Sandra Dolores Yawn has been locked up, left for dead on a Florida highway and chased through the Red Sea by pirates.

In the summer of 2018, Leah Rae Shafer reached out on Facebook to send Ms. Yawn her blessings. Not because she thought Ms. Yawn, who goes by Captain Sandy, needed her well wishes, but because she had started watching “Below Deck Mediterranean” on Bravo.

The show follows a crew tasked with catering to a revolving cadre of guests who have chartered a superyacht. Ms. Yawn, a star of the series, is at the helm. Ms. Shafer had written to congratulate her on the show’s success. There was another reason, too. “I thought she was hot,” she said.

Ms. Yawn, 59, has been a yacht captain for more than 30 years. Her foray into television, which started in 2017, was not exactly foreordained. Until her mid-20s, “I was a mess,” Ms. Yawn said. “I was always in trouble. I got kicked out of 11th grade. I didn’t go to college.” At 13, at the start of an adolescence spent between Dundee, Fla., where her father lived, and Bradenton, Fla., where her mother lived, she started drinking. By 17, “I was getting arrested so many times I couldn’t even count how many,” she said. Usually a parent bailed her out. Her father’s refusal to do so after one drunken incident landed her a night in jail.

In 1989, when she was 25, the revolving door of South Florida treatment centers she had been pushing through quit spinning when a counselor told her she couldn’t return. “She said, ‘Sandy, as soon as you get some money in your pocket you’re going to start drinking again,’” Ms. Yawn said.