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An Encyclopedia of the History of Technology part 56 ppt

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PART THREE: TRANSPORT 532 In the post-war years surprisingly few radical changes in ship design were evident, apart from the general adoption of a more streamlined appearance pioneered by more enterprising owners in the 1930s. Crews now needed better quarters, entailing more superstructure, while advanced navigational and radio equipment developed during the war years was generally fitted. The diesel engine steadily improved in efficiency, although gas turbines seemed to have little application in merchant as compared to fighting navies. Thanks to steel hatch covers and improved methods of construction, ships could now be given larger hatches than ever before, with consequent improvements in cargo handling. The growth of air travel, and increasingly stringent safety requirements, steadily drove the great passenger liners out of operation or into the cruise business, for which new and luxurious, but smaller, vessels were built. From the 1960s onwards the cargo ship, refrigerated or otherwise, steadily gave way to the container ships, very large and fast, with holds designed to carry cargo of all kinds in internationally standardized rigid containers which ports of all major nations have been adapted to handle. The old tramp ship has been replaced by the much larger bulk carrier working to specialized terminals. Oil tankers have grown to vast size: the very large crude carrier (VLCC) attains 382,500 tonnes and ultra large crude carriers (ULCCs) of up to 408,000 tonnes have been built. All these new types adopted engines aft and, progressively, diesel engines, especially after the increase in oil prices of the 1970s. WARSHIPS The sailing man-of-war had developed slowly; a seaman of the seventeenth- century Dutch Wars would not have been too unfamiliar with a naval ship of the 1840s. The only essential difference from the contemporary sailing merchant vessel was in armament: numerous guns were mounted along the naval ship’s sides, on two or three decks for a line of battle ship, only one on frigates or sloops, and also on forecastle and quarter-deck in larger types. Naval ships were rated according to the number of guns they carried: three- deckers 90 or more, two-deckers (the majority of ships of the line) 70 to 80, frigates 26 to 60, sloops 20 or fewer. The introduction of steam and iron had a revolutionary effect on warship design. Steam-driven paddle-wheels were fitted to naval vessels from the late 1820s to supplement their sail power. Because the wheels and boxes took up most of a ship’s sides, pivot guns (used earlier to some extent in smaller ships) were more often mounted, as well as larger guns fore and aft; many of the guns of this period fired explosive shells, as proposed by the French General Paixhans. Paddle-wheels, however, occupied much valuable space and were PORTS AND SHIPPING 533 exceedingly vulnerable to gunfire; once the superiority of screw propulsion had been established a very rapid transformation of navies took place between 1850 and 1860. For frigates and ships of the line it was the practice to fit boilers and engines into existing ships, often lengthened, or to complete ships on the stocks in a similar way. For smaller craft, iron or slender wooden hulls following the clipper form (see p. 525) were adopted, in conjunction with a few pivot guns. The experience of the Crimean War (1854–6), together with further advances in gun-making, initiated another radical change. The need to engage powerful fortifications, already to the fore in the 1830s and 1840s, increased and produced the idea—said to originate with the French Emperor Napoleon III—of vessels covered with an armour of iron plates. Several such floating batteries were built by both Great Britain and France, slow but heavily armed, and it was a short step to seagoing craft on the same principle. The French Gloire of 1859 was a wooden ship with armour attached, but the British Warrior of 1860 was built of iron throughout, and of great speed for her day. The ship of the line, even with screw engines, was outclassed, and the naval world was plunged into a period of great uncertainty and rapid change. The early ironclads were armed, like their predecessors, with broadside guns, although these were larger and fewer. Additionally, they were now rifled, for greater accuracy, and in most countries breech-loading, too, although in Britain difficulties with the Armstrong type led to a temporary reversion to the old muzzle-loaders. British guns increased in size from the 4.8 tonnes, the largest used during the Crimean War, successively to 7, 9, 12, 25 and 39 tonnes by 1870. Such weights were impossible for the hand-worked wooden guncarriages of the past and much more elaborate iron carriages with an increasing element of power were developed. The type which eventually proved most satisfactory was the turret, introduced about the time of the Crimean War simultaneously by Captain Cowper Coles RN and Ericsson, the Swedish