Teams of four or five per yacht sail from Barmouth to Fort William, with two of the crew climbing the highest mountains of Wales, England and Scotland en route, running the equivalent of three marathons in 3 or 4 days.
Use of engines is not allowed, except for safety reasons in specific areas in ports. However, a unique feature of the race is that rowing is allowed, and over the years, many teams have been known to row during light airs and periods of calm.
Back up support teams can meet the teams on land but are restricted in what support they can give. Many teams participate without any form of back up at all.