Chase Poust, his 4-year-old sister and their father went fishing off the Florida coast Friday night.
While the boat was anchored, Chase and his sister Abigail got out to swim--but the current was too strong.
"The current was so strong that my sister--she usually hangs out at the back of the boat and--she let go so I let go of the boat and grabbed her and then I was stuck," Chase recalled in an interview with a local news station.
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Their father immediately jumped into the water to help.
Abigail had on a life jacket, but Chase and his father did not.
"I told them I loved him because I wasn't sure what's going to happen," Steven Poust said. "I tried to stick with her as long as I could--with both of them. I wore myself out, and she drifted away from me."
While his father tried to save his sister, Chase started swimming to shore.
For an hour, he would swim for a while, then float on his back to rest. Eventually he made it to shore.
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That's when he ran to a neighbor's door to get help. Together they called 911 and got rescue crews into the water.
Florida Fish and Wildlife crews quickly found and rescued Abigail and her father.
"We're here. By the grace of God, we're here," Steven said.