Port and Harbour Engineering

Adrian Jarvis

• Publisher: Routledge
• Year: 2016
• Print ISBN: 9780860787556
• eBook ISBN: 9781351909914
• Edition: 1
• Topic: History
• Subtopic: World History
• Index: History

During the 19th century, the engineering of ports and harbours became a large and specialised branch of the profession. This development began in ports in physically difficult locations and may be particularly identified with the growth of the Port of Liverpool. Stimulated by the arrival of ever-larger steamships and the heavy investment in port facilities that they demanded, it spread around much of the world. The opening papers give examples of what could be achieved in antiquity; the following ones set out the advances in design and technology from 1700 to the start of this century - and note some of the failures and recurrent problems. They also illustrate the critical importance of political and economic factors in determining what the engineers achieved.

1
The development of harbour and dock engineering¹

Sir Cyril Reginald Sutton Kirkpatrick

Ancient Harbours.

THE oldest maritime nations whose records are preserved are Egypt, Crete, and later Phœnicia. There are evidences of intercourse between Egypt and Crete in the pre-dynastic period of Egypt, say 6,000 years ago, and one of the earliest known representations of sea-going vessels is on a bas-relief of about 2600 B.C., found in a pyramid tomb near Cairo. These vessels have masts and paddles for propelling and steering. An interesting feature is the " hogging truss," a cable stretched from bow to stern and kept in tension, to prevent the ship from drooping at the ends. This principle is employed in shallow-draught ships of the present day. There are also other records of ships almost as ancient, some actually unearthed, others on sculptures, seals, and hieroglyphics.

The early Egyptian havens were in the mouths of the Nile, but Crete is almost riverless and had to make its harbours in the open sea. There are remains of very ancient harbour works in Crete, but owing to earth-movements most of the ruins are under water, and some have been built over by later works. The most complete records of an ancient harbour in the Cretan manner are those at Alexandria, discovered by Mr. Gaston Jondet, late Engineer-in-Chief of Egyptian Ports and Lighthouses. The date of the original works is estimated at about 2000 B.C., that is 1,700 years earlier than Alexander's harbour. Figs. 1, Plate 1, show the harbour of Alexandria in three stages of its history: the harbour of 2000 B.C., which we are discussing, the harbour of Alexander of 332 B.C., and the harbour as it is to-day, covering altogether a period of 4,000 years.

Though the location is in Egypt and the work is of the very massive character reminiscent of Egyptian works, yet the methods of construction and the placing of the harbour on the open sea are outside Egyptian tradition and belong to Minoan Crete. It is assumed that the work was done by Cretan engineers and artisans in co-operation with the Egyptian Government, for there are many records of Cretan workmen being employed in Egypt on engineering and architectural work. While the port built by Alexander was between the island of Pharos and the mainland, the older harbour was on the seaward side of the island. The Great Basin of 150 acres made use of a natural depression in the sea-bed and had its entrance on the south through a naturally deep channel. The landing-quay to the east of the entrance was 46 feet wide and built of rough-hewn blocks up to 16 feet long. The south wall of the harbour had angular salients typical of Cretan building and was 2,300 feet long. The great breakwater on the north side was 6,500 feet long. The western portion followed a submerged reef and was a single wall, while the eastern portion was of two walls 25 to 40 feet wide at the top, with rubble filling between them, giving a breakwater about 200 feet wide. To the seaward of the great breakwater was another breakwater enclosing a basin half as large as the great basin, while to the east was another small harbour. The material used was limestone quarried at Mex on the mainland.

Sir Arthur Evans, who has carried out recent investigations, is of the opinion that there was trade between Crete and Britain in the Early Bronze Age, between 1600 and 1200 B.C., several centuries before the Phœnicians came to England. The main evidence is the finding of a Cretan or Egyptian type of bead in the Bronze Age barrows of the South of England, as well as in Spain, Sicily, and other places.

The highly-developed ancient civilization of Minoan Cretans depended on the insular position of their country, which for 1,000 years kept them out of the wars which troubled other people. With peace the Minoans were able to develop their arts, industries, and commerce, but in the course of time other nations of the Eastern Mediterranean developed their sea power, and the supremacy of Crete was broken, its civilization decayed, and many of its inhabitants scattered to settlements on the coasts of Asia Minor, some joining the Philistines who in Biblical times lived on the Syrian coast.

Figs.1.

A later, but better-known centre of maritime commerce was Phœnicia, on the coast of what is now Syria. The first port of Phœnicia was Sidon, and after the capture of that city by the Philistines some fugitives founded Tyre in 1245 B.C. The first city was on the mainland and had a harbour and fortifications, but all these were destroyed by Nebuchadnezzar after a siege of 13 years. The inhabitants withdrew to an island off the coast and built a new city of Tyre, which surpassed the old one in wealth and importance; they sent out trading expeditions, including some to Britain, and founded several colonies, notably Utica, Carthage, and Cadiz. Timber for shipbuilding was obtained from the forests of Lebanon. There were two harbours, a naval one on the north and a commercial one on the south, both protected by moles terminating in lighthouses. The moles were probably of dumped stone foundations with masonry superstructure, the ends being in 25 or 30 feet of water. On the shores were places for building and careening ships, as well as storehouses and other necessary buildings. Tyre was strongly fortified, but in 332 B.C. Alexander the Great destroyed it after a 7 months' siege. He attacked the island city by building out a causeway from the mainland to carry forward his primitive artillery. This causeway held up the drifting sands and became an isthmus, so that now the site of Tyre is on a peninsula.

