Chris Todd, 35, is making plans for a two-day-long, 66-mile (106 km) walk across the Irish Sea.
The Wiltshire, England, engineer intends to "walk on water" from Wales to Ireland in a giant homemade hamster wheel for charity.
Todd hopes to raise £20,000 ($32,000 CAD) for the Wiltshire Blind Association and the Royal National Lifeboat Institution.
"Imagine spending 48 hours on a stepping machine in the gym without getting any sleep. It is going to be one of the toughest things I've ever done," Todd told the Sun.
Todd's paddlewheel raft, or "Tredalo," took 11 months to make and can handle waves of up to 1 metre, BBC News reports.
"I've tested it on lakes and in the sea but that has only been for a couple of hours, which is totally different to a couple of days," Todd told BBC News.
"But the only way we are going to know if it will stand up to the battering from the waves is to actually do it."
Todd will have to consume around 30 litres of water and more than 36,000 calories to sustain himself during the grueling ordeal.
Todd believes the mental challenges of the trek will be more demanding than the physical ones:
"It is a bit like being on one of those fairground rides, where you walk though a rotating tunnel and end up losing your balance. And unlike endurance races on land, the horizon is going to be bleak and featureless," he said. "So it will be mentally challenging as well as physically."
The endurance challenge is scheduled for next month.