s any obstruction of wood, stone, or other material, as a boom or raft of wood, sunken vessels, &c., placed before the entrance of a port or harbour, or any projection from the land into the sea, as a pier, mole, or jetty, so placed as to break the force of the waves, and prevent their action on ships and vessels lying at anchor within them. Thus the piers of the ancient Piraeus and of Rhodes; the moles of Naples, Genoa, and Castellamare; the piers of Ramsgate, Margate, Folkestone, Howth, and the wooden dike de Richelieu, thrown across the port of Rochelle, may all be denominated Breakwaters. In French it is sometimes called Batte d'Eau; a name which appears to have been applied to the mole at Tangier, a work commenced in 1663, under the direction of Lord Tiviot, Sir J. Lawson, and Sir Hugh Cholmley, and finished, or rather discontinued in 1676, after having cost this nation the sum of L.243,897, 5s. 4½d. The term Breakwater, however, has of late years been considered as more peculiarly appropriate to large insulated dikes of stone, whether of regular masonry or sunk promiscuously in rough masses, so placed as to form an artificial island across the mouth of an open roadstead, and thereby, from obstructing and breaking the waves of the sea, to convert a dangerous anchorage into a safe and commodious harbour for the reception of ships of war or merchantmen.
Of this description of dike for creating an artificial harbour on a grand scale, fit for the reception of ships of war of the largest class, there are remarkable examples in the breakwater of Cherbourg, of Plymouth, Portland, &c. Breakwater of Cherbourg. In M. de Cessart's Description des Travaux Hydrauliques, will be found a very minute and laborious detail of all the preparatory operations, the progress, and the expense of constructing the breakwater of Cherbourg, up to the period of the Revolution. But the history of this great undertaking is summarily stated in a report made to the National Assembly in 1791, by M. de Curt, in the name of its Committee of Marine, concerning the marine establishment of Cherbourg.
Its history. It had always been a source of considerable annoyance to the French (and more particularly since the demolition of the works and basin of Dunkirk, which cost them more regret than the useless and expensive projects for that port ever could be worth), that while the whole line of their coast bordering on the English channel presented only sandy shores with shallow water, or an iron-bound coast bristled with rocks, nature had lavished on their "eternal rival" of the opposite coast, the incalculable advantages of a succession of deep and commodious harbours, or of safe and extensive roadsteads, inviting their possessors to commerce and navigation, and placing in their grasp "the sceptre and the sovereignty of the seas." M. Curt observes, that "the misfortunes of La Hogue, which all the talents of Tourville could not prevent, taught Louis XIV. that, in completing the defence of his frontiers by land, he had too much neglected his frontiers on the sea; that this great prince, however, profiting by experience, soon discovered that England owed the superiority of her marine to the military establishments which she possessed in the Channel." With a view of securing to France similar advantages, the Maréchal de Vauban was directed to visit the coasts of Normandy, for the purpose of adopting measures for placing in security against hostile attacks all such bays, harbours, and inlets, as were favourable for the disembarkation of troops; and to furnish plans of such works as he might judge to be necessary, not only for military, but for naval purposes. Among other projects, he reported that the roadstead of Cherbourg possessed the means of attack, of defence, and of protection; that it was very capable of exerting an influence on maritime war, and in their commercial relations with the northern powers; that it was the spot on which the head-quarters should be established on the coast of the Channel; and, in short, that it was a central advanced post with regard to England. He moreover reported, that it might be made a port for the safe retreat of a squadron crippled by stormy weather, or beaten by an enemy, or even for the reception of a victorious fleet with its prizes. By thus converting the present exposed roadstead of Cherbourg into a safe and protected anchorage for a fleet of men of war, France, he said, would be able to watch the motions of England, to oblige her at all times to keep a corresponding fleet in the Channel, and to menace her shores with invasion, of which she at all times stood so much in dread.
Opinions, however, being divided between the advantages of La Hogue and Cherbourg, Louis XVI., immediately after the conclusion of the American war, issued his directions to M. de Castries, secretary of state for the marine, to appoint a special commission to consider and report which of these two roadsteads combined the most advantages, and was in all respects preferable for constructing a port and naval arsenal capable of receiving and equipping from eighty to one hundred vessels of war of different descriptions. The commissioners had little hesitation in deciding upon Cherbourg, because, by means of a breakwater, it would be capable not only of admitting a fleet to ride securely at anchor when thus sheltered from the sea, but also of affording them protection against any attempt of an enemy. It was added, that Cherbourg was an admirable place for watching Portsmouth; without appearing to have once recollected what an excellent anchorage Spithead was for watching Cherbourg.
Directions were accordingly given to M. de Caux, commanding officer of engineers at Cherbourg, to commence, as a preparatory measure, with the construction of a fort on the island of Pelée, and another on Du Homet, according to plans given in by Vauban in 1679. By these works the roadstead would be flanked on the right and left. The interval, however, being found too great to afford sufficient protection to all the ships that might require to be anchored in the roadstead, M. de Caux presented a plan to the minister at war for constructing an intermediate fort in the sea, which should be casemated, and sufficiently large to contain all the buildings necessary for a garrison. The surrounding walls were proposed to be sunk in caissons of 6000 feet square at the base, and fifty-two feet in height. The top of the platform was to be eighty feet above the bottom of the sea, and the area of its surface 1000 square toises. This plan, however, was not considered as calculated to afford sufficient shelter to a fleet from the winds and waves, and new projects were called for by the government.
In 1777 M. de la Bretonnière, capitaine de vaisseau, one of the commissioners who had been named to report on the comparative merits of the two roadsteads of Cherbourg and La Hogue, had addressed a memorial to the minister of marine, in which he expatiated at great length on the numerous advantages held out by the former, and particularly with regard to the security of the anchorage. He proposed to construct, at the distance of a league in the sea, a stone dike of 2000 toises in length, leaving three open passages into the roadstead it was intending to cover, one in the middle, and one at each extremity. This dike, like that which was sunk before Rochelle, was proposed to have as its nucleus a number of ships filled with masonry, floated off and sunk in proper situations, and afterwards to be cased with large sunken stones to the height of fifty feet above the bottom of the sea. The reason assigned for sinking the stone vessels was the supposition, that an under current might cause so much motion at the bottom of the sea as would derange the level, and work away the loose stones; so little appears at that time to have been known of the increasing tranquility of the waves of the sea in proportion to the increasing depth of water.
On this plan the commissioners observed, 1. That in order to construct a dike of 2000 toises in length, with sloping sides proportioned to its height, there would be required so great a number of old ships as could hardly be collected in all France in less than ten years; and if purchased from foreigners, the expense would be enormous. 2. That the assembling and employing the necessary number of seamen would be next to impossible, but, if possible, highly impolitic, when, just at the close of a maritime war, commerce felt a pressing want of their services; whereas it might be practicable, and would be advantageous, to employ the military for some time before disbanding them. 3. That no comparison would hold good between the roadstead of Cherbourg, with an opening to the sea of 3600 toises, and a depth of forty to forty-two feet of water at the lowest ebb, and the closing up of the entrance of the port of Rochelle, which is only 740 toises in length, and the depth of water only five or six toises. 4. That the upper part of the projected dike, being exposed to the violent action of the sea, the stability of that part could not be depended on; and besides, a dike covered at high spring-tides with eighteen feet water would not fulfil the two indispensable conditions—smooth water, and protection against an enemy. These arguments were deemed con- clusive, and the plan of M. de la Bretonnière was abandoned.
