Sule Skerry Lighthouse Stromness, Scotland

Text courtesy of Historic Environment Scotland. © Crown Copyright, reprinted under the Open Government License.

Britain's most remote lighthouse, lying 40 miles west of Orkney and 37 miles NE of Cape Wrath. Its isolated position made it unsuitable for the accommodation of keepers' families; hence provision was made in Stromness (see separate list description). Designed and constructed by David Alan Stevenson, a member of Britain's foremost lighthouse engineering family, the Sule Skerry light answered a need for increased protection of the 'north-about' route around Britain, owing to additional congestion and resultant collisions in the English Channel. Although Sumburgh and North Ronaldsay were already lit, and the eastern side of Orkney being fairly well protected, the 160 miles of seaboard between the Pentland Firth and Muckle Flugga were dangerously unlit. Consequently, a series of important lights was built around the northern fringes of Britain - 2 on Fair Isle in 1892, Sule Skerry and Ratray Head in 1895 and the Flannan Islands in 1899. Sule Skerry island is fairly low lying, rising to 45 feet above high water, and is almost out of sight of land, the combination of these two factors necessitated the need for an extra-powerful light source on top of the 88 foot tower. To this end, lighting was delayed for a year after completion of the structure, while the Board of Trade and Trinity House argued with the Commissioners about the cost and character of the apparatus. As larger burners were used to increase the intensity of the light, they produced too much heat for the compact optical apparatus. As a result, the Stevensons increased the focal distance between the centre of the light source and the 'cage' of glass to 52 inches in what they called a 'hyper-radiant' apparatus. They also employed an arrangement of equi-angular prisms which caused less light loss and divergence than other types of lens. The lantern therefore required was larger than any previously designed for lighthouse service, being 16 feet in diameter instead of the normal 12. Stevenson's plans show how the lighthouse was divided internally; beneath the plinth was the water and provision store; the coal store was sited at the 1st stage, providing the all-important fuel to keep the lamps lit; a dry store was located above that, with the bedroom situated high, below the lamp room. With no accommodation structures outside the lighthouse, Stevenson provided a multi-bed chamber for the keepers within convenient reach of the lamp room. Plans show that three layers of paired bunks were stacked above two layers of paired drawers; a compact solution to manning a lighthouse with no accommodation block. Stevenson's plans also show the existence of fluted columns supporting H-girders in the lamp room. Now automated and unmanned.