Smeaton and Lighthouses / A Popular Biography, with an Historical Introduction and Sequel

by Anonymous

In the month of August 1838, operations were commenced by inserting nine of Mitchell’s patent mooring-screws, each four feet and a half in diameter, and furnished with shafts of wrought iron about twenty-five feet in length and five inches thick. One of these screws served as a centre to the remainder, which occupied the angles of an octagon forty-two feet in diameter. The screws were turned into the sands to the depth of twenty-one feet and a half, the upper extremities being left standing about five feet above the surface of the sands. For the purpose of fixing the screws, a stage or raft of timber, thirty feet square, was floated over the spot, with a capstan in the centre, which was made to fit on the top of the iron shaft, and firmly keyed to it. A power of about thirty men was employed for driving the screws, and their labours were continued until their united force could scarcely turn the capstan. This stage or raft, which had been formed in two thicknesses crossing each other at right angles, and bolted at their intersection, was, as a precautionary measure, allowed to remain. It covered the whole site within the piles, and also extended some distance beyond them. A curb about eighteen inches high was raised round this stage; on its surface was arranged a quantity of brushwood, and then about two hundred tons of rough stone, which sunk the stage into the sand and prevented it from being displaced. Between the spaces of the stage and the brushwood the sand was allowed to wash its way, and it soon filled the interstices of the stone. The whole mass soon became embedded below the surface of the sand, and gave considerable lateral support to the piles, and formed a solid body for the water to wash upon.

In this state the whole was allowed to remain for about two years, during which time every change in the surface of the sand was observed, and although early in the year 1839 violent storms occurred, yet the screw-piles stood firmly, and the sand at no time was lowered more than three feet. In August 1840 the raft was found to have completely settled down, the piles were as firm as if they had been screwed into clay; a lighthouse was therefore erected within the short space of three months; and on the 16th February, 1841, a dioptric fixed light was exhibited off this dangerous spot, and was visible ten miles off in all directions.

But while the preparatory steps for this lighthouse were being taken, a screw-pile lighthouse was begun and completed at Port Fleetwood on the Wyre, near Lancaster; which being the first of the kind ever constructed, deserves particular notice.

The preparatory stages were of a similar nature to those already described. The foundation was formed of seven screw-piles, six occupying the angles of a hexagon forty-six feet in diameter, and the seventh being placed in the centre. From each screw proceeded a pile fifteen feet in length, at the upper end of which was another screw for securing a wooden column. These columns were prepared of Baltic timber; the one in the centre was fifty-six feet, and each of the remainder forty-six feet in length, bound firmly round with iron hoops and coated with pitch.

The framing upon which the house stands is firmly secured round the centre column and to the heads of the outer columns by means of hollow cast-iron capitals let down over the heads of the columns and secured with screw-bolts. To give lateral strength to the building, round iron angle-braces were applied, by which means a resisting power equal to at least three hundred and fifty tons is presented in every direction.

The platform upon which the house stands is twenty-seven feet in diameter. The dwelling-house is twenty feet in diameter, and nine feet high: it has an outside door, and three windows, and is divided into two apartments, one having a fire-place; the floor is tiled, and the walls and ceiling lathed and stuccoed. Access to the platform is secured by means of a Jacob’s ladder of wrought iron secured to one of the columns: access to the lantern is by a winding stair within the house.

From the summit of the house rises the lantern; it is twelve-sided, ten feet in diameter, and eight feet high. The light is thus elevated about forty-six feet above low-water level. It is of the dioptric kind, and is bright, steady, and uniform, ranging over an horizon of eight miles, and visible at the distance of ten miles from a coaster’s deck. During foggy weather a bell is tolled by machinery. Tide-time for vessels of twelve feet draft is also denoted by signals. Signals put out by vessels requiring a Wyre pilot will also be understood at this lighthouse, where corresponding signals are hoisted until the pilot is provided.

This admirable and useful structure was erected in two of the shortest day months of the year, in which time day-light did not occur at any low-water period; the workmen therefore had to depend on torches and moonlight. Nor is the portability of this form of building its least advantage: should there occur any local changes which might threaten the safety of the house, it can be taken down, and erected in another site within a month.

Perhaps one of the boldest schemes ever devised for lighthouses was the structure proposed to be erected by Mr. Bush, on a plan patented by him, on the Goodwin Sands, or on the Varne in the channel between Folkestone and Cape Grisnez, in four fathoms water. This plan, was recommended to the consideration of parliament by several merchants, ship-owners, and other influential persons. The building proposed to be called ‘The Light of all Nations,’ was to consist of a Doric column one hundred and twenty-five feet high supporting a lantern twelve feet in diameter, surmounted by a colossal statue of the Queen, her sceptre being the point of a lightning-conductor. This column was to rise from a base one hundred feet in height, and fifty in diameter, to be formed by a caisson composed of cast-iron plates bolted together: the part under water was to be divided into four pyramidal chambers, opening into and supporting one another; the lower one resting on the rock beneath the sands, and the whole forming a conical core to the cylindrical base. The only part of this plan that was executed was the cast-iron caisson, which was deposited in its place among the sands. In this situation, during one dark and stormy night, it was struck by a ship and shivered to a thousand fragments. This untoward accident has led to the abandonment of the design.

One of the characteristics of this country is the mode in which we lay out the mineral wealth which nature has bestowed upon us so liberally in the shape of coal and iron. With the assistance of the former we mould the latter into a thousand shapes of usefulness, neatness, and durability, and so much attached are we to this material, that it is daily superseding the use of the more cumbrous wood and stone, and other substances which were once in great demand. Iron furnishes most of the multifarious instruments required in the mechanical and agricultural arts—it ministers alike to war and to peace, by furnishing the sword and the ploughshare. It supplies some of the most useful domestic apparatus for the kitchen, the parlour, and the bed-room, and now even the bedstead itself may be formed of iron. It has been long used in some of our great public works: we have iron roads—iron bridges—iron statues—steam-boats of iron—houses of iron, and lastly, iron lighthouses.