engineer. It was the only really sound method for mounting very large guns where steam or hydraulic power were to be used for training, elevating and loading. All through this period great controversy raged about the design of warships, with little practical experience to provide guidance. It was feared that all warships would have to be armoured, but this was clearly too costly to provide enough ships for the duties required, and the smaller types continued along established lines with the corvette now as the largest class below the ironclads followed by sloops, gun-vessels and gunboats in descending order of size. While their guns were adapted to new standards, all these were really sailing vessels with engines, usually fitted with a hoisting screw which was lifted out of the water to reduce drag when the ship was under sail. This compromise was not the result of pure conservatism: all naval ships were liable to have to make ocean passages either where coal was unobtainable or so long that not enough could be carried to fuel the engines, or both. PART THREE: TRANSPORT 534 With the ironclads, the main argument was between the proponents of the gun turret and those who preferred broadside guns. The turret made its mark in the American Civil War with small, slow, low-freeboard ships called monitors after the pioneer vessel which fought a Confederate ship in Hampton Roads in 1862, and the type was used by many nations although only for coastal defence. Some ocean-going ships were built with turrets, but more had broadside guns or the variant central battery type, in which the guns could also fire ahead or astern, using suitable recesses in the ship’s side and pivot mounting. This became increasingly unwieldy as guns grew larger and the numbers that could be mounted therefore tended to decline. The ram became popular as a weapon after Hampton Roads and an incident at the Battle of Lissa in 1866, resulting in ships much shorter than the early ironclads in order to achieve better manoeuvrability; a few freak ships were designed with the sole purpose of ramming. In the event, however, several accidental collisions proved more disastrous than they need have been. Eventually, in about 1880, after years during which every fleet of the world was composed of a heterogeneous collection of individual ships, a consensus emerged. The battleship had two turrets, one fore and one aft, mounting one or two guns in each, usually 30cm (12in) or thereabouts, with a variety of smaller guns along the sides, and a belt of armour along the waterline, armoured deck over the engines and boilers, and armoured bases to the turrets and over the magazines. These smaller guns resulted from developments in the smaller classes of ships. With the evolution and increasing economy of the marine engine (see p. 530), it became feasible to abandon sails and, about the same time as the battleship’s form was becoming stabilized, the former frigates and corvettes were replaced by cruisers, fully-powered fast ships with a considerable battery of lighter guns, the larger often with some armour and guns up to 25cm (10in). Such ships took over many of the so-called ‘police’ tasks overseas and also acted as scouts for the main fleets. Below them came small, fast steamers carrying a totally new weapon—the torpedo boats. These craft, and the powerful charges of their torpedoes, seemed to threaten the existence of the great battleships, and one response was to fit both battleships and cruisers with many small guns of the new quick-firing type, whose projectiles were quite sufficient to damage or sink the lightly built torpedo craft. Another was to build larger but still fast vessels to chase and sink the torpedo boats before they could come within range of the big ships. The first essay in this direction, the torpedo-gunboat, was too slow and clumsy; it was succeeded by the torpedo boat destroyer, in practice a larger version of the torpedo boat armed with quick-firing guns. In fact they absorbed both attacking and destroying roles and eventually developed into powerful sea- going warships on their own account. PORTS AND SHIPPING 535 By 1900, therefore, naval fleets consisted of battleships, large armoured cruisers which scouted ahead, and supported light cruisers which did more of the scouting, and torpedo boat destroyers, which either attacked the enemy battle fleet or countered the efforts of enemy torpedo boats. In the decade up to 1914 warships, like merchant ships, increased greatly in size, a process accelerated by the great Anglo-German naval race of the period. The appearance of the steam turbine (see p. 288ff.) offered higher speeds with more economy and easier working, while gunners realized that a ship with more guns of one calibre was more effective than one carrying several sizes, such as had developed in the early 1900s. As a result of the reforms instituted in the British navy by Lord Fisher, the Dreadnought of 1906 was the first of the class of all-big-gun battleships called by her name, although other countries were about to build similar vessels. At first they mounted 30cm (12in) guns, but