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.