US tourists tell story of 'miracle' survival after swimming for 14 hours to safety after deep sea fishing boat sinks in rough seas off St Lucia

Dan Suski and his sister Kate were stranded off the coast of St Lucia

Kate Suski, right, and her brother Dan (AP)

Two American tourists have recounted a remarkable story of survival against the odds after swimming for 14 hours when their deep-sea fishing boat sank in the Caribbean.

Dan Suski, a 30-year-old business owner and IT expert from San Francisco, and his sister Kate Suski, a 39-year-old architect from Seattle, were stranded after their boat sank in rough seas off St Lucia.

Mr Suski had been attempting to land a 200lb marlin with help from his sister when the boat began to take on water.

He was still trying to reel in the fish when water rushed into the cabin and flooded the engine room, prompting the captain to radio for help as he yelled out their coordinates.

As water flowed into the cabin of the 'Reel Irie', which they had chartered from a local company, the captain threw the pair lifejackets and shouted at them to jump, Kate Suski recalled in a telephone interview with The Associated Press.

The brother and sister jumped into the water along with the captain and first mate.

The boat sank five minutes later.

What followed was an exhausting 14-hour swim to safety through waters where sharks are a regular sight.

The tourists found themselves at least eight miles (13 kilometers) from shore, and swimming amid waves more than twice their size.

"The captain was telling us to stay together, and that help was on its way and that we needed to wait," Kate Suski said. The group waited for about an hour, but no one came.

"I was saying, 'Let's swim, let's swim. If they're coming, they will find us. We can't just stay here,"' she recalled.

As they began to swim, the Suskis lost sight of the captain and first mate amid the burgeoning swells. Soon after, they also lost sight of land amid the rain.

"We would just see swells and gray," Dan Suski said.

Despite a plane and a helicopter passing over them, the group was not spotted.

As night fell Kate Suski says she began to reflect on the situation and all the possible ways in which her and her sibling could die.

"There's this very real understanding that the situation is dire," Kate Suski said.

"You come face-to-face with understanding your own mortality ... We both processed the possible ways we might die. Would we drown? Be eaten by a shark?"

They group swam for 12 to 14 hours, talking as they pushed and shivered their way through the ocean.

The group came across land after midnight that night but were unable to climb ashore because the potential danger of being crushed against the rocks.

They swam until they noticed a spit of sand nearby. When they got to land the siblings hiked through thick bush until they reached a farm where they waited for police.

The Suskis were hospitalized and received IV fluids, with doctors concerned they couldn't draw blood from Kate Suski's arm because she was so dehydrated.

They also learned that the captain and mate were rescued after spending nearly 23 hours in the water.

St. Lucia's tourism minister called it a miracle, and the island's maritime affairs unit is investigating exactly what caused the boat to sink.

Marine Police Sgt. Finley Leonce said they have already interviewed the captain, and that police did not suspect foul play or any criminal activity in the sinking of the ship.