THE growth of the shipping business, and the increase in our home and foreign commerce, led to numerous improvements in the harbours of Britain about the beginning of the present century.  The natural facilities of even the most favourably situated ports, though to some extent improved by art, no longer sufficed for the accommodation of their trade.  Comparatively little had as yet been done to improve the port of London itself, the great focus of the maritime and commercial industry of Britain. [352]  It is true, that its noble river the Thames provided a great amount of shipping room between Millwall and London Bridge; but the rise and fall of the tide twice in every day, and the great exposure of the vessels lying in the river to risks of collisions, and other drawbacks, were felt to be evils which the shipping interest found it necessary to remedy.

    Besides the crowding of the river by ships and lighters—the larger vessels having to anchor in the middle of the stream as low as Blackwall, from which their cargoes were lightered to the warehouses higher up the Thames—the warehouse accommodation was found very inadequate in extent, as well as difficult of access.  It took not less than a month to deliver an East Indiaman of 800 tons of her cargo; while a coasting ship of 350 tons required eight days in summer and fourteen in winter.  The quantity of plunder also, stolen from ships lying in the river was something extraordinary.  Mr. Colquhoun, the police magistrate, estimated the annual depredations on the foreign and coasting trade to amount to not less than half-a-million sterling!

    The lightermen, watermen, labourers, sailors, mates and sometimes captains, and often the officers of the revenue, were leagued together in a system of pilfering valuables from the ships while lying at anchor in the river, or from the barges into which the goods had been transferred.  Mr. Colquhoun stated the number of pilferers and thieves to amount to 10,850; and the number of receivers to 550.

    The plunderers were divided into various gangs.  There were the River Pirates, a set of desperate and depraved characters, who attacked the ships while lying at anchor at night.  They would weigh the ship's anchor, hoist it into their boat, set the ship adrift, and then make clear off; or, they would Mount the ship's side while the crew were asleep, cut away bags of cotton, cordage, spars, oars, throw them into their boats, and make away.  They were usually armed, and defended themselves by force when attacked.  They carried on their operations by day as well as night, and they were usually permitted to escape by the other labourers on the river, who were for the most part as bad as themselves.

    There were also the Night Plunderers—mostly watermen, who worked together in gangs of four or five in number, and plundered the lighters and other craft into which goods had been stored.  They were usually in league with the watchmen of the lighters, with whom they shared the plunder.  But sometimes the watchmen did not allow their own lighters to be plundered, but would point out others which were without any guard; and in this way, while appearing honest themselves, they shared in the general system of thievery.

    The Light Horsemen were the nightly plunderers of West India ships.  There was an arrangement between them, the mates of the ships, and the criminal receivers, by which an incredible quantity of sugar and other articles was abstracted from the ships in the river.  The mates claimed the sweepings, that is, the drainings of sugars which remained in the hold after the cargo had been discharged.  The connivance of the revenue officers was necessary in order to get these sweepings landed.  A payment of from 30 to 50 guineas was sufficient to allow the Light Horsemen—who consisted of coopers, watermen, lumpers, and receivers to get on board at night for the sweepings.  They then opened as many hogsheads of sugar and bags of coffee as possible, and plundered the ship without control.  The ships subject to this species of depredation were known as Game Ships, and they frequently suffered the loss of as many as from fifteen to twenty hogsheads of sugar, with corresponding quantities of coffee and rum.

    The Heavy Horsemen, or lumpers—who often worked, or desired to work, on board of West India ships without wages,—generally connived with the mates or revenue officers to carry away large quantities of stuff in their dress.  They had an under-waistcoat, containing pockets all round, called a Jemie; and long bags, pouches, and socks, tied to their legs and thighs under their trousers, in which they concealed sugar, coffee, pimento, ginger, rum, and other articles.  When employed upon a game ship, these thieves used to divide from three to four guineas every night from the produce of their plunder, independent of the hush-money paid to the mates and revenue officers.

    Then there were the Game Watermen, who would wait upon West India ships in course of discharge, and take on their backs bags of sugar, coffee, and such like, handed to them by the lumpers and others in the delivery of the cargo.  The game watermen divided with the lumpers and others the money obtained from the receivers of the stolen goods.

    Besides these river thieves and pirates, there were also the Game Lightermen, who concealed in the lockers of their lighters considerable quantities of valuable goods, for the purpose of selling them; the Mud Larks, who prowled about in the mud at low water, under the quarters of West India ships, pretending to pick up old ropes, iron, and such like, but really waiting to have bags of sugar, coffee, rum, and pimento, lowered down to them from the thieves on board the ship; the Revenue Officers, who were paid a very small sum for their services, and eked it out with plunder; the Scuffle Hunters, who stole promiscuously from the crowded quays and wharves where the goods were discharging; and the Copmen, or receivers of stolen property, who were themselves often parties to the robbing of ships in company of the light horsemen.

    These criminals not only plundered in gangs, but they had the audacity to form a club for the purpose of resisting the attacks made upon them, under the powers of an Act passed in 1792, [p.356-1] commonly called the Bumboat Act; and by this means many of the scoundrels apprehended, escaped the punishment due to their crimes.  As a proof, amongst others, of the enormous extent of the river plunder, the convictions for misdemeanors between August 1792, and August 1799, exceeded 2200; of which number about 2000 culprits paid the penalties—partly from their own resources, but chiefly, it is believed, from the funds of the club—amounting in all to about £4,000, in the course of seven years. [p.356-2]

    The Thames Police was established, in 1798, for the purpose of checking this system of wholesale depredation; but, so long as the goods were conveyed from the ship's side in open lighters, and the open quays formed the principal shore accommodation—sugar hogsheads, barrels, tubs, baskets, boxes, bales, and other packages, being piled up in confusion on every available foot of space—it was clear that mere police regulations would be unequal to meet the difficulty.  It was also found that the confused manner in which the imports were brought ashore led to a vast amount of smuggling, by which the honest merchant was placed at a considerable disadvantage, at the same time that the revenue was cheated.  The Government, therefore, for the sake of its income, and the traders for the security of their merchandise, alike desired to provide an effectual remedy for these evils.

    Mr. Rennie was consulted on the subject in 1798, and requested to devise a plan.  Before that time, various methods had been suggested, such as quays and warehouses, with jetties, along the river on both sides; but all these eventually gave place to that of floating docks or basins communicating with the river, surrounded with quays and warehouses, shut in by a lofty enclosure-wall, so that the whole of the contained vessels and their merchandise should be placed, as it were, under lock and key.  By such a method it was believed the goods could be loaded and unloaded with the greatest economy and despatch, whilst the Customs duties would be levied with facility, at the same time that the property of the merchants was effectually protected against depredation.

    About the middle of last century a small dock had existed on the Thames, called the Greenland Dock; but it was of very limited capacity, and was only used by whaling vessels.  Docks had existed at Liverpool for a considerable period; so that there was no novelty in the idea of providing accommodation of a similar kind on the Thames, though it is certainly remarkable that, with the extraordinary trade of the metropolis, the expedient should not have been adopted at a much earlier period.

    The first docks constructed on the Thames were the West India Docks, and the London Docks.  The former occupied the isthmus that formerly connected the Isle of Dogs with Poplar, and were designed and constructed by Mr. William Jessop. [p.358]  At the same time that the West India Docks were in course of construction, a company was formed by the London merchants, in 1800, for the purpose of constructing docks, at a point as near the Exchange as possible, for the accommodation of general merchandise; and of this scheme Mr. Rennie was appointed the engineer.  Several designs were proposed for consideration, on a scale more or less extensive, and alternative plans were submitted to the directors.  Suggestions were also invited, which were afterwards worked up into more complete designs.  As the future trade of London was an unknown quantity, Mr. Rennie wisely provided for the extension of the docks, as circumstances might afterwards require.

    In carrying out the London Docks it was deemed advisable, in the first instance, to limit the access to the present Middle River Entrance at Bell Dock, 150 feet long and 40 feet wide, with the cill laid five feet below low water of spring tides.  The entrance lock communicated with a capacious entrance basin, called the Wapping Basin, covering a space of three acres, and this again with the great basin called the Western Dock, 1260 feet long and 960 feet wide, covering a surface of 20 acres. The bottom of the dock was laid 20 feet below the level of high water of an 18 feet tide. The quays next to the river were five feet above high water, increasing to nine feet at the Great Dock.  From the east side of the latter it was ultimately proposed to make two or more docks, communicating with each other and with a larger and deeper entrance lower down the river at Shadwell; all of which works have since been carried out.

    As the site of the Docks was previously in a great measure occupied by houses, considerable time necessarily elapsed before these could be purchased and cleared away; so that the works were not commenced until the spring of 1801, when two steam-engines were erected, of 50-horse power each, for pumping the water, and three minor engines for other purposes, such as grinding mortar, working the pile-engine, and landing materials from the jetty—an application of steam power as an economist of labour which Mr. Rennie was among the first to introduce in the execution of such works.  The coffer-dams for the main entrance, and the excavation of the Docks, were begun in the spring of 1802; [p.361] after which time the works were carried forward with great vigour until their completion on the 30th of January, 1805, when they were opened with considerable ceremony.

    At a subsequent period Mr. Rennie designed the present westernmost or Hermitage entrance lock and basin, the former of which is 150 feet long and 38 feet wide, with the cill laid two feet below low water of spring tides; the basin and main dock covering a surface of one acre and a quarter.  Another small dock of one acre was afterwards added on the north-east side of the Great Basin, exclusively devoted to the tobacco trade; and it was ultimately extended to the Thames at Shadwell, as contemplated in the original design.

    After the docks had been opened for trade, Mr. Rennie gave his careful attention to the working details, and he was accustomed from time to time to make suggestions with a view to increased despatch and economy in the conduct of the business.  Thus, in 1808, he recommended that the whole of the lifting-cranes in the Docks should be worked by the power of a steam engine, instead of by human or horse labour.  He estimated that the saving thus effected, in the case of only twenty-six cranes, would amount to at least £1,500 a-year, besides ensuring greater regularity and despatch of work; and, if applied to the whole of the cranes along the Docks and in the warehouses, a much greater annual saving might be anticipated.  It was, however, regarded as too bold an innovation for the time; and for many years the cranes in the London Docks continued to be worked by hand labour, at a great waste of time and money, as well as loss of business.

    Another of Mr. Rennie's valuable suggestions, with a view to greater economy, was the adoption of tramways all round the quays, provided with trucks, by means of which the transfer of goods from one part of the Dock to another might be effected with the greatest ease and in the least possible time.  But this, too, was long disregarded.  Labour-saving processes were then less valued than they are now.  The application and uses of machines were as yet imperfectly understood, and there were in most quarters powerful prejudices to be overcome before they could be introduced.  The goods in the London Docks are still hauled in trollies, waggons, or hand-barrows from ship to ship, or from the vessels to the respective bonded warehouses; and it still remains matter of surprise that a system so clumsy, so wasteful of time, so obstructive to rapid loading and unloading in dock, should be permitted to continue.

    Shortly after these works were set on foot, and when the great importance and economy of floating docks began to be recognised by commercial men, another project of a similar character was started, to provide accommodation exclusively for vessels of the East India Company, of from 1,000 to 1,800 tons burden.  A company was formed for the purpose, and an Act was obtained in 1803, the site selected being immediately to the west of the river Lea, near the point at which it enters the Thames; and where at that time there were two small floating basins or docks, provided with wooden locks, and surrounded with wooden walls, called the Brunswick and Perry's Docks.  These it was determined to purchase and include in the proposed new docks, of which, however, they formed but a small part.

    Mr. Rennie and Mr. Ralph Walker were associated as engineers in carrying the works into execution, and they were finished and opened for business on the 4th of August, 1806.  They consisted of an entrance lock into the Thames 210 feet long and 47 feet wide, with the cill laid 7 feet below low water of spring tides.  This lock is connected with a triangular entrance basin, covering a space of 4½ acres, on the west side of which it communicates by a lock with a dock expressly provided for vessels outward bound, called the Export Dock, 760 feet long and 463 feet wide, covering a surface of 8⅓ acres.  At the north end of the entrance basin is the Import Dock, 1410 feet long and 463 feet wide, covering a surface of 8⅔ acres.  The depth of these basins is 22 feet below high water of ordinary spring tides. The total surface of dock room, including quays, sheds, and warehouses, is about 55 acres.