After destroying Tyre in 332 B.C., Alexander founded Alexandria. It is not certain whether at this time there were any remains of the Cretan harbour, or whether the works were already submerged by a land subsidence which is known to have taken place in this region, but as to the date of which there is a difference of opinion. The work was entrusted to Dinocrates, who placed the town on the narrow strip of land between Lake Mariut and the sea. A causeway, called the Heptastadion, was built between the Island of Pharos and the mainland, forming two harbours connected by two bridged channels. Later, the great lighthouse of Pharos, said to be 450 feet high, was built by Sostrates on a rock to the east of the island. The rock and the island were connected by a causeway.

Besides the Mediterranean trade, Alexandria had access by a canal to the Nile and the interior of Africa, and by a further canal from the Nile to the Red Sea and the Orient.

The lower part of Figs. 1 shows the modern port of Alexandria. The causeway between the mainland and the island has now grown by accumulation to an isthmus ½ mile wide. The main harbour is now the western one, a reversal of the older order, and is now enclosed by a long breakwater. Channels have been dredged through the shoals off the shore, and many improvements have been made recently, while further development is in view.

Of the other ancient Mediterranean ports, there is time only to mention a few. Athens had a well-developed port at the Piræus, with minor harbours in the neighbourhood. Syracuse was a Greek colony in Sicily. Messina was a harbour of refuge on the Straits of Messina. Carthagena was a colony of Carthage in Spain. Rhodes —known for its Colossus—was on an island off the coast of Asia Minor.

Of Roman harbours, Taranto and Brindisi are still in use. Others were Otranto, Reggis, Lune, Miseno, Rimini, Ravenna, Ostia, and Ancona.

The ships of the ancient Greeks and Romans were rowing galleys with anything up to four banks of oars one above the other. The rowing benches were staggered, so that the banks were only about three feet apart vertically. A large trireme would have up to 200 oars. Sails were also carried, but these were auxiliary.

In naval harbours it was the practice to keep the galleys each in a separate little dock, perpendicular to the shore, roofed over to protect the ships from the sun and from the eyes of strangers. Sometimes inclined slips took the place of these little wet docks, and the ships were hauled up them by windlasses. From the remains of the slips at the Piræus we can judge the sizes of the vessels, for each slip was about 145 feet long by 21 feet wide.

The ancient Roman harbour of Ostia is described in a Paper ¹ read before The Institution by Sir John Rennie in 1845. The mouth of the Tiber was being blocked by the formation of a bar by the deposition of silt brought down by the river, and drift carried by currents along the shore. Legend tells that Ancus Martius founded Ostia in the 7th century B.C., to the south of the Tiber, and had the river embanked and its waters confined in one channel by moles built out to sea. This increased the velocity and scouring power of the river, and the channel was kept open. In the course of time a new bar was formed farther out to sea. As there were no means of dredging in those days, it became necessary to find another means of providing water access to Rome and to provide shelter for the fleet. The Emperor Claudius decided on an entirely new harbour, independent of the Tiber. This was established to the north of the river. An area of 130 acres of water was enclosed by two breakwaters, with a detached island breakwater between their ends. The main breakwaters were each about 1,900 feet long and 180 feet wide, while the island was about 780 feet by 400 feet, leaving two entrances. The entrance was probably difficult, as in 62 A.D. 200 ships were wrecked in a storm off Ostia. Two canals behind the harbour joined the Tiber to the sea, one of the canals communicating with the harbour. Trajan, about 100 A.D., added an artificial octagonal basin of 70 acres, using part of the two canals as entrances and filling up the rest of the canals. A new canal farther back was made, connecting the harbour, the Tiber, and the sea. Covered docks or " cellæ," as already described, were provided for the galleys.

The south mole was probably founded on a rubble mound and consisted of solid masonry walls with filling between. This mole had to keep out the silt brought down by the Tiber. To permit some access of the current from the north, and yet to break up the force of the waves, the north mole was built of arches. The piers were on pozzolana concrete foundations, made by placing a wet mixture of pozzolana and stone inside wooden caissons which were removed when the concrete had set. The island breakwater had on it a lighthouse, built on piles and a caisson made from a sunk ship. Sheds were built on the moles, which were also used as promenades. The outer harbour is believed to have been 15 to 20 feet deep and the inner harbour 10 feet deep at low water.

