An Account of the Bell Rock Light-House / Including the Details of the Erection and Peculiar Structure of That Edifice; to Which Is Prefixed a Historical View of the Institution and Progress of the Northern Light-Houses

by Robert Stevenson

(Signed) John Rennie.

To the Honourable the Commissioners of the Northern Light-houses.

REPORT by Mr Stevenson.

Edinburgh, 15th November 1806.

In the year 1800, when the Reporter laid before the Commissioners various models of a Light-house for the Bell Rock, the prospect of the undertaking was so distant, that it then appeared unnecessary to trouble the Board with any scheme for carrying the work into execution; but since the passing of the act of Parliament for this purpose, the case is materially altered. In preparing any method for carrying on a work, the most difficult in its nature, and one to which the common tests of experience can hardly be applied, he is aware, that it is impossible, by any previous arrangement, to determine what will answer in all respects. In so far as the operations on shore are considered, the ordinary rules of practice apply, but, in forming plans for the Rock itself, matters must be adjusted to the situation and circumstances of the case.

Certain measures, of a preliminary nature, are, however, indispensably necessary, while others may be of doubtful application; among the former, it appears to be essentially necessary to provide a vessel to be moored at the distance of from three quarters to one mile north-west of the Rock. She must, of course, be fitted up as a store-ship, with accommodation for the artificers, and ground-tackle for riding in from 17 to 20 fathoms water, on rather a hard bottom. This vessel, besides answering as a store-ship for water and provisions, may occasionally take on board lime, cement, and other materials from the small craft at the Rock, when lying at anchor with them on board may be found inconvenient. There is also another and most important service, which this vessel will fall to perform in terms of the act of Parliament, which is the carrying of a Light upon her mast, for the benefit of shipping, and to enable a duty to be collected, even before the commencement of the work, agreeably to the suggestion of Mr Cuningham.

The Reporter, in order to inform himself more fully regarding the construction of such a vessel, while attending the progress of the Bill in London, visited the Floating-light ship at the Nore, under the command of Mr Bennet, who very politely described every particular connected with the business. He had also frequent communications with Captain Huddart of the Trinity House, who takes a particular charge of the Floating-lights under the management of that Board, since which he has also corresponded with him upon the subject, who has obligingly stated his ideas relative to a vessel and moorings fitted for the Bell Rock. Upon the whole, the Reporter is of opinion, that a dogger, or Dutch-built vessel, is best calculated for this service. Such a vessel would require to be from 80 to 100 tons burden, moored with a mushroom-anchor, weighty iron mooring-irons, having likewise on board a hempen cable of 16 inches in circumference. The mushroom-anchor, which is but a late invention, is now in use at all the Floating-lights on the coast, and even in some of his Majesty’s store-ships. Its great property consists in its being hardly possible for a vessel to foul her anchor with it; and the construction is such, that it may be made in part, or wholly, of cast-iron, agreeably to the accompanying model, from which an idea may more easily be formed of its application. (See [Plate X.]). This vessel must be furnished with such a light as to be readily distinguishable from the Coal-light on the Island of May; and although the Dudgeon Floating-light, off the Norfolk coast, which carries two lanterns, is at a great distance, yet, as it is the nearest Floating-light to the Bell Rock, it may be advisable to distinguish it from that also. As a vessel cannot be dispensed with for the accommodation of the artificers, it will be found to be a great saving to employ her as a store-ship. As this vessel is only meant to answer a temporary purpose, by purchasing one of the Dutch or Prussian prize-ships, now for sale in Leith, she might perhaps be fitted up for about L. 2000.