In 1781 M. de Cessart, inspector-general of bridges and embankments, received directions to prepare a plan that should cover a fleet of from 80 to 100 ships of war in the roadstead of Cherbourg from the attack of an enemy, and protect them against the elements. M. de Cessart was fully aware, that to raise a barrier in front of this roadstead, and in the middle of the sea, capable of resisting the impetuosity of the waves, and repelling the enterprises of the enemy, was no easy task. "Nothing," says he, "that I had ever performed, or that I had ever read of in ancient or modern history, appeared to me to be worthy of being placed in comparison with the grandeur of this project." He suggested, as the preferable and only mode of answering the purpose of producing smooth water in the roadstead, that, instead of one continued dike or mole, a number of large masses, separated from each other, of a circular form, with an elevation greatly inclined, should be substituted; in short, a series of truncated cones, which, touching each other at their bases, might present to the sea at the surface alternate obstacles and openings, and thus interrupt and break down the waves previous to their entering the harbour. He also considered that, as these openings at the surface would not exceed seventy-two feet, a sufficient barrier would be formed against the passage of an enemy's vessel; and that, if necessary, in time of war it might be rendered still more secure by placing strong chains of iron across the intervals. It was proposed to construct these conical caissons of wood, the number of which, to cover a front of 2000 toises, would amount to ninety, which, at 360,000 livres for each cone, would cause a total expense of 32,400,000 for the whole. The number, however, was afterwards reduced to sixty-four, and the time estimated for completing the work thirteen years. Each cone was to be 150 feet in diameter at the base, and sixty feet in diameter at the top, and from sixty to seventy feet in height, the depth of water at spring tides in the line in which they were intended to be sunk varying from about fifty-six to seventy feet. They were proposed to be sunk without any bottoms in them, by which the upward resistance of the water, acting on a base whose surface was equal to 17,678 square feet, would be avoided. The caissons, floated off by casks attached to their inner and outer circumference, being towed to the spot where they were destined to be sunk, were then to be filled with stones to the tops, and left for a while to settle; after which the upper part, commencing with the line of low water, was to be built with masonry laid in pizzolana, and encased with stones of granite.
This plan of a stone dike or breakwater being laid in detail before the minister of marine, it was deemed proper, on a subject so entirely novel, and of such great national importance, to consult the ablest men in France before any steps should be taken for carrying it into execution. The details were accordingly submitted to the four commissioners, M. de Borda, a naval officer and member of the Academy of Sciences; M. de Fleuriel, capitaine de vaisseau, and director of ports and naval arsenals, afterwards minister of marine; M. Peronnet, member of the Academy of Sciences, chief engineer of bridges and embankments; and M. de Chezy, inspector and director of the school of engineers. They recommended that, in the first instance, an experimental cone should be constructed and floated off. Instead, however, of sixty feet in height, the cone made at Havre was only thirty-six feet; the circumference of its base 472 feet, and having a slope of sixty degrees; the upper circumference was 339 feet. Within the exterior cone, at the distance of five feet ten inches from it, was an interior and concentric cone, bound together by beams of wood pointing to the common centre, each being the section of the radius. The frame of each cone was composed of eighty large upright beams, twenty-four feet long and one foot square. On these were erected eighty more, of fourteen feet in length, making in the whole 320 of these large uprights; the machine was then planked, hooped, and firmly fixed together with iron bolts.
The cone at Havre being completed, the next operation was to tow it off to the particular spot where it was to be sunk. Being open at the bottom, it was found necessary to attach to the lower circumference 284 large casks, part to the exterior and part to the interior cone; besides fifty casks, attached by lines of equal lengths, from the bottom of the inner circle, to float towards the centre, and thus assist in keeping it upright and steady. It was easy enough, by these means, to float off a vessel of this kind. M. de Cessart observes, that the force of 7200 pounds produced by a capstan, was found sufficient to draw it on the water to a distance equal to the length of its own diameter, or about twenty-five toises, in two minutes.
"The success of the experiment made at Havre," says M. Curt, "had inspired such veneration for the conical caissons, that those persons who had been most disposed to object to the plan were now obliged to be silent." The result of the experiment at once decided the government to commence operations at Cherbourg. M. de Cessart was appointed director of the works, with four engineers to assist him. A permanent council, consisting of commanders in chief, directors, engineers, &c. was ordered to reside for six summer months at Cherbourg, and the other six in Paris; and a considerable body of troops were marched down to the neighbourhood, to furnish a competent number of artificers and labourers, to be employed on this great national undertaking.
In 1783 the buildings were commenced for lodging the principal officers of the civil and military departments, and their respective establishments; a naval yard was marked out and inclosed; roads of communication were opened with the forts; and at Becquet, about a league to the eastward of Cherbourg, a small harbour was dug out for the reception of about eighty vessels, which were to be employed in transporting the stones from thence by sea.
On the 6th June 1784 the first cone was floated off and sunk, and the second on the 7th July following, in presence of 10,000 spectators, assembled on the shores and quays of Cherbourg; but before the cavity of the latter could be filled with stones, a storm, in the month of August, which continued five days, entirely demolished the upper part of this cone. In the course of this summer the quantity of stones sunk within the cavities of the two cones, outside their bases, and in the intermediate space, amounted to 4600 cubic toises, or about 65,000 tons.
In 1785 three more cones were completed and sunk at irregular intervals; and, at the end of that year, the quantity sunk amounted to 17,767 cubic toises, or about 250,000 tons. In 1786 five additional cones were completed and sunk, one of them in presence of the king; and the quantity of stones thrown within them, and deposited on the dike connecting the cones, amounted, at the end of this year, to 42,862 cubic toises, or 600,000 tons. In 1787 five more cones were sunk and filled with stones, making, in the whole, fifteen; and the distance between the first and fifteenth cone was 1203 toises, and the quantity of stones deposited within these cones and the connecting dike, at the end of this year, amounted to 71,585 cubic toises, or more than 1,000,000 tons. The violent gales of wind that are frequent in November and December carried away all the upper parts of the five cones which were sunk this year. In 1788 three more were sunk, but the upper parts of the first two were carried away as the others had been; the height of the third was, therefore, reduced, so as to be, when sunk, on a level with low water; but this cone was upset and soon went to pieces.
The enormous expense, and the delay that had been occasioned, in completing and sinking these eighteen cones, exhausted the patience of the government, so that in the following year, 1789, it caused the three cones, then on the building slips, to be sold for whatever they would fetch.