Eventually the trouble of silting re-asserted itself, and the harbour became inaccessible and had to be abandoned. In the reign of Trajan a new harbour for Rome was established at Civita Vecchia, 30 miles farther north, and this still remains the port of Rome. The site of the harbour of Ostia is now 1½ mile from the sea.

Looking back at such records ¹ as exist of these ancient works, here so briefly described, one cannot but be impressed by the boldness of their conception and the almost modern methods of their construction, which were not far different from those of similar works of modern times. Further, it seems that in those days public opinion demanded from its harbours not only utility but beauty, showing a level of æsthetic appreciation to which we have not yet risen, or at any rate which for reasons of economy we do not yet apply.

It must be borne in mind, however, that these ancient empires had unlimited supplies of slave labour, though they were handicapped by having none of our modern constructional equipment and no mechanical power. The absence of any means of dredging was also a great handicap, as we see so clearly in the case of Ostia.

Middle Period.

After the fall of the Roman Empire, the art of engineering, like moat branches of knowledge, fell into decay. Not till many centuries later was the standard of Roman construction overtaken. The centre of maritime activity moved out of the Mediterranean into Northern Europe. Here the different conditions of geography and climate had their reactions both on shipbuilding and on harbours. In the Mediterranean the long periods of calm made rowing possible and indeed necessary. The rougher water and the more frequent winds of the northern seas discouraged rowing and favoured the use of sails. War vessels, though they carried sail, still relied on oarsmen for the rapid and accurate manœuvring necessary in battle. The warships of the Danes and Saxons, so active on the coasts and rivers of Britain between the 5th and 10th centuries, were probably similar to the Viking ship unearthed at Gokstad, Norway, in 1880, of which a model is to be seen in the Science Museum at South Kensington. The length of this ship was 79 feet, beam 16½ feet, and draught about 4 feet. There were sixteen oar-ports a side, and the full complement would be about seventy men. The single mast would carry a square sail, and steering was by a special oar. The ship is clinker built of oak and is a better example of shipbuilding than are many later vessels. Merchantmen used sails in preference to oarsmen, thus saving man-power and increasing cargo-space.

The ships of the 13th century were of the type shown on the seals of Dover and other Cinque Ports.

Up to the 16th century the same ships were used for both trade and war. Fore and aft castles were added temporarily for the use of the fighting men, but they are interesting as showing the beginnings of enclosed cabins. These ships were much broader in proportion to length than the Viking ships, their length being about three times their breadth. They were "carvel" built, that is, the planks butted together instead of overlapping, and they were caulked. Though oars were probably still carried for emergencies, more use was made of the single square sail. Tonnages ranged from 40 to 160 tons.

North Europe is richer in natural harbours than is the Mediterranean. There are many fiords, and the greater ebb and flow of the tide along most of the coast prevents the blocking of rivers by deltas and promotes the formation of estuaries, giving at high tide much greater depth than the water flow of the river alone could give. For many centuries these natural facilities, with a few of the simplest improvements, sufficed for the shipping of the time.

At the end of the Roman occupation in 407 A.D., Britain had an established overseas trade, exporting corn and raw materials and importing manufactured goods. Sea-going ships were small enough to reach as far inland as Oxford, Cambridge, Lincoln, and York.

There are no direct evidences of quays or warehouses in Roman days. In London, ships would unload in the Fleet River and the Walbrook, now both covered over. Others would moor in the river and discharge or load by small boats.

The Romans were followed by the Saxons, who were familiar with the sea, but only from the point of view of warfare. Trade was not encouraged.

The Danes began their attacks on England in 787 A.D.; and up to 1016 A.D., when Canute gained the English throne, there was a succession of naval fights round the south and east coasts. Several times the Danes landed and sacked inland towns. For defence against the Danes, the number of English ships was largely increased, and in the peaceful intervals they were used for foreign trade, which grew in spite of difficulties.

By the e...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Contents
• Acknowledgements
• General Editor's Preface
• Introduction
• 1 The development of harbour and dock engineering
• 2 Presidential address of Sir Leopold Halliday Savile, K.C.B. (President ICE, 1940–41)
• 3 Do docks make trade?: the case of the port of Great Grimsby
• 4 The engineers of Sunderland Harbour, 1718–1817
• 5 The construction of Ramsgate Harbour
• 6 Thomas Steers
• 7 The engineering history of Hull's earliest docks
• 8 Joseph Whidbey and the building of the Plymouth Breakwater
• 9 G.P. Bidder at the London Dock extension works, 1826–1828
• 10 Building the Millwall Docks
• 11 Nineteenth century engineers in the port of Bristol
• 12 The improvement of the River Tyne, 1815–1914
• 13 G.F. Lyster and the role of the dock engineer, 1861–1897
• 14 Beyond the river wall: the attack on the Mersey Bar, 1890–1923
• 15 The first harbour works at Port Natal: the role of John Milne from 1849–1857
• 16 Imperial ports and the modern world economy: the case of the Indian Ocean
• 17 The development of the port of Fremantle, Australia's western gateway
• Index