A businessman hopes to become the first person to single-handedly circumnavigate the world via the poles without stopping.
Adrian Flanagan on his French-made yacht, Barrabas
Adrian Flanagan, 45, from Ludgersall, near Bicester, set off on his 11-month, 35,000-mile quest on Friday afternoon.
Mr Flanagan will head south around South America, through the Bering Strait and round northern Europe in his French-made yacht Barrabas.
Save the Children and Oxford Children's Hospital will receive cash raised.
The father-of-two announced his ambitious plans during Cowes Week on the Isle of Wight in August.
His previous longest journey was across the Atlantic as part of the Times Clipper Race in 2000.