WATERFRONT IN DUN LAOGHAIRE – MARINE PARADE SCOTSMAN’S BAY
I would like to take this opportunity to wish every one a “Happy Christmas” and a “Wonderful New Year”.
John Rennie (1761-1821), who was Scottish, was one of the leading civil engineers of his day. He designed many bridges, canals and docks, including those at Hull, Liverpool, London and Leith.
Keeping an effective link between Ireland and England was vital in the early 19th century and Rennie was responsible for the construction of Howth Harbour a decade earlier than Dunleary. He had been asked for his observations on Dublin Bay just two years after Bligh’s survey in 1800. Rennie suggested that: “Dunleary, or rather a little to the east of it was a good site for the construction of a harbour of asylum, for ships which, under unfavourable circumstances get embayed in Dublin Bay and cannot with safety enter the present harbour”.
Rennie was appointed Chief Engineer for the construction of the harbour in 1815. Originally it was intended that only one pier (the East Pier) would be built (3,500 feet long), but when John Rennie was appointed directing engineer for the work, he insisted that a single pier would result in sand drifting behind the pier and that a second West Pier (4,950 feet long) would prevent this from occurring. He was correct as the sand has built up behind the west pier. The harbour once built was renamed ‘The Royal Harbour of Kingstown’ in 1821 on the occasion of the visit of George IV.
The material for the harbour is Dalkey Hill granite. The granite was provided by Richard Toucher (a long time campaigner for the new harbour) at no cost to the construction team. The foundations of the piers are 300′-0″ wide and 24′-0″ below low water level. Many options were considered for the width of the space between the two pier heads. Rennie wrote to the Harbour Commissioners that the opening should be 430′-0″ wide with the pier heads turned into the harbour to control swells within the harbour. His demands were never met and the harbour opening was built at 1,066′-0″. This was clearly too wide and was subsequently reduced to 760′-0″.