SAN JUAN, Puerto Rico (AP) — The fishing trip off the rugged north coast of St Lucia was supposed to last all day, but about four hours into the journey, the boat’s electric system crackled and popped.

Dan Suski, a 30-year-old business owner and information technology expert from San Francisco, had been wrestling a 200-pound marlin in rough seas with help from his sister, Kate Suski, a 39-year-old architect from Seattle. It was around noon April 21.

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.

It would be nearly 14 hours and a long, long swim before what was supposed to be a highlight of their sunny vacation would come to an end.

As the waves pounded the boat they had chartered from the local company ‘Reel Irie’, more water flooded in. The captain threw life jackets to the Suskis.

“He said, ‘Jump out! Jump out!'” Kate Suski recalled in a telephone interview yesterday with The Associated Press.

The Suskis obeyed and jumped into the water with the captain and first mate. Less than five minutes later, the boat sank.

The group was at least eight miles (13 kilometres) from shore, and waves more than twice their size tossed them.

“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.

A plane and a helicopter appeared in the distance and hovered over the area, but no one spotted the siblings.

Several hours went by, and the sun began to set.

“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?”

“Hypothermia?” Dan Suski asked.

“Would our legs cramp up and make it impossible to swim?” the sister continued.

They swam for 12 to 14 hours, talking as they pushed and shivered their way through the ocean. Dan Suski tried to ignore images of the movie Open Water that kept popping into his head and its story of a scuba-diving couple left behind by their group and attacked by sharks. His sister said she also couldn’t stop thinking about sharks.

“I thought I was going to vomit I was so scared,” she said.

When they finally came within 30 feet (9 metres) of land, they realised they couldn’t get out of the water.

“There were sheer cliffs coming into the ocean,” she said. “We knew we would get crushed.”

Dan Suski thought they should try to reach the rocks, which they could see in the moonlight, but his sister disagreed.

“We won’t survive that,” she told him.

They swam until they noticed a spit of sand nearby. When they got to land, they collapsed, barely able to walk. It was past midnight, and they didn’t notice any homes in the area.

“Dan said the first priority was to stay warm,” she recalled.

They hiked inland and lay side-by-side, pulling up grass and brush to cover themselves and stay warm. Kate Suski had only her bikini on, having shed her sundress to swim better. Dan Suski had got rid of his shorts, having recalled a saying when he was a kid that “the best-dressed corpses wear cotton”.

They heard a stream nearby but decided to wait until daylight to determine whether the water was safe to drink.

As the sun came up, they began to hike through thick brush, picking up bitter mangoes along the way and stopping to eat green bananas.

“It was probably the best and worst banana I’ve ever had,” Dan Suski recalled.

Some three hours later, they spotted a young farm worker walking with his white dog. He fed them crackers, gave them water and waited until police arrived, the Suskis said.

“We asked if he knew anything about the captain and mate,” Kate Suski said. “He said he had seen the news the night before and they hadn’t been found at that time. I think we felt a sense of tragedy that we weren’t prepared for.”

The Suskis were hospitalised 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, noting that their relatives called and took care of them after the ordeal.