    The original capital of the East India Dock Company was £660,000; but Mr. Rennie constructed and completed the Docks for a sum considerably within that amount.  Eventually they were united to the West India Docks, under the joint directorate of the East and West India Dock Company. [p.363]  Mr. Rennie also introduced into these Docks many improved methods of working; his machinery, invented by him for transporting immense blocks of mahogany by a system of railways and locomotive cranes, having, in the first six months, effected a saving in men's wages more than sufficient to defray their entire original cost, besides the increased expedition in the conduct of the whole Dock business.

    Some of Mr. Rennie's harbour works at other places were of considerable magnitude and importance; the growing trade of the country leading to his frequent employment in constructing new harbours, or extending and improving old ones.  In almost every instance he had the greatest possible difficulty in inducing the persons locally interested to provide harbour space sufficiently extensive as well as secure.  When asked to give his advice on such questions, he began with making numerous practical inquiries on the spot he surveyed the adjacent coast, took soundings all round the proposed harbourage, noted the set of the currents, the direction of the prevailing winds, the force and action of the land streams, and the operations of the scour of the tides upon the shore.

    He also inquired into the trade to be accommodated, the probability of its expansion or otherwise, and prepared his plans accordingly.  Writing to Mr. Foster, of Liverpool, in 1810, he said, "It seems to me that your merchants are much less liberal in their ideas than is generally supposed.  The account you give me furnishes another strong proof of the necessity of enlarging your scale of docks." Adverting to another scheme on which he had been consulted, he added, "It is my intention to impress upon the minds of the promoters the necessity for a much larger scale of docks than is proposed; and though they may blame me now, they will thank me afterwards; as larger accommodation will not only afford great and immediate relief to the shipping now, but will save the expenditure of much money hereafter."

 Liverpool's famous dock engineer, Jesse Hartley. [p.366]
Photo Wikipedia (E. Chambré Hardman Archive).

    As early as 1793 Mr. Rennie was employed by the Commissioners of British Fisheries to report as to the best means of improving the harbour of Wick,—the only haven (capable of affording shelter for ships in certain states of the wind) which was to be found along an extent of 120 miles of rock-bound coast.  In his masterly report he boldly proposed to abandon the old system of jetties, and to make an entirely new harbour beyond the bar; thus at once getting rid of this great and dangerous obstacle to improvement, securing at the same time greater depth of water, better shelter, and the means of easier access and departure for vessels of all burdens.

    In order to accommodate the trade of Wick, he recommended that a canal should be made from the new harbour, having a basin at its termination in the town, where vessels would be enabled to float, and to load and unload at all times.  He also proposed an effective plan of sluicing, with the view of scouring the outer harbour when necessary.  It is much to be regretted that this plan was not carried out, and that so important a national work has been postponed almost until our own day; nor does the plan since adopted, though exceedingly costly, seem calculated to secure the objects which would have been obtained by executing Mr. Rennie's more comprehensive yet much more economical design.

    He was consulted about the same time respecting the improvement of the harbour of Aberdeen; but though want of means then prevented his recommendations from being acted on, his report [p.367] produced a salutary effect in pointing out the true mode of dealing with a difficult subject, and most of his suggestions have since been carried out by other engineers.

    Of still greater importance was his report on the improvement of the navigation of the river Clyde, for the accommodation of the rapidly increasing trade of Glasgow.  Perhaps in no river have the alterations, executed after well-devised plans, been more extraordinary than in this.  Less than a century ago, the Clyde at Glasgow was accessible only to herring-boats, whereas now it floats down with every tide vessels of thousands of tons burden, capable of wrestling with the storms of the Atlantic.  Watt, Smeaton, and Golborne had been consulted at different times, and various improvements were suggested by them, Watt laid out a ship-canal from Glasgow to the sea.  Smeaton proposed to construct a dam and lock at Marlin Ford, so as to allow vessels drawing only four feet of water to pass up to the quay at the Broomielaw.

    The clearing out of the channel by artificial means was, however, found the most effectual method of opening up the navigation of the river, and at length all other plans have given way to this.  Colborne had run out jetties at various points, by which the scour of the tide had been so directed that considerably greater depth had been secured.  Mr. Rennie examined the entire river below Glasgow in 1799, and the result was his elaborate report of that year.  He recommended numerous additions to the jetties, as well as many improvements in their direction.  He also advised that a system of dredging should be commenced, which was attended with the best possible results; and the same course having been followed by succeeding engineers, the Clyde has now become one of the busiest navigable thoroughfares in the world.  The plan which Rennie shortly after prepared and submitted, of a range of commodious docks along both banks of the river at the Broomielaw, showed his sagacity and foresight in an eminent degree; but unhappily it was considered too bold, and perhaps too costly, and it was not then carried out. [p.368]

    At the opposite end of the island he was consulted (in 1796) as to the best method of improving the harbour of Torquay, and he submitted a series of able plans, only a small part of which were carried into effect.  Shortly after (in 1797) we find him inspecting the sluicing arrangements of the harbour then under construction at Grimsby, when he furnished a plan of the great lock which it was found necessary to place at the entrance of the canal leading to the dock, and which was in his opinion indispensable for scouring the harbour entrance and keeping it clear of silt.  This lock was executed according to his plans by the local engineer; but it appeared that sufficient precautions had not been taken in founding and proportioning the dimensions of the retaining walls, on which Mr. Rennie had not been requested to give an opinion, the work appearing to be of so simple and ordinary a character.

    Shortly after the building had been begun, a considerable portion of the lock walls gave way, and Rennie was again sent for to inquire and report as to the cause of the failure.  He found that the defect lay in the nature of the ground on which the foundation was built, which was so soft that it would not bear the weight of solid walls of the ordinary construction.  Always ready with an expedient to meet a difficulty, he directed that, without diminishing the quantity of material employed, it should be distributed over a greater base, for the purpose of securing a larger bearing surface.  With this object he prepared his plan of the requisite structure, adopting the expedient of hollow walls, which he afterwards employed so extensively in his pier and harbour works.  They not only bore upon a larger base, but were found even stronger than solid walls containing an equal quantity of material.  Those at Grimsby have stood firm until the present day.  The contrivance was thought so valuable, that some years after Mr. Rennie had invented it, Sir Samuel Bentham (in 1811) took out a patent for the plan: but of this Mr. Rennie took no notice, having himself, as we have seen, been the original inventor of the process.  Indeed, his attention had long before this time been directed to the best form of walls for resisting the pressure of water; and, as early as the year 1793, we find him recommending the adoption of curved walls, in place of the inclined straight-faced walls with perpendicular back, as formerly adopted. [p.370]

    Another important harbour on which Mr. Rennie was early employed was that of Holyhead, situated at the point of the island of Anglesea nearest to the Irish capital.  Although so conveniently placed for purposes of embarkation, everything had as yet been left to nature, which had only provided plenty of deep water and many bold rocks.  But Holyhead had neither pier nor jetty, nor any convenience whatever adapting it for harbour uses.  Besides, the place was almost inaccessible from inland by reason of narrow, rugged, and in many places almost precipitous roads.  The dangerous ferries at Conway and Menai also presented serious obstacles to travelling by that route; and hence the port of Liverpool, and Park Gate on the Dee near Chester, continued to be the principal places of embarkation for persons proceeding to Ireland, until the beginning of the present century.

    When the Act of Union was passed, the Government determined to bring the two countries into closer communication with each other; first by means of convenient roads through North Wales, and next by capacious harbours at Holyhead on the one coast and at Kingstown on the other.  In the year 1802, Mr. Rennie was requested to report upon the subject, and he proceeded to Wales for the purpose of examining the Conway and Menai ferries, and the capabilities of Holyhead as a port.  It was on that occasion that he recommended the construction of the permanent fixed bridges across both Straits after the plans already referred to.  Nothing was, however, done towards carrying out his suggestions, and the whole question slept until the year 1809, when he was requested by Government to prepare plans of a harbour at Holyhead, as the first step towards the desired improvement; and his design having been approved, the works were begun in the following year.

    The form of the harbour of Holyhead has been determined, in a great measure, by the cliffs which overhang the sea, and on the verge of which stand the ancient church and cemetery of the town.  The works designed by Mr. Rennie consisted of a pier 1150 feet long, extending in a direction nearly due east from the inner side of Salt Island, which is separated by a narrow channel from the main island of Holyhead.  The pier terminated at a depth of about 14 feet at low water of spring tides.  At 80 feet distant from the extremity of the main pier there was a jetty 60 feet long, carried out at right angles to its inner face, to check any swell which might come round the pier-head from entering the harbour, and to throw it upon the opposite shore.  The roadway was 50 feet wide, and 8 feet above the level of high water of spring tides, the parapet being 7 feet higher.  The outer or sea side of the pier was formed by a flat paved slope of rough stone, laid at an inclination of 5 to 1.  The quay-wall was curved on the face one-fifth of the height; the thickness of the masonry being 10 feet upon the average, strengthened at the back by strong counterfoots, at the regular distance of 15 feet apart.  The foundation of this wall was laid below low water by means of long stones, inclined to each other, in the same manner as at Howth Harbour, where the plan had been found to answer remarkably well.  The centre of the pier was composed of loose rubble, taken from the adjacent shore, packed solidly; the outside being paved with large angular blocks varying from one to ten tons in weight, well wedged together.  The inside of the parapet was built of solid masonry.  The pier-head and jetty were founded below low water by means of the diving-bell.  The works were begun in 1810 and finished in 1824, and during their progress a small pier was run out from the Pibeo rock on the opposite shore, 550 feet long, leaving an opening between it and the main pier of 420 feet.  This pier was provided with a jetty on the inside, similar to that on the main pier, composed of the same kind of materials, and finished in like manner.  Within it was a small dry dock for merchant vessels.  The total low-water space covered by these two piers was about six acres; but there was more than double that area at high water, besides a large shallow space of about thirty acres for timber.

    In conformity with his usual practice, Mr. Rennie so laid out this harbour as to be capable of extension on the same principles, according as the trade of the port might require.  Part of his original design was to devote a large space in the inner portion of the bay, which is dry at low water, to a wet dock of 23 acres.  Had this been carried out, it would have proved of immense advantage to the numerous land-bound vessels which have occasion to put into the port.  His original plan also contemplated a pier extending from the outer end of Salt Island, parallel to the one above described, 1500 feet long, terminating at a depth of 25 feet at low water; and as it would have been about 1400 feet distant from the other, and was to be provided with a jetty at right angles to its extremity, it would have provided an additional low-water harbour of 40 acres.  The estimated cost of this work was £240,000; and if to this be added the probable outlay on the additional wet dock above mentioned of £124,000, it will be found that a total low-water space of 46 acres, and an additional tidal space of 25 acres, together with a wet dock of 23 acres, or a total floating area of about 94 acres, with an ample extent of quay accommodation, sufficient for any amount of packet or general commercial business, would have been provided at a comparatively moderate expenditure.

    Unhappily Mr. Rennie's plans were not carried out; and though his original design admirably answered the purpose intended, and the whole of the packet service was satisfactorily performed at the old port for many years, when an extension of Holyhead Harbour was determined upon, the Government (after Mr. Rennie's death) employed an engineer who proceeded upon an entirely new plan, the execution of which, when completed, will probably cost upwards of two millions sterling; and, after all, when the rocky and bad nature of the holding-ground within it, is taken into account, [p.375-1] its security and convenience are still matters of considerable doubt amongst naval men.

    During the period in which he was engaged in carrying out the works at Holyhead, Mr. Rennie was also constructing harbours at Howth and Kingstown, with the same object of facilitating the communication between the ports of England and Ireland.  Howth Harbour was opened for packets in 1819, previous to which time they had sailed from the Pigeon House, at the mouth of the Liffey, in Dublin Bay.  When the piers at Kingstown Harbour were sufficiently advanced to be available for the service, the packets were removed to that port, the depth of water being greater, and the situation on the whole more convenient. [p.376-1]

    Among the other harbour works constructed by Mr. Rennie in England, were the Hull Docks.  These were of great importance, and urgently required for the accommodation of the large trade of that rising port.  What is called the Humber Dock was begun in 1803 and finished in 1809. [p.376-2]

    The principal difficulty encountered in the execution of these works was in getting in the foundations of the dock walls—the bottom presenting a great depth of soft mud.  They were set on timber piles and platforms well bound together, with truncated arches of stone over them.  A powerful steam-engine was employed to draw the water from the coffer-dam in front of the Humber entrance, to enable the foundations of the cill to be got in, and the lock gates (which were of stout oak) to be fixed.

