An Encyclopedia of the History of Technology part 54 ppsx

The Morris Canal joined the Lehigh Canal at Easton and in order to pass boats from one canal to the other the Morris was widened following financial reorganization in 1845.. On British c

New York, but by a more southerly route, was the Morris Canal running from Easton on the Delaware to Newark Conceived in 1824, it was opened in 1832 and then extended to Jersey City in 1836 It was remarkable for having 23 inclined planes, water-powered by turbines, over which boats were carried dry

in cradles running on rails The Morris Canal joined the Lehigh Canal at Easton and in order to pass boats from one canal to the other the Morris was widened following financial reorganization in 1845 With railroad competition

it gradually declined and it was closed in 1924

The Lehigh Canal had started as a river improvement Arks were loaded with coal and taken down the river to Philadelphia, where the coal was discharged and the boats broken up There were no return trips The rapids were passed by what was termed a ‘bear trap’ lock This was in effect an inclined plane or water chute down which the boats were launched in a ‘flash’

of water The slope was eased off at the bottom to prevent the boats hitting the water too violently and breaking up The Lehigh Canal was opened in 1823 It was reconstructed in a conventional manner in 1829 and after a very successful period gradually closed down owing to damage from floods, until it finally ceased operation in 1942

The growing industrial importance of Philadelphia and its relationship with Pittsburgh and the Ohio required improved transport and so in 1825 a canal was authorized between the two cities The problem was the 600m (2000ft) range of the Allegheny Mountains between them, and it was decided that the route would be partially rail worked The first section, planned as a horse wagonway and later converted to a locomotive-hauled railroad, ran westwards from Philadelphia to Columbia From there a canal was built along the Susquehanna valley to Hollidaysburg, and what became known as the Allegheny Portage Railroad began there This consisted of a series of five inclined planes over which the canal boats were carried to the summit of the ridge at yoom (2300ft) and then the line descended by five more planes to Johnstown on the western side of the range The cradles on the planes were counterbalanced with steam assistance From Johnstown a 60-lock canal ran to Pittsburgh The 630km (394 mile) link was completed between the two cities

in eight years and the first boat passed through in 1834 Unhappily the route did not survive long, for it was bought by the Pennsylvania Railroad who closed the western canal in 1863 and most of the remainder by the end of the century Most of the other canals between the Ohio and the eastern seaboard had also succumbed to the thrust of the railways

All the foregoing were canals associated with industry but further south there was an attempt to use canals for the benefit of agriculture South Carolina was sparsely populated but it had a major river system formed by the Santee, Saluda and Wateree rivers The first canalization, proposed about

1785, led to general improvements between Columbia and Charleston and by

1820 no less than ten small lateral canals had been constructed which carried a

great deal of cotton until by the 1850s the railways were taking over There are still remains of some of these canals and one, the Landsford Canal by the Wateree river, is being restored as a State Park

The great developments leading into the modern waterway scene were on the Mississippi and the Ohio The Ohio is formed by the confluence of the Allegheny and the Monongahela rivers at what is now Pittsburgh, and from the beginning of the nineteenth century the industrialists of the town had been trying to get improvements to the river, which was notorious for the treacherous rocks and shoals in its bed These problems were exacerbated in summer because of periods of drought With an improved river, traffic would

be able to pass down the rivers to New Orleans and thence world-wide Various proposals were offered for improvements during the century but nothing was done until a powerful figure, General Moorhead, who had rescued the Monongahela Navigation Company, building locks and dams with his own capital, visualized similar improvements to the Ohio but with the injection of public money This the Federal government would not supply for a long time Eventually in 1870 work started on the Davis Island Lock and this was the forerunner of the complete transformation of the Ohio The lock, 183m by 33.5m (600ft by 110ft) incorporated an entirely new feature which was to be adopted in various parts of the world on very wide locks This was a horizontally travelling gate moving into a recess in the lock wall, with its weight carried on wheels running on rails laid transversely to the axis of the lock It thus replaced the mitre gates which for the large capacity locks were becoming very heavy and cumbersome The creation of the lock, which would eventually take pushtows, and the dam alongside provided the control which enabled a harbour to be formed at Pittsburgh, materially assisting the growth

of the city

The Ohio connected with the Mississippi and thus with the Missouri and in all this river system there were roughly 20,000km (12,000 miles) of navigable waterways although, being river navigation, a vast amount of training works had to be undertaken to make them safe Once steamboats were introduced in about 1812, traffic on all these rivers steadily increased until the onslaught of the railways caused a decline after the 1880s This decline lasted until 1918, but thereafter traffic again increased following the realization of the economic advantages of water transport This has been emphasized by the spectacular growth of pushtowing and the capacities involved on the Mississippi and its associated rivers