The total quantity of stone that was sunk within the cones, and on the intermediate dike, from the year 1784 to the end of December 1790, being seven years, amounted to 373,459 cubic toises, or about 5,300,000 tons.
These eighteen cones being sunk at irregular distances from each other, some being 25 toises, and others 300 toises from centre to centre, occupied a line of 1950 toises in length. The distance of the first cone from the island Peleé, on the east, was 510, and of the eighteenth, to Fort Querqueville, on the west, 1200 toises; so that the whole entrance or opening of the roadstead of Cherbourg was originally 3650 toises, more than one-half of which was now imperfectly covered by the breakwater.
The expense of this great undertaking was not, we suspect, accurately known, and could not, probably, be ascertained. M. de Cessart estimates the eighteen cones alone at 6,231,407 livres, or about L260,000; and the total expense incurred between the 1st of April 1783 and the 1st January 1791, he states as under:
| Livres | |--------| | The value of the materials of the cones | 2,462,369 | | The value of the workmanship | 1,560,560 | | The conveyance and sinking of stones | 14,880,074 | | Incidental expenses for buildings, magazines, &c. | 2,359,489 | | Contingent expenses | 385,926 |
Making the general total | 21,658,420 |
or L900,000 sterling. In this estimate the extra pay to the troops and seamen employed would not appear to be included; for M. de Curt, in his report to the national assembly, states the total expense to have amounted to 32,000,000 livres, or L1,300,000 sterling; and that a farther sum would be required of 879,648 livres, to bring the top of the dike to an uniform height, namely, a little above the level of the surface at low water of ordinary tides.
The number of people employed was prodigious. To enable M. de Cessart to complete and sink five cones a year, he found it necessary to employ 250 carpenters, 30 blacksmiths, 200 stone-hewers, and 200 masons; in all 680 artificers. The number of quarrymen and others employed in transporting 174,720 cubic toises of stone for the 64 cones originally intended, or 13,650 yearly, was estimated at 400 workmen, 100 horses, 30 drivers, 24 chasses-marées, each carrying seven cubic toises, or about 98 tons, with 100 seamen; making an aggregate for this service of 526 men, and for the whole operation from 1200 to 1500 artificers and labourers, to which were actually superadded about 3000 soldiers.
A very considerable part of the expense might have been saved by dispensing altogether with the cones, all of which burst, as might have been expected, from the superincumbent weight of a deep column of water pressing the stones within against their sides. The ninth cone, which was sunk in 1786, went to pieces in 1800, after standing fourteen years; another reached the duration of five years; six remained on an average about four years; and all the rest went in pieces within a year from the time of their being sunk.
The failure of the cones, and the breaking out of the Revolution, put an entire stop, for some time, to all operations at Cherbourg. The attention, however, of the national assembly was speedily called to what they considered to be an object of great national importance. In 1791 they directed their committee for the marine to make out a detailed report of the operations that had already been carried on. On this report being given in by M. de Curt, in the name of the committee, it was read and approved by the assembly, and funds to a certain extent decreed, to complete the undertaking on a new plan, proposed by M. de Cessart. The principal feature of this plan was that of casing over the surface of the dike as it then stood with large blocks of stone, and of carrying the height of the breakwater along the whole of its extent, so far above the high-water mark of spring tides as to render it capable of receiving batteries on the summit, at the middle, and at the two extremities.
The slope of the side next to the roadstead was found on examination to sustain itself unaltered at an angle of forty-five degrees, but the slope on the side next to the sea, whose base was three for one of height, had given way to the depth of fourteen feet below the low-water mark; and the materials being composed of small stones, were washed away, and had formed themselves into a prolonged slope of one foot only in height for ten feet of base, which was therefore concluded to be the natural slope made by the sea when acting upon a shingly shore; a conclusion, however, too vague to be correct, as the slope occasioned by the action of the sea must depend on the nature of the materials against which it acts, and the force and direction of the acting power. A sandy beach, for instance, has invariably the most gradual slope, gravel the next, shingles the next, and large masses of rock or stone the most precipitous. At the present time the stones of the breakwater, by constant friction, have worn away the sharp angles, and it has been found that the base on the side next to the sea is on the average fully eleven for one of perpendicular height.
It was proposed, therefore, to cover the side with a coating of stone twelve feet thick, to consist of blocks of twelve, fifteen, twenty, and thirty cubic feet, or from one to two tons each, which casing was to be carried to the height of twelve feet above the high-water mark of the highest spring-tides; the size of the stones to increase towards the summit, so as to be capable of resisting the percussion of the waves, which is there the strongest. It was calculated that this covering of twelve feet thick on both sides would require for each toise in length seventy cubic toises of stone, and that the whole length of the dike would consequently require 136,500 cubic toises, which, by deducting for the vacant spaces between the stones, would be reduced to 113,750 cubic toises of stone, or about one million and a half of tons. It was further calculated, that the expense of quarrying, the transport to the quays, the loading, conveyance, and discharging machinery, together with the commissioners, clerks, &c. would cost for each cubic toise deposited on the dike the sum of fifty-five livres, which for 113,750 cubic toises would amount to 6,256,250 livres, and, adding for contingencies 600,000 livres, the total estimate amounted to 6,856,250 livres.
The machinery employed for thus casing the breakwater may be seen in Plate CXXXIX., in which fig. 4 represents a section of a lighter on which it is erected.
AZX is an elevated deck or platform.
Y, three rollers of six inches diameter.
TK, two beams or sheers, moving on trunnions in grooves at T.
S, hooks to hold the sheers at the proper angle of inclination. L, the axle of the windlass or wheels B, round which the rope of the pulleys passes. The wheels are 12 feet in diameter.
Fig. 5, a chasse-marée laden with blocks of stone.
E, the block and its hook laying hold of an iron chain round a stone.
F, the stone hoisted to the platform AZ (fig. 4), when the brace is unhooked at S; the hoisting continued until the summit K of the sheers is brought to V, when they rest against the frame which supports the windlass; the stone F is then lowered upon the rollers as at M, from whence it is pushed forward by men to the inclined plane, off which it is rolled into the water upon the side of the dike.
It was calculated that, by employing a certain number of these machines, 34,090 toises might be deposited in one year, reckoning only six working months, or 5682 toises per month, or that 487 superficial toises of the dike might be covered in one season, and the whole completed in four years. Very little progress, however, had been made at the commencement of the war in 1803. At that period the centre of the dike only had been brought above the high-water mark, in which was placed a battery and a small garrison of soldiers, the whole of which were swept away by a heavy sea, occasioned by a tremendous gale of wind in the year 1809, when all the buildings which had been erected on this part of the breakwater, the men, women, and children which composed the garrison, together with several workmen, were washed away; at the same time two sloops of war in the roadstead were driven on shore and dashed in pieces. This disaster was such as might have been expected. The effect of sinking large stones upon the small ones, already rounded by constant attrition, could not be otherwise; the latter acting as so many rollers, carried out the former even beyond the extremity of the base, to which the breakwater had naturally been brought by the action of the sea.
