the Portuguese in the 17th century. In 1766 Haider Ali of Mysore defeated the Samoothiri of Kozhikode – an English East India Company dependant at the time – and absorbed Kozhikode to his state. After the Third Mysore War, Malabar was placed under the control of the Company; the status of the Samoothiri as independent rulers was changed to that of pensioners of the Company. The title "Samoothiri" appears in sources only after the c. 15th century, first time in the writings Ibn Batutah. It is safe to assume that the Eradis of Nediyirippu assumed the title of "Samoothiri" in a period; the Samoothiris used the title "Punthurakon" in inscriptions, in palace records known as the Granthavaris, in official treaties with the English and the Dutch.
No records indicate the actual personal name of the ruler. Punthura may be a port of great fame; the title "Kunnalakkon" and its Sanskrit form "Shailabdhishvara" are found in literary works. Thrikkavil Kovilakam in Ponnani served as a second home for the Samoothiris of Kozhikode. Other secondary seats of the Samoothiri of Kozhikode, all established at much time, were Trichur and Cranganore; the chief Kerala ports under control of the Samoothiris in the late 15th century were Panthalayini Kollam, Kozhikode. The Samoothiri of Kozhikode derived greater part of his revenues by taxing the spice trade through his ports. Smaller ports in the kingdom were Puthuppattanam, Tanur, Ponnani and Kodungallur; the port of Beypore served as a ship building center. The port at Kozhikode held the superior economic and political position in Kerala, while Kollam and Kannur were commercially confined to secondary roles. Travellers have called the city by different names – variations of the Malayalam name; the travellers from Middle-East called it "Kalikooth", Tamils called the city "Kallikkottai", for the Chinese it was "Kalifo" or "Quli".
In the Middle Ages, Kozhikode was dubbed the "City of Spices" for its role as the major trading point of Asian spices. The Chinese and Middle-Eastern interests in Malabar, the political ambition of the newly emergent rulers, i.e. the Samoothiris, the decline of port Kodungallur, etc. boosted the prosperity of the port. The rise of the Kozhikode, both the port and the state, seems to have taken place only after the 13th century AD. Kozhikode, despite being located at a geographically inconvenient spot, owed much of its prosperity to the economic policies of the Samoothiris of Kozhikode. Trade at port Kozhikode was managed by the Muslim port commissioner known as the Shah Bandar Koya; the port commissioner supervised the customs on the behalf of the king, fixed the prices of the commodities and collected the share to the Kozhikode treasury. The name of the famous fine variety of cotton cloth called calico is thought to have derived from Kozhikode. Known as "Fandarina", "Shaojunan". Located north of Kozhikode, close to a bay.
The geographical location is ideal for the wintering of ships during the annual monsoon rains. Presence of Chetti and Jewish merchants among others. According to K. V. Krishna Iyer, the court historian in Kozhikode, the members of the royal house of Samoothiri belonged the Samanta community; the Samantas claimed a status higher than the rest of the Nairs. The Hindu theological formula that the rulers must be of Kshatriya varna may have been a complication for the Nair Samantas of the Kodungallur Chera monarch. So the Samantas – crystallized as a distinctive social group, something of a "sub-caste" – began to style themselves as "Samanta Ksatriyas"; the Samantas have birth and death customs identical to the Nair community. In the royal family, thalis of the princesses were tied by Kshatriyas from Kodungallur chief's family, which the Samoothiri recognised as more ancient and therefore higher rank; the majority of the women's sambandham partners were Nambudiri Brahmins. The
Early modern period
The early modern period of modern history follows the late Middle Ages of the post-classical era. Although the chronological limits of the period are open to debate, the timeframe spans the period after the late portion of the post-classical age, known as the Middle Ages, through the beginning of the Age of Revolutions and is variously demarcated by historians as beginning with the Fall of Constantinople in 1453, with the Renaissance period, with the Age of Discovery, ending around the French Revolution in 1789. Historians in recent decades have argued that from a worldwide standpoint, the most important feature of the early modern period was its globalizing character; the period witnessed the exploration and colonization of the Americas and the rise of sustained contacts between isolated parts of the globe. The historical powers became involved in global trade, as the exchange of goods, animals, food crops, slaves extended to the Old World and the New World; the Columbian Exchange affected the human environment.