One of the tributaries of the Mississippi is the Tennessee which flows north

to join the Ohio just east of Cairo, Illinois Flowing south through Alabama is the Tombigbee river which enters the Gulf of Mexico at Mobile The Tombigbee is navigable and it had as one of its tributaries the Coosa river, which had also been made navigable by the end of the nineteenth century The Tennessee had by the end of the Second World War been improved to a

(2.7m) deep navigation for 1040km (648 miles) from Knoxville, Tennessee, to the Ohio It was then considered advisable to link the Tennessee and the Tombigbee rivers by a 375km (234 miles) canal This was authorized in 1946, but work did not begin until 1971 It was finally completed with locks 183m

by 33.5m (600ft by 110ft), the present standard size for major waterways, to accommodate pushtows, and was opened on 18 January 1985, the first commercial tow having passed through a day earlier

THE PANAMA CANAL The idea for a canal or other means to transfer vessels across Central America had long been canvassed and various schemes on different sites proposed, but

it was not until de Lesseps had called a congress in 1879 that a decision was taken to build a canal across the Isthmus of Panama A French-sponsored company, with capital raised mainly in France, undertook the work, but by

1888 it was bankrupt The United States, for political and military reasons, decided to take over the scheme and in 1894 a new company was formed, though there was still argument over the site Eventually a new State of Panama was created, which granted a concession to the United States of a Canal Zone Work restarted in 1908 and, amid appalling difficulties including medical ones, it was completed with two flights of locks at Miraflores and Gatun and a single lock at Pedro Miguel through which ocean vessels were hauled by power units on the banks It was formally opened on 15 August

1914 and remains one of the major ship canals in the world

CANAL AND RIVER CRAFT Virtually every waterway system had its own designs of craft built largely for the convenience of the nature of its traffic, the dimensions of the waterway and the peculiarities of the system Collectively, but usually inaccurately, the vessels have been generally known as barges but locally as well as technically they had distinctive names Their capacity has ranged from the shallow draft 25 tonne capacity boats on the Chelmer and Blackwater Navigation to the 2000 tonne Rhine barges On British canals with narrow locks and limited dimensions in tunnels and bridges the boats with a beam of approximately 2m (7ft) were known as narrow boats to distinguish them from the wide boats used on the broader waterways

On the earlier waterways the boats would be hauled, often by gangs of men; later by mules or horses Where the canal passed through a tunnel in which there was no towpath, recourse had to be had to legging This was carried out

by professional leggers who worked in pairs lying on their backs on a plank

which extended across the beam of the boat They would then ‘walk’ along the sides of the tunnel, thus propelling the boat The alternative was to shaft or pole the boat through the tunnel by pushing with a pole against the tunnel wall Even on confined waters and rivers it was possible with skilful handling to use sailing barges, or, to quote their more specific names, keels, wherries,

sloops or trekschuiten They continued to be used, and indeed still are, even after

the development of a steam propulsion which goes back to the end of the eighteenth century, for example Fulton’s experiments at Worsley, near Manchester, in 1797 Diesel-type engines were introduced at the end of the nineteenth century and by the First World War they were in regular use Apart from unit propulsion with the engine mounted integral with the vessel itself installations were adopted where mechanical haulage was provided by traction units running either on rails or on roads along the bank of the waterway, although these never found favour in Britain Towards the end of the nineteenth century the newly available electricity was adopted in a similar way to an electric tramway system, with the traction unit taking its power from an overhead line as was installed on the Brussels to Charleroi Canal in the 1890s The tractor was attached to the barge by a cable and would haul the barge until it met another approaching from the opposite direction Cables would be exchanged between the tractors which would then reverse direction while the barges continued as before Elsewhere a similar shuttle service was performed by diesel tractors Non-powered boats could thus be hauled without difficulty

Yet another system was to lay a cable or chain along the bed of the canal and a tug, by means of winches mounted on its deck, would haul itself along and at the same time tow a string of barges behind This system was particularly useful through tunnels but it was also used elsewhere, as on the River Neckar in Germany