the 33.75cm (13.5in) and then the 37.5cm (15in) appeared before 1914. Accompanying the dreadnoughts came Fisher’s other innovation, the battle cruiser, less well armoured than a battleship and with fewer heavy guns, but much faster and therefore, because of the extra power needed, much larger. Battle cruisers superseded the earlier armoured cruisers. The turbine was also adopted for a new type of fast light cruiser for scouting and supporting the destroyers, which by 1914 had reached 800–1000 tonnes. The First World War inevitably speeded up the development of detailed improvements to various types, especially in the case of British light cruisers and destroyers. Submarines, both British and German, similarly made great progress and indeed became almost the decisive weapon, with profound effects on both surface tactics and the protection of trade (see p. 537). The underwater mine, which had been used during the Crimean War and, greatly improved, to much effect in the Russo-Japanese War of 1904–5, was very extensively employed. Mines were laid, often by ships converted from other roles, for both offensive and deterrent purposes and, after early attempts to clear them by aircraft flying off ships, a new specialized type of vessel emerged, the minesweeper. These initially operated in pairs, towing between them a cutting line to sever the moorings of the mines, which were destroyed by gunfire when they reached the surface. A new anti-submarine weapon, the depth charge, was designed to explode at a predetermined depth. Oil proved its great convenience as a fuel and was generally adopted. Between 1918 and 1939 the lessons of war were applied to new construction. At first few battleships were built, as a result of the disarmament treaties; those that were carried stronger and more concentrated armour, special anti-torpedo protection and 40cm (16in) guns. The naval powers in general added aircraft carriers to their fleets, many converted from the battleships abandoned by treaty. Aircraft carriers had to be large, and many problems of layout had to be overcome, but by the 1930s new ships were embodying the experience gained. Cruisers took a fresh PART THREE: TRANSPORT 536 course following the Washington Treaty limits of 10,000 tons (10,160 tonnes) and 8in (20cm) guns, but many countries found these too large and returned to the more economical 15cm (6in) gun ships, usually now with turrets rather than single open-mounted guns. The final wartime designs had produced a very effective destroyer which was the basis of most post-war designs, although France and Japan built some much larger vessels. Submarines displayed similar progress. In the 1930s rearmament brought some new designs, and the progress of aircraft led to an interest in ships with powerful arrays of dual purpose guns of about 12.5cm (5in) to fight both surface and air targets; these became the secondary guns of new and rebuilt battleships and the main armament of light cruisers and destroyers. Two important innovations were being developed: radiolocation, or radar, as it was later called, and the anti- submarine finding aid asdic, using the general idea of the echo-sounder, nowadays known as sonar. The Second World War was fought, especially in the larger classes, with the ships recently built and under construction when it started, although there were very large building programmes for small types. Aircraft were shown to be an even more potent threat to the bigger vessels than had been expected, and more strengthening of anti-aircraft armament, both heavy and the light 20mm and 40mm Oerlikon and Bofors guns, took place, sometimes at the expense of the main armament. By the same token, the aircraft carrier emerged as the new arbiter of sea power. While destroyers and submarines tended to maintain prewar types, with up-to-date modifications, the importance of the anti-submarine campaign for the Allies led to the introduction of two new types of warship, although they were given old names. The corvette, a small ship of about 1000 tonnes, and then the rather larger frigate were both built in large numbers and carried progressively newer weapons. The course of the war also necessitated the construction of new and ingenious landing craft for transporting troops and their equipment from sea-going ships on to beaches. Mine warfare was diversified by the introduction of magnetic and acoustically detonated mines, requiring new techniques to deal with them. After the war the development of the atomic bomb, combined with general economic conditions, was recognized as rendering big ships vulnerable and prohibitively expensive, while guided missiles were coming forward to replace guns. Battleships soon almost disappeared, while cruisers of the old type survived little longer. Most new construction was of destroyer-sized vessels, armed largely for anti-submarine work. Aircraft carriers remained of primary importance: still of necessity large ships, they were improved by the introduction of the angled deck to provide more space on the flight-deck and then the steam catapult to assist aircraft take-off. Helicopters