New economies and institutions emerged, becoming more sophisticated and globally articulated over the course of the early modern period. This process began in the medieval North Italian city-states Genoa and Milan; the early modern period included the rise of the dominance of the economic theory of mercantilism. The European colonization of the Americas and Africa occurred during the 15th to 19th centuries, spread Christianity around the world; the early modern trends in various regions of the world represented a shift away from medieval modes of organization and economically. Feudalism declined in Europe, while the period included the Protestant Reformation, the disastrous Thirty Years' War, the Commercial Revolution, the European colonization of the Americas, the Golden Age of Piracy. By the 16th century the economy under the Ming dynasty was stimulated by trade with the Portuguese, the Spanish, the Dutch, while Japan engaged in the Nanban trade after the arrival of the first European Portuguese during the Azuchi–Momoyama period.
Other notable trends of the early modern period include the development of experimental science, accelerated travel due to improvements in mapping and ship design rapid technological progress, secularized civic politics, the emergence of nation states. Historians date the end of the early modern period when the French Revolution of the 1790s began the "late modern" period. Dates are approximate. Consult particular article for details. Early modern themes Other In Early Modern times, the major nations of East Asia attempted to pursue a course of Isolationism from the outside world but this policy was not always enforced uniformly or successfully. However, by the end of the Early Modern Period, China and Japan were closed and disinterested to Europeans while trading relationships grew in port cities such as Guangzhou and Dejima. Around the beginning of the Ming dynasty, China was leading the world in mathematics as well as science. However, Europe soon caught up to China's scientific and mathematical achievements and surpassed them.
Many scholars have speculated about the reason behind China's lag in advancement. A historian named Colin Ronan claims that though there is no one specific answer, there must be a connection between China's urgency for new discoveries being weaker than Europe's and China's inability to capitalize on its early advantages. Ronan believes that China's Confucian bureaucracy and traditions led to China not having a scientific revolution, which led China to have fewer scientists to break the existing orthodoxies, like Galileo Galilei. Despite inventing gunpowder in the 9th century, it was in Europe that the classic handheld firearms, were invented, with evidence of use around the 1480s. China was using the matchlocks by 1540, after the Portuguese brought their matchlocks to Japan in the early 1500s. China during the Ming Dynasty established a bureau to maintain its calendar; the bureau was necessary because the calendars were linked to celestial phenomena and that needs regular maintenance because twelve lunar months have 344 or 355 days, so occasional leap months have to be added in order to maintain 365 days per year.
In the 16th century the Ming dynasty flourished over maritime trade with the Portuguese and Dutch Empires. The trade brought in a massive amount of silver. Prior to China's global trade, its economy ran on a paper money. However, in the 14th century, China's paper money system suffered a crisis, by the mid-15th century, crashed; the silver imports helped fill the void left by the broken paper money system, which helps explain why the value of silver in China was twice as high as the value of silver in Spain during the end of the 16th century. The Ming dynasty suffered an economic collapse in the seventeenth-century because of heavy inflation of silver, the European trade depression of the 1620s; the economy sunk to the point where all of China's trading partner cut ties with them: Philip IV restricted shipments of exports from Acapulco, the Japanese cut off all trade with Macau, the Dutch severed connections between Gao and Macau. The damage to the economy was compounded by the effects on agriculture of the incipient Little Ice Age, natural calamities, crop failure and sudden epidemics.
The ensuing breakdown of authority and people's livelihoods allowed rebel leaders, such as Li Zicheng, to challenge Ming authority. The Ming dynasty fell around 1644 to the Qing dynasty, the last ruling dynasty of Chi
Romeyn de Hooghe
Romeyn de Hooghe was an important and prolific late Dutch Baroque, sculptor and caricaturist. He was born in Amsterdam, was a skilled etcher, painter and medalist, he is best known for political caricatures of Louis XIV and propagandistic prints supporting William of Orange. During his career, de Hooghe produced over 3500 prints, he illustrated books, his illustrations can be found in some of the most important texts of his period. The Hieroglyphica of Merkbeelden der oude volkeren was a well known emblem book and sourcebook for classical mythology and its iconography. According to Houbraken he was good at inventive arrangements of subjects in engravings, he was a gifted painter and painted large panels for the rooms of the mayor's office in Enkhuizen and a room in the estate of Mattthijs van den Broeck in Dubbeldam. Houbraken disapproved of his dissolute lifestyle however, felt that despite an enormous talent, as he grew older, he engraved shameful subjects that were a disgrace to the profession.