With the large present-day barge the almost universal mode of propulsion is

by a powerful diesel engine on the vessel itself or by a diesel-powered tug which will either tow or push a group of barges The formations of barges which are pushed are known as pushtows and the constituent barges are so tightly assembled that the pushtow becomes in essence a large unified vessel The advantage is that the expensive power unit is not left idle when the barge

is unloading or discharging The barges themselves are, of course, non-powered and types have been developed which can be carried on board ship across the ocean and then linked together to proceed to their destinations along inland waterways

THE CONTEMPORARY SCENE The use of waterways in all countries has in general shown a steady progression through four phases: first, the employment of natural water

resources—rivers, lakes, estuaries etc—with little or no adaptation; second, improvement to remove dangers from their courses, possibly to bypass rapids and rocky areas and to even the flow of the current by dams and weirs; third, the construction of artificial canals to link river valleys and to provide local transport; fourth, the enlargement of existing rivers and canals to accommodate mass national and international transport of goods

The first three phases arose from the need, in the absence of other satisfactory modes of transport, to provide a reasonably integrated system by which goods could be moved within commercially acceptable time limits The fourth phase, while including that object, also involves the growing realization

of the economic saving in energy costs offered by water transport This saving

is partly demonstrated by the relative energy requirements (with pipeline costs

as a baseline) per tonne/kilometre for various modes of transport: pipeline 1, water transport 2, rail 3, road, 10, air 100 An example of the side benefits in canal construction and operation is illustrated in the advance incorporation of hydroelectric power generation plants on the line of the new Rhine-Main-Danube canal (see p 494), where the sale of power is partly financing canal construction and will reduce operating costs

The fourth, current, phase is therefore not a mere expansion of an existing and otherwise outmoded means of transport but a stage in the evolution of a co-ordinated system which can operate efficiently within modern economic constraints In addition, moving bulk freights to waterways relieves congestion

in urban areas, and many countries are realizing that improvement of an existing water route is cheaper than building a new motorway—and that it is less costly to maintain Moreover, those navigations in current use serve a multi-purpose function of water supply, drainage and environmental benefits,

as well as transport

Intensive land use in Britain has militated against developments which have been seen elsewhere in improvements to waterways Even here, however, where the decline in commercial traffic almost led to the complete abandonment of the system, the environmental benefits have been recognized

At the critical moment there began an upsurge in interest in leisure activity and the recognition of the need for greater facilities The realization that canals could offer a multi-purpose and desirable source of leisure enjoyment was stimulated by L T.C.Rolt’s account of his experiences on the waterways in his

book Narrow Boat, first published in 1944 In turn this enthusiasm led to the

formation of the Inland Waterways Association and the burgeoning voluntary involvement in the restoration of redundant and abandoned waterways The restoration movement has now spread to many other countries, and especially in the United States Even in those countries where there is a major commercial activity and new waterway construction those canals which no longer carry intensive freight traffic, for example the Canal du Midi and the Nivernais Canal in France, are supporting an important growth in the leisure

industry Other minor and branch canals such as the Canal du Berry, also in France, are undergoing restoration and maintenance There is now virtually world-wide recognition of the tourist potential and ecological value of waterways which for so long have been regarded solely as of importance in the industrial and commercial economy of a country

GLOSSARY

Balance beam the heavy beam projecting landwards from a lock gate which, in

providing the leverage for opening the gate, balances the weight of the gate Found especially on British lock gates

Cylindrical sector rotating gate a modern type of lock gate which rotates horizontally

through 90° from the vertical position where it closes the lock to a horizontal position in the bed of the canal to allow boats to pass over it

Flash a body of water suddently released to provide greater depth to allow navigation

over shoals and shallows in a river

Flash lock an arrangement on rivers whereby the water could be held or penned back

by a removable barrier across the flow When a boat travelling downstream wished

to pass the barrier was removed and a flash of water rapidly flowed through the opening earning the boat over shallows below the barrier For vessels travelling upstream a wait was necessary until the flow had diminished and then the boats would be manually hauled or winched to the upper level Also known as staunches