    It was in the course of executing the Hull Harbour works that Mr. Rennie invented the dredging-machine, as it is now used, for the purpose of clearing the basins of mud and silt.  Various unsuccessful attempts had before been made to contrive an apparatus with this object.  A series of rollers, armed with spikes to rake up the deposit, followed by buckets and spoons to lift it from the bottom, worked by means of a walking wheel between two barges, was the most common practice; but it was clumsy, tedious, and inefficient.  Other machines for a similar purpose were driven by tread-wheels.  At length the idea was taken up of fixing a series of buckets to an endless chain, worked by horse power.  Mr. Rennie carefully investigated all that had previously been attempted in this direction, and then proceeded to plan and construct a complete dredging-machine, with improved machinery, to which he yoked the power of the steam-engine.  He was thereby enabled to raise as much as 300 tons of mud and gravel in a day from a depth of 22 feet; and the expedient proved completely successful.

    The same kind of machine was extensively used by Mr. Rennie in executing his various harbour works.  One of these, constructed for the excavation of the Perry Dock at Blackwall in 1802, was furnished with a powerful apparatus for splintering rocks and large stones, which could not otherwise be removed; and it answered the purpose most effectually.  In the Clyde, the Thames, the Mersey, and the Witham, as well as in various foreign rivers, the dredging-machine, as contrived by Mr. Rennie, has been found invaluable; and there is scarcely a port or harbour in the United Kingdom in which it has not been most beneficially employed.

    In addition to these docks and harbours, Mr. Rennie furnished the plans of the new quays and docks at Greenock on the Clyde in 1802; and those at Leith, the port of Edinburgh, in 1804.  Neither of these schemes was carried out to the full extent, chiefly for want of funds; but the improvements effected at the former port were considerable, and at Leith two large docks, 1500 feet long, and two small ones, 750 feet long, constructed along the shore between the old tidal harbour and the village of Newhaven, provided a large amount of additional accommodation for the growing trade of the port.

    Mr. Rennie was also consulted in 1805 respecting the improvement of Southampton; and the measures which he recommended in his elaborate and able report, formed the beginning of a series of works of almost national importance.  Mr. Rennie's clear-sighted prognostications of the future prosperity of the port—arising from its great natural advantages in respect of security, capability of extension, the excellent anchorage of Southampton Water, the central situation of the place on the south coast, and its moderate distance from London—have been amply fulfilled; its subsequent connection with the capital by railway having given an impulse to its improvement and prosperity far beyond what even his sagacious mind could at that time have foreseen. [p.379]

    In his harbours, as in all his engineering works, Mr. Rennie proceeded upon certain definite principles, which he arrived at after a careful study of the whole subject.  He was averse to all makeshifts and temporary expedients.  When he was asked to give his advice as to the best means of rendering a harbour efficient, he stated his views fully and conscientiously, holding nothing in reserve.  He set forth the whole cost which he believed would be incurred, and no less.  He abhorred setting traps in the shape of low estimates, to tempt men to begin undertakings, when he knew that they would be exceeded.  He spoke out the whole truth.  "You want a harbour," he would say, "of such strength as to be safe, with piers able to resist the greatest possible force of the sea.  Well, here is the plan I recommend: it is the best that I can suggest.  But I tell you the whole cost which I think will be incurred in its construction.  Adopt the plan or not, as you think proper."

    He would never consent to reduce the strength of his piers and retaining walls, under the limits which he thought essential for their stability.  He would not risk his reputation and character upon slop-work; he would rather lose his chance of employment altogether.  Hence so many of his large but effective designs for the improvement of our most important harbours remained unexecuted, or have been only carried out to a limited extent, sometimes by engineers who had not mastered the fundamental principles on which his plans were founded, and in such a manner as frequently to lead to vast inconvenience and almost endless expense.

    In his report on the Earl of Elgin's proposed harbour at Charleston, on the north shore of the Frith of Forth, in the year 1807, he very clearly laid down the broad principles on which he held that such works should be designed: "Every harbour," he said, "should be so constructed as to have its mouth as much exposed as possible to the direction from whence vessels can most conveniently enter in stormy weather, when they are least manageable; but the Heads should be made of such a form as to admit of the least sea entering it, or so as to occasion as little swell within the haven as possible.  This cannot, by any practicable construction, be entirely avoided; but means should be provided within the harbour so as to reduce the recoil of the waves to a minimum,—for it is the undertow or retiring sea, after the breaking of a wave, that renders vessels most unmanageable by causing the helm to lose its effect.  At such a time the mariner is at a loss what to do, or how to manage his vessel; and for the want of due attention to these particulars, many of the most considerable artificial harbours in the kingdom are exceedingly difficult of access, and some of them are most unsafe even when entered."  The great point, he held, was not only to make a harbour to keep out the sea, but to do so in such a manner as to render its entrance from the most exposed or dangerous quarter easy in stormy weather, when its shelter was most needed; and while it must be so designed as to afford a safe shelter for shipping, it must also be safe to enter and safe to get out of. [p.381]

    That so many modern harbours, constructed at great cost, are found comparatively inaccessible in severe weather, is, we believe, to be accounted for mainly by the circumstance, that they have been laid out after no definite rule or principle whatever.  If they succeed, it is the result of a happy accident; and if they fail, it is supposed that the failure could not have been helped.  Even within the last twenty years several expensive havens have been constructed, which have proved to be so dangerous that they can scarcely be used.  But by Mr. Rennie's forms of piers, vessels, if they have only steerageway, must enter the harbour in safety.  They cannot strike on the pier-heads, and, if ordinary care be used, the very recoil of the waves forces them forward into port; and, as any swell which might enter would have ample space to expend itself, the ship could either be brought up, or take the beach without damage if necessary.

    Again, a sailing vessel, on leaving the harbour, supposing the wind to be blowing right in, could lie out upon either tack and make an offing, if it were prudent to put to sea at all.  And although the narrowed distance between the two pier-heads might be termed the entrance, yet in effect it is not so; for the moment the vessel gets within the outer angles of the two return arms or kants, she may be said to be in or out of the harbour, as the case may be.  In this way the fullest width of entrance and the smallest space for the admission of swell are ingeniously and effectually secured.

    Whilst occupied on the works of the Ramsgate Harbour, of which he was appointed engineer in 1807, Mr. Rennie made use of the diving-bell in a manner at once novel and ingenious.  It will be remembered that Smeaton had employed this machine in the operations connected with the building of the harbour; [p.383] but his apparatus being wood, was exceedingly clumsy, and very limited in its uses.  In that state Mr. Rennie found it, when he was employed to carry on the extensive repairs of 1813.  The east pier-head was gradually giving way and falling into the sea at its most advanced and important point.  No time was to be lost in setting about its repair; but from the peculiarly exposed and difficult nature of the situation, this was no easy matter.  The depth at the pier-head was from 10 to 16 feet at low water of spring tides; besides, there was a rise of 15 feet at spring and 10 feet at neap tides, with a strong current of from two to three knots setting past it both on the flood and at the ebb.  The work was also frequently exposed to a heavy sea, as well as to the risk of vessels striking against it on entering or leaving the harbour.

    Mr. Rennie's first intention was to surround the pier-head by a dam; but the water was too deep and the situation too exposed to admit of this expedient.  He then bethought him of employing the diving-bell; but in its then state he found it of very little use.  No other mode of action, however, presenting itself, he turned his attention to its improvement as the only means of getting down to the work, the necessity for repairing which had become more urgent than ever.  Without loss of time he proceeded to design and construct a bell of cast iron, about 6 feet in height, 4½ wide, and 6 feet long, having one end rather thicker and heavier than the other, that it might sink lower, and thus enable the exhausted or breathed air more readily to escape.

    At the top of the bell, eight solid bull's-eyes of cast glass were fixed, well secured and made water-tight by means of leathern and copper collars covered with white lead, and firmly secured by copper screw bolts.  To the top of the inside were attached two strong chains for the purpose of fastening to them any materials that might be required for the work, and flanges were cast along the sides of the bell, on which two seats were placed, with footboards, for the use of the men while working.  In the centre of the top was a circular hole, to which a brass-screwed lining was firmly fixed, and into this a brass nozzle was screwed, having a leathern water-tight hose fastened to it, 2½ inches in diameter.  The hose was in lengths of about 8 feet, with brass-screwed nozzles at each end, so that it could be lengthened or shortened at pleasure, according to the depth of water at which the men in the bell were working.

    For the purpose of duly supplying the machine with air, a double air-pump was provided, which was worked by a sufficient number of men.  The air-pump was connected with the hose referred to, and was either placed on the platform above or in a boat which constantly attended the bell while under water.  Two stout wrought-iron rings were fixed on the top of the machine, to which ropes or chains were attached for the purpose of lowering or raising it.  The whole weighed about five tons; and it was attached to a circular framework of timber, strengthened by iron, erected over where the intended circular pier-head was to be built, and so fixed to a pivot near the centre of the work, that it was enabled easily to traverse its outer limits.

    On the top of the framework was a truck, made to move backwards or forwards by means of a rack on the frame, and a corresponding wheel provided with teeth, worked by a handle and pinion.  On the truck were placed two powerful double-purchase crabs or windlasses, one for working the diving-bell suspended from it, and the other for lowering stone blocks or other materials required for carrying on the operations at the bottom of the sea.  By these ingenious expedients the building apparatus was so contrived as to move all round the new work, backwards and forwards, upwards and downwards, so that every part of the wall could be approached and handled by the workmen, no matter at what depth; while the engineer stationed on the pier-head above could at any time ascertain, without descending, whether the builders were proceeding in the right direction, as well as the precise place at which they were at work.

    Everything being in readiness for commencing operations, the divers entered the bell and were cautiously lowered to the place at which the building was to proceed.  A code of signals was established by which the workmen could indicate, by striking the side of the bell a certain number of strokes with a hammer, whether they wished it to be moved upward, downward, or horizontally; and also to signal for the descent of materials of any kind.  By this means they were enabled, with the assistance of the workmen above, to raise and lower, and place in their proper bed, stones of the heaviest description; and by repeating the process from day to day, and from week to week, the work was accomplished with as much exactness, and almost as much expedition, under water, as though it had been carried on above ground.

    Thus the entire repairs were completed by the 9th of July, 1814; and to commemorate the ingenuity and skill with which Mr. Rennie had overcome the extraordinary difficulties of the undertaking, the trustees of the harbour caused a memorial stone to be fixed in the centre of the new pier-head, bearing a bronze plate, on which were briefly recorded the facts above referred to, and acknowledging the obligation of the trustees to their engineer.  They also presented him at a public entertainment with a handsome piece of plate in commemoration of the successful completion of the work.  The diving-bell, as thus improved by Mr. Rennie, has since been extensively employed in similar works; and although detached divers, with apparatus attached to them, are made use of in deep-sea works, the simplicity, economy, and expeditiousness of the plan invented by Mr. Rennie, and afterwards improved by himself, continue to recommend it for adoption in all undertakings of a similar character.

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CHAPTER IX.

MR. RENNIE'S WAR DOCKS AND OTHER GOVERNMENT WORKS.

FROM an early period Mr. Rennie's eminent practical abilities pointed him out for employment in the public service; and he was consulted by the Ministry of the day more particularly as to the machinery used in the Government establishments, as to the formation of royal docks, and the construction of breakwaters.   At the recommendation of Mr. Smeaton he was called upon by the Victualling Department of the Navy to advise them as to the improvement of their flour-mills at Rotherhithe, which were worked by the rise and fall of the tide; and the manner in which he performed that service was so satisfactory, that it led to his advice being taken on other subjects, some of which might at first sight be supposed to lie beyond the range of engineering experience.

    Great alarm prevailed in 1803 as to the warlike intentions of the French, who threatened to invade England.  The 'Moniteur' and the 'Brussels Gazette' were openly speculating as to the time that it would take for the French army to reach London.  It therefore behoved England to be upon her guard.  All the possible lines of approach from the coast to the Capital were carefully examined; and it appeared to military men that the eastern side of London was the most accessible to the advance of an enemy landing near the mouth of the Thames, or on the Essex coast.  Mr. Rennie was employed to examine the valley of the Lea, to ascertain whether means could be devised for suddenly laying it under water, if necessary, to check the approach of a hostile army from that quarter.  After careful consideration, he laid before the Government a plan with that object, which included a series of dams furnished with sluices,—one at the junction of the Lea with the Thames, another across the valley at Bow, a third at Temple Mills, and others higher up that river, as far as Amwell.  These were contrived so that the waters should be penned up, and the valley flooded at will.  The works were, however, only partially carried out.  Five dams were formed above Bromley, with jetties at different points to increase the current; but happily the defensive works were never required, Napoleon's warlike ambition having shortly after become diverted in another direction.