At present small spots only are visible above the surface of the sea at low water of spring-tides, and nowhere such spots exceed three feet in height; the intermediate spaces are from three to fifteen feet below the surface; and, taking the average, the whole dike from one end to the other may be about four feet below the surface of low water at the spring-tides. Near the middle, however, there is about 100 yards where the height rises to eighteen or twenty feet above high water, but it exhibits only a shapeless mass of ruins. In one spot a large heap of stones has been accumulated, as if to try how much weight might safely be trusted upon it, before the attempt be made to rebuild the fort. The largest of the stones in this mass may be about four tons, and they descend to the size of 200 or 300 pounds.
Of the remainder of the dike very few parts are visible at low water; and at this moment the greater part is four feet below the surface of low water. It is sufficiently high, however, to break the force of the waves, and to make the port of Cherbourg a safe anchorage in some winds for about forty sail of the line.
On the renewal of the war after the rupture of the treaty of Amiens, Bonaparte began to bestow a greater share of attention on the navy of France; and though for a time the unparalleled victory of Trafalgar checked his efforts, it did not induce him to abandon them. His plans were vast, and at the period of his fall were in rapid progress towards their completion. He had determined on a fleet of 200 sail of the line, and the noble port of Antwerp gave him every facility for ship-building. For the better security in forming a junction of his two great fleets of Brest and Antwerp, Cherbourg now became more valuable as a convenient port of retreat in case of accident; but it had no dock-yard, nor means of giving to a ship a large refit or repair. He might have thought too, as we believe most of our naval officers do, that a fleet of ships riding at anchor behind the breakwater are easily attackable by fire-ships, as the same wind which carries a vessel in at one entrance will carry her out at the other, and the course would lie directly through the centre of the fleet at anchor. Besides, it might be possible, in certain winds, under the lee of the centre part of the breakwater, to bombard a fleet at anchor in the roadstead within it.
He determined, therefore, to establish a large dockyard at Cherbourg, not merely for repairing, but also for the construction of the largest class of ships of war; to dig a basin that should contain fifty or sixty sail of the line; to construct dry-docks and slips for building and repairing; and to make it a naval port of the first rank. In 1813 this basin was completed at an expense, as Bonaparte is said to have asserted when on board the Northumberland, and which has since been confirmed, of £3,000,000 sterling. A wet-dock of the same magnitude communicating with it was then begun.
The only description that we have been able to find in print of this great work, which took ten years in carrying into execution, is contained in a short letter from M. Pierre-Aimé Lair, secretary to the Society of Agriculture and Commerce of Caen, who was present at the ceremony of opening and consecrating the great basin, in presence of the Empress Maria Louise, on the 27th August 1813. He describes this basin as excavated out of a rock of granite schist, or gneiss, the density and hardness of which increased as the workmen descended from the surface. He compares it to an immense trough dug out of a single stone, and capable of containing many millions of cubic feet of water. We now know, however, that M. Lair is mistaken; that it is not one mass of rock, but rock and gravel mixed; that the whole of the sides are cased with a well-constructed wall of red granite; and that a noble quay, built of the same material, and extending between the two forts of Galet and Homet, separates the basin and wet-dock from the sea.
The dimensions of the new basin he states to be about 900 feet in length by 720 in width, and the average depth fifty-five feet from the edge of the quay; and as this edge is five feet above the high water mark of the equinoctial spring-tides, the depth of water in the basin is then fifty feet, and the mass of water, after making allowance for a slope of the solid sides inward in an angle of forty-five degrees from the height of about twenty-five feet, amounts to about thirty millions of cubic feet; and that it is calculated to contain about thirty sail of the line. We have reason to think that it is considerably larger, about 1000 feet by 770 feet, and consequently contains a surface of about eighteen acres, which, at three per acre, will contain fifty-four sail of the line, and the adjoining wet-dock, when finished, an equal number. The dike or breakwater seems to be abandoned, the works having long been stopped, and the stone vessels going rapidly to decay. The French officers say indeed that it has occasioned the roadstead to become shallower, by the deposition of sand that has taken place.
The entrance canal leading from the outer harbour into the basin is at right angles to the latter, and its direction east-north-east. Its dimensions are as under:
| Feet-In. | |----------| | Width between the two moles in the direction of their axis | 196 | | Width at its opening into the basin | 308 | | Length from the axis of the moles or piers to the line of wall forming the side of the basin | 274 |
2 q The basin, having no gates, is said to have been excavated to the depth of nine feet below the bottom of the canal; the former having, as before mentioned, fifty feet water, and the latter only forty-one at high spring-tides, which, as they ebb twenty feet, would leave only twenty-one feet in the passage or canal at low water. This inequality, we presume, is intended to keep the ships afloat in the basin at low water, when the depth in the canal is not sufficient for that purpose; but after so much expense incurred in digging the basin, one would suppose a little more might have been expended in digging the canal to the same depth, so as to let ships pass into and out of the basin in all states of the tide; an advantage of the utmost importance for speedily securing the ships in the basin, when in danger of an attack from the enemy in the roadstead, or for speedily putting to sea and escaping the vigilance of a blockading squadron. No reason is assigned for leaving the basin without gates; but we suspect that M. Lair is again mistaken, and that the passage has depth of water sufficient for ships of the largest class to run into the basin at all times of the tide. But even here they do not lie in safety; for the wide entrance facing the northeast is covered only in that direction by the isle of Pelée, so that the water in the basin partakes of the swell in the road, which is sometimes so great as to make it necessary to apply ten or twelve cables to hold ships steady in the basin.
Another serious inconvenience likely to arise from this particular construction of the basin is, that whatever silt or mud is carried in by the tides must be deposited there, and cannot possibly escape. The quantity is probably not very great in the water of the Channel opposite to Cherbourg, but higher up towards Ostend it is very considerable. When we took possession of that port, it was found that, in the course of the revolutionary war, the harbour, by neglect, had been filled up with six or seven feet of mud.
Several pieces of cannon are intended to be mounted on the two piers, to protect the entrance into the basin. On one of them is likewise placed a light-house, and on the other a Semaphore telegraph. Four slips of granite, for building large ships, were at this time constructed on the southern side of the basin, and on each of them was a ship of the line in progress: L'Inflexible of 118 guns, Le Centaure of eighty, Le Jupiter and Le Généreux of seventy-four guns each. Two other ships of the line were on the stocks without the dock-yard, nearly ready for launching; Le Zélandais of eighty, the first line-of-battle ship laid down at Cherbourg, and the Duguay-Trouin of seventy-four guns; and in the roadstead were Le Polonais and Le Courageux. In the centre of the same side of the basin, with two slips on each side of it, a noble dry-dock was cut out, or rather built, of solid granite, in which ships of the largest class might be built or repaired. Its dimensions were,
| Length | 230 feet | |--------|---------| | Width | 74 feet | | Depth | 26 feet |
Cherbourg is unquestionably one of the first naval arsenals in Europe. The fortifications for the protection of the anchorage in the roadstead, and the new naval arsenal, are—1. Fort de Querqueville, mounts 46 guns; 2. Fort de la Roche Chavaignac; 3. Fort St Anne; 4. Fort du Homet, mounts 52 guns; 5. Fort du Galet; 6. Fort des Flamands; 7. Fort Royal, Ile Pelée, mounts 90 guns. Three forts are also in course of construction on the breakwater. The roadstead is chiefly protected by the forts on the island of Pelée, du Homet, and Querqueville. Many of the forts have circular faces towards the sea, with each two tiers of guns and turrets above them. On the landside Cherbourg is entirely surrounded by detached forts, redoubts, &c.