Inclined plane a device by which boats can be carried from one level to another either

on cradles or in tanks travelling up and down a slope

Lift a device on the same principles as an inclined plane but with the tanks rising and

falling vertically

Lock a means by which boats can move from one level of a navigation to a different

level

Paddle door a gate either pivoted or capable of rising and falling for opening and

closing the orifice through which water enters or leaves a lock

Péniche the standard 300 tonne French canal barge A law passed in 1879, under the

direction of Charles de Freycinet, included minimum dimensions for the French waterways: depth 2m (7ft), locks 38.5m by 5.2m (127ft by 7ft), bridge clearance 3.7m (12ft) Barges which conformed to these constraints were said to be of Freycinet type

Pound lock a chamber, generally in brick or masonry, with gates at each end in which

the water is impounded and through which boats pass from one level to another The change is effected by the opening of paddles, paddle doors or sluices to allow water to enter or leave the chamber when the gates are closed The gates are opened when the water level in the lock is the same as that either below or above the lock The gates can be single, as on some narrow canals, or double so that the gates meet at an angle to withstand the water pressure In this case they are called mitre gates Also used are guillotine gates, which are raised and lowered vertically; radial gates, which turn on a horizontal axis to lie under the water below the

draught of the vessel; or sliding horizontal gates which retract into recesses constructed in the side of the lock

Shaft lock a modern type of very deep lock with a fixed structure across the lock at the

lower end This structure houses a guillotine gate which rises from the canal into the structure and thus exposes a tunnel through which the boats pass to the lower level of the canal Normal gates are provided at the upper level but gates would be impracticable at the lower level owing to the height of water impounded in the chamber

Staunch, see Flash lock

Summit level where a canal passes across a ridge from one valley to another the

highest part of the canal is called the summit level Into this generally run the feeders which supply the principal water for the locks on both sides of the ridge

Tide lock a lock provided where a canal enters the sea or a tidal estuary to allow

vessels to pass at different states of the tide

Transporter bridge a type of bridge, generally in flat country, a number of which were

built at the end of the nineteenth and beginning of the twentieth century, sufficiently high to allow tall-masted vessels to pass under the structure A frame ran

on rails at the upper level of the bridge and from this was suspended a cradle on which road traffic crossing the canal could be carried The cradle passed to and fro between piers on the banks and thus shipping was not impeded by the passage of road traffic Examples can be seen in England at Middlesbrough across the Tees and

at Rendsburg in Germany across the Kiel or Nord-Ostsee Canal

FURTHER READING The literature on world canals and waterways as a complete survey of the subject is regrettably limited For a modern overview of the past and present scene the only

comprehensive work is Charles Hadfield, World canals Inland navigation past and present

(David & Charles, Newton Abbot, 1986) A much shorter account is given in

Charles Hadfield, The canal age (David & Charles, Newton Abbot, 1988) An earlier work dealing primarily with the engineering features is L.F.Vernon-Harcourt, Rivers

and canals Two volumes, 1896 Again on special engineering structures is David

Tew, Canal inclines and lifts (Alan Sutton, Gloucester, 1987).

For individual countries both the quantity and the quality is very variable The British

Isles is admirably covered in Charles Hadfield’s series The canals of the British Isles

(David & Charles, Newton Abbot, 1967–72) Canada is fully dealt with in Dr

Robert Legget The canals of Canada (David & Charles, Newton Abbot, 1976) Professor Joseph Needham’s monumental work Science and civilisation in China Vol.

IV.3 (Cambridge University Press, Cambridge, 1971) contains a detailed account of

the improvement of rivers and construction of canals in China Roger Calvert Inland

waterways of Europe describes European waterways with a greater emphasis on

cruising rather than on detailed history.

PORTS AND SHIPPING

A.W.H.PEARSALL

OAR AND SAIL Antiquity to the Middle Ages Man’s first attempts to travel by water, most likely on rivers and lakes, were presumably by sitting on floating logs; in time it was discovered that a log could

be hollowed out, by cutting or burning, and that a raft could be constructed by tying branches together to make a floating platform With the ability to work materials came the evolution of a recognizable boat, with a supporting keel and sides made up of wooden sections Other available materials included wicker, reeds and animal hides, from which coracles—circular, oblong or square —could

be constructed All these craft could be propelled: by paddling with the hands or with a short, flattened piece of wood; by rowing, with two longer wooden oars, wider at one end; or by sculling, working a single oar over the rear end of the vessel; and all could be to some extent steered by the action of paddle or oar against the water Such simple boats have continued in use to the present day in unindustrialized societies: the coracle was common in inshore waters around the British Isles within living memory

