The race starts from La Gomera in the Canary Islands and could take competitiors around 10 weeks to reach the finish line at Nelson's Dockyard in Antigua.
Billed as the world's toughest row, each boat taking part in the challenge can only be propelled by the muscle power of its crew, the wind, waves and currents. Evelyn will be up against crews and other solo rowers from across the UK, US, Antigua, Australia, Italy, Mexico and South Africa.
Evelyn said: "My father was very well looked after when he was treated for cancer some years ago at the old Princess Margaret Hospital and when I heard about the Radiotherapy Appeal I knew I wanted to give something back.
"I've done a lot of challenges before, such as the Marathon de Sables in the Sahara desert last year, but I've never done anything on water before. It will be phenomenal to be so close to nature and I'm sure it'll be a breathtaking experience.
Evelyn will be spending a gruelling 15 hours a day rowing and because the challenge does not allow any outside assistance, he will be eating and sleeping on board for the entire race.
He said: "It's going to be scary and it's going to be lonely but I'll have my iPod and iPad to take the edge off and a satellite phone so I'll be able to get in touch with people. I'll miss my family and my cat!
"The thing I'm most looking forward to is finishing in one piece - it'll be a great accomplishment. I'm just hoping I don't get caught in any storms or hurricanes on the way!"
We are so pleased that Evelyn has chosen to raise funds for our charity as part of his challenge. Equally we are keen to support Evelyn in the challenge and will be tracking him closely on his progress across the Atlantic.
As one of only six solo rowers his experience will no doubt challenge Evelyn both physically and mentally and we will be thinking of him over the Christmas period too.
How to donate
You can show your support to Evelyn and the Radiotherapy Appeal through Evelyn's Just Giving page. (www.justgiving.com/Evelyn-Williams2).