Contrary to this, the historian Simon Schama wrote in the aftermath of the Charlie Hebdo killings of 2015 that: "The first great modern graphic satirist was Romeyn de Hooghe, enlisted by William III at the end of the 17th century in his relentless war to the death with Louis XIV. De Hooghe obliged with sprawling cartoons representing the wars against the French monarch and his allies as a battle between liberty and religious despotism". According to the RKD he became a member of the Confrerie Pictura in 1662 and again in 1683 in the Hague, he was engaged to Maria Lansman of Edam in 1673, their child was baptized in the Nieuwezijds Kapel in Amsterdam in 1674. He is known for decorative borders on large-scale city maps, his pupils were Filibert Bouttats, Filibertus Bouttats, Frans Decker, François Harrewijn, Jacobus Harrewijn, Aernout Naghtegael, Laurens Scherm, Adriaen Schoonebeek. De Hooghe died in Haarlem. Romeyn de Hooghe on Artnet The Battle of Chocim - A copperplate engraving by Romeyn de Hooghe at the Wilanów Palace Museum Finding aid for Romeyn de Hooge etchings at the Getty Research Institute Emblems Book
Military tactics encompasses the art of organising and employing fighting forces on or near the battlefield. They involve the application of four battlefield functions which are related – kinetic or firepower, protection or security, shock action. Tactics are a separate function from control and logistics. In contemporary military science, tactics are the lowest of three levels of warfighting, the higher levels being the strategic and operational levels. Throughout history, there has been a shifting balance between the four tactical functions based on the application of military technology, which has led to one or more of the tactical functions being dominant for a period of time accompanied by the dominance of an associated fighting arm deployed on the battlefield, such as infantry, cavalry or tanks. Beginning with the use of melee and missile weapons such as clubs and spears, the kinetic or firepower function of tactics has developed along with technological advances so that the emphasis has shifted over time from the close-range melee and missile weapons to longer-range projectile weapons.
Kinetic effects were delivered by the sword, spear and bow until the introduction of artillery by the Romans. Until the mid 19th century, the value of infantry-delivered missile firepower was not high, meaning that the result of a given battle was decided by infantry firepower alone relying on artillery to deliver significant kinetic effects; the development of disciplined volley fire, delivered at close range, began to improve the hitting power of infantry, compensated in part for the limited range, poor accuracy and low rate of fire of early muskets. Advances in technology the introduction of the rifled musket, used in the Crimean War and American Civil War, meant flatter trajectories and improved accuracy at greater ranges, along with higher casualties; the resulting increase in defensive firepower meant infantry attacks without artillery support became difficult. Firepower became crucial to fixing an enemy in place to allow a decisive strike. Machine guns added to infantry firepower at the turn of the 20th century, the mobile firepower provided by tanks, self-propelled artillery and military aircraft rose in the century that followed.
Along with infantry weapons and other armoured vehicles, self-propelled artillery, guided weapons and aircraft provide the firepower of modern armies. Mobility, which determines how a fighting force can move, was for most of human history limited by the speed of a soldier on foot when supplies were carried by beasts of burden. With this restriction, most armies could not travel more than 32 kilometres per day, unless travelling on rivers. Only small elements of a force such as cavalry or specially trained light troops could exceed this limit; this restriction on tactical mobility remained until the latter years of World War I when the advent of the tank improved mobility sufficiently to allow decisive tactical manoeuvre. Despite this advance, full tactical mobility was not achieved until World War II when armoured and motorised formations achieved remarkable successes. However, large elements of the armies of World War II remained reliant on horse-drawn transport, which limited tactical mobility within the overall force.
Tactical mobility can be limited by the use of field obstacles created by military engineers. Personal armour has been worn since the classical period to provide a measure of individual protection, extended to include barding of the mount; the limitations of armour have always been weight and bulk, its consequent effects on mobility as well as human and animal endurance. By the 18th and 19th centuries, personal armour had been discarded, until the re-introduction of helmets during World War I in response to the firepower of artillery. Armoured fighting vehicles proliferated during World War II, after that war, body armour returned for the infantry in Western armies. Fortifications, which have been used since ancient times, provide collective protection, modern examples include entrenchments, barbed wire and minefields. Like obstacles, fortifications are created by military engineers. Shock action is as much a psychological function of tactics as a physical one, can be enhanced by the use of surprise.
It has been provided by charging infantry, well as by chariots, war elephants and armoured vehicles which provide momentum to an assault. It has been used in a defensive way, for example by the drenching flights of arrows from English longbowmen at the Battle of Agincourt in 1415 which caused the horses of the French knights to panic. During early modern warfare, the use of the tactical formations of columns and lines had a greater effect than the firepower of the formations alone. During the early stages of World War II, the combined effects of German machine gun and tank gun firepower, enhanced by accurate indirect fire and air attack broke up Allied units before their assault commenced, or caused them to falter due to casualties among key unit leaders. In both the early modern and World War II examples, the cumulative psychological shock effect on the enemy was greater than the actual casualties incurred; the development of tactics has involved a shifting balance between the four tactical functions since ancient times, changes in firepower and mobility have been fundamental to these changes.
