Dan Martin is in training to swim, run and cycle around the world
A teacher and athlete from Peterborough is aiming to swim across the Atlantic as part of a global sporting feat.
Dan Martin, from Haddon, is in training for an 18-month global triathlon, which he will begin in Canada in May.
He aims to swim more than 3,600 miles (5,000km) from Nova Scotia to Brest in France and then cycle across Europe.
The 28-year-old will cross Russia and Siberia at the coldest time of the year to traverse the Bering Straits to Alaska and onward to run across Canada.
He will end up at Nova Scotia having circumnavigated the world swimming, running and cycling.
The largest part of the journey is the Atlantic swim and he anticipated this would take about four months.
"I will be accompanied by a boat with a crew of five, including a cameraman, to record the crossing and will swim up to eight hours a day in three bursts.
"Every night we will take a GPS reading and return to that spot the next day so that I can swim the whole ocean."
He is adopting the rules for crossing the English Channel which means he will wear trunks, goggles and swimming hat with petroleum jelly or grease to prevent chafing in the salt water.
Temperatures in parts of the ocean can drop to 8C so the cold will be a problem and he is also concerned about storms, barnacles and sharks.
Mr Martin is practising in a confined tank to build up the mental strength he needs to swim alone for long periods.
He said the cycling section would also be hazardous as he would cross Russian Siberia at one of the coldest times of the year and was concerned about prowling wolves, polar bears and other threats.
"This will be a real battle against the elements whereas the swimming will be a mental struggle and the running really physical pounding your body day after day."
Mr Martin describes himself as an extreme sportsman and has already cycled from London to Cape Town in South Africa.
Now as well as preparing to set out in May he is busy raising money.
He has built up a fund of £80,000 so far, but said this was about half of what he needed for the trip.
A charity has also been set up as Mr Martin hopes to raise £1m for orphanages across the world.