An epic 2,000-mile rowing race around the entire coast of Britain is now underway.
The Royal Rowbarge Gloriana led the racers through London's Tower Bridge as they embarked on the GB Row 2013 event.
Sally Kettle, 36, who was the first woman to row the Atlantic Ocean twice from east to west, is part of a two-woman team in the race.
She said: "It's not going to be as physically tough as an ocean row. We've got six hours with the tide and six hours without. It's going to be a mental challenge more than anything else."
Kettle, from Kingston upon Thames, south-west London, said the fact that the race was around Britain meant it could be tempting to pull into land and take a break.
"I can smell a fish and chip shop from a mile away," she joked. "Seeing land is quite tough and actually avoiding land is quite tough too. It's very dangerous around the coast of the UK with tankers and the coastline."
Another competitor, Jason McKinlay, 42, from Salcombe in Devon, said he was looking forward to the unique views they will enjoy during the race.
"We're gong to see the UK from a different perspective," he said. "As tough as it is, it's going to be absolutely stunning out there so we're looking forward to bringing some of those memories back."
McKinlay appeared confident that he would be able to cope with the physical demands of rowing around Britain.
"It's more mental than physical because you might not be on the oars all the time," he said. "You can conserve some of your energy rowing for around 90 minutes to two hours if the weather is good and if the tidal streams are going with you, so actually you get as much time to rest and eat as you do actually rowing."
The fastest time ever recorded for the course is 26 days, 21 hours and 14 minutes set by a crew of four men in 2005. The first of the six boats home will win £15,000 while £100,000 is on offer for setting a new record.