Skerryvore
Skerryvore is a remote island that lies off the west coast of Scotland, southwest of Tiree. Skerryvore Lighthouse is located on these rocks, built with some difficulty between 1838 and 1844 by Alan Stevenson.
At a height of it is the tallest lighthouse in Scotland. The shore station was at Hynish on Tiree ; operations were later transferred to Erraid, west of Mull. The remoteness of the location led to the keepers receiving additional payments in kind. The light shone without a break from 1844 until a fire in 1954 shut down operations for five years. The lighthouse was automated in 1994.
Geology
In pre-historic times the rocks that now form Skerryvore were covered by the ice sheets that spread from Scotland out into the Atlantic Ocean beyond the Outer Hebrides. After the last retreat of the ice around 20,000 years ago, sea levels were up to lower than at present. Although the isostatic rise of land makes estimating post-glacial coastlines a complex task, circa 14,000 BP it is likely that the reef was at the south western end of a large island consisting of the modern islands of Tiree and Coll and the surrounding land.Steadily rising sea levels would then have slowly isolated and finally all but submerged the shoals of Skerryvore, a barrier of innumerable metamorphic remnants that stretch for lying in a south-westerly direction. A detailed survey undertaken in 1834 listed more than 130 main rocks including Am Bonn Sligheach and Am Bogha Ruadh.
The rocks have been worn smooth by the action of the waves and are constantly affected by spray. Alan Stevenson wrote: "The effect of the jet d'eau was at times extremely beautiful, the water being so broken as to form a snow-white and opaque pillar, surrounded by a fine vapour in which, during sunshine, beautiful rainbows were observed ".
It is an isolated outpost of the Inner Hebrides archipelago composed of Lewisian gneiss, formed in the Precambrian eon, these rocks being amongst the most ancient rocks in Europe. A further hazard to shipping is a magnetic anomaly in the area.
Planning and construction of the lighthouse
Surveys
Between 1790 and 1844 more than thirty ships were known to have been wrecked in the area. Robert Stevenson, chief engineer of the Northern Lighthouse Board landed on the reef in 1804 and reported on the need for a beacon of some kind there. In 1814 he returned in the company of Sir Walter Scott and a party of NLB Commissioners. Scott wrote:Later that year an Act of Parliament was passed enabling construction of a lighthouse, yet despite pleas for a light arriving almost weekly at the NLB, events proceeded only slowly. It was not until 1834 that Robert Stevenson returned in the company of his son Alan. A painstaking survey made it clear that there was little choice for a location. The single largest area was a rock that measured only at low tide. Readings for wave pressure indicated that any tower would have to withstand forces of. There were suggestions that a tower of cast iron or bronze might be sufficient, but Stevenson senior wrote that "no pecuniary consideration could in my opinion have justified the adoption of an iron lighthouse for Skerryvore." On more than one occasion the surveyors had to warn passing vessels of the danger. A ship from Newcastle, whose charts showed only the main rock some miles away, was boarded near Bo Ruadh. The Master, oblivious to the dangers, was found lying at ease smoking a pipe with his wife beside him knitting stockings.
Still the Commissioners prevaricated, daunted by the potential costs, estimated by Robert Stevenson at £63,000. They set up a special Skerryvore Committee, whose members decided to visit the site by steamer to see for themselves. Just off Skerryvore a fire broke out in the boiler room crippling the ship. It was extinguished and no harm was done, but the experience may have been persuasive.
Alan Stevenson was duly appointed as the engineer for the project aged only 30. He designed a tower high with a base of, narrowing to just at the lantern gallery. The lowest sections would be solid, although at feet high they were less than half the height of the base of the later light at nearby Dubh Artach. Nonetheless, the structure would weigh and the volume of the base would be more than 4 times larger than the entire structure of the Eddystone light and twice that of the Bell Rock. With 151 steps to the top it would be the tallest and heaviest lighthouse yet built anywhere in the modern world, and today it is still one of the tallest lighthouse in the United Kingdom.
