In 1954 Prince Charles, then five years old, was travelling on the inaugural voyage of the Royal Yacht Britannia.
According to former Royal yachtsman Ellis Norel, at one point the Prince woke a sailor by shaking his hammock.
In response the sailor “picked him up by the scruff of the neck”.
The sailer then warned Prince Charles: “Don’t you ever do that again or you’ll never live to be King.”
The revelation was made on an ITV documentary, Queen of the World, which aired last night.
It dealt with the Queen’s role on the world stage during her long reign.
The Royal Yacht Britannia sailed on its maiden voyage from Portsmouth to Valletta, Malta on April 14 1954.
Britannia arrived seven days later on April 22 1954.
Both Prince Charles and Princess Anne were on the vessel during the trip.
Mr Norel claimed the Royal children enjoyed their time aboard.
He asserted: “The children, they loved it.
“They came down to our mess sets for tea.
“They wanted to know how the lads got into their hammocks.”
Princess Anne is also interviewed on the documentary about the trip.
She claimed: “The journey out, and the sea nannies we had to stop us launching ourselves over the side, were very good memories.”
The Royal Yacht Britannia was a 412 foot long yacht available to the Queen and other members of the Royal family.
After arriving with Prince Charles and Princess Anne in Valletta it headed to Tobruk in Libya, meeting the Queen and Duke of Edinburgh at the end of a Royal Commonwealth tour.
The Queen boarded the Britannia in Tobruk for the first time on May 1 1954.