Paul and Donna Beason, from Portsmouth, were sailing towards the Caribbean island of St Lucia when their boat started taking on water.

They made an emergency call to Falmouth Coastguards on Wednesday morning and had to wait more than 20 hours clinging to their craft 350 miles off the Cape Verde Islands before help arrived.

The lines started snapping so the boat skewed round, spinning 180 degrees and crashing up against the side of the tanker Paul Beason

A spokesman for Falmouth Coastguards said their position would have put them out of range of most radio frequencies.

He said they used the yacht's satellite to call Falmouth Coastguards who then alerted the US Navy coastguard.

"The US Navy in Norfolk, Virginia, have got a satellite system which can report all vessels in a given area, and that's how we found the nearest vessel," said the spokesman.

The crew of the Docebay, a Liberian-registered oil tanker, diverted to the Beasons' position and picked them up at around 0600 GMT on Thursday.

Life-line

Mr Beason, 49, speaking from the bridge of the Docebay, told the Times newspaper: "The transfer on to the boat was exciting to say the least.

"We had big seas and strong winds. When we tried to come up alongside, 20ft waves would crash against the sides of the tanker."

He told how his wife climbed up a rope ladder on to the deck.

"It was hair-raising because each time a wave hit the boat the ladder lifted 15 foot," he said.

"That was when the problems really started. The lines started snapping so the boat skewed round, spinning 180 degrees and crashing up against the side of the tanker."

Mr Beason said crew members had to throw a lifering on a line to him before pulling him up.

The Falmouth Coastguard spokesman said: "They were very lucky. They rung us because they wanted to speak to someone English and they didn't have too much time.

"There is quite a history of people ringing us from remote places to get assistance."

The couple had reportedly sold their home to fund the trip and had already sailed around France, Spain and the Canary Islands before heading for St Lucia.