    But again, about 1806, when Napoleon's legions were assembled on the heights above Boulogne, and all his flat-bottomed boats were in readiness to receive them, further steps were taken to defend the south-east coast from the expected invasion.  Martello towers were erected along the coast from Folkestone to Beachy Head; and among the other means adopted was the formation of a military canal from Sandgate to Rye, the designing of which was entrusted to Mr. Rennie.  In a letter to Mr. Boulton of Birmingham, dated the 22nd May, 1806, he observes:—
 

"You may possibly remember that from the cliffs west of Sandgate, to a place called Cliffend, about three mile west of Rye, in Sussex, there is an extensive marsh, which lie along the sea-coast, composed of Romney Marsh, Guildford Marsh, the Mead, Winchelsea, and Pet Levels, all of which make about 60,000 acres. [p.391-1]  On the interior site of the marshes the country rises suddenly to the height of some 100 to 150 feet.  A canal, about thirty miles in extent, is now being constructed, and is indeed nearly finished, round the marsh, and at the foot of the high land.  This canal is 60 feet wide and 9 feet deep.  It is defended on the land side by a strong rampart with bastions which flank it from end to end.  Within the rampart, there is a wide military road on which artillery can be transported with great expedition, under cover of the rampart, from one bastion to another, as may be required.  The bridges across this canal are all temporary, and may be broken down on the approach of an enemy." [391-2]

This is the branch of the Royal Military Canal runs from Port Lympne to the coast. The canal was built with ‘kinks’ to allow enfilading fire along its length if an enemy attempted to cross it.
© Copyright Ian Capper and licensed for reuse under this Creative Commons Licence.

    Mr. Rennie was also consulted as to the best site for a low-water harbour on the south-east coast, for the purpose of accommodating frigates to watch the opposite shore.  His opinion was in favour of Folkestone as the best site for such a port, where a ridge of rocks outside its then small tidal basin offered unusual facilities for the formation of a haven capable of accommodating vessels of considerable burden.  This work was not, however, carried out, and Folkestone Harbour is now devoted to more pacific purposes. [p.391-3]

    When Fulton proposed the scheme of his famous torpedo for blowing up ships at sea, by stealthily approaching them under water, Earl Stanhope made so much noise about it in the House of Lords, that a commission, of which Mr. Rennie was a member, was appointed to investigate its merits.  Little importance was attached to Fulton's pretended "invention;" nevertheless it was determined to afford him an opportunity of exhibiting the powers of his infernal machine, and an old Danish brig, riding in Walmer Roads, was placed at his disposal.  He succeeded, after an unresisted attack of two days—during which he had also the assistance of Sir Home Popham—in blowing up the wretched carcass, and with it his own pretensions as an inventor. [p.392]

    Among other subjects on which we find Mr. Rennie consulted by the Government authorities, were the improvement of the machinery of the Waltham Powder Mills, especially as to the more economical application of the water power—the fixing of moorings in the tideways of the royal harbours—the clearing of the Thames in front of Woolwich Dockyard of its immense accumulation of mud—the erection of a quarantine establishment in the Medway [p.393] the provision of wet docks for the Royal Navy—and the introduction of improved machinery at the various dockyards; on which last subject Mr. Rennie was especially competent to give advice.

    A Commission of Civil Officers of the Navy was appointed, in 1806, to consider the best means of turning out work from the dockyards with the greatest despatch and economy.  Private manufacturing establishments were then a long way ahead of the Government yards, where methods of working, long abandoned everywhere else, still continued in practice; and to call a mechanic or labourer on the Thames "a regular dockyarder" was to apply to him the lowest term of reproach that could be used.  Foreign governments were introducing steam-engines and the most improved kinds of machinery, whilst our Admiralty were standing still, notwithstanding the war with France, which called for more than ordinary despatch in the building and repairs of ships of war.

    In Mr. Rennie's report to the Commission, he incidentally mentions mechanical appliances which he was engaged at the time in manufacturing for exportation.

"I am erecting," he said, "a steam-engine for the royal dockyard at Copenhagen, for the purpose of blowing all the bellows in the smithies, and another for pumping water out of the docks.  I also understand they mean to construct machinery there for forging anchor-palms and other large iron work.  Rolling-mills for bars, bolts, hoops, &c., might also be employed with advantage.  Saw-mills, such as I have constructed at Calicut, on the coast of Malabar, for sawing plank, beams, and other articles, would be very serviceable.  Block-machinery and rope-works might likewise be worked by steam-engines, as well as mills for rolling copper, machinery for working cranes, and other purposes."

    He pointed out, that dockyards ought to be so laid out as to enable work of the same kind to be carried on by continuous operations, as in a well-ordered manufactory.  He showed that the water at the entrance of all the dockyards, excepting Plymouth, was too shallow to enable large ships to be docked for repairs, without dismantling them and taking out their guns and stores, which was a cause of much delay, damage, and expense; and he urged the provision of a dockyard in which the largest ships might lie afloat at low water, and be docked and undocked in all states of the tide.  He would also have powerful steam-engines provided, by which any dock might be pumped dry in a few hours, so as to enable repairs to be at once proceeded with.  He had no doubt that the cost of constructing such a harbour and dock would be saved to the nation in the course of a very few years.  He also urged, as of still greater importance, the necessity for concentrating all dockyard work as much as possible.  Himself the head of a large manufacturing establishment, he was well aware that the more the several branches are kept apart from each other, the less is the efficiency secured, and the greater is the waste of material as well as loss of time.  He therefore urged above all things concentration, and he broadly held that without it economy was impossible.

    Portsmouth, Plymouth, Pembroke, Sheerness, Chatham, Woolwich, and Deptford were mostly far apart, some of them very badly adapted for the purposes of royal dockyards, and at nearly all of them the same costly process of patching, cobbling, and waste was going forward.  Indeed, he held that it would be much cheaper, viewed as a money question only—not to mention the increased despatch of business and the improved quality of the workmanship—to construct an entirely new dockyard, where every department could be laid out in the most complete and scientific manner.  These views looked so reasonable, and they pointed to results so important, that the Board of Naval Revision determined to pursue the investigation; and they requested Mr. Rennie to examine all the royal dockyards, and report as to the improvements that might be made in them with the above object; and also on his plan of a new and complete naval arsenal suitable to the requirements of the nation.

    The result of his inquiries was set forth in the elaborate report delivered by him on the 14th May, 1807.  He had found most of the royal harbours in a state of decay, silted up with mud or sand, and in a generally discreditable condition.  Of all the naval arsenals, he found Plymouth had suffered the least, in consequence of less alluvial matter flowing into the harbour from the rivers discharging themselves into the Sound—the principal objection to that port being that it was exposed to the violence of south-westerly and south-easterly winds.  Portsmouth he found to be in a very defective state, much silted up with mud, the depth on the bar having become reduced within a century from 18 to 14 feet, whilst the works generally were in a condition of great decay.  The docks were also, in his opinion, quite inadequate to the accommodation of ships requiring repairs, whilst the storehouses, workshops, and building-slips were ill laid out, having been run up in haste after no well-digested plan, involving bad work and waste both of money and of time. [p.396]

    Deptford Royal Dockyard, the oldest on the Thames, was objectionable because of the decreasing depth of water, which rendered it less and less available for ships of large burden; and hence it was gradually being abandoned for ship-building purposes; Mr. Rennie recommending that it should for the future be exclusively used as a victualling yard.  Woolwich also he considered ill adapted for the purposes of a royal harbour and arsenal: it was situated too high up the river, where the water was shallow, and the place was incapable of enlargement to the required extent, except at an enormous cost.  He held that large ships, even if built there, must go down the stream into deeper water before they could take in their guns, stores, and provisions, thus involving the risk of damage and the certainty of delay and increased expense.

    With reference to the naval arsenals on the Medway, although considerable improvements had been made in the dry and wet docks at Chatham, yet he held that the place was from its situation, incapable of being adapted to the important purposes of a naval establishment, of such extent and accommodation as should be commensurate with the national requirements.  Besides, the navigation of the Medway from the Nore was very intricate, and the upper part too shallow for ships of large burden.

    Then, as for Sheerness, his opinion was that the yard there, besides being on too small a scale to adapt it for the purposes of a national harbour and arsenal, would be exposed to great risk in event of a war, being almost incapable of effectual defence.

"On the whole," he observed, "it appears to me, on consideration of all the facts I have been able to collect respecting the principal naval arsenals of the empire, that they are far from possessing such properties, either in point of situation, extent, arrangement, or depth of water in the harbours, as the large and growing naval power of this country demands."

    In reviewing the sites of the different arsenals, Mr. Rennie says he was struck with surprise to find them mostly placed on the lee shore of their respective harbours the worst of all positions.  Plymouth, Portsmouth, Chatham, and Sheerness were thus situated; Deptford was on the weather shore, and Woolwich had the prevailing wind blowing across it.  He also pointed out that, at all the royal dockyards, vessels had to take in their stores and be rigged and fitted out in the open harbours; and, with the exception of Plymouth, the materials were clumsily and expensively conveyed from the shore to the ship's side in lighters.  There being no wet docks at any of the royal yards, vessels in ordinary lay moored out in the open tideway; and the expense of moving them, of placing men on board to watch them, and the various accidents to which they were thus liable, were the constant cause of heavy loss to the nation.

    Regarding the subject in all its bearings, and with a view to despatch, efficiency, and economy, Mr. Rennie strongly recommended the construction of capacious wet and dry docks, in some convenient situation on a weather shore, provided with sufficient storehouses and workshops, fitted with engines and machinery on the most improved plans for the building and repair of ships; and he expressed his strong opinion that the political importance of adopting such a measure would far outweigh the expense, however large, which it might be necessary to incur.

    The subject was felt by the Admiralty authorities to be of so much importance, that Mr. Rennie was again requested to report as to the most advisable site for a great naval harbour and arsenal such as he had proposed; and he was requested by Lord Howick (then First Lord) more particularly to state his views as to the eligibility of Northfleet on the Thames, which had been suggested as the most desirable situation.  In his visit of inspection to the place, Mr. Rennie was accompanied by his venerable friend James Watt, and his confidential assistant Mr. Southern, together with Mr. Whidbey, acting master-attendant at Woolwich Dockyard; and he had the benefit of their great experience in maturing the design which he shortly after laid before the Admiralty for their consideration.

    The proposed site seemed to him most convenient for the purpose of a great naval harbour and arsenal.  "Northfleet," he said, "possesses every advantage that can possibly be wished for In a naval station, and it is capable of being rendered as complete and perfect an establishment as can be made for building, repairing, and fitting out vessels of war of all classes, on the largest Seale."  The Thames at that point presented abundant depth of water; there was a large space of flat land available for the harbour and docks, which might be so laid out as to be almost indefinitely extended; the situation was on the weather shore, well protected, and capable of being strongly defended; it would be in direct connection by water with Woolwich, Deptford, and London, as well as with Chatham and Sheerness; and as a great national harbour and arsenal, he regarded its situation on the Thames, at the entrance to the greatest port in the world, as in all respects the most suitable and appropriate.  Accompanying his report was a carefully devised and most elaborate plan, [p.400] which unhappily was never carried out.

    Mr. Rennie was also consulted respecting the improvement of the old royal dockyards, and submitted various plans with this object, the most important of which were only carried out after the Northfleet project had been finally abandoned.  Of the new works executed after our engineer's designs those at Sheerness were the most extensive.  The royal dockyard there was felt to be a public disgrace.  It consisted of a number of old wooden docks and basins, formed by ships' timbers roughly knocked together from time to time, as necessity required.  The ground, in its original state, had been merely an accumulation of mud and bog, surrounded by a wide extent of flat wet land.

    It is easy to conceive how, in ancient times, Sheerness must have been regarded as of importance, occupying as it does the extreme north-western point of the Isle of Sheppey, and commanding the entrance both of the Thames and the Medway.  But, with the improvements in modern artillery, the place has in a great measure ceased to be of value as a public arsenal, being incapable of efficient defence against a hostile fleet.  Mr. Rennie entertained a strong opinion as to the inferiority of the site compared with others which he pointed out; but from the time when he was directed to prepare plans for the reconstruction of the dockyards, his business was confined to carrying out his instructions in the best possible manner.

