Veteran British yachtsman Sir Robin Knox-Johnston put to sea at 1200 BST on Sunday in the prestigious 5 Oceans solo round-the-world yacht race.
Knox-Johnston was the first man to sail solo non-stop around the world
The 67-year-old, who in 1969 became the first person to sail non-stop around the world alone, is sailing against seven others in the race from Bilbao.
Britons Mike Golding and Alex Thomson and Swiss star Bernard Stamm are also in the field.
The three-leg race includes stops in Fremantle, Australia, and Norfolk, USA.
You only get one life, so paint it in bright colours
Knox-Johnston was 30 when he took 312 days to circumnavigate the world in his 32ft wooden yacht Suhaili in the Sunday Times Golden Globe race. He was the only competitor to finish.
"I didn't enter this race just to participate," he said.
"People often think that life winds down for the over 50s, but this simply isn't true - life is for living - months of preparation, hard work and anticipation, I can't wait to get out there and start racing.
Knox-Johnston was the only competitor to finish the 1969 Golden Globe race
"If it was easy it wouldn't be very interesting would it? It's the difficult things in life that give you satisfaction."
Knox-Johnston is returning to racing after a self-imposed retirement since his wife died from cancer. He last raced in 1994 when, with the late Sir Peter Blake, he broke the round-the-world sailing record and won the Jules Verne Trophy.
He said: "I haven't been able to sail for a while and I've missed it. I've been missing racing too.
"I came to the conclusion that actually there is a race left in me and I had better get on and do it now.
In 1969, my weather forecasting system consisted of a barometer from the wall of a pub
"I want to get back to doing what I love. You only get one life, so paint it in bright colours."
Ocean racing has changed significantly in the 37 years since Knox-Johnston set his record, with constant communication, up-to-date weather forecasts and a huge leap in boat-building technology.
"I will be going a hell of a lot quicker this time round, while there were no satellites last time," he said.
"I had radio contact once a week but that broke after two months so my only interaction with the outside world for eight and a half months was being sighted from the shore or passing another ship.
"Now it's got to the stage where it will be more like being a racing car driver, because I will be in constant communication with the outside world.
This race remains unfinished business for me
"In 1969, my weather forecasting system consisted of a barometer from the wall of a pub, the wind direction and the clouds - I never knew what was coming until it hit me.
"Now the forecast can be delivered regularly, enabling us to predict where best to position the yacht to maximise progress in the most favourable conditions."
Former fireman Golding, 46, offshore sailing's world champion, is one of the favourites for the race after finishing third in the 2005 Vendee Globe non-stop around-the-world race.
"This race remains unfinished business for me," he said.
"It is the only event I have not completed in my professional sailing career and provides me with an immediate opportunity to go for a bullet in a major solo around the world race."
The 32-year-old Thomson is the rising star of British ocean racing after making his name skippering a team of amateurs to win the 1998-99 Clipper round-the-world race.
He is also the holder of the solo 24 hour monohull distance record, covering 468 nautical miles at an average boat speed of 19.5 knots when finishing third in a solo trans-Atlantic race in 2003.
British sailor Ellen MacArthur holds the single-handed non-stop around-the-world record of 71 days and under 15 hours, set in 2005.
This year marks the 25th anniversary of this solo round-the-world race, know previously as the BOC Challenge and Around Alone.