Various models have been proposed to explain the interaction between the tactical functions and the dominance of individual fighting arms during different periods. J. F. C. Fuller proposed three "tactical cycles" in each of the classical and Chri
Battle of the Yalu River (1894)
The Battle of the Yalu River was the largest naval engagement of the First Sino-Japanese War, took place on 17 September 1894, the day after the Japanese victory at the land Battle of Pyongyang. It involved ships from the Chinese Beiyang Fleet; the battle is known by a variety of names: Battle of Haiyang Island, Battle of Dadonggou, Battle of the Yellow Sea and Battle of Yalu, after the geographic location of the battle, in the Yellow Sea off the mouth of the Yalu River and not in the river itself. There is no agreement among contemporary sources on the exact numbers and composition of each fleet. Japan's initial strategy was to gain command of the sea, critical to its operations in Korea. Command of the sea would allow Japan to transport troops to the mainland; the Imperial Japanese Army's Fifth Division would land at Chemulpo on the western coast of Korea, both to engage and push Chinese forces northwest up the peninsula and to draw the Beiyang Fleet into the Yellow Sea, where it would be engaged in decisive battle.
Depending on the outcome of this engagement, Japan would make one of three choices. If the engagement were to be a draw and neither side gained control of the sea, the army would concentrate on the occupation of Korea. Lastly, if the Combined Fleet was defeated and lost command of the sea, the bulk of the army would remain in Japan and prepare to repel a Chinese invasion, while the Fifth Division in Korea would be ordered to hang on and fight a rearguard action. With tensions with Japan increasing over the situation on the Peninsula, the Chinese government chartered three British steamers to carry reinforcements to Korea in late July to bolster their position in Korea; the three troopships were escorted by three naval vessels, the cruiser Jiyuan and the gunboats Kwang-yi and Tsao-kiang. A Japanese force consisting of the cruisers Akitsushima and Naniwa intercepted the three Chinese warships off Pungo Island. Within one hour, the engagement which ended in a Japanese victory, Jiyuan was forced to flee, Kwang-yi became stranded on a shoal and Tsao-kiang had been captured.
Although the first two of the three troopships arrived safely in Korea, on 25 July 1894, Naniwa intercepted the third, carrying 1,200 Chinese troops. The Chinese troops on board refused to surrender or to be interned and Naniwa was forced to sink the vessel. Admiral Ding Ruchang had learned about the engagement at Pungdo on the morning of 26 July, when at 6.00am, the damaged cruiser Jiyuan arrived at Weihaiwei. Although the Chinese admiral had not been aware of the sinking of Kowshing, he considered the destruction of Kwang-yi and shelling of Jiyuan as an act of war. On the same day, without notifying Li Hongzhang, he left Weihaiwei with eleven warships and seven torpedo boats and headed for the Korean coast, while the damaged Jiyuan sailed to Port Arthur for repairs. After arriving in Korean waters on the morning of the following day, the Chinese ships cruised the area looking to engage the enemy. However, the abrupt change in the weather made the patrolling of the Korean waters more arduous for the small torpedo boats and the Chinese fleet returned to Weihaiwei on 28 July.
The Chinese warships resupplied themselves with coal while the weather improved, the main force of the Beiyang Fleet was put to sea again on the following day but without the torpedo boats, heading for the Korean coast. This second cruise lasted longer, until 3 August. At the beginning of September, Li Hongzhang decided to reinforce the Chinese forces at Pyongyang, by employing the Beiyang Fleet to escort transports to the mouth of the Taedong River. About 4,500 additional troops were to be redeployed, these had been stationed in the Zhili. On 12 September, half of the troops embarked at Dagu on five specially chartered transports and headed to Dalian where two days on 14 September, they were joined by another 2,000 soldiers. Admiral Ding wanted to send the transports under a light escort with only a few ships, while the main force of the Beiyang Fleet would locate and operate directly against Combined Fleet, in order to prevent the Japanese from intercepting the convoy. However, the appearance of the Japanese cruisers Yoshino and Naniwa near Weihaiwei, which were on reconnaissance sortie, thwarted these plans.