    The plan finally decided upon was that of a river-front, extending from the Garrison Point to near the Old Town Pier of Sheerness, of the length of 3,150 feet, including the entrances, and enclosing within it three basins: one to the north, 480 feet long and from go to 200 feet wide, containing a surface of about two acres, 4 feet below low water of spring tides, with two frigate-docks and a building-slip and boat-slips; a central tidal basin 220 feet square, of the depth of 2 feet below low water, with storehouses around it for the reception and delivery of victualling and other stores; and on the west end of the dockyard a basin 520 feet long and 300 feet wide, covering a surface of nearly four acres, provided with dry docks for ships of the line on the south side, with their tills and the bottom of the basin laid 9 feet below low water of spring tides, westward of which were the mast-ponds, mast-locks, and work-shops.  In the rear, on the south of these works, were placed sawpits, timber-berths, and the officers' houses.  The total surface of the dockyard was 64¾ acres.  The foundation-stone of the docks was laid by the late Lord Viscount Melville in 1815, and the works were commenced and continued without interruption until the year 1826, when the whole were completed.

    Their execution was attended with many difficulties, and necessarily required a great deal of Mr. Rennie's care and attention.  The foundations were a soft running sand, extending to an almost fathomless depth.  The strong currents flowing past the place rendered it necessary to adopt an entirely new system of operations, which were carried out to an extent never before attempted in so exposed a situation.  That form of sea-wall was devised which should most effectually resist the strong pressure of the current, and the heavy swell beating upon its outer side, without yielding to the lateral pressure or thrust of the water of the basins and the earth by which it was backed.  At the same time the weight necessary to ensure stability must not be such as to sink vertically.  Mr. Rennie adopted the means to secure these objects which he had employed with such success at Grimsby Docks in 1797, namely, to take the like quantity of materials as would have been necessary for an ordinary wall, and dispose of them in such a form, that the same weight should be distributed over a greater surface, thus diminishing the vertical pressure.

    In the foundations of the walls he also adopted the method employed by him in similar works, of driving the piles and cutting off their heads at an angle inclining inwards, or towards the land side, laying the courses of stone at the same angle; by which a greater resistance was offered to the pressure of the earth, and the building was prevented from being pushed outwards, as was more or less the case in most of the walls built on the old construction.  The entrance gates to the great basin were also planned and executed with great skill, Mr. Rennie carrying into effect the same simple but correct principles laid down by him in his report on the Northfleet docks, making the direction of the entrance suitable to the current in the river Medway, and from which the ships entered the port.

    The coffer-dams in which these Cyclopean walls were built demand a passing notice because of their gigantic dimensions and the great depth at which they were founded, at not less than from 27 to 28 feet below low water of spring tides.  They were composed of four rows of piles about 12 to 14 inches square.  The two centre rows were carried about 4 feet above the level of high water of the highest spring tides, and were driven from 20 to 30 feet into the sea-bottom.  The outer and inner rows were about 7 feet from the two centre main rows, but only extended up to the level of the half tide, and were driven from 15 to 20 feet into the ground.  All the piles were hooped and shod with wrought iron, firmly bound together at the bottom, middle, and top, with timber braces and wrought-iron bolts and ties in every direction.  The joints were caulked with oakum and covered with pitch, and the spaces between the piles were filled with well-tempered clay, so that they were as nearly water-tight as notwithstanding the tremendous weight of the of the sea outside at the top of each tide.  Though the dams somewhat changed form by this pressure and inclined inwards, the piles were prevented from being forced in that direction by powerful counteracting braces, and the whole stood fast until the completion of the work, contrary to the expectations of many, who regarded it as an altogether impracticable thing to construct coffer-dams of such magnitude in so exposed a situation, where the pressure to be resisted was so enormous.

    The only accident which occurred to the cofferdams was in 1820, when the old 'Bellerophon' line of battle ship, which had been anchored outside to break the swell, was forced from her moorings by a fierce storm from the north-east, and driven against the piling, a large extent of which gave way, and the waters rushed in upon the works.  Fortunately, the building of the wall was by this time considerably advanced, so that no great damage was done.  On the fall of the tide the dams were repaired without difficulty, and the works proceeded to completion.

    Among Mr. Rennie's other dock works may be mentioned the new river-wall, with a ship-basin and two building-slips, at Woolwich; the new dockyard, building-slips, and dry dock at Pembroke; the new entrance to Deptford Basin; and various improvements at Chatham, Portsmouth, and Plymouth.

    One of Mr. Rennie's most ingenious plans was that proposed by him for the improvement of Chatham Dockyard. He saw large sums of money expended from year to year in the ineffectual patching-up of the old yards, with little good result; and he foresaw that eventually the Government, if it would secure efficiency and avoid waste, must fall back upon some such plan as his Northfleet Docks to obtain the requisite economy by concentration of dockyard work.  In 1818 he was requested to report on the best means of improving Chatham Dockyard, when he again pointed out the great loss to the nation by maintaining so many separate yards, all of which were being tinkered and mended at an enormous cost.

    He then boldly recommended that the Government should sell Deptford Dockyard, which he held to be comparatively useless, and devote the proceeds to the improvement of Chatham, after the plan which he submitted.  It consisted in cutting a new channel from a point in the river Medway, a little below Rochester Bridge, to another point lower down the river at Upnor Castle, thus straightening its channel, increasing its current, and consequently improving its depth.  By this simple means the whole of the bend in the present river would be converted into a capacious wet dock, extending along the whole front of the dockyard, and shut in by gates at either end.  He so proposed to make another cut from its lower end to join the Medway at Gillingham, where there is ample depth of water at all times for ships of the largest burden.

    Lord Melville was much struck with the simplicity and at the same time the comprehensive character of the plan, and wished to have an estimate of the cost.  The whole amount—including land, labour, and materials—according to the engineer, would not exceed £685,000 against which there was to be set the heavy annual cost for moorings in the tide-way (which would be saved) or equal to a capital sum of £200,000; the expense of watching vessels lying at moorings, amounting to about £15,000 a year, or equal to a capital sum of £300,000; and the amount realised by the sale of the disused dockyard at Deptford, which of itself would have been almost sufficient to defray the entire cost of this magnificent new arsenal, not to mention the saving in the steam and other vessels employed in carrying stores to the men-of-war lying in ordinary along the course of the Medway, and the great despatch and economy which would have been secured in all the operations connected with the building, fitting, and repairs of ships.

    The plan, however, was too comprehensive, and was not adopted.  Building and patching are still going on at Chatham, at a cost far exceeding that required to carry out Mr. Rennie's design; but it still remains to be seen whether anything like the same amount of concentration and efficiency will be secured.

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THE harbour at Plymouth being situated at the entrance to the English Channel, nearly opposite two of the principal French coast arsenals, has always been regarded as a naval station of national importance.  The great area of the Sound, its depth of water, and its connection with the two spacious and secure inner harbours of Hamoaze and Cat Water, admirably fit it for such a purpose.  The Sound is more than three miles wide in all directions, and includes an area of about four thousand acres, with a depth of water varying from four to twenty fathoms at low water of spring tides.  Its shores are bold and picturesque, rising in some places in almost perpendicular cliffs; in others, as at Mount Edgcumbe, the land, clothed with the richest verdure, slopes gently down to the waterline.

    The only natural defect of the haven—and it was felt to be a serious one—was that the Sound lay open to the south, and was consequently exposed to the fury of the gales blowing from that quarter during the equinoxes.  The advantages presented by its excellent anchorage and great depth of water were thus in a considerable degree neutralised, and the cases were not unfrequent of large vessels being forced from their moorings during storms, and driven on shore.

    From an early period, therefore, the better protection of the outer harbour of Plymouth was deemed to be a matter of much importance, and various plans were proposed with that object.  One of these was, to carry out a pier from near Penlee Point, at the south-western entrance to the Sound, for a distance of above 3,000 feet, into deep water; another was, to construct a pier several thousand feet long, from Staddon Point to the Panther rock; and a third contemplated a still more extensive pier, of above 8,000 feet in length, extending westward into deep water, from the south-eastern entrance to the Sound.  While the question was under discussion, the Lords of the Admiralty called upon Mr. Rennie to report upon these several plans, and to advise them what, in his opinion, was the best course to be pursued.  In his preliminary inquiry, which was of the most thorough kind, he was assisted by Mr. Joseph Whidbey and Mr. James Hemmans.

    Mr. Whidbey had been a sailing master in the Royal Navy, and was a most able and meritorious officer.  He had sailed round the world with Vancouver, and raised himself from the station of a man before the mast to the highest position a non-commissioned officer could reach.  His varied experience had produced rich fruits in a mind naturally robust and vigorous.  As might be expected, he was an excellent seaman.  He was also a person of considerable acquaintance with practical science, and had acquired from experience a large knowledge of human nature, of a kind that is not to be derived from books.  He was afterwards raised to the office of Master-Attendant at Woolwich Dockyard, and was greatly beloved and respected by all who knew him.  Mr. Hemmans was Master-Attendant of Plymouth Dockyard, and possessed an intimate practical knowledge of the locality, which proved of much value in the course of the investigation.

    The result of Mr. Rennie's careful study of the object to be accomplished, and the best mode of fulfilling the requirements of the Admiralty, was embodied in the report presented by him on the 22nd of April, 1806.  He there expressed himself of opinion that, of the three plans which had been proposed, that of a pier extending westward from Andurn Point, near the Shagstone, at the south-eastern extremity of the Sound, was the best; but even that was objectionable, as calculated to produce shoaling of the harbour by favouring the deposit of silt—a process which was then going on, and which it was most desirable to prevent.  Looking at the main object of the proposed work, which was to render the Sound a safe haven for vessels riding at anchor there, as well as to increase the security of Plymouth inner harbour, he considered that another method might be adopted, with greater certainty of success, at much less cost, and without any risk of silting up the entrance of the harbour.

    It may here be explained that, in its original state, there were three channels of entrance into the Sound: one on the west side, 3,000 feet wide, between the Scottish Ground rocks and the Knapp and Panther rocks; another, on the eastern side, 1,800 feet wide, between the shore and the Tinker, St. Carlos, and Shovel rocks; and a third in mid-channel, also about 1,800 feet wide, which was rarely used, being through dangerous rocks on either side.  Any works which might be constructed across this middle channel, it appeared to Mr. Rennie, would be of no detriment to the navigation of the Sound.  On the other hand, by narrowing the passage through which the tidal waters flowed in and out, the tendency would be to increase the scour, and consequently to deepen the two remaining channels—an object only second in importance to the protection of the harbour itself.

    His plan accordingly was, to form a Breakwater across the middle channel by throwing into the sea large angular blocks of rubble, of from two to twelve tons each, leaving them to find their own base, and to continue this process until a sufficient mass had been raised to the level of half-tide, so as to make a ridge, about 70 yards broad at the base and 10 yards at the top, these dimensions to be afterwards varied and increased according to circumstances. He proposed that the Breakwater should be of a total length of 5,100 feet; of which 3,000 feet, forming the central part, was to be in a straight line across the Sound, and 1,050 feet at either end inclined inwards at an angle of 160 degrees.  It was also proposed to run out a pier of 2,400 feet, in two arms, from Andurn Point, at the south-eastern entrance to the Sound, but this part of the design was not carried into effect.  The total estimate of cost, including the Point Andurn pier, was £1,102,440.

    The formation of breakwaters by a similar process had been practised from an early period; and by such means the moles of Venice, Genoa, Rochelle, Cherbourg, and other ports, had been formed.  Mr. Rennie had himself adopted the same method in forming the harbours of Howth, Kingstown, and Holyhead; and the success which had followed his operations at those places left no doubt in his mind as to the practicability of constructing an efficient breakwater across Plymouth Sound, though the situation was admitted to be much more difficult.  Mr. Rennie considered that a ridge of rough, heavy stones would be the simplest and least costly, as it would probably be found the most efficient plan of protection that could be devised.  By throwing in the blocks in the given line, and allowing the waves by their own action to form the slope or angle of repose at which the materials would lie, the expenditure of an infinity of labour and money would be avoided.  In this kind of work he held that success was to be secured by following the laws of nature; and, with reference to the proper slope, his own expression was that "the waves were the best workmen."