The archaeological record demonstrates that by the first millenium BC larger vessels were made up of the elements familiar in wooden boats today The foundation was a sturdy timber keel, running the length of the hull, into which bow and stern post were scarfed—joined by bevelling the two members and keying one into the other—with strakes, or side planks, running from bow to stern and secured, successively, with thongs, trenails (hardwood dowels or pins), and iron nails As hulls grew too long to allow the use of single timbers for the strakes, ‘U’-shaped frames were added as transverse shapers and strengthened, and linking their tops with beams as further reinforcement gave thwarts, on which rowers could sit, or as support for decking The two standard forms of outer planking also evolved at this early stage: carvel, where the strakes are shaped to fit edge to edge,

and clinker, where each overlaps the one below it A variation on the framed type of construction was found in ancient Egypt, where a shallow, lightly built hull was reinforced by overhead arched trusses, a method used for river craft into modern times

Vessels were small, less than 30m (98ft) long, and virtually double-ended; many were solely oar-driven, although sea-going ships might have a square sail set on a single mast; steering was by means of a large oar over one of the stern quarters In the classical era the two main maritime divisions were already established, between merchant and fighting ships The trader had a greater beam: length ratio, and was probably decked to protect the cargo War galleys were longer and narrower, for speed, and given manoeuvrability

by numerous oars, usually handled by slaves The largest Greek warship, the trireme, is thought to have had its oars arranged in three tiers, but this layout remains a matter of dispute Classical war galleys were equipped with a pointed ram at the bow, used to hole enemy ships, and carried foot soldiers and archers This type of combat ship was used in the Mediterranean into the sixteenth century— Christian and Turkish galleys fought at the battle of Lepanto in 1571—and its general configuration was echoed by the Viking longship of the Dark Ages

In fact ship design changed only in detail in the centuries up to the mediaeval era Individual advances are difficult to trace, but local variations

in hull form to suit local conditions began to evolve, and increased trading in bulk commodities demanded bigger ships which could carry larger cargoes over greater distances Mediaeval merchant vessels included the hulk, with a rounded hull, bow and stern, and the cog (Figure 10.1), also rounded at bow and stern, but with a flatter bottom more suited to the tidal and shallow coastal waters of northern Europe The sternpost rudder, directly controlled

by the horizontal tiller, was introduced in the mid-thirteenth century Warships were fitted with fore- and aftercastles, superstructures at bow and stern from which fighting men operated, and these were also adopted in merchant ships

With increased size, oars were no longer a practicable means of propulsion The square sail, set on a transverse yard but without a boom to stiffen its lower edge, was probably still the commonest sailing rig, although

it has been suggested that it was used in the manner of a fore-and-aft sail as much as for simply running before the wind To suit wind conditions, sail area could be reduced by tying tucks in the canvas with reefing points, or increased by lacing on additional strips of canvas, later called bonnets The triangular fore-and-aft lateen sail, familiar in the Mediterranean continuously from antiquity to the present day, was adopted in Europe for the carrack, the foremost trading vessel of the thirteenth and fourteenth centuries This was square rigged on foremast and mainmast, with the lateen sail on the mizen (stern) mast, and with a cog hull

Fifteenth to eighteenth centuries Quite suddenly, and by a chain of development which it has not yet been possible

to trace fully, the three-masted square-rigged ship succeeded the carrack in the mid-fifteenth century (Figure 10.2) The additional masts and increased sail area made them more manoeuvrable than their single-masted predecessors and better able to sail to windward, square sterns provided improved accommodation, and they became progressively larger They offered the technical conditions for oceanic voyages, and opened up the great age of discovery

The original form of the three-masted ship never changed fundamentally, although it was greatly modified over the course of time It carried a fore- and mainmast set with square sails only, the fore usually slightly shorter than the main, and a much shorter mizen with one square sail (later more) and a fore-and-aft sail set aft of the mizen and later known as a spanker Forward there was a bowsprit, inclined at about 30° and projecting beyond the stem, carrying headsails Originally the headsails were square, set on a yard under the bowsprit and on a small mast rigged in a perilous-looking way at its end Towards the end of the seventeenth century these were replaced by triangular fore-and-aft sails set on stays running from bowsprit to foremast, which did their work far more effectively;

Figure 10.1: Model of a mediaeval ‘cog’.