(CNN) -- One moment they were reeling in a fish, and the next they were shipwrecked .
Two American siblings, Dan and Kate Suski, are recovering on the Caribbean island of Saint Lucia after a weekend fishing trip turned into a harrowing experience.
Their charter boat sank Sunday, and the pair endured many hours in the water before reaching a beach, a Saint Lucia police detective said.
Four people were on the boat -- the two Americans, a captain and one crew member.
A Saint Lucia resident found the Suski siblings on the beach and called police, the detective said. The captain and crew member were found hours later.
"We are feeling stronger each day and looking forward to reuniting with family and friends," Dan Suski told CNN via e-mail. He and his sister expect to return to the United States by Sunday.
"They told me they had a fish on the line, and were fighting the fish, then heard a noise," said David Suski, an older brother who was not on the trip but was briefed by his siblings.
The captain checked out the engine room, which was filling up with water, David Suski said. It was only about "three to five minutes from the time they heard the noise to when they had to abandon the boat and it sank," he said.
The sea was very rough, and it soon became dark, David Suski said. Officials later told them their boat sank about 12 miles off the coast.
"They are feeling lucky to be alive -- it was quite an ordeal -- both my brother and sister were treated for dehydration and when they made it shore, they drank from a stream, so they also were given antibiotics in case the water wasn't clean," David Suski said.
Both Dan and Kate Suski can swim and had life jackets on, but that didn't make it any less scary.
The pair spent two days in a hospital after reaching land.