Lightships and Lighthouses

by Frederick Arthur Ambrose Talbot

The French Government was sorely puzzled as to how to overcome this danger. The engineers fought the elements valiantly for forty years in an effort to crown Horaine with a beacon, but time after time they were defeated. Landing on the reef is highly dangerous. The rocks are surrounded by surging, eddying currents, running at anything from six miles upwards per hour, while the slightest ruffle of wind is quite sufficient to stir up the water so as to fling it swirling over the rocks even at lowest tide. Once or twice, when a period of abnormal calm prevailed, the engineers struggled on to the rock and hurriedly built a substantial masonry beacon, but its life was always brief. The first two or three gales which pounded and roared over the chain invariably scattered the handiwork of man in all directions.

Then another expedient was attempted. A party landed upon the ridge, drove a hole into the solid rock, and there set a vertical iron girder 4 inches in thickness, trusting that it would hold fast and indicate the reef sufficiently during the day. But its life was short. A gale came along and snapped the post in twain, leaving a twisted, bent stump, some 36 inches long, remaining on the rock.

PREPARING THE FOUNDATIONS OF THE JUMENT LIGHT.

This illustration conveys an idea of the difficulties encountered in connection with this work.

In 1890 another bold effort to subjugate the ridge was made. An hexagonal structure was designed, and it was determined to plant this on the rock by hook or by crook, and so firmly as to resist the most powerful hammerings to which it could be subjected by the waves. Six holes were bored into the rock surface to form the corners of the hexagon. But before commencing the work proper it was decided to insert an iron post, 6½ inches thick, into one of the holes, and to leave it to see what would happen. Time after time it was inspected, and was found to be safe and sound. Two years had slipped by, practically, since the post was planted, and it was still intact. The engineers thought they had triumphed, and were preparing their plans, when the news came that a heavy storm, which had swept the coast, had broken the pillar off flush with the rock.

This necessitated another change in the designs and the plan of campaign. After further discussion it was decided to proceed right away with a masonry tower, although the engineers were prepared for a mighty tussle. The surveys showed that, as the rock upon which the building was to be erected was covered by 10 feet of water during the highest spring-tides, work upon the foundations would be confined to the lowest neap-tides, when about 4 feet of the rock were exposed. But the tide sinks to the very low level desired infrequently—about four days in every month. Even then work would be possible for only about an hour per day—four hours per month! The prospect certainly was far from being attractive, especially as even to accomplish this meed of toil the calmest weather and smoothest sea were imperative, and it was scarcely to be expected that everything would be in favour of the engineers at one and the same time.

Another adverse feature was only too apparent. If unpropitious weather prevailed just after an hour or two’s work had been completed, the chances were a thousand to one that it would be swept away. But this was a contingency which had to be faced. The engineer could only do the utmost humanly possible to secure his work, and then must trust to luck.

With infinite difficulty a small corps of daring workmen and appliances of the simplest description, together with materials, were got out to the rock upon the first favourable day when there was a very low tide. An outer wall of bricks was built piecemeal, and the space within was filled with concrete. This stood, and so the engineer secured a level plinth upon which to place his tower. He selected an octagonal building, the angles of which touch the circumference of a circle 20 feet in diameter described on the rock. It was to be 50 feet in height, bringing the warning light about 40 feet above high-water. The beacon was to be a concrete monolithic structure at least for the greater part of its height, as the light was to be of the unattended class. Accordingly, the mould was formed by setting a cast-iron post, 18 inches in height, at each corner of the octagon, this support being anchored into the solid rock beneath. These posts contained grooves to admit sliding wooden uprights, which were to be firmly wedged, these joists being inclined to take the angle, or batter, proposed for the tower. Heavy transverse pieces of timber were laid between these posts, forming a capacious octagonal box, into which the concrete was poured. As the filling process behind the wooden wall advanced, angle pieces of steel were superimposed and bolted up.