"The wind is beginning to pick up. It is back up to 20 knots and I am expecting that by midnight tonight I could have 35-50 knots with gusts to 60 so I am off to sleep before it really picks up," she wrote.
Abby's goal at the outset of her trip, to become the youngest sailor to pull off a solo nonstop circumnavigation, ended in April, when she was forced to stop in South Africa because her autopilot malfunctioned.
She still was bidding to become the youngest sailor to perform a solo circumnavigation.
In a June 2 report titled "How Young Is Too Young?," "20/20" described Sunderland's circumnavigation attempt.
"I am definitely nervous," Abby told "20/20." "People say you shouldn't be nervous if you are really ready to do this. But I understand [the] ocean, and I understand how dangerous what I am doing actually is, and I understand how careful I need to be out there."
Late last year, Abby began talking publicly about her plan to circumnavigate the globe by herself in a 40-foot boat. It would be, she said, the fulfillment of a dream she sprang on her parents when she was 13.
Laurence and MaryAnne Sunderland, Abby's parents, helped their daughter to prepare for the attempt.
"Could there be a tragedy?" MaryAnne Sunderland said. "Yeah, there could be. But there could be a tragedy on the way home tonight, you know, or driving with her friends in a car at 16. You minimize the risks."
"You arm them with the coping skills," Laurence Sunderland said. "And then you pray."
Not everyone who heard of Abby's plan has been as supportive.
"Child abuse. Child endangerment," said T.J. Simers, a sports columnist for the Los Angeles Times and father of two grown daughters. "I just don't understand the idea of risking life. This kid's going to be out there all by herself. Death is a possibility. Bad weather. Are you kidding me? Who's responsible for this? She's a kid."
Laurence Sunderland answers his critics by saying they don't know his daughter and her abilities.
"When any of my kids come to me with an ambition, I don't laugh at it," said Abby's father, Laurence Sunderland. "I like to listen to my kids. There was a part of me that was even excited, because she's jumped into an arena where I know a little bit about it."
Sunderland schooled Abby in seamanship, testing her, he said, with tougher and tougher solo scenarios through her teens.
"When things went wrong, I'd bring [it to] her attention," Sunderland said. "It was a particularly rough day and her boat was rocking from gunnel to gunnel. ... I knew she was freezing cold, tired and hungry, and we'd been at it for, you know, 20 hours at that stage. I said, 'So Abby, are you ready to sail around the world now?' To which she replied, 'Where is my boat?'"
MaryAnne Sunderland, Abby's mom, joined the story.
"She ended up getting a sponsor," she said. "All she needed was approval, you know, from us."
Laurence Sunderland said the easiest thing for them to have said as parents would have been "No." But then he thought of his daughter and all her talents.
Abby is not the first talented teenager to dream of sailing around the world solo. In 1999, a 17-year-old named Jesse Martin accomplished just that. Yet while at sea, the teen struggled with loneliness and life-threatening storms that left him emotionally devastated.
But Martin witnessed some unforgettable sights along the way -- and made it safely. His adventures were chronicled in the documentary "Lionheart."