The principal channel from the road to the sea is at the western end of the breakwater, which, for large ships, is not more than half a mile in width; and this want of space will always make it difficult for ships of the line to work out; but, on the other hand, a fleet may push out to the westward in southerly winds, which lock up the English ports in the Channel.
The eastern channel is a very indifferent one, and, from the position of the isle of Pelée and the main, it is likely to become worse, from the accumulation of sand, which the French officers say is actually the case.
Such, then, were the mighty preparations of the extraordinary man who ruled France, for the destruction of the naval power of Great Britain, and with it of our national glory, pride, and prosperity, which, whether elated with success or depressed by reverses, he never ceased to devise schemes for humbling.
To give the greater eclat to this grand undertaking, he sent the Empress Maria Louisa to be present at the opening of the basin. When the time arrived for the water to be let in, and the dam broken down, her approach was announced by flourishes of warlike music and numerous discharges of artillery. "Cries of joy," says M. Lair, "were mingled for a long time with the thunder of the batteries. Her Majesty took her place in the pavilion which had been prepared for her, when the Bishop of Constances, surrounded by his clergy, advancing towards her, pronounced an address suitable to the occasion. After the ceremonies and customary prayers, he turned round towards the basin, and blessed this work of man. It is delightful to see a nation consecrating by religious rites an event so memorable, and causing the Divinity to intervene in all its grand undertakings."
He speaks with rupture of the gratification he derived from seeing men born on the shores of the Tiber, and on the banks of the Guadalquivir, working under the direction of French engineers, at the establishment of a port in the Channel, formidable to the English navy; and he suffers no expression of regret to escape him at the idea of these poor Italian and Spanish prisoners of war being compelled to labour in chains at a work for which they were not paid, and in which they could not take the least possible interest.
The Breakwater in Plymouth Sound is a work of a break-similar nature to that of Cherbourg, but constructed on water in sounder principles, with less machinery and fewer people. Plymouth Sound compared in extent and dimensions with that of Cherbourg Sound, it is only in the ratio of about one to four. The gross sum expended upon it is L1,528,639, and a further vote of L13,000 has been taken for the year 1864-55.
There is no port and harbour on the S.W. coast of England possessing so many advantages as Plymouth; none so well situated for assembling and equipping a fleet to watch the movements of the enemy in the harbour of Brest. Its dockyard may be considered as the second in the kingdom in point of size, convenience, and effective strength, and to it a steam factory has recently been added at Keyham, situated on the left bank of the Tamar, with extensive workshops, smithery, docks, caissons and basins capable of admitting the largest ships of the line. These two yards will be connected by means of a tunnel. The estimated cost of these great works at Keyham is as follows, viz. for constructing the south basin and two docks, cofferdam in front of the basins, and clearing the ground for buildings and purchase of ground for magazines, &c. L675,000 Constructing the north basin ........................................... 170,000 Factory buildings .......................................................... 210,000 Remainder of works to complete the establishment, 170,000
Total.................................................. L1,225,000
To which must be added L35,000, the estimated cost of the tunnel. Of this sum there has been already expended the sum of £900,389 up to the end of the year 1853, and a further vote of £60,000 was taken for the year 1854-55.
The south basin and greater part of the north basin, with their docks and various other works are completed; and on the 7th October 1853, H.M. ship Queen, of 116 guns, was safely docked and undocked the following day. The magnificent harbour of Hamoaze is nearly land-locked, and of a capacity sufficient for mooring safely a hundred sail of the line in excellent anchorage, and in water that carries its depth to the very quays of the yard. On the opposite or eastern side of the Sound, and at the distance of about three miles from Hamoaze and the dockyard, is another sheet of water at the mouth of the river Plym, called Catwater, not quite so deep, nor so well sheltered, as Hamoaze, but, since the progress made in the breakwater, forming a safe and commodious harbour for merchant vessels of every description. These two harbours open into Plymouth Sound and Cawsand Bay, in which ships employed in the blockade of Brest, or those refitted in Hamoaze, were accustomed to assemble and prepare for putting to sea. But the very exposed situation of Plymouth Sound, and the heavy swell that almost constantly rolled in, especially when the wind blew fresh from the S.W. to the S.E., made it so inconvenient and so unsafe an anchorage for ships of the line, that, during the late war, the fleet employed in blockading Brest had been in the practice of bearing up, when driven from its station, for the more distant anchorage of Torbay, though little better with regard to security, and worse in every other respect, than Plymouth Sound. It was, for instance, a more ineligible rendezvous for the western squadron, from the chance of the fleet being caught there by an easterly wind, and unable to get out, when it was the most favourable wind for the enemy to put to sea; from the danger to which the ships were liable when so caught in an anchorage thus open and exposed; and from the inconvenience, delay, and expense of obtaining the necessary supply of stores and provisions from the other ports, there being none at Torbay. In short, this open and exposed bay bore so bad a character among naval officers, that Lord Howe used to say it would one day be the grave of the British fleet.
It was, besides, an object of the first importance then, as it is now, to the efficiency of every naval arsenal, to have a safe and commodious roadstead in its neighbourhood, like that of Spithead to the harbour and dockyard of Portsmouth. Here those ships which might have gone through a course of repair or refitment, or those new from the stocks, might assemble and complete their final equipment for sea; and here, also, ships returning from sea might safely lie at anchor till the wind and tide might serve them to go into harbour. But in Plymouth Sound, ships coming out of Hamoaze, or ships going into that harbour, had no such security. By the rolling sea that set in, they were exposed to the double danger of parting their cables, or striking against the hard and rocky bottom, either of which would be almost certain destruction. The introduction of steam has, however, in a great measure lessened these delays as well as the dangers.
It was most important, therefore, to render Plymouth Sound, if possible by any means, and almost at any expense, a safe roadstead for ships of war. To ascertain the practicability of this measure, Mr Rennie the civil engineer, and Mr Whidby the master-attendant of Woolwich dockyard, were sent down to Lord Howick, now Earl Grey, at the suggestion, we believe, of Lord St Vincent, in the year 1806, with directions to examine and report, whether by any and by what means a sufficient shelter might be given to insure a safe anchorage for a fleet of ships of the line. The report was favourable; and several plans were offered for sheltering this sound, so as to render it capable of containing in safety above fifty sail of the line at their anchors. Nothing, however, was done or attempted, notwithstanding the increased and mighty preparations of the enemy, till Mr York presided at the Board of Admiralty, when one of his first measures was to carry into execution this grand and important national object; the most important that perhaps was ever undertaken for the glory and the safety of the British navy. The delay that took place can only be explained by the frequent changes of the Board of Admiralty, which, we believe, have been fatal to many important measures for the benefit and advantage of this great bulwark of the nation.
