Bell Rock Lighthouse, the world’s oldest surviving sea-washed lighthouse, has saved countless lives over the past two centuries. Located on the east coast of Scotland, it was built to alert seagoers to the dreaded Inchcape Rock, 11miles out from Arbroath Harbour.
The need was urgent. According to some reports, fear of hitting the treacherous rock was so great, that more ships were shipwrecked on its
neighbouring shores than on Inchcape in their attempt to avoid it.
Constructed by Robert Stevenson in 1811, the lighthouse posed huge engineering challenges at the time. Because of its position, the surface of the rock was exposed only at low water, while at high water it was submerged to depths of up to 16 feet (4.9m).
“The light is too weak for a place of such maritime importance”
The method of trenails and wedges was carried out so that the lower part of the lighthouse would remain upright when covered by high tides. Each stone had two circular holes for trenails to pass through and continue six inches into the already-laid stone below.
Wedges were then driven into the vertical joints of the stones to align them before grouting.
Nearly a hundred years later, The Engineer reported that while the lighthouse showed no sign of weakness, the optical system of the tower was in need of modernisation: ’Both the lantern and the machine are antiquated and the light is too weak in power for a place of such maritime importance…The Commissioners accordingly resolved some time ago to renew these parts of the installation, and they are exhibited at Glasgow with his consent.’
The 200th anniversary of the lighting of the beacon will be on 1 February. Since 1811 it has not required a single repair to its stonework and the tower continues to stand proudly as one of the greatest feats of 19th century British engineering.