    The report in which Mr. Rennie embodied these recommendations excited great interest amongst naval men, and led to much discussion.  Many pronounced the scheme to be visionary and impracticable.  It was also alleged that, even if it could be executed, such a work would prove altogether useless.  Others held that it would destroy the Sound for purposes of navigation, and lead to its complete silting up; whilst a greater number criticised and condemned it in all its details.  Amongst other critics, one of the most severe was the late General Sir Samuel Bentham, a brother of Jeremy the philosopher, who strongly recommended a plan of his own, consisting of one hundred and forty wooden towers, with stones sunk between them in a double line.  Five years' controversy thus passed, and numerous designs were prepared, submitted, and considered, all of which were referred to Mr. Rennie, who still remained as firmly satisfied as ever of the expediency of his design, and vindicated its superiority over all others which had been proposed.  At length the Lords of the Admiralty were won over to his views, as well as Earl St. Vincent, Lord Keith, and many other leading naval officers.  Lord Melville was then at the head of the Admiralty, and when he had become fully persuaded as to the merits of Mr. Rennie's plan, and ascertained that there was a growing unanimity of opinion in its favour, he exerted himself strenuously to have it carried into effect.

    The result was, that an Order of Council was issued on the 22nd June, 1811, by which the requisite powers were given to proceed with the works.  Mr. Rennie was appointed engineer in chief, and Mr. Whidbey resident engineer, with Mr. William Stewart as assistant.  It was very difficult to find contractors willing to undertake the execution of a work of so novel and extensive a character, except at prices which the engineer could not sanction; and it was therefore determined only to contract for the labour of the several operations in detail, so that there might be an opportunity for revising the scale of prices from time to time, [p.417]—the Government undertaking to find the requisite plant and materials.

    A piece of ground was purchased from the Duke Of Bedford at Oreston, up the Cat Water, containing twenty-five acres of limestone, well adapted for the purposes of the work; and steps were taken to open out the quarry, to lay down railways to the wharves, to erect cranes, to build vessels suitable for conveyance of the stone, and to provide the various appliances required for carrying out the undertaking.

    On the 12th of August, 1811, the birthday of the Prince Regent, the first stone of the main ridge was deposited on the Shovelbank rock, nearly in the centre of the work.  Lord Keith, commander of the Channel Fleet, was present, attended by the chief naval, military, and civil authorities of the port, together with the staff and men of the building establishment.

    From this time forward the operations were carried on with despatch when the weather would permit. The workmen began at the centre and worked towards the extremities.  The lines of the Breakwater were carefully marked out by buoys, to which the barges laden with the stone blocks were attached whilst they were being emptied into the sea; after which they returned to the quarry wharves, about five miles distant, for fresh cargoes.

    For nearly two years this process of emptying in the rubble proceeded; until, in March 1813, portions of the work began to be visible at low water, and by the end of July there appeared a continuous line of about 720 yards.  By the month of March in the following year the ridge had been so raised, that its effect in tranquillising the waters of the Sound during violent south-westerly gales was very considerable, and vessels of all classes sought its protection and came to anchor behind it with perfect confidence.

    The Admiral's ship on the station, the 'Queen Charlotte,' of 120 guns, had been heretofore accustomed to ride in Caws and Bay; but it was now brought to an anchor under the lee of the Breakwater.  Among other vessels which took shelter there in 1814 was a large French three-decker, which rode out a severe gale in safety.  The year after, when Napoleon entered Plymouth Sound on board the 'Bellerophon,' he expressed himself as greatly surprised with the magnitude of the work, and spoke with admiration of the intentions with which it had been designed and executed.

    By the 11th of August, 1815, not less than 615,057 tons of stone had been deposited, and a length of 1,100 yards was raised above low water of spring tides.  The complete success of the work was now beyond dispute, and exceeded the most sanguine anticipations.  Even the most sceptical became convinced of its great practical utility, and many who had before offered vehement opposition to its being begun, became clamorous for its completion on even a larger scale than Mr. Rennie had originally intended.

    It was at length determined by the Admiralty, after advising with the engineer, to carry the whole Breakwater twenty feet, instead of ten feet, above the level of low water of spring tides.  While the original plan of Mr. Rennie was calculated to afford complete security to the larger class of vessels, this addition to the height doubtless gave more adequate protection to the smaller craft.  The finishing of the work above the low-water line, however, involved a more expensive kind of workmanship; for the greatest force of the waves is exercised between the lines of high and low water.

    Hence it became necessary to render this upper part of the Breakwater so strong as to present the greatest possible amount of resistance.  Mr. Rennie suggested the propriety of increasing the seaward slope to about 5 to 1, so as to give greater strength, and present an increased resistance to the force of the waves.  But this recommendation was overruled for the time, and the work proceeded.

    The operations were continued without intermission, the stone blocks being deposited at the rate of 1,030 tons a-day during the year 1816—a greater average than has since been accomplished in carrying out any similar work, notwithstanding the improved modern appliances of stages provided with steam power, and railways worked by powerful locomotives. [p.420]  Towards the end of the year, about 300 yards, of the west end of the Breakwater had been raised to the full height of two feet above high water, and 20 feet above low water of spring tides.

    Success, as usual, produced over-confidence; and the authorities on the spot, believing that if the sea slope of the rubble were roughly put together at an inclination of 3 to 1, it would present sufficient resistance, as well reduce the expense, directed it to be so executed.  But about this time a succession of severe gales set in from the south-west and sent a tremendous sea upon the Breakwater,—especially one of great violence, which occurred on the 17th of January, 1817.

    On examining the work, after the return moderate weather, it was ascertained that a length of about 200 yards of the rubble of the upper part had been displaced or deranged—that several blocks of stone, varying from two to five tons, had by the force of the waves been thrown over from the south or sea slope to the north or land slope—and that their further effect had been to increase the inclination of the former to 5⅓ to 1, instead of 3 to 1, as it had originally stood.

    Nevertheless, the great mass of the Breakwater remained unmoved, and large numbers of vessels, availing themselves of the secure protection which it provided, had been enabled to ride out the storm in safety.  Unfortunately, however, the 'Jasper' sloop of war and the 'Telegraph' schooner, anchored without the line of protection, were driven on shore and wrecked under the citadel, when a melancholy loss of life took place.

    Mr. Rennie was of opinion that this storm had proved of great service by forcing the stones together and consolidating the work more firmly.  His recommendation as to the necessity of increasing the seaward slope having been so singularly confirmed by the action of the waves, he now advised that it should be allowed to remain as left by the storm of the 17th, and that the rest of that face of the Breakwater should be made uniform with it.  It would, however, appear that Mr. Whidbey, the resident engineer, contrived to finish most of the exterior face at a slope of only 3 to 1, as before; and thus it stood without any material interruption until several years after Mr. Rennie's death.  By that time nearly the whole of the intended rubble, amounting to 2,381,321 tons, had been deposited, and the main arm, with 200 yards of the west arm, making 1,241 yards in length, had been raised to the required level.

    The work had arrived at that stage when it had to experience the full force of another terrific storm, which took place on the 23rd of November, 1824.  It blew at first from the south-south-east, and then veered round to the south-west; and the effect of this concurrence of winds was to heap together the waters of the Channel between Bolt Head and Lizard Point, and drive them with terrible force into the narrow inlet of Plymouth Sound.  This storm was not only greatly more violent, but of much longer duration, than that of 1817.  When the Breakwater could be examined, it was found that, out of the 1,241 yards of the upper part which had been completed with a slope of 3 to 1, 796 yards had been altered as in the previous storm, and the immense blocks of stone which formed the sea-face of the work had by the force of the waves been rolled over to the landward side, thus reducing the sea-slope, as before, to about 5 to 1.

    The accuracy of Mr. Rennie's view as to the proper slope—which was indicated by the action of the sea itself—was thus a second time confirmed; and the same view having been taken by the engineers [p.423-1] who were called upon to make an inspection of the work, and to report as to the best means of rendering it permanently secure,—it was determined to make the permanent slope of the same inclination, and the works were so carried out accordingly. [p.423-2]  The total quantity of rubble deposited to the end of 1848—when the work may be said to have been completed—was 3,670,444 tons, besides 22,149 cubic yards of masonry, or an amount of material at least equal to that contained in the Great Pyramid.  The whole cost of this magnificent work was about a million and a half sterling, including a convenient and spacious watering place at Bovesand Bay.

    As forming a convenient and secure haven of refuge for merchant ships passing up and down Channel, along the great highway between England, America, and India—as well as a capacious harbour for vessels of war, wherein fifty ships of the line, besides frigates and smaller vessels, can at all times find safe anchorage—Plymouth Breakwater may in every respect be regarded as a magnificent work, worthy of a great maritime nation.

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CHAPTER XI.

MR. RENNIE'S LAST WORKS—HIS DEATH AND CHARACTER.
 

JOHN RENNIE, F.R.S., Civil Engineer.
(1761-1821)
Picture Wikipedia.

ON undertakings such as these, of great magnitude and importance, Mr. Rennie was engaged until the close of his useful and laborious life.  There was scarcely a project of any large public work on which he was not consulted; sometimes furnishing the plans, and at other times revising the designs which were submitted to him.  Numerous works of minor importance also occupied much of his attention, as is shown by the extent of his correspondence and the number of his reports, which contain an almost complete repository of engineering practice.

    While he was engaged in designing and superintending the construction of his great London Bridges, the formation of Plymouth Breakwater, the building of the docks at Sheerness, the cutting of the Crinan Canal, and the drainage of the Fens by the completion of the Eau Brink Cut, he was at the same time consulted as to many important schemes for the supply of large towns with water.  His report on the distribution of the water supplied by the York Buildings Company in the Strand—in which he proposed for the first time to appropriate a distinct service to the several quarters of the district supplied—was a masterpiece in its way; and the principles he then laid down have been generally followed by subsequent engineers.  He also reported on the improved water-supply of Manchester, Edinburgh, Bristol, Leeds, Doncaster, Greenwich and Deptford, and many other large towns in England and Scotland, as well as in the colonies and in foreign countries. [p.427]

    In addition to the various mills and manufactories fitted up by him with new and improved machinery, we may mention that he advised the Bank of England on the subject of the more rapid manufacture of bank-notes by the employment of the steam-engine; and that he entirely re-arranged the Government machinery at Waltham for the manufacture of gunpowder.  He erected the anchor-forge at Woolwich Dockyard, considered to be the most splendid piece of machinery in its day; he supplied Baron Fagel (then Dutch minister in this country) with designs of dredging-engines for clearing the mud out of the rivers and canals of Holland; and constructed the principal part of the celebrated machinery for making ropes, according to Captain Huddart's patent.

    Captain Joseph Huddart, F.R.S., was a man of sound judgment, great nautical experience, and excellent skill as a mechanic and engineer.  He was often consulted by Mr. Rennie in reference to marine works of more than ordinary importance.  His origin was humble, like that of so many of our early engineers; and, like them also, he was attracted to the pursuit by the force of his genius, rather than by the peculiar direction of his education.  He was born at Allonby, in Cumberland, in 1740,—the son of a small farmer and shoemaker.  From his mother he inherited a strong spirit and a vigorous constitution, combined with sound moral principles, which he nobly illustrated in his life.

    Huddart received an ordinary share of education at the common school of his village, to which he added a knowledge of mathematics and astronomy, obtained from the son of his teacher, who had studied those branches of science at Glasgow University.  He seems to have been an indefatigable learner, for he also acquired some knowledge of music from an itinerant music-teacher, whose execution he very shortly excelled.  His mechanical tastes early displayed themselves.  Watching some millwrights employed in constructing a flour-mill, he copied the machinery in a model which he finished just as they had completed their mill.  He also made a model of a 74-gun ship, after the drawings given in Mungo Murray's 'Treatise on Navigation and Shipbuilding.'

    At an early age, Huddart was employed in herding his father's cows on a hill-side overlooking the Solway Frith, and commanding a view of the coast of Scotland.  There he took his books, with a desk of his own making, and, while not forgetting the cattle, he occupied himself in reading, drawing, and mathematical studies.  When a little older, his father set him on the cobbler's stool, and taught him shoemaking,—though the boy's strong inclination was to be a sailor.  Large shoals of herrings having made their appearance about this time in the Solway Frith, a small fishing company was started by the Allonby people, in which his father had a share, and young Huddart was sent out with the boats, very much to his delight.  He now began to study navigation, carrying on shoemaking in the winter, and herring-fishing at the time when the shoals were on the coast.  On the death of his father, he succeeded to his share in the fishery, and took the command of a sloop employed in carrying the herrings to Ireland for sale.  During his voyages he applied himself to chart-making, and his chart of St. George's Channel, which he afterwards published, is still one of the best.