Although it would be perfectly impossible to do any thing with much effect at the Bell Rock, without a vessel stationed in the offing; yet as she must necessarily be moored at the distance of about a mile from it, to give a sufficient birth for swinging, according to the wind, and also to give sea-room to clear the Rock, in the event of her breaking adrift, the inconveniency and difficulty of the frequent passage between the Floating-light and the Rock must be very considerable. It therefore occurs to the Reporter, that the greatest advantages would arise from the erection of a temporary residence for the artificers upon the Rock during the working-months of summer, and also to answer as a store for some of the materials. The greatest difficulties which Mr Smeaton had to struggle with at the Edystone, arose from the smallness of the rock, which at once precluded any attempt of this kind from being undertaken, and subjected the work to all the disadvantages and trouble so particularly described as experienced in communicating on all occasions with the store-ship. But, from the extent of the Bell Rock, an opportunity may be had for erecting a temporary residence, for facilitating the work. It was under the conviction that such an accommodation might be constructed, that the clause was introduced into the act for allowing the collection of half-duties upon the erection of a Beacon. But, independently of these advantages, the Reporter conceives some erection of this kind necessary, to give confidence to the artificers, in the event of accident to the boats, of which they might lay hold, until assistance could be procured from the store-vessel. This temporary residence is provided for in his estimate for the Light-house, and having modelled it, he proposes that it should consist of beams of timber, not less than 50 feet in length, and of proportional strength; the beams are coupled together at the top, where they form a cabin for the workmen, and, at the same time, answer all the purposes of a Beacon.

The next material object to be considered, is a method which may prolong or extend the working hours at the Rock, especially in the first instance, to low water of neap, as well as spring tides. In this respect we also find, that Mr Smeaton had no alternative, having had barely extent for the foundation of the Light-house; but, in this respect, he had less occasion for such an apparatus, as the top of the Edystone Rock was rather above high-water, although, from its shelving form, the level of the ground-course was not more than nine feet above low water of spring-tides. The ground-course of the Bell Rock, however, will not be more than about two feet above low-water of such tides. It therefore becomes an object of great importance, to construct a water-tight fence round the site of the building, which might be the means of saving a whole season with the work, and securing the proper execution of the lower courses, by enabling the workmen to go on in a more deliberate manner with their operations. The Reporter has had several methods in view for raising a coffer-dam for this purpose to the height of about six feet or thereby, which would allow the work to proceed regularly in moderate weather at low water of neap as well as spring-tides. He has, accordingly, modelled a coffer-dam with this view, which he proposes to be three feet more in diameter than the base of the building, and, from its exposed situation, the greatest attention must be paid to the strength and fitness of the materials. At first he intended this to be of timber, but at length fixed upon cast-iron, strongly connected with iron-bolts, passing through flanges raised upon the joints, which are to be provided with a groove, for the conveniency of tightening them. The whole of this apparatus is estimated to weigh about 40 tons, and is so constructed, that when all the pieces are landed on the rock, and laid in their places, the foundation for them being prepared, they may be set up, and temporarily fixed, in the course of a good spring-tide.

There is no part of this critical work which will be attended with so much difficulty as the landing of heavy materials, nor is there any part of the business that has occupied so much of the Reporter’s attention. Mr Smeaton appears to have had a great deal of trouble upon this head; and in conversing with one of those having charge at the South Rock Light-house, on the coast of Downshire in Ireland, while it was building, it was stated, that there was more time lost in getting a regular supply of materials, and more vexation attending this department, than any other part of the operations, although this rock is exposed and dry at every tide, and only 3 miles from the shore, with a beach where vessels were laid to discharge their cargoes; whereas the Bell Rock is about 11 miles from land, forming neither a steep-face, like that of the Edystone, nor a sloping beach, like that of the South Rock, while it is so low in the water, that it can afford little or no shelter to vessels, if brought alongside of it. Under all these adverse circumstances, the landing of the materials becomes a consideration of the most perplexing nature. He has sometimes thought that the depth of water upon the rock might be turned to advantage in landing the stones at high-water; yet this mode has its disadvantages, and could not always be depended upon; others must, therefore, be resorted to, more certain in their application. Vessels of an easy draught of water, and not exceeding 20 tons burden, might in very moderate weather be brought close into some of the small creeks of the rock. Some of these will admit of improvement, where cranes might be fixed for unloading them. This may, perhaps, turn out to be the surest mode upon trial; but it may also be necessary to resort to others, such as having buoys moored in different directions, at a convenient distance from the rock; by making fast a hawser to the buoy best suited to the direction of the wind; the hawser may be veered out till the vessel with the materials gets so close to the Rock as to discharge. Some have even supposed, that the materials may be transported to the Rock under these circumstances by a float of cork or timber, and when the vessel is thus cleared of her cargo, she may be hauled off again, and so make sail. The stones, when landed, if not immediately built, may be stowed into the cast-iron coffer-dam, which, for this purpose, will be found of the greatest use, while the lower courses of the building are in progress; and as the work advances, other plans will present themselves.