Of the plans proposed for sheltering the Sound, one was to throw a pier from Staddon Point to the Panther Rock, a distance of 2650 yards; another, to construct a pier from Andurn Point to the Panther, a distance of 2900 yards; and a third, to carry a pier from the same Point to the Shovel Rock, being only 900 yards.
The objection urged against throwing out piers from either of these Points, and abutting against the shore, was principally grounded on the certain effect they would have of changing the current of the flux and reflux of the tide to the opposite side of the Sound, and of increasing its strength and velocity on that side, while it left all calm on the other; the inevitable consequence of which would be a deposition of mud or silt in the calm part or eddy, which, in process of time, would shallow the water, already not too deep, to such a degree as to unfit it for the reception of large ships of war.
Besides, of the three passages for large ships into Plymouth Sound from the sea, the two best are those on the two sides, while the worst was that in the middle. Either of the plans, therefore, which proposed piers to be thrown from the mainland, must have destroyed one of the best passages, and left the worst open, which was nearest to the anchorage behind the proposed pier. The middle passage might, in fact, be almost considered as shut up against very large ships by the St Carlos and the Shovel Rocks; whereas, if this middle passage should be shut up altogether, it would rather serve to deepen, by giving an increased velocity to the tide, which would scour out the bottom, than to shallow the two side passages.
On these considerations, Messrs Rennie and Whidby proposed that an insulated pier or breakwater should be thrown across the middle of the entrance into the Sound, having its eastern extremity about sixty fathoms to the eastward of St Carlos Rock, and its western end about 500 fathoms west of the Shovel, the whole length being about 1700 yards, or close upon a mile. They stated with confidence, that such a breakwater might, with every chance of success in its favour, be constructed; and that it would give shelter to ships in the Sound, without any danger of lessening the depth of water.
The middle part of the breakwater was proposed to be carried in a straight line for the length of 1000 yards; but they recommended that the length of 350 yards at each end should incline towards the straight part at an angle of 120°. See the figure, Plate CXL. These inclined ends would not only give shelter to a greater extent of the Sound, but would, in a greater degree, prevent the rushing in of the tide from agitating the water at the anchorage, than if the two extremities were left in the same straight line, and at right angles with the direction of the current into the Sound.
It was also proposed, in order to cover the Sound more effectually, that a pier should be thrown from Andurn Point towards the principal breakwater, of about 800 yards in length, with the same inclined point of 120° as the head of the breakwater. This pier, however, does not appear to have been thought necessary, and might have been in some respects injurious to the Sound. It might, however, have made Bourisland Bay a good anchorage for frigates and smaller vessels, and given them the advantage of a fine stream of fresh water, which falls into that bay. It was recommended, as the most practicable and best mode of constructing this great work, to heap together promiscuously large blocks of stone, which were to be sunk in the line of the intended breakwater, leaving them to find their own base, and take their own position; and it was conceived that stones of the weight of from one and a half to two tons each would be sufficiently large to keep their places, without being rolled about by the tremendous swell which, in stormy weather, is thrown into Plymouth Sound; and thus avoid the inconvenience as well as loss of time and labour which the French had experienced at Cherbourg by throwing down small rubble stones. It was thought, that, in those places where the water was five fathoms or thirty feet deep, the base of the breakwater should not be less than seventy yards broad, and the summit ten yards, at the height of ten feet above the low water of an ordinary spring-tide; in other words, that the dimensions of the breakwater in those places should be forty feet high, thirty feet across the top, and 210 feet wide at the foundation.
The surrounding shores of Plymouth Sound and Catwater were next examined, with a view to determine from what quarter materials for this great undertaking could most conveniently be obtained, as to quality, cheapness, and celerity of conveyance. On the west or Cornish side of the Sound, nothing appears but hard granite; at the head of the Sound, and in Catwater, on the Devonshire side, all is marble and limestone. In Catwater alone, it was estimated, on a rough calculation, that 20,000,000 of tons might be procured in blocks fit for the work, which was about ten times the quantity that would probably be wanted. The time required for the completion of the work depended on a variety of circumstances. It is obvious that, if the two sides of the Sound had furnished proper materials for the purpose, the time would have been considerably abridged, as, in that case, when the wind was easterly vessels might deposit stones on the eastern end of the breakwater, and in westerly winds on the western extremity, and the work would thus be proceeding with an uninterrupted progress; whereas, if the stones were to be brought from one point, and that point was on the shore of Catwater, a strong southerly and south-westerly wind, those most prevalent in this country in the winter months, would generally impede and frequently render it impossible for vessels to go off with their cargoes.
Catwater, however, having many advantages, especially for the convenience of loading the vessels, and the facility of procuring blocks of any size from the quarries, was considered, on the whole, as entitled to the preference over any other place. Besides, the quarries here being in the neighbourhood of villages, lodgings and conveniences would be afforded for the workmen; and, on the whole, it was calculated that the work might be completed from hence at a cheaper rate, and perhaps in less time, than from situations much nearer to it, but much more exposed to the wind and waves.
An estimate of the expense could not be made with any degree of accuracy, as no correct section of the bottom had been taken. Supposing, however, the great breakwater to be 1700 yards in length, thirty feet in width at the top when carried ten feet above low water of spring-tides, with a slope on the southern or sea side of three feet horizontal to one foot perpendicular, and on the Sound or land side of one foot and a half horizontal to one perpendicular, it was calculated that the whole mass of stone required would be about 2,000,000 of tons. If then a hundred sail of vessels of fifty tons burden each were employed in carrying stone, and each vessel carried only 100 tons a-week, the quantity deposited in one week would amount to 10,000 tons, or 500,000 tons a-year, and at this rate the breakwater would be completed in four years; but making allowance for time lost in preparations, contingent delays, unfavourable weather, and deductions in the quantity of stone for the shallow parts over which the line of the breakwater was carried, the completion of the work might safely be calculated within the period of six years.
Nor would the building of the pier from Andurn Point, if so determined, protract the time of completion. If carried from the shelving rocks within the Point, leaving a passage between them, the pier would require about 360,000 tons of stone, which, by employing about thirty vessels, might be deposited in three years.
It was recommended by the gentlemen above mentioned, that the great breakwater should be begun on the Shovel and extended on both sides of it, as, by so doing, the effect produced on the Sound would be observed as the work proceeded; and that buoys should be placed along the line, so that the whole of the vessels employed might, if necessary, deposit their cargoes at the same time without interrupting each other.