    The herrings having left the frith, Huddart got the command of a brig, his excellent character securing him the post; and he made a successful voyage to North America and back.  His progress was steady and certain.  A few years later we find him in command of an East Indiaman.  After many successful voyages, in which he happily brought all his ships to port, and never met with any serious disaster, he retired from the service; having been in command of ships of greater or less burden for a period of twenty-five years.  He now published many of his charts, the results of the observations he had made during his numerous voyages.

    His eminent character, not less than his known scientific knowledge, secured his introduction to the Trinity House as an Elder Brother, and to the direction of the London and East India Docks, in which situations he was eminently useful.  The lighting of the coast proceeded chiefly under his direction, and many new lighthouses were erected, and floating-lights placed at various points at his recommendation.  Among others, he superintended the construction of the lighthouse at Hurst Point.  He also surveyed the harbours of Whitehaven, Boston, Hull, Swansea, St. Agnes, Leith, Holyhead, Woolwich Dockyard, and Sheerness; several of these in conjunction with his friend Mr. Rennie, who was always glad to have the benefit of his excellent judgment.  He made many improvements in ship-building; but the invention for which the nation is principally indebted to him is his celebrated rope-making machinery, by which every part of a cable is made to bear an equal strain, greatly to the improvement of its strength and wearing qualities.  This machinery, constructed for him by Mr. Rennie at Limehouse, was among the most perfect things of the kind ever put together. [p.430]

    In his capacity of advising engineer to the Admiralty, Mr. Rennie embraced every opportunity which his position afforded him of recommending the employment of steam power in the Royal Navy.  His advice met with the usual reception from the inert official mind: first indifference next passive resistance; then active opposition when he pressed the matter further.  Naval officers, who had grown old in sailing tactics, could ill brook the idea of navigating ships of war by means of a mechanical invention.  Skill in seamanship, of which the old salts were so proud, would be entirely superseded.  The navy had done well enough heretofore without steam; why introduce it now?  It was a smoky innovation, and if permitted, would only render ships liable to the risk of being blown up by boiler explosions.

    Lord Melville, however, listened to Mr Rennie's suggestions, and at length consented to the employment of a small steam-vessel as a tug for a ship of war, by way of experiment.  Mr. Rennie then hired the Margate steamboat, the 'Eclipse,' to tow the 'Hastings,' 74, from Woolwich to two miles below Gravesend, against a rising tide.  The experiment was made on the 4th of June, 1819, and proved so successful that the Admiralty were induced to authorise a steamboat to be specially built at Woolwich for similar service.  This vessel was named the 'Comet;' it was built after the designs and under the direction of the late Mr. Oliver Lang, assisted to a considerable extent by Mr. Rennie, who attended more particularly to the designing and fitting of the engines, which were made by Boulton and Watt.  The 'Comet,' though a small vessel, was the parent of other royal ships of vastly greater dimensions.  She was only 120 feet long between the perpendiculars, and 22 feet 6 inches in extreme breadth; the draught of water was about 6½ feet, and the power of her engines about 40 horses.

    The Admiralty had great doubts as to the width of the paddle-boxes; but Mr. Rennie encouraged them to make the experiment after his design.  "Steam-vessels," he observed, "are as yet only in their infancy, and can scarcely be expected to have arrived at anything approaching perfection.  Much, however, will be learnt by experience; but unless some risk is run in the early application of the new power, no improvements are likely to be made." [p.432-1]  The 'Comet' proved a most efficient vessel—the best that had up to that time been constructed.  She fully answered the purpose for which she was intended; and the result was so satisfactory, that vessels of increased size and power were from time to time built, until the prejudice amongst naval men against the employment of steam power having been got over, it was at length generally introduced in the Royal Navy. [p.432-2]

    The last of Mr. Rennie's great designs was that of New London Bridge, which, however, he did not live to complete.  The old bridge had been gradually falling into decay, and was felt to be an increasing obstacle to the navigation of the river.  The starlings which protected the piers had of late years been seriously battered by the passing of hogs, barges, and lighters, on which they had inflicted equal injury in return; for vessels were constantly foundering on them, and many were sunk and their cargoes damaged or destroyed.

    Emptying stones into the river, to protect the decayed pile-work, had only had the effect of further obstructing the navigation, the scour of the current having formed two great banks of stone across the bed of the river: one about 100 feet below the bridge, and the other about the same distance above it, with two deep hollows between them and the piers, from 25 to 33 feet deep at low water.

    The piers and arches were also becoming decrepit.  Though the top-hamper of houses had long been removed, and the piers patched and strengthened at various times, the bridge was every year becoming less and less adapted for accommodating the increasing traffic to and from the City.  At last it was regarded as a standing nuisance, and generally condemned as a disgrace to the capital.  To maintain the structure, inefficient and unsafe though it was, cost the City not less, on an average, than £3,500 a year, and this expense was likely to increase very fast.

    The Corporation felt that they could no longer avoid dealing decisively with the subject.  They then resolved to take the opinion of the best engineers and architects; and Mr. Daw, the architect of the Corporation, Mr. Chapman, the engineer, and Messrs. Alexander and Montague, two eminent City architects, were consulted as to the best steps to be taken under the circumstances.  The result of their deliberations was a recommendation to the Corporation to remove eight of the arches and to substitute four larger ones, as well as to make extensive repairs in the remaining arches, piers, and superstructure.

    This plan was referred to Mr. Rennie, Mr. Chapman, and Messrs. Montague, for further consideration.  In accordance with Mr. Rennie's custom before making any report, he proceeded at once to master the whole of the facts.  He could not otherwise give an opinion that could be relied on.  He had the tides and currents watched and noted; he had the river carefully sounded, above and below bridge, from Teddington Lock to the Hermitage entrance of the London Docks.  He examined the piers down to their foundations, and explored the bottom of the river, making borings at various points between the one shore and the other.

    In the report which he made to the Corporation on the 12th of March, 1821, a great deal of new and accurate information was first brought to light respecting the flow of the tide through the arches, and the additional depth of water likely to be secured by their removal.  Although it was pronounced quite practicable to carry out the alterations which had been recommended, by erecting four new arches in lieu of the eight old ones, he was of opinion that the cost would be very considerable; and, after all, the old foundations would still present great defects, which could never be wholly cured.  Mr. Rennie therefore suggested the propriety of building an entirely new bridge of five arches, with a lineal waterway of not less than 690 feet, in lieu of the then waterway of 231 feet below the top level of the starlings, and 524 feet above them.

    Besides the greatly increased accommodation, which would be provided by a new bridge, for the large traffic passing between London and Southwark, Mr. Rennie held that not the least advantage which it promised was the much greater facility which it would afford for the navigation of the river to and from the wharves above bridge; for coasters and even colliers, by striking their masts, might then be enabled to navigate the whole extent of the City westwards.  The increased waterway would also enable the waters descending from the interior to flow more readily away, floods often inflicting great damage along the upper shore, especially in the winter months, when the arches of the old bridge had become choked up with ice.

    The report was felt to be almost conclusive on the subject; and the more it was discussed the deeper grew the conviction in the minds of all concerned, that its recommendations ought to be adopted.  The Corporation accordingly applied to Parliament, in the year 1821, for an Act enabling them to purchase the waterworks under the arches of the old bridge, and to erect an entirely new structure.  The bill, of course, had its opponents; some arguing that there was no necessity for a new bridge, and that its erection would be only a useless waste of money, whilst the old one could be repaired and made fit for traffic at so much less outlay.

    The case in favour of the new bridge was, however, too strong to be resisted, and Mr. Rennie's evidence was considered so clear and conclusive that committees of both Houses unanimously approved the bill, and it duly received the sanction of Parliament.  Power was conferred by the Act, enabling the Treasury to advance from the Consolidated Fund such sums as might be necessary to supply any deficiency in the funds at the disposal of the Corporation applicable to the erection of the bridge; the Government regarding the work as one of national importance, and consequently entitled to national assistance.

    During the progress of the bill through Parliament, Mr. Rennie prepared the general outlines of a design for the new structure.  It consisted of five semi-elliptical arches, the centre one 150 feet span, the two side arches 140 feet, and the two land arches 130 feet, making a total lineal waterway of 690 feet; the height of the soffit or under-side of the centre arch being 29 feet 6 inches above the level of Trinity high-water mark.  The general principle of this design was approved and embodied in the bill.  Very shortly after the Act had passed, Mr. Rennie was seized by the illness which carried him off, and it was accordingly left to others to execute the great work which he had thus planned.

    The Corporation of London then appealed to the whole engineering and architectural world for competitive designs, and at least thirty were prepared in answer to their call.  These were submitted to a Committee of the House of Commons in the year 1823, and after long consideration the plan originally proposed by Mr. Rennie was finally adopted; on which the Corporation of London selected his son, the present Sir John Rennie, as engineer in chief, to carry it into effect; and the nomination having been approved by the Lords of the Treasury, in conformity with the provision of the Act, steps were forthwith taken to proceed with the work.

    It is scarcely necessary to say how admirably Mr. Rennie's noble design has been executed.  New London Bridge, in severe simplicity and unadorned elegance of design—in massive solidity, strength, and perfection of workmanship in all its parts—not less than as regards the capacious size of its arches and the breadth and width of its roadway and approaches—is perhaps the finest work of its kind in the world. [p.438]

    It will be observed from the preceding chapters, that Mr. Rennie's life was one of constant employment, and that, apart from his great engineering works, his career contains but few elements of biographic interest.  Indeed, his works constitute his biography, occupying, as they did, almost his entire life, and nearly the whole of his time.  His personal wants were few; his habits regular; and his pleasures of the most moderate sort,—consisting chiefly in reading and in the enjoyment of domestic life.  At the age of twenty-nine he married Miss Mackintosh, an Inverness lady.  She made his home happy; and he became the father of nine children, six of whom survived him.  In the early part of his career in London he lived in the Great Surrey Road, from which he afterwards removed to Stamford Street, not far from his works.

    His close and often unremitting application early began to tell upon his health.  In 1812, when arrived at the age of fifty-one, he was occasionally laid up by illness.  While occupied one day in inspecting the works of Waterloo Bridge, he accidentally set his foot upon a loose plank, which tilted up, and he fell into the water, but happily escaped with only a damaged knee.  Though unable for some time to stir abroad, he seized the opportunity of proceeding with the preparation of numerous reports, and of working up a long lee-way of correspondence.

    In the following year he was frequently confined to the house by a supposed liver-complaint; but his correspondence never flagged.  He tried the effects of change of air at Cheltenham; but he had no time for repose, and after the lapse of only a week he was again in harness, giving evidence before a Committee of the House of Commons on Lough Erne drainage.  He made another hurried visit to Cheltenham, but evidently took no rest; his absence from active business only affording him an opportunity for writing numerous letters to influential persons at the Admiralty on the subject of his grand scheme of the Northfleet Docks.  To one of his correspondents we find him saying he was "better, though only half a man yet."  In course of time, however, he partially recovered, and was forthwith immersed in business—engaged upon his docks, bridges, and breakwaters.

    He very rarely "took play."  In 1815 his venerable friend, James Watt, of Birmingham, urged him to pay a visit with him to Paris, shortly after the battle of Waterloo.  But Mr. Rennie was too full of work at the time to accept the invitation, and the visit was postponed until the following year, when he was accompanied by James Watt, jun., then of Aston Hall, near Birmingham.  This journey was the first relaxation he had taken for a period of thirty years; yet it was not a mere holiday trip, but partly one of business, for it was his object to inspect with his own eyes the great dock and harbour works executed by Napoleon during the Continental war, of which he had heard so much; and to gather from his inspection such experience as might be of use to him in the improvement of the English dockyards on which he was then engaged.

    The two set out in September 1816, passing by Dover to Calais and thence to Dunkirk, where Mr. Rennie carefully examined the jetties, arsenal, docks, and building-slips at that port.  From thence they proceeded to Ostend, and afterwards to Antwerp, where our engineer admired the great skill and judgment with which the dock works there, still incomplete, had been laid out.  From Antwerp they went to Paris, where they stayed only two days, and then to L'Orient and Brest, accompanied by Mr. Joliffe, the contractor.  At both these ports, Mr. Rennie took careful notes of the depths, dimensions, and arrangements of the harbours in detail, receiving every attention from the authorities.

