Most robots can freely move in any direction so long as there are no obstacles. Autonomous sailing presents a different kind of challenge: the boat can't sail directly towards the wind, so it has to zig-zag ('tack') to get to a point upwind. It's also important to keep saltwater and electronics carefully separated.
Sophia told the Python Group about the adventures of the Southampton Sailing Robot Team, which came together at the start of 2016 to build an autonomous boat. In September, the team travelled to Viana do Castelo, Portugal, to compete in the World Robotic Sailing Championships, where they won the Micro Sailboat class (boats under 1.5m). We learned about the challenges the team faced, and the hardware and software they used.
The team is already planning to compete again next year, and will be recruiting new members later in October.