MARITIME HERITAGE
It was the position of the isles in the North Atlantic that led to their focus on maritime activities, as a place of rest rather than trading ports. However, the maritime world brought St Mary’s both its most tragic association and its greatest legacy. On 22 October 1707, British admiral Sir Cloudesley Shovell, his flagship, the HMS Association and much of his fleet were wrecked on the island’s Gilstone Rocks, with the loss of 1,400 lives. This shocking event was caused because there was no truly accurate way of ships knowing their position. Prizes were promised to whoever could fashion a reliable means of determining longitude at sea, accurate within half a degree, on a great circle equal to 30 nautical miles at the Equator. The resulting invention of the chronometer by John Harrison improved upon the greatly flawed method of ‘dead reckoning’, a calculation based on speed and position. As a result, the Longitude Act was passed in 1714. Despite this tragedy, the Scillies are a relatively safe place for maritime travellers. “We employed the method of taking the length of a given stretch of coastline and dividing it by the number of known wrecks” says historian Richard Larn. A resident of St Mary’s for 22 years, he spent nine years producing Lloyd’s Shipwreck Index of the British Isles, a catalogue of more than 50,000 ship losses around the UK, published in 2002. “North and South Cornwall have 26 per mile, while County Durham, because of the historic coal trade, has 43. Scilly has approximately 1,000 wrecks along its 100 miles of coastline, making it just 10 per mile.”