Missing teen sailor 'sobering' for Jess

Jessica Watson didn't think much about the dangers when she was at sea, but the search for her missing sailor mate has brought it all home, her mother says.

Jessica, who last month became the youngest person to sail solo, non-stop and unassisted around the world, has been in touch with the family of Abby Sunderland amid a search for her.

The 16-year-old American was past the halfway mark of her own solo sailing trip on Thursday when she hit trouble, activating two distress beacons off Australia's west coast.

Julie Watson said her daughter and Abby formed a friendship during Jessica's round the world trip, and they were all praying for Abby and her family.

"They've been communicating (Jessica and Abby) and we've been communicating with the family as well," Mrs Watson told the ABC.

"We heard from them this morning ... they're just waiting for information. Our hearts go out to them."

Mrs Watson said the dangers of solo sailing had been brought home to Jessica now that she was back on land.

"She just knows exactly what's going on," she said of her daughter, who was imagining what conditions were like for Abby.

"She was probably a little bit surprised about how she felt back on shore. When you're in the thick of it, she said, you don't think about it that much."

"But when you're on shore, she has a new appreciation for the stuff that we went through and also the stuff that Abby's family and her team are going through."

Earlier Jessica's spokesman Andrew Fraser said everyone was hoping for the best.

"We are hoping she's OK and are trying to stay positive," he said.

A search and rescue mission involving authorities from Australia, the United States and France is underway.

A Qantas passenger jet, tasked by the Australian Maritime Safety Authority, is on its way to the scene - about 2,000 nautical miles west-south-west of Perth. It is expected to reach the area on Friday afternoon.