assumed an important position as part of ships’ armament, being used for anti-submarine operations as well as all sorts of other tasks. New PORTS AND SHIPPING 537 types of torpedo have been produced, electrically powered and wire-guided. Mine warfare remains a serious threat; minesweepers and minehunters are usually built of glass fibre plastic to foil varied methods of detonation. Fleet auxiliaries have increased in importance, refuelling and restoring ships at sea. The gas turbine has proved an advantageous power plant for the faster ship, a major facility being that a complete unit can be replaced, rather than having to be repaired in situ. Modern warships, therefore, consist of aircraft carriers, destroyers and frigates (the distinction between them not being very clear), patrol vessels, minehunters and minesweepers, submarines (nuclear-powered and conventional—see below), as well as small gunboats, torpedo boats and missile carriers. Armament includes one or two automatic guns for each vessel, ship- to-ship and ship-to-air missiles, some light guns, and depth charges with various means of discharging them, all backed up by extensive control systems based on radar, radio communication and sonar, together with devices for confusing hostile radar and missile guidance systems. SUBMARINES Late mediaeval scholars speculated on the possibility of navigating beneath the surface of the sea, and early attempts to build a practicable craft included those of William Bourne in 1578 and Cornelius van Drebbel in 1620. The first successes were by Americans: David Bushnell’s Turtle attacked HMS Eagle off New York in 1776 and Robert Fulton’s Nautilus sank a schooner off Brest in a demonstration in 1802. Both boats were driven by screw propellers operated by hand. In 1850 a German craft Bauer’s Der Brandtaucher, was actually used in war and in the following year was the occasion of the first recorded escape from below the surface. Several other such craft were built in Russia, France and Spain, as well as by both sides in the American Civil War, when in 1864 the submarine claimed its first victim when a hand-driven ‘David’ sank the USS Housatonic, although at the cost of its own loss with all its crew of nine. All these efforts suffered from problems of controlling the craft, as well as the lack of a suitable power source and a feasible underwater weapon. In the 1860s and 1870s iron or steel provided a material that could be made watertight and the torpedo appeared, but trials of steam, oxygen, compressed air and paraffin engines all failed. In 1886 the French Gymnote, designed by Dupuy de Lôme and Gustave Zède, provided a basis for development, using electric motors driven by batteries. The work of J.P.Holland and Simon Lake in the USA produced worthwhile prototypes, and other vessels were built by Laurenti in Italy, Peral in Spain, and the Krupp firm in Germany. All used electricity under water and steam or petrol engines on the surface, until about 1909 when diesel engines became general. PART THREE: TRANSPORT 538 Submarines came into full use during the First World War and, although a number of experimental types were built, moderate-sized boats of simple design were found most satisfactory, the German U-boats (Unterseeboote) achieving a high level of combat effectiveness, as they did again in the Second World War. Towards the end of that war the Germans were improving their submarines by fitting the schnorkel, a type of air tube to enable them to remain below water for long periods, as well as developing a submarine of great underwater speed driven by hydrogen peroxide. While the latter proved unsuccessful, all nations were soon using air tubes, called snorts in English, and streamlining hulls to achieve greater underwater speeds. All these vessels were essentially surface craft which were able to dive and to cruise under water for limited periods. The development in the USA of a nuclear-powered propulsion unit enabled the USS Nautilus of 1952 to initiate the era of true submarine craft, capable of travelling submerged, at unprecedented speeds of over 55ph (30 knots), for virtually unlimited periods of time, aided by inertial navigation systems. Some of these vessels are intended to hunt and sink other submarines, while others carry ballistic missiles of strategic use. HOVERCRAFT AND HYDROFOILS The ideal of obtaining high speeds at sea by reducing or eliminating the water drag has attracted inventors since the seventeenth century, but its achievement depended upon suitable materials. Just before 1914, an Austrian, and Hans Dinesen, a Swede, built craft depending upon a thin air cushion to hold them above water, but neither succeeded, and it was not until the work of the Englishman Christopher Cockerell in the 1950s that a practical craft was devised. By having a deeper air cushion and using air taken off the aero-type engines, Cockerell’s craft could go over waves and equally rough ground, particularly after an improved skirt devised by C.H.Latimer-Needham was provided. A useful craft was built in 1959, and was followed by larger ones for service across