Six naturists, including a Birmingham man, abandoned their charity attempt to swim three lengths of Loch Ness in the nude because of " atrocious" weather.
The four men and two women were making their way up the loch in one-person onehour relays, with the others following along in a boat.
But having completed the first 23-mile length in plunging temperatures and strengthening winds, they decided on Saturday not to try the second length against the current.
British Naturism had organised the sponsored relay in support of Cancer Research UK, having raised £1,500 for Children in Need in a similar event on Loch Ness in July
The group included Stuart Buffrey, a 36-year-old computer programmer from Birmingham.
Kevin Mitchell, the first swimmer to set off from Fort Augustus at 7pm on Friday, said the wind was so strong that the boat could not have stayed with the swimmer.
The 56-year-old writer, from Harrow, Middlesex, said: "We swam all through the night and completed one length in 14 hours and four minutes but the conditions were so bad we couldn't go on.
"The waves were so big and the wind was so strong that we couldn't keep the boat with the swimmer and that made it unsafe to continue."
British Naturism president Pat Thompson said: "The loch looked like the sea and for safety reasons they had to stop."
British Naturism is a 40-year-old organisation for nudists in the UK and has about 16,000 members. The other swimmers were John Taylor, 47, an engineer from Clitheroe in Lancashire; Trevor Coleman, 51, a policeman from London; Ann Cameron, 45, a housewife from London, and Carol Singh, 56, a swimming teacher from California.