Another buoy, Sherwell's patent bell-buoy, was placed nearby in Autumn 1881 and was substituted for the original bell-buoy in March 1882. The Cornishman newspaper reported in March 1883 that the spherical buoy was removed and replaced with a bell buoy, which was knocked off by a passing vessel sometime around October 1885. Other When the Longships Lighthouse was rebuilt in the early 1870s, its fixed white light was provided with a pair of red sectors to indicate nearby hazards, one of which was angled towards the Runnel Stone. Shipwrecks Between 1880 and 1923 over thirty identified steamships were wrecked, stranded or sunk in the area. On a calm midsummer day during World War I, a Royal Navy minesweeper hit the rock despite a local fisherman serving on board as a rating. He was aware that the ship was on a collision course, but was advised to keep quiet by a colleague in case he might be disciplined for criticising his superiors. On a foggy day at 3pm, 8 October 1923, the 6,000 ton SS City of Westminster bound from Belfast to Rotterdam with a cargo of South African maize knocked the top of the reef clean off. A total of seventy-two people were taken off by the Sennen and Penlee lifeboats. Today, the remains of the ship lie in of water, jammed into a gully on the eastern side of the stone. The rock is now less dangerous and there have been no wrecks since. Diving Due to its exposure to the ocean currents and its relative accessibility of slipways at Porthgwarra and Lamorna, the Runnel Stone is known as one of the best dive sites in the whole of Cornwall. Diving must be carried out at slack water, which is about one and a half hours before high water at Newlyn. The highlights include visibility of up to 20m, numerous wrecks, and anemones in a vast array of colours. Marine Conservation Zone The Runnel Stone Marine Conservation Zone (also known as Land's End (Runnel Stone)) was designated on 29 January 2016 and covers 20 km². The Conservation Zone boundary is a 3.5 km arc based on and to the south of the National Coastwatch Institution lookout on Gwennap Head. Included is the coast from Gwennap Head to Hall Dinas on the east side of Treryn Dinas. As well as protecting deep sea rocks on the Runnel Stone reef, the