22 October 1707, Isles of Scilly
Dubbed the shipwreck that changed the world, this is still recognised as one of the worst disasters in British maritime history.
The wrecking of HMS Association, and three other ships in its fleet, left 1,450 sailors dead but, crucially, this tragedy would transform the future of shipping as it lead to two acts of parliament and the establishment of longitude.
“It was the second biggest loss of life in the Royal Navy in one night, which must have been horrible for the people on the Isles of Scilly because think of all those bodies washing up around the off islands,” explained Mr Larn, who has an encyclopedic knowledge of shipwrecks.
Mr Larn said the ship wrecked due to navigational errors, created by the inability of seafarers to calculate longitude meaning ships often ended up wildly off course.
HMS Association was the flagship of Sir Cloudesley Shovell, who had worked his way up from lowly cabin boy to become Admiral of the Fleet in 1705.
Queen Anne and the government gave a £20,000 prize to carpenter John Harrison, who – after years of commitment – came up with a chronometer that did calculate the elusive longitude.
Its wreck was found by a team with Mr Larn in 1967.