The base of the West tower was 196 feet above high water and during the construction a great sea swept the partly built tower, two courses high, and much of the building materials clear into the sea. The two towers were finally completed and a massive storm wall was built on the sea side of the towers. When the two lights at night, or towers in daytime, were in line they guided vessels past all dangers from Blacksod Bay to Broadhaven including The Stags. The towers, built of cut stone quarried on the Island were painted white and had first order catoptric fixed white lights visible for twenty miles in clear weather. The works were not quite complete when the lights were first established on the night of 29th September 1835.
Eagle Island seems destined to be struck by severe storms.
On the night of 17th January 1836 the lantern of the West tower was struck by a rock shattering one of the panes of glass and extinguishing the light but the Keepers had the light working again within an hour. The Keepers' dwellings were badly damaged and in those days Keepers and their families lived on the island. Both lanterns were badly damaged by a violent gale on 5th and 6th February 1850 and the lights were not restored until the 11th because the man sent out to repair them could not make the passage until the 14th, when a landing was effected and the whole story told. On the 11th March 1861 at midday the light room of the East tower was struck by the sea smashing 23 panes, washing some of the lamps down the stairs, and damaging the reflectors with broken glass beyond repair. In spite of the efforts of the Keepers to repair the damage it wasn't until the night of the 12th that the light was restored and then only with 12 lamps and reflectors.