The original rough estimate for completing this great national work, made on the grounds above stated, was as follows:
**Estimate of the Probable Expense of a Breakwater and Pier for the Sheltering of Plymouth Sound and Bournemouth Bay.**
| Description | Cost | |---------------------------------------------------------------------------|--------| | 2,000,000 tons of limestone, in blocks from 1½ to 2 tons weight each, for the great breakwater, at 7s. 6d. per ton. | £750,000 | | 360,000 tons in the pier proposed to be built from Andurn Point, at 7s. | £126,000 | | Contingencies, say at 20 per cent. on the whole | £175,200 |
Total for the great breakwater: £1,051,200
**Estimate of the Probable Expense of a Cut-Stone Pier and Two Lighthouses to be built on the top of the Great Breakwater.**
| Description | Cost | |---------------------------------------------------------------------------|--------| | 42,000 cubic yards of masonry, in the out and inside walls of the pier, at 27s. | £44,700 | | 62,000 cubic yards of rubble filling between the out and inside walls, at 6s. | £18,600 | | Paving the top of the pier with large blocks of stone, 8500 square yards... | £22,90 | | Two lighthouses, with reflectors and argand lamps | £5,000 | | Contingencies 20 per cent. | £28,650 |
Total for the pier and lighthouses: £119,900
Breakwater, £1,528,639
Total estimate of completing the works: £1,171,100
The estimate for the works of Plymouth Breakwater now stands thus (1854):
| Description | Cost | |---------------------------------------------------------------------------|--------| | Total estimate for the work | £1,524,000 | | Gross sum already expended | £1,528,639 | | Sum voted for the years 1854-5 | £13,000 | | Further estimate for completing the work | £21,000 |
It was not until the opinions of the best engineers, men of science, and naval officers eminent in their profession, had been collected, compared, and seriously considered, that Mr Yorke determined to carry into execution this great undertaking; one of the chief supporters of which was Sir John Barrow, then secretary of the Admiralty. The principal objection started against it was, that it might cause the anchorage in the Sound to be destroyed in the course of time by the deposition of mud and silt along the whole eddy within it. But there does not appear to be any solid ground for this objection. The water brought by the tides from the sea is at all times perfectly clear and transparent, and that which proceeds from Hamoaze, and is supplied by the Tamar and the Tavy, is almost wholly free from any alluvial matter, these rivers holding their course through a fine granite soil. The fact is sufficiently proved by the circumstance of no deposit being made in the recesses of Hamoaze along the dockyard wall leading into the docks, nor in the numerous eddies that are caused by the projecting jetties and salient angles of that wall. Another objection started against the undertaking was, that by the diminished quantity of water thrown by the tide into Hamoaze and Catwater, the Sound would gradually fill up, and these harbours be destroyed. But no perceptible alteration has as yet taken place in the height of the water in Hamoaze, or in the strength or set of the tides.
A rock of limestone, or rather gray marble, situated at the Oreston, on the eastern shore of Catwater, consisting of a surface of twenty-five acres, was purchased from the Duke of Bedford for the sum of £10,000. Quays for shipping the stone were erected in front of it; iron railways leading from the quarries to the quays were laid down; ships were hired by contract to carry off the stone, and others built at the dockyard. Mr Whidby was appointed to superintend the work. The quarries were opened on the 7th August 1812; the first stone was deposited on the 12th of the same month; and, on the 31st March 1813, the breakwater made its first appearance above the surface of the Sound at low water of the spring-tide. The system of quarrying the stone was conducted with admirable skill, and stones of the proper size were obtained with less waste of small rubble than might have been expected. In working these quarries an extraordinary phenomenon was discovered in the very body of the great mass of this old marble rock. At the depth of sixty-five feet from the summit of the rock, and twenty-five from the margin of the sea, a cavity, or rather a nodule of clay, was discovered, of twenty-five feet long and twelve square, or thereabouts, in the midst of which were found several bones of the rhinoceros, in a more perfect state, and containing less animal matter in them than any fossil bones that have yet been dug out of rock or earth.
The vessels employed for conveying the large blocks of stone were of a peculiar construction, adapted to carry with ease masses of marble weighing from three to five tons each. These great blocks of marble were placed on trucks at the quarries, and run down thence on iron railways to the quays, against which the vessels lay with their sterns. The two stern ports were made sufficiently large to receive the trucks with the stones upon them. Each truck was passed separately through the port-hole on an inclined plane, and run to the fore-part of the vessel in the hold on an iron railway. The two sides of the hold of the vessel were calculated each to contain eight of these loaded trucks, which, at five tons on each truck, gave eighty tons of stone for one cargo. The stones thus placed on the trucks remained till the vessel arrived at the point in the line of the breakwater where they were to be deposited. By means of a crane on the deck of the vessel, the two trucks nearest to the two stern ports were then drawn up the inclined plane, and run upon a frame on movable hinges, called the typing-frame; by the falling of this frame in the manner of a trap-door the stone or stones were discharged from the trucks on the slope of the breakwater; but the typing-frame remained, by means of a catch, in the position in which it was left at the moment of discharging the stones, until the empty truck was pulled up by the crane to the after-part of the deck, whence it was run forward to make room for the second pair of loaded trucks in the hold. The catch being now disengaged, the typing-frame returned to its former position, ready to receive the next pair of loaded trucks, and so on till the whole sixteen were discharged; and the light trucks ran upon the deck of the vessel, ready to be run out at the quay, and thence to the quarries, to take in fresh loads of stone. In this manner a cargo of eighty tons was discharged in the space of forty or fifty minutes. The vessels were placed in the proper places for depositing the stones by means of buoys, and the exact line of the breakwater was preserved by observing lights or staves placed at a distance on the shore.
The following description, referring to Plate CXXXIX, will convey an accurate idea of these excellent vessels for the purpose for which they were constructed.
Fig. 1 shows the stern of the vessel in the act of depositing the stones. The runner R being hooked to the fore-part of the truck, raises it up, and by that means tips the stone overboard. When the stone is in the act of being drawn up out of the hold on the inclined plane B (fig. 3), the runner is hooked to the fore-part of the truck, and lashed down to the after-end over the stone, which prevents the latter from sliding off the truck in its progress up the inclined plane. The empty trucks are for the most part lodged on the fore-part of the deck, and some placed on edge against the side of the vessel.
Fig. 2 shows the stern of the vessel when loaded, with the ports up or closed.
Fig. 3 is a longitudinal or sheer-section of the vessel when loaded, with the trucks on one side of the hold and deck, showing the number which the vessel usually stows on each side. The stones being frequently longer than the trucks, the number carried in the hold must be proportioned accordingly. In bad weather it is unsafe to send many trucks on deck; and, in general, not more than four are sent into the Sound in that way at one time; the amount of the cargoes, therefore, vary, according to circumstances, from forty to sixty-five tons; the largest stone hitherto deposited being about eight tons.
The after-part of the deck under the tiller is divided into two parts lengthways, and made to move up and down; the fore-parts are secured to a beam by hinges. This movable deck, when raised as at X, allows the stones to come out of the hold, and when down, as at Y, serves to convey the empty truck from the port to the deck, in order to make room for another stone.
D is a common windlass for heaving the trucks out of the hold up the inclined plane B.
C, the hinges of the typing-frame.