    At Cherbourg, in like manner, he examined the building-yards and docks, as well as the progress made with the famous Digue [p.441]—a rival to his own Breakwater at Plymouth.  At Cherbourg he was joined by Mr. Whidbey, who had come over in a vessel of war to meet him.  Mr. Rennie returned to England after less than a month's tour; and though he had made a labour of his pleasure-trip, the change of air and scene did him good, and he entered with zest upon the business of clearing off the formidable arrears of work which had accumulated during his absence.  We may add, as an illustration of his habit of turning everything, even his pleasure, to account, that one of the first things he did on his return home was to make an elaborate report to Lord Melville, then First Lord of the Admiralty, of the results of his investigations of the foreign harbours which he had visited in the course of his journey.

    After a few years' more devoted application, his health again began to give way.  When consulted by Mr. Foljambe of Wakefield, in June 1820, respecting a railway proposed to be laid down in that neighbourhood, he excused himself from entering upon the business because he was so full of work, and his health was so delicate.  Shortly after we find him writing to a friend that the new works executed by him during the past year had cost about half a million, besides those in progress at Sheerness, which would cost a million.  He was then busy with his investigations relative to New London Bridge, the report on which he prepared while laid up with an attack of gout.  He persisted in going abroad as long as he could, and went to his doctor in a carriage for advice, instead of letting the doctor come to him.  But his resistance, however brave, was useless against disease, and at length he was compelled to succumb.

    To the last, he went on issuing instructions to his inspectors in different parts of the country relative to the works then in progress—the docks at Chatham and Sheerness, the harbours at Howth and Kingstown, the bridge at New Galloway, the Eau Brink Cut, the Aire and Calder Navigation, and the pumping-engines for Bottesham and Swaffham, in the Fens.  He was especially anxious about the Eau Brink Cut, nearly ready for opening, urging his assistants to report to him from time to time, giving full particulars of the progress made.  In the midst of all this, he writes a letter to a harbour-master at Bridlington, giving him detailed instructions as to the arrangement of tide tables!  His last business letter was written to the Navy Board respecting the proper kind of gates to be used for the dry dock at Pembroke: it was dated the 28th September, 1821.  A little before this he had written to his friend Mr. Jerdan, the Edinburgh engineer, that he had completed all business connected with his preparation for the next session of Parliament, when he had many bills to carry through.

    But how often are the intentions of the bravest defeated!  Day by day he grew weaker, struggling with the whole force of his will against the disease that was slowly mastering him.  Although extremely ill, he insisted on rising from his bed, and tottered about, even taking an occasional airing in a carriage.  In this state he continued until the 4th of October.  On that day he did not get up.  His mind had until then been as clear and vigorous as ever; but now it began to wander.  There was no resisting the hand of death, which was already upon him.  He took no further heed of what passed around him, and about five in the evening, he was seized by a fit of paralysis, from which he never rallied.  About an hour later he expired, in the sixty-first year of his age.

    The portrait prefixed to this memoir expresses, so far as an accurate delineation of his features can do, the actual character of the man.  It is grave and thoughtful, yet has an expression of mildness perfectly in unison with his gentle yet cheerful disposition.  Raeburn painted his portrait, and Chantrey chiselled his bust; but the chalk drawing by Archibald Skirving, [p.444] after which our engraving is made, is on the whole the most lifelike representation of the man as he lived.  In person he was large, tall, and commanding; and strength was one of the attributes belonging to his family.

    But physical endurance has its limits, and we fear that Mr. Rennie taxed his powers beyond what they would fairly bear.  He may be said to have died in harness, in the height of his fame, after threescore years, forty of which had been spent in hard work; still his death was premature, and in the case of a man of such useful gifts, it was much to be lamented.  He himself held that life was made for work; and he could never bear to be idle.  Work was with him not only a pleasure, it was almost a passion.  He sometimes made business appointments at as early an hour as five in the morning, and would continue incessantly occupied until late at night.  It is clear that the most vigorous constitution could not long have borne up under such a tear and wear of vital energy as this.

    He was very orderly, punctual, and systematic, and was hence enabled to get through such an enormous amount of business.  No matter how numerous were the claims upon his time, nothing was neglected nor hurried.  His reports were models of what such documents should be.  They set forth all the facts bearing upon the topic under consideration, in great detail; but with much plainness, force, and clearness.  His harbour reports were especially masterly; in them he elaborately stated all the known facts as to the prevailing winds, currents, and tides, usually drawing very logical and conclusive inferences as to the particular plan which, under the circumstances, he considered it the most desirable to adopt.  In his estimates he was careful to conceal nothing, stating the full sum which in his judgment the work under consideration would cost; nor would he understate the amount by one farthing in order to tempt projectors to begin any undertaking on which he was consulted.

    He took the highest ground in his dealings with contractors.  He held that the engineer was precluded by his position from mixing himself up with their business, and that if he dabbled in shares or contracts, either openly or underhand, half his moral influence was gone, and his character liable to be seriously compromised.  Writing to Playfair at Edinburgh, in 1816, he said—"Engineers should be entirely independent of these connections—not dabblers in shares—and free alike of contractors and contracts."  By holding scrupulously to this course, Mr. Rennie established a reputation for truthfulness, honesty, and uprightness, not less honourable and exalted than his genius as an architect and an engineer was illustrious.

    He was a man of powerful and equally balanced mind—not so clever, as profound; not brilliant, but calm, serene, and solid, like one of his own structures.  While he lay on his deathbed, his last letters to his assistants urged upon them attention, punctuality, and despatch—qualities which he himself had illustrated so well in his own life.  In his self-education he had overlooked no branch of science cultivated in his day; and in those which bore more especially upon his own calling, his knowledge was well-arranged, complete, and accurate.

    Withal he was an exceedingly modest, unpretending, and retiring man.  His great aim was to do the thing he was appointed to do in the best possible manner.  He thought little of fame, but a great deal of character and duty.  If his time was so entirely pre-occupied that he could not personally devote the requisite attention to any new undertaking brought before him, he would decline to enter upon it, and recommended the employment of some other leading engineer.  He considered it his duty himself to go into the minutest details of every business on which he was consulted.  He left as little as possible to subordinates, making his calculations and estimates himself; and he wrote and even copied his own reports, perhaps improving them in the copying; deeming no point, however apparently unimportant, beneath his careful attention and study.

    Hence great reliance was placed upon his judgment by those who consulted him; and the accurate though comparatively reserved manner in which he expressed himself before Committees of Parliament, gave all the greater weight to his evidence.  "What I liked about Rennie," says one who knew him well, "was his severe truthfulness."  When under examination on such occasions, he could always give a strong clear reason, in support of any scheme he recommended, based upon his own careful preliminary study of the whole subject.  But when asked any question outside the line of his actual knowledge, he had the honesty to say at once, "I do not know."  He would not guess nor attempt to give ingenious answers to show his cleverness, nor act the special pleader in the witness-box, but confine himself solely to what he positively knew.

    In the course of his professional career, Mr. Rennie experienced the great advantage which he had derived from his early training as a millwright.  His practical knowledge enabled him to select the best men to carry out his designs, and he took pride and pleasure in directing them how to do their work in the most efficient manner.  His manufactory was indeed a school, in which some of the best mechanics of the day received a thorough training in machine work; and many of his workmen, like himself, eventually raised themselves to the rank of large employers of skilled labour.  Mr. Rennie was never ashamed to put his hand to any work where he could teach a lesson or facilitate despatch, and to the end of his career he continued as "handy" as he had been at the beginning.

    A curious illustration of his expertness at smith-work occurred during a journey into Scotland, when on his way to visit the Earl of Eglinton at Eglinton Castle.  He went by the stage-coach, in company with some Ayrshire farmers and one or two rather important "Paisley boddies."

    When travelling over a very bad piece of the road, the jolting was such as to break the axletree of the coach, and it came to a stand on a solitary moor, with not a house in sight.  Mr. Rennie asked the coachman if there was any blacksmith near at hand, and he was told there was one a mile or two off.  "Well, then, help me to carry the parts of the axle there, and I'll see to its being mended."  The blacksmith, however, was not at home; but Mr. Rennie forthwith lit the forge fire, blew the bellows, and with the rather clumsy assistance of one of his fellow-passengers, he very soon welded the axle in a workmanlike manner, helped to carry it back to the coach, and after the lapse of a few hours the vehicle was again wheeling along the road towards its journey's end.

    Mr. Rennie's fellow-passengers, who had been communicative and friendly during the earlier part of the journey, now became very reserved, and the "boddies" especially held themselves aloof from "the blacksmith," who had so clearly revealed his calling by the manner in which he had mended the broken axle.  Arrived at their journey's end for the day, the travellers separated; Mr. Rennie proceeding onwards to Eglinton Castle.  Next morning, when sitting at breakfast with his noble host, a servant entered to say that a person outside desired to have a word with the Earl.  "Show him in."  The person entered.  He proved to be one of Mr. Rennie's fellow-travellers; and great indeed was his surprise and confusion at finding the identical blacksmith of the preceding day, breakfasting with "my Lord"!  The Earl was much amused when Mr. Rennie afterwards described to him the incident of the mending of the broken axle.

    One of his few hobbies was for old books; and if he could secure a few minutes' leisure at any time, he would wander amongst the old book-stalls in search of rare volumes.  Froissart's and Monstrelet's 'Chronicles' were amongst his favourites, and we find him on one occasion sending a present of duplicate copies to his friend Whidbey, accompanied with the wish that he might derive as much pleasure from their perusal as he himself always did from reading "honest John Froissart."  He also commissioned his friends, when travelling abroad, to pick up old books for him; and in 1820 we find him indulging his "extravagance," as he termed it, so far as to request Sir William Jolliffe to bring £300 worth of old books for him from Paris.

    Although Mr. Rennie realised a competency by the practice of his profession, he did not accumulate a large fortune.  The engineer was then satisfied with a comparatively moderate rate of pay, very different from the slashing charges of modern railway engineers.

    We do not wonder that Mr. Rennie complained of the small remuneration of £350 awarded to him by the Kennet and Avon Canal Company for constructing their canal works; and we are surprised to find his bill against the Manchester Waterworks Company for his year and-a-half's advice and service, amounting to only £159 7s., his charge to them for a whole day's labour being only six guineas.

    Mr. Rennie's charge of seven guineas for an entire day's work, was afterwards objected to by General Brownrigg, the head of the Ordnance Department.  "Why, this will never do," said the General, looking over the bill; "seven guineas a-day!  Why, it is equal to the pay of a Field Marshal!"  "Well," replied Mr. Rennie, "I am a Field Marshal in my profession; and if a Field Marshal in your line had answered your purpose, I suppose you would not have sent for me!"  "Then you refuse to make any abatement?"  "Not a penny," replied the engineer; and the bill was paid.

    Mr. Rennie was blamed in his time for the costliness of his designs, and it was even alleged of him that he carried his love of durability to a fault.  But there is no doubt that the solidity of his structures proved the best economy in the long run.  Elevated by his genius and his conscientiousness above the thoughts of immediate personal gain, no consideration would induce him to recommend or countenance in any way the construction of cheap or "shoddy" work.

    He held that the engineer had not merely to consider the present but the future, in laying down and carrying out his plans.  Hence his designs of docks and harbours were usually framed so as to be capable of future extension; and his bridges were built not only for his own time, but with a view to the uses of generations to come.

    In fine, Mr. Rennie was a great and massive, yet a perfectly simple and modest man; and though his engineering achievements may in some measure have been forgotten in the eulogies bestowed upon more recent works, they have not yet been eclipsed, nor indeed equalled; and his London bridges—not to mention his Docks, Harbours, Breakwaters, and Drainage of the Fens—will long serve as the best exponents of his genius.

    The death of this eminently useful man was felt to be a national loss, and his obsequies were honoured by a public funeral.  His remains were laid near those of Sir Christopher Wren in St. Paul's Cathedral, the dome of which overlooks some of his greatest works.

East Linton - Bronze plaque of John Rennie.
On a wall on the original Great North Road out of the village heading for Dunbar, this is a memorial to the great civil engineer, who was born at Phantassie Farm in 1761.

© Copyright james denham and licensed for reuse under this Creative Commons Licence.