Standing sentinel over the rock the Irish call Carraig Aonair (lone rock), is the Fastnet lighthouse, an iconic structure built in the early 1900s. The world renowned lighthouse situated 3.5 miles from Cape Clear, south west Ireland, has warned shipping of the inherent danger for over 120 years.

The lighthouse is in fact equally both Irish and Cornish in a funny sort of way. The lighthouse is not constructed of Irish stone. The 4,450 tons of granite used in the construction came from the Carnsew quarry at Mabe from where it was quarried in a major operation that began in 1899.

The stone was then transported to Freeman’s yard at Freeman’s wharf, Penryn to be expertly and precisely cut by professional stone masons.

Penryn firm John Freeman & Co won the contract to supply the granite which was cut flawlessly from plans submitted by the Irish Lights Commissioners in Dublin whose inspectors examined every one of the 2,074 blocks of granite at the Freeman’s wharf workshop.

The beautiful lighthouse which took five years to build costing £84,000 was designed to withstand the force of the Atlantic, by William Douglass, Engineer to the Commissioners of Irish Lights, who came from a family of distinguished lighthouse engineers.

Fastnet standing at 54 metres high and 16 metres wide is the tallest and widest rock lighthouse tower in Ireland and Great Britain and was a monumental achievement when completed in 1904. Each of the granite stones of the tower is dovetailed into those around it, bonding the structure into a virtual monolith. The foundations of the lighthouse are 6 metres thick made of Cornish granite.

From the photo of Freeman’s yard you can see that individual stones were marked and numbered as they were part of what we would call in these modern times a giant Lego set.

Every stone weighing between one and three tons was cut and placed in its position in the yard, and was so constructed that each stone fitted into the other exactly, "dowelled" and "joggled" as they say in the stone trade, which means the same as “dovetailing” in the building trade.

The Irish Lights Commissioners, under whose authority the lighthouse was built, had through their inspectors, examined every stone and section. If in a stone there was the presence of the slightest discolouring element, they discarded it at once; and, consequently, they were not the easiest men in the world to please.

Each section or course of the lighthouse, which numbered 84 courses was laid out at the Penryn yard, inspected and then shipped to Crookhaven, Ireland which was the base port for the construction. A new steamship called Ierne was built to take the stone offshore.

After eight years of work the Fastnet came into service in June 1904.

Fastnet’s height, when completed was 52 metres. The amount of granite measures about 60,000 cubic feet, and the weight totals up some 4,450 tons. The width at the base is 16 metres , gradually becoming narrower on the way up until it contracts to 8 metres at the top. It contains eight rooms divided by granite floors most intersected in the main portion of the structure.

In winter heavy seas batter the lighthouse which can withstand the full fury of the Atlantic. A wave recorded at 48 metres high struck the Fastnet in 1985.

The ill fated liner Titanic sailed past the lighthouse on her maiden voyage in 1912.

The first light on Fastnet was established in 1854 with a new medium for lighthouse towers and keepers' dwellings was used with cast-iron plates bolted together, with an inner lining of brick.

The Board of Trade completed running a deep sea telegraphic cable from the mainland to the Fastnet in July 1895 whereby lighthouse keepers could report all passing vessels and give them their orders. This 1854 structure was eventually replaced by the Fastnet lighthouse we know today.

During the Irish War of Independence (1919-1921) a daring raid by the IRA on 20th June 1921 saw armed men storm the Fastnet looking for explosives used for fog signals and warning ships of danger. During a two year period the IRA conducted 24 such raids on 12 lighthouses and fog signal stations to steal explosives and detonators.