Ten vessels of this construction, for carrying large masses of stone, built in the King's Yards, and forty-three hired by contract, averaging about fifty tons each, were employed in conveying stones from the quarries. The contractors' vessels were not of the same construction as those in the immediate employ of government; they carried stones of less weight, which were hoisted out of the hold by a chain and windlass, and thrown overboard. A load of fifty tons was discharged from one of these vessels in about three hours. By all these vessels the quantity of stone deposited in 1812 was 16,045 tons; in 1813, 71,198 tons; in 1814, 239,480 tons; in 1815, 264,207 tons; and in 1816, up to 12th August, 206,033 tons, at which time the total quantity of stone sunk amounted to 896,963 tons; and at the conclusion of the year to upwards of 1,000,000 tons.
Of this quantity the proportions of the different sizes of the blocks deposited were nearly as follow:
| Size | Quantity | |-----------------------|----------| | Of one ton each stone, and under | 423,904 | | Of one to three tons each | 309,706 | | Of three to five tons each | 150,593 | | Of five tons and upwards | 12,760 |
The original contract price for quarrying the stone was 2s. 9d. per ton, and the original contract price for conveying it to the breakwater 2s. 10d. per ton; but the former was reduced to 2s. 5d., and the latter to 1s. 10d. per ton. The cost of each ton of stone sunk in the breakwater, including the building of quays, purchase of land, salaries, and every other expense, according to the nearest calculation that can be made, amounted to about 8s. 14½d., which, upon the whole quantity deposited, gave a total sum expended up to 12th August 1816 equal to L364,000. And as the work might be considered as more than half completed, it would have been finished considerably within the original estimate, and, if parliament had thought fit to grant the money, within the time.
The greatest quantity of stone sunk in any one week was 15,379 tons; and the part of the breakwater at the date just mentioned, above the level of low-water spring-tides, was in length 1100 yards. The length completely finished to the height of three feet above the level of the highest spring-tides, and thirty feet wide at top, was at the same time 360 feet. The large stones of the upper part of the breakwater were deposited to any nicety by means of a vessel constructed for the purpose, having the same sheer or slope at the bow with the side of the work, so that by a projecting beam or mast the largest stones could be taken out of the vessel, and placed on the opposite side, or middle, or any other part of the breakwater.
The whole establishment for carrying on the Plymouth breakwater was as follows:
| Persons | | --- | | A superintendent, with proper officers and clerks, to keep and control the accounts | 10 | | Warrant officers and masters of the ten stone vessels in the immediate employ of the public | 21 | | Seamen and boys to navigate these vessels | 90 | | Seamen employed in the superintendents' vessels; the light vessel, boats' crews, &c. | 45 | | Masons, blacksmiths, carpenters, sail-makers, and labourers, employed at Oreston | 39 |
In the immediate pay of government | 205 | Seamen employed in the contractors' vessels | 170 | Quarrymen, labourers, &c. employed at Oreston by the contractors | 300 |
Total establishment | 675 |
The result of this great work has completely answered the expectation of its warmest advocates. The good effects of it were, indeed, very sensibly felt at the end of the second year, when about 800 yards of the central part, where the water was shallowest, were visible at low-water spring-tides. The swell was then so much broken down and destroyed at the head of the Sound, that the fishermen were no longer able as heretofore to judge of the weather outside the Sound; and ships of all sizes, and among others a French three-decker, ran in with confidence, and anchored behind the breakwater. Since that time near two hundred sail of vessels of all descriptions, driven in by tempestuous weather, have, at one time, found safe shelter within this insulated mole, where a fleet of twenty-five to thirty sail of the line may at all times find a secure and convenient anchorage, with the additional advantage of having a stream of excellent water from a reservoir constructed above Bourvian Bay, capable of containing from ten to twelve thousand tons, or a quantity sufficient to water fifty sail of the line. This water is brought down in iron pipes to Staddon Point, opposite to the anchorage, where a jetty has been completed, from which the water descends through the pipes into the ships' boats. The whole expense of this most useful appendage to the breakwater was calculated at about L16,000.
During the winter of 1816–17 the gales of wind were more frequent and tremendous than had been known for many years; and, on the night of the 19th January, such a hurricane came on as had not been remembered by the oldest inhabitants. The tide rose six feet higher than the usual height of spring-tides. The Jasper sloop of war, and the Telegraph schooner, being anchored without the cover of the breakwater, were driven to the head of the Sound, and both lost; but a collier deeply laden, and under its cover, rode out the gale. No damage was sustained by any of the shipping in Catwater; but it was the general opinion, from former experience, that, if no breakwater had existed, the whole of the ships there must have been wrecked, and the storehouses and magazines on the victualling premises, and most of the buildings on the margin of the sea, must have been entirely swept away. Till this tremendous gale the breakwater had not sustained the slightest damage from the heavy seas that, through the winter, had broken against it with unusual violence, not a single stone having moved from the place in which it was originally deposited; but after the hurricane above-mentioned, and the high tide which accompanied it, it was found that the upper stratum of the finished part, extending about 200 yards, and thirty yards in width, had been displaced, and the whole of the huge stones, from two to five tons in weight each, had been carried over and deposited on the northern slope of the breakwater. In no other part could it be discovered that a single stone had been displaced. Since that time a considerable portion of the sea-front has been cased with masonry of immense masses of stone, but smoothly and beautifully laid; and the better to protect this, the foot of the slope has been extended seaward, in order to protect the foot of the masonry, by throwing in a great quantity of large and rubble stones.
The want of a harbour, or any place of safety to which ships can resort in bad weather, or in distress, between the ports of Plymouth and Portsmouth, led to the suggestion of Portland Roads being converted into a secure harbour by Portland means of a breakwater. It was estimated that the construction of such a stone dike, extending from the north-east part of Portland Island, about two miles and a quarter in length, covering an anchorage of about four square miles, and completely sheltering the pier, harbour, and bathing place of Weymouth, would require about four millions of tons of stone, five years to complete it, and an expense of about six hundred thousand pounds sterling. The capstone alone, which covers the Portland stone, and which, being unmarketable, is not only useless, but a great incumbrance, would be sufficient to complete this great undertaking. Such a secure anchorage in this situation, in which the largest fleets, either naval or mercantile, might ride at anchor in all winds and the most stormy weather in perfect security, was not unworthy the consideration of the public; and, perhaps, in the present increased state of our population, there can be no truer policy than that of carrying on great national works of public utility. Many years have elapsed since the propriety of a breakwater in Portland Roads was first under discussion; but it is only recently that this magnificent work has been taken in hand, together with other noble breakwaters or harbours of refuge, such as those at Harwich, Dover, Holyhead, the Channel Islands, &c.
The estimated cost of these magnificent harbours of refuge, formed by the construction of breakwaters, is as follows, viz.—Dover (estimate for a pier 800 feet long at Cheese-man's Head), L245,000; Harwich, L110,000; Alderney, L620,000; Jersey, L700,000; Portland (harbour and breakwater), L588,959.