A marine chronometer by Thomas Mercer, numbered 28285 English circa 1900-1920 dial 12 cm diameter case 18 cm square 17 cm high, Thomas Mercer marine chronometers are revered in British maritime history and are most famously linked to Shackleton's trans-Antarctic expedition (1914-1916). After his ship Endurance became trapped in the ice and destroyed, Shackleton managed to lead his 27 crewmen to safety – using his Thomas Mercer chronometer (now on permanent display at the National Maritime Museum in Greenwich) during the open boat trip on the James Caird. When Francis Chichester embarked on the Atlantic Challenge he relied on a Thomas Mercer marine chronometer. Skippers of notable vessels, including the Royal Yacht Britannia, depended on our timekeepers. Winston Churchill's private aircraft boasted a Thomas Mercer clock, and so his presidential suite on the Queen Mary. The story of British marine navigation is the story of Thomas Mercer., dial 12 cm diameter case 18 cm square 17 cm high