The Chinese mistook them for the main Japanese fleet. On 12 September, the entire Beiyang Fleet departed Dalian, heading for Weihaiwei and arriving in near the Shandong Peninsula the following day; the Chinese warships spent the entire day cruising the area. However, since no sighting of the Japanese, Admiral Ding decided to return to Dalian, arriving there in the morning of 15 September; the Japanese victory at Pyongyang had succeeded in pushing Chinese troops north to the Yalu River, in the process removing all effective Chinese military presence on the Korean peninsula. Shortly before the convoy's departure, Admiral Ding received a message concerning the battle at Pyongyang. Although it was rather inaccurate, it informed him about the defeat and subsequently made the redeployment of the troops to near the mouth of the Taedong River unnecessary. Admiral Ding, who correctly assumed that the next Chinese line of defence would be established on
An ironclad is a steam-propelled warship protected by iron or steel armor plates used in the early part of the second half of the 19th century. The ironclad was developed as a result of the vulnerability of wooden warships to explosive or incendiary shells; the first ironclad battleship, was launched by the French Navy in November 1859. The British Admiralty had been considering armored warships since 1856 and prepared a draft design for an armored corvette in 1857. After the first clashes of ironclads took place in 1862 during the American Civil War, it became clear that the ironclad had replaced the unarmored ship of the line as the most powerful warship afloat; this type of ship would come to be successful in the American Civil War. Ironclads were designed for several roles, including as high seas battleships, coastal defense ships, long-range cruisers; the rapid development of warship design in the late 19th century transformed the ironclad from a wooden-hulled vessel that carried sails to supplement its steam engines into the steel-built, turreted battleships and cruisers familiar in the 20th century.
This change was pushed forward by the development of heavier naval guns, more sophisticated steam engines, advances in metallurgy which made steel shipbuilding possible. The quick pace of change meant that many ships were obsolete as soon as they were finished, that naval tactics were in a state of flux. Many ironclads were built to make use of the ram or the torpedo, which a number of naval designers considered the important weapons of naval combat. There is no clear end to the ironclad period, but towards the end of the 1890s the term ironclad dropped out of use. New ships were constructed to a standard pattern and designated battleships or armored cruisers; the ironclad became technically feasible and tactically necessary because of developments in shipbuilding in the first half of the 19th century. According to naval historian J. Richard Hill: "The had three chief characteristics: a metal-skinned hull, steam propulsion and a main armament of guns capable of firing explosive shells, it is only when all three characteristics are present that a fighting ship can properly be called an ironclad."
Each of these developments was introduced separately in the decade before the first ironclads. In the 18th and early 19th centuries fleets had relied on two types of major warship, the ship of the line and the frigate; the first major change to these types was the introduction of steam power for propulsion. While paddle steamer warships had been used from the 1830s onwards, steam propulsion only became suitable for major warships after the adoption of the screw propeller in the 1840s. Steam-powered screw frigates were built in the mid-1840s, at the end of the decade the French Navy introduced steam power to its line of battle; the desire for change came from the ambition of Napoleon III to gain greater influence in Europe, which required a challenge to the British at sea. The first purpose-built steam battleship was the 90-gun Napoléon in 1850. Napoléon was armed as a conventional ship-of-the-line, but her steam engines could give her a speed of 12 knots, regardless of the wind conditions: a decisive advantage in a naval engagement.
The introduction of the steam ship-of-the-line led to a building competition between France and Britain. Eight sister ships to Napoléon were built in France over a period of ten years, but the United Kingdom soon managed to take the lead in production. Altogether, France built ten new wooden steam battleships and converted 28 from older ships of the line, while the United Kingdom built 18 and converted 41; the era of the wooden steam ship-of-the-line was brief. In the 1820s and 1830s, warships began to mount heavy guns, replacing 18- and 24-pounder guns with 32-pounders on sailing ships-of-the-line and introducing 68-pounders on steamers; the first shell guns firing explosive shells were introduced following their development by the French Général Henri-Joseph Paixhans, by the 1840s were part of the standard armament for naval powers including the French Navy, Royal Navy, Imperial Russian Navy and United States Navy. It is held that the power of explosive shells to smash wooden hulls, as demonstrated by the Russian destruction of an Ottoman squadron at the Battle of Sinop, spelled the end of the wooden-hulled warship.
The more practical threat to wooden ships was from conventional cannon firing red-hot shot, which could lodge in the hull of a wooden ship and cause a fire or ammunition explosion. Some navies experimented with hollow shot filled with molten metal for extra incendiary power; the use of iron instead of wood as the primary material of ships' hulls began in the 1830s. There followed from Laird, the first full-blown warships with metal hulls, the 1842 steam frigates Guadelupe and Montezuma for the Mexican navy, but a thin iron skin, while not being susceptible to fire or lethal splintering like wood, was not the same thing as providing iron armor calculated to stop enemy gunfire. In 1843, the United States Navy launched USS Michigan, on the Great Lakes; this pioneering iron-hulled, steam-powered ship served for 70 years in the peaceful region. Following the demonstration of the power of explosive shells against wooden ships at the Battle of Si