the English Channel, carrying passengers and cars, in 1968. These craft are propelled by aero engines and airscrews; another type, the Denny Hovermarine, uses rigid side walls and water propellers, but is consequently more restricted in its movements. The other approach to the problem uses the principles of the high-speed hydroplanes with stepped hulls and of aerofoils. Before the First World War, Enrico Forlanini and Alexander Graham Bell worked with some success on a hydrofoil which as its speed increased raised itself on to its foils, and skimmed the surface, while between the wars Baron Hanno von Scherkel reached the stage of having a Rhine passenger vessel built. He continued his work after the war, and in 1956 a regular service began between mainland Italy and Sicily, PORTS AND SHIPPING 539 followed by others elsewhere. Much of von Scherkel’s knowledge fell into Soviet hands, and many hydrofoils operate in the USSR. The US Navy took a considerable interest in such craft, and both Grumman and Boeing produced patrol vessels, and also passenger derivatives employed since the end of the 1970s on routes across the English Channel. LIFEBOATS AND LIFESAVING In Britain, local boats went to the assistance of ships in offshore waters on an ad hoc basis until the end of the eighteenth century. Lionel Lukin patented an ‘unsinkable’ boat for the purpose in 1785, and in 1798, William Greathead won a competition to design a specialized lifeboat. Craft of this type, strong, stable and capacious rowing boats fitted with fenders and protection round their sides, and with buoyancy boxes, were provided by public subscription on a local basis until 1824; in that year the Royal National Lifeboat Institution (as it was later named), formed by Sir William Hillary, began to co-ordinate lifeboat provision and operation throughout Britain. In the late nineteenth century new boats were designed to be self-righting if capsized, using high buoyancy boxes fitted fore and aft. By this time too, most lifeboats could sail as well as being rowed. Although some steam lifeboats were built, they suffered from the fact that steam could not be raised quickly, and the pulling and sailing boats were, in many cases, towed towards the wreck by a tug or other vessel if available. The petrol engine offered good prospects; the first was fitted about 1910 to an otherwise normal boat, and it proved so useful that motors were steadily fitted to existing craft and to all new ones. Different types of boat were built for certain types of station, some being slipway launch, others having to take the boat down a beach, while the largest boats lay afloat. Since 1945 many changes have been introduced, such as more covered accommodation, modern navigational equipment and more powerful diesel engines. Some boats were built possessing great stability, but not self-righting; after some casualties, all boats have been provided with self-righting equipment. From 1965 onwards, several new types have been developed with much higher speed by abandoning, where possible, slipway launch and the consequent difficulties of design, in favour of being permanently afloat. Recently, a new design has been produced of a fast boat capable of being launched from a slipway. The other important advance in recent years is the use of inflatable or semi-inflatable boats, which can work satisfactorily close inshore, yet have high speed, and these craft have proved invaluable. Other important components of the rescue services are the Coastguard, which since early in the nineteenth century has provided rocket and breeches buoy equipment to use from the shore, and also navy and air force helicopters, PART THREE: TRANSPORT 540 which have vastly improved the possibilities of saving life. All these are now co-ordinated by the Coastguard. The ship’s lifeboat originated with the small boats carried (or towed) by all ships for general purposes. Passenger vessels like the East Indiamen usually had a more liberal supply, but, with the need for legislation to protect the interests particularly of emigrants, came a requirement for passenger ships to carry lifeboats. Scandals in emigrant ships and wrecks of steamers carrying large numbers of passengers produced progressively more stringent rules for ships seeking to have a passenger certificate to have lifeboats, lifebelts and other equipment. The culmination came with the Titanic disaster of 1912, after which ocean-going passenger vessels had to be able to accommodate all their licensed number of passengers in their boats. Coastal ships had only to provide for a proportion, but with enough liferafts to cover the total number. The liferafts usually doubled as deck seats. The circular kapok lifebelt was introduced during this period, while individual life-jackets, also using kapok, were provided for seamen and the RNLI lifeboats and later for passengers too. Passenger ships were required to hold regular exercises for both crew and passengers. Since 1912 much progress has been made. The actual lowering of the boats from their davits (the small cranes from which they are kept suspended ready for