Major lighthouses are also equipped with battery powered emergency lights of shorter range which switch on automatically in the event of total failure of both the main and standby light or generator plant. As a consequence of automation it is no longer possible to permit members of the general public to visit lighthouses. In addition to lights some buoys have bell or whistle fog signals, or Racons. Traditionally acetylene gas has powered lighted buoys but this has given way to solar power. Unlighted buoys are provided in areas designated for daytime navigation but all remaining unlighted buoys will be lit in the next two years.
Beacons are usually large stone structures or towers, often painted for better visibility.
Perches are metal structures or poles with identifiable top marks, normally on rock outcrops close to navigable channels. Each of the granite stones from which it is built is dovetailed into those around it, bonding the structure into a virtual monolith. Kish Lighthouse, completed in 1965, was the first lighthouse in the world built on the telescopic principle to be placed in the open sea, and is more than twice as big as any lighthouse of this type previously built. It was built in Dun Laoghaire Harbour as a concrete caisson and floated to its position on the Kish Bank, where it was sunk on the sea bed and then extended up to its full height 52 metres above the seabed. The Irish Lights vessel Granuaile is deployed to maintain the Aids to Navigation provided by the Commissioners.