Swimming at times in total darkness, a six-strong team will brave freezing waters and stinging jellyfish in their bid to break a world record.
The group will attempt a three-way crossing of the English Channel to raise up to £5000 for charity.
Emma Ross, 29, from Livingston, and her teammates aim to complete the feat – a distance of 63 miles – in under the current record of 30-and-a-half hours.
The sportswear designer and other members of the Andy’s Channel Ladies team have already broken the world record for the fastest two-way crossing of the Channel, but now want to test their mettle with an even greater challenge.
They will be forced to contend with floating debris in one of the busiest waterways in the world, where water temperatures can plunge as low as 12 degrees – and with no wetsuits.
Emma said: “I think this is my most daring challenge yet and most of my friends think it’s a little bit crazy.
“Swimming through the night is difficult because of general tiredness and the cold – and jellyfish are definitely up there with my worries.
“We would like to go under 30 hours but that is so weather-dependent and if it’s choppy it might just be a case of trying to finish the challenge.
“I’m a bit apprehensive, and I have no doubt there will be some wobbly moments, but we are all very supportive of one another.”
The money raised will be split equally between children’s charity Unicef and the British Heart Foundation.
Their swimming costumes will be fitted with lights so the pilots can monitor their progress from the boat during the hours of darkness.
Throughout the challenge each team member will swim for an hour before handing over to their teammate to do the next hour, repeating this process until they finally finish back in Dover.
Emma, who attended the James Young High School in Livingston, is a member of the Swim West Lothian Masters team, better known as ‘Team Orange’ and hails from a swimming dynasty. Her father, Alistair Ross, 52, is a swimming coach while her mother, Sharon, 52, and grandmother Irene Coles, 82, also swim competitively.
Emma has completed a number of open water swims including the Firth of Forth, Loch Rannoch, the Solent and Lochore Meadows.
Last year, she was a member of a six-person team that took part in the Channel swim in Manchester event, held at Salford Quays.
Emma won four bronze medals in the masters European Championships in the Ukraine in 2011 and has also been part of a number of masters relay teams which have broken European and world records.
She specialises in middle and long-distance swimming, clinching a first and a third prize in her age category, the ASA Masters Open Water National Championships, on Sunday.
She now lives in Wakefield in West Yorkshire with her partner and met the rest of the team while swimming in the Trafford Masters in Manchester.
WILLIAM “Ned” Barnie from Portobello was the first Scot to swim the Channel in 1950, aged 54, and the following year he became the first man to swim it in both directions in one season.
He held the record of the oldest person to do so for 28 years. A plaque in Straiton Place marks the place he lived.
He swam regularly in the Forth and completed about 200,000 lengths of Portobello Baths in one year.