service) is obviously crucial; better types such as the Welin and the gravity type davit kept the boat clear of the ship’s side, and these were power worked. Recently a chute method has been introduced. The boats themselves, originally wooden, have been replaced by steel and now often glass reinforced plastic. Some modern ones are covered. Ships must have at least two motor boats; the others can be hand propelled, with the object of keeping the survivors active. Life-jackets are now inflatable, and have small lights and sometimes small radio transmitters. The old raft-seats are now replaced or supplemented by inflatable liferafts, which save both weight and space. ANCHORS AND CABLES Anchors and fixed moorings are essential to the safe operation of ships. Originally a heavy stone, or even a basket of stones or perhaps a suitably shaped log, would be secured to a rope and put over the side at the appropriate time. As ships became larger, these expedients were replaced by wood or iron devices shaped like a hook with a spade-like extremity so that it might dig into the bottom. By the sixteenth century, a consensus had been reached that the best results were obtained from a shank (main stem) with two arms, straight or curved in a ‘U’ or ‘V’ shape, with wider ends (flukes), and a stock at right angles to the arms to ensure that the anchor would lie in a manner in which it could grip. The stock was wooden, the rest was forged iron, although later stocks were made of an iron bar. Such anchors involved much skilled work in their manufacture, but it was impossible to avoid PORTS AND SHIPPING 541 imperfections in the forging, and despite weights of up to 4 or 5 tonnes, failures with disastrous consequences were not unknown. The anchor cable, the largest of ropes, could go up to 60cm (2ft) in diameter. In the early years of the nineteenth century, investigation not only led to improved manufacture, but also new types of anchor, while chain cable, pioneered by Lieutenant Samuel Brown RN, proved to be stronger and more manageable than hemp and came into general favour. The new types of anchors, such as Trotman’s or Rodgers’, usually embodied some method of pivoting the arms to allow them to dig into the bottom when strain came on. In this, they led the way to the stockless anchor, which heralded a complete change in the actual working of anchors. In sailing days, the anchors hung from catheads forward. Letting go was not too difficult, but to heave in the cable was an ‘all hands’ task, using the capstan, situated amidships, and a messenger rope running round a bollard forward. The cable, too unwieldy to do other than run from hawse-hole to cable locker, was attached to the messenger by rope nippers and so slowly drawn in. When the anchor came aweigh, it had to be transferred to the cathead by tackles and more hauling. These problems remained in early steamships, and although the development of steam capstans or winches removed much of the heaving work, the difficulties of housing the anchor remained. The cathead was replaced by an anchor bed, but the anchor still had to be hoisted and swung. The stockless anchor could, however, be drawn right into the hawsehole, and there secured. Small vessels had a windlass driven by hand levers with pawls to hold it, the smaller cable being less difficult to work. Anchors are also used for laying permanent moorings for ships. Sometimes these are chains, picked up as required, but often they have buoys to which the ship’s cable is attached. In restricted waters, a ship would lie to moorings fore and aft, but elsewhere she could swing to one buoy ahead. Special designs of anchor are used for these purposes, and for vessels like lightships which are permanently moored in one position, although even stone blocks have been employed in this manner. Screw piles have also been extensively used for moorings. Here, the pile is a tube with a pointed end to drive into the bottom and two turns of a screw thread to take hold. They have also been used in building lighthouses. An important development in recent years has been the use of buoys of special design not only to moor very large tankers, but also to discharge their cargo via a pipeline and flexible pipes to the buoy. LIGHTS AND BUOYS Navigational marks—lighthouses, lightships, buoys and daymarks—not only warn of dangers but provide the mariner with points of reference for his further voyaging. Other prominent buildings or natural features can be used . movements. The other approach to the problem uses the principles of the high-speed hydroplanes with stepped hulls and of aerofoils. Before the First World War, Enrico Forlanini and Alexander Graham. the development of steam capstans or winches removed much of the heaving work, the difficulties of housing the anchor remained. The cathead was replaced by an anchor bed, but the anchor still had to. heavy and the light 20mm and 40mm Oerlikon and Bofors guns, took place, sometimes at the expense of the main armament. By the same token, the aircraft carrier emerged as the new arbiter of sea

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