What survives, if anything survives at all, lies somewhere between the tideline and eroded cliff edge, and the most a visitor might find today are large, ambiguous lumps of masonry on the beach below, possibly the remains of a Martello tower, possibly something else entirely. The batteries themselves have left no visible trace.

The installations at Shanganagh were part of a coordinated programme of coastal defence built in response to the threat of Napoleonic invasion. Construction of the Dublin-area Martello towers and their associated batteries began in 1804 under the supervision of Colonel Benjamin Fisher of the Royal Engineers. A Martello tower is a small, squat, round fortification, typically of thick masonry, designed to be garrisoned by a small number of men and difficult to demolish by cannon fire. By December 1805, all towers in the Dublin series were armed and complete. The Shanganagh installation was designated Tower No. 4, and it was an unusually substantial position: a mid-nineteenth-century plan recorded in Kerrigan (1995) shows the tower flanked by semi-circular glacis to the east and west, with a battery approximately 500 feet to the north and another 500 feet to the south. A glacis, in this context, is a sloped earthwork designed to deflect or absorb incoming fire. The tower and both batteries stood on a cliff some sixty feet above the beach. The armament listed for No. 4 in December 1805 included four 24-pounders and one 18-pounder, presumably distributed between the two batteries, each of which is thought to have mounted two guns. The tower itself was dismantled in the early years of the twentieth century, and the defensive redoubt associated with it has since been removed by coastal erosion.

Taylor's 1816 map of the environs of Dublin, surveyed at two inches to the mile, recorded the positions of both the tower and the batteries before the worst of the erosion had taken hold, and it gives a clearer sense of how commanding this clifftop position once was. Today there is nothing formal to see; no signage, no preserved remains, no obvious access point to the beach beyond what the coastline itself offers. The large masonry fragments on the beach below are worth examining if the tide allows, though their origin remains uncertain. The site is more an exercise in reading absence than in reading ruins.