Shore station
Hynish on Tiree was the initial shore station and construction site. Located on the south west corner of Tiree, its proximity to Skerryvore and the resulting abundance of bounty from the wrecks, led to rentals being higher here and on the rest of the west coast than elsewhere on the island. Work on the new facilities began in 1837; granite blocks were quarried from Mull and brought to the village to be cut and shaped before being shipped out to the reef. Several cottages for the keepers were built in 1844 from the same stone as well as a massive pier and a tall granite tower to enable signalling to and from Skerryvore itself. Stevenson remarked that the hive of activity there contrasted with the "desolation and misery" he imagined to be the lot of the surrounding population.Barrack and foundation
In 1838 £15,000 in wages alone was spent on constructing a 150-ton steamer in Leith to ferry workers and materials out to the reef. The difficulties should not be underestimated. Although Skerryvore is a dozen miles from Hynish it is from the mainland. The first work to be undertaken on Skerryvore itself was the construction of a six-legged frame on top of which a wooden barrack to house 40 men was placed. The building was created in Gourock before being dismantled and re-built on site.Initial work began on the rock on 7 August 1838. Stevenson and 21 workmen arrived on board the sailing vessel Pharos and began to unload the barrack, whose massive legs were set into holes blasted out of the rock. After only two days the site had to be abandoned as a storm swept in from the Atlantic. It was a further six days before they could resume the punishing schedule of 16 hours a day work between 4 am and 8 pm. Fearing sea sickness, many of the man preferred to attempt to sleep on the damp rocks than on the ever-rolling Pharos.
Work for the season lasted only until 11 September, by which time the barrack legs had been secured although not the main structure. Less than two months later Stevenson received a letter from the storekeeper at Hynish, Mr. Hogben. It began: "Dear Sir, I am extremely sorry to inform you that the barrack erected on Skerryvore Rock has totally disappeared." The structure had been destroyed during a gale on 3 November and four months effort had been wasted. Stevenson hired a boat to take him out to inspect the damage the same day he received this news. Firm in his self-belief, he resolved to build a stronger but otherwise identical replacement. Work began in April 1839 and by early September the completed barrack stood above the rock. Entry was via ladders attached to the legs that led into the lowest level containing a kitchen. The middle level contained two cabins, one for Stevenson, the other for his master of works, whilst the top level provided sleeping quarters for a further 30 to 40 men.
Work on the foundations for the lighthouse continued until 30 September. A total of 296 charges were used to remove of rock and Stevenson believed that the rock was so hard that the effort involved was four times that required for boring Aberdeenshire granite. The work went well but by the end of the second season, no blocks had yet been laid. However, between April 1839 and June 1840 4,300 blocks had been fashioned, the stone donated by the Duke of Argyll from quarries on Mull. The roughly hewn rock was taken to Hynish where the blocks were hammered and chiselled into shape. The largest weighed over, the smallest and the precision required meant that a single block could take 320 worker-hours to complete.
Tower
The new barrack withstood the violence of the storms during the winter of 1839–1840. Work re-commenced on the rock on 30 April 1840, and after the arrival of the new steamer Skerryvore the carefully fashioned blocks began to arrive on site. The first one was laid by John Campbell, 7th Duke of Argyll on 4 July. His son George later wrote:Soon up to 95 blocks a day were arriving from Hynish, although the weather continued to play its part. During the summer of 1840 the steamer was unable to reach the reef for fourteen consecutive days, and on another occasion no landings were possible for seven weeks and supplies began to run low. When work ceased again in the autumn, 800 tons of granite standing high stood on Skerryvore, and up to 80 craftsmen continued to labour on the blocks at Hynish all winter. The first three courses of the base are of hard Hynish gneiss, the remainder are granite from the Ross of Mull.
Work continued during 1841–42, a crane being used to hoist the huge blocks as the tower rose. The last one was raised to the parapet in July 1842. Robert Stevenson, then aged 70, visited the site on his last annual voyage of inspection. The walls at the base are thick, and thick at the top. The lightroom and lantern sit above nine apartments in diameter. The total cost of the works undertaken by the Northern Lighthouse Board was £86,977, including the cost of establishing the shore station at Hynish, estimated at £13,000. It is a credit to Stevenson, his foreman Charles Stewart, and Captain Macurich the landing master, that not a single life was lost during the construction.
Fitting out
The final season of work in 1843 was spent in fitting out the interior. By then Alan had become chief engineer to the NLB and the final work was undertaken under the supervision of his brother Thomas. The light, which had eight lenses revolving around a four wick lamp with pyramidal lenses above and reflecting prisms below each one, was constructed by John Milne of Edinburgh. The machinery was ready by the beginning of 1844, but it was seven weeks before a landing could be undertaken on the rock. The lamp was finally lit on 1 February and it shone without interruption for the next 110 years.Skerryvore was Alan Stevenson's greatest achievements from both an engineering and aesthetic perspective. No philistine, he chose a hyberbolic curve for the outline for stylistic reasons. His nephew Robert Louis described it as "the noblest of all extant deep-sea lights" and according to the Northern Lighthouse Board it is "asserted by some that Skerryvore is the world's most graceful lighthouse".