Wrecks over 100 years old and archaeological objects found underwater are protected under the National Monuments (Amendment) Acts 1987 and 1994. Significant wrecks less that 100 years old can be designated by Underwater Heritage Order (UHO) on account of their historical, archaeological or artistic importance as is the case with the wreck of the RMS Lusitania lost off the Old Head of Kinsale in 1915. UHOs can also be used to designate areas of seabed or land covered by water to more clearly define and protect wreck sites and archaeological objects . https://www.archaeology.ie/underwater-archaeology
Cork Harbour, in Southern Ireland, is one of the finest deep water harbours in the world. In the 19th Century, this harbour accommodated the mooring of up to 300 vessels at one time.
The failings of this port, historically, were in the inability of shipping of any appreciable size, to navigate safely to the city of Cork, approximately seven miles away. This was essential for the growth and prosperity of the city. Until the mid-19th Century, trading ships would mainly moor in the main part of Cork Harbour, or slightly up the river at Passage. Vessels known as lighters, which were small shallow drafted vessels, would take portions of cargo to the city, seven miles away, then return with outward cargo or ballast for the larger ship. This was a very inefficient way of transporting goods, involving extra labour and cost, as well as wasted time.
Plan of Cork Harbour showing Lough Mahon (1790)
From the 19th Century, efforts were made to resolve this problem. In 1820, the British Parliament approved a bill for a Harbour Board, to manage the River Lee and Harbour.
From the 1820’s onwards, limited dredging took place, but it was between 1845 and 1860, that significant improvements in making a navigable passage to Cork were made. These were accomplished under the stewardship of Sir John Benson, Engineer to the Cork Harbour Commissioners. The largest obstacle to shipping, was the massive expanse of water known as Lough Mahon, between Horse Head, in Passage, and Blackrock Castle. This tidal estuary, though large in size, consisted of a series of shallow mudflats, with the meandering channel of the River Lee flowing through it.
Even staying in the complicated channel, meant a depth, at low tide of only four feet. There were many strandings and a few wreckings in this body of water.
Much work was done to the river and quays in the city. It was at this time that the shape of Cork City as we know it was formed, with decent quays on the north and south channels of the City. The dredging of a useable channel through the length of Lough Mahon was an essential task. None of these could have been accomplished without the new technology of steam dredgers, and the revolutionary steam pile.
By 1858, the channel through Lough Mahon was in place, of good width, with a depth of 10 feet at low water. The channel was maintained periodically by the Harbour Commissioners dredgers. A deputation of local ship owners pleaded with the Harbour Board to improve navigation on the new channel. There was a fixed light at Blackrock Castle, but this left a large area with poor transits for navigation. This made travel on Lough Mahon dangerous, especially in winter, when there would invariably be only one flood tide in daylight hours.
Sir John Benson, of the Harbour Board, designed a new lighthouse for Lough Mahon, loosely based on Mitchell's iconic Spit Bank Lighthouse, which had been such a success in the lower harbour area.
The Lough Mahon light, was to be constructed using round wooden piles, sheathed against marine organisms. On top of these piles was an octagonal iron two-roomed keepers quarters, surmounted by the light. The light was to be 25 feet above HWL.
The tender for construction was won by P. R.Roddy, and the total build cost was £800. The lighthouse was complete and the light operational by November 1859. It was manned by one lightkeeper, the first being Humphery Scannell.
Blackrock, Dunkettle, and Lough Mahon lights (1884)
The light was a great success, preventing shipping straying into the mud banks west of the channel, but it created demand for a second lighthouse, opposite the Lough Mahon light. This was because there were large areas of shoal ground along the north of Lough Mahon also.
The new light fitted on a tripod structure, was called the Dunkettle Light, and had a green lantern. This light was operational from 1862. Other lights on the upper river were Kings Quay (Blackrock) and Tivoli.
In 1874, tragedy struck, when the Lough Mahon lightkeeper, Jeremiah Callinan, and his wife, were drowned attempting to row from the lighthouse to the shore in a thunderstorm.
The inquest, held in Blackrock, was heavily critical of the boat supplied by the Harbour Commissioners, which was felt to be old, waterlogged, and too small. A Mr Regan was appointed keeper in place of the late Jeremiah Callinan.
Lough Mahon lighthouse continued as a ‘watched light’ until 1910, when an unattended oil lamp was fitted. This was changed to an acetylene lamp in 1924, mainly due to repeated thefts of oil from the storage tanks.
Dunkettle lighthouse lasted until 1926, when the SS Freddy Fisher collided with it and demolished it.
The end for the Lough Mahon lighthouse came in January, 1930. The SS Ardmore, of the City of Cork Steam Packet Company, was on passage from Liverpool to Cork, in clear weather, when the accident occurred. There was an error of judgement in negotiating the channel, when the ship collided with, and demolished the lighthouse.
In turn the SS Ardmore grounded heavily and was not gotten off the mud until 24 hours later.
This marked the end for the lighthouse in Lough Mahon. The structure was not replaced, and today, a system of lateral, lit buoyage has replaced this light, and that of Dunkettle.