John Harrison was not a sailor, but his contribution to maritime history and development is possibly more significant than many of the greatest explorers of the sea.

Harrison had already designed and built a number of innovative improvements for clocks and watches – including a highly accurate pendulum – when he travelled to London to compete for the most sought-after scientific prize of the time – the Longitude Prize.

The Longitude Prize was created by the British government and offered up to £20,000 to whoever could create a precise way for sailors to determine longitude. John Harrison worked doggedly on a maritime clock, or chronometer, which could accurately keep time at sea.

Harrison came up with his first prototype in 1761, but the Board of Longitude rejected several of his prototypes and demanded further tests for a further 12 years, until Harrison finally received the prize in 1773. He had little time to enjoy his new-found riches, as he died three years later, aged 87.