(CNN) When Eric Wagner bought the "Amen" six years ago, he had no way of knowing the boat would be the actual answer to two Florida teenagers' prayers.

Wagner and his crew were sailing the 53-foot yacht from Delray Beach, Florida, to New Jersey last month when they heard "a desperate scream" over the engines, wind and choppy waves.

They were about 2 miles off shore, so Wagner didn't believe his ears at first.

Then they saw an arm flailing in the water behind them.

"It was kind of surprising we heard them. Especially when they were 150 yards away, almost 200 yards away," he said. "But it was definitely the scream that we heard, and that's why we were looking around."

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