As some of the world's most advanced yachts jostle for position in Sydney Harbour on Boxing Day, crews may also have to keep a close eye on what's buzzing overhead.
New Zealand-owned Giacomo racing in the Sydney to Hobart race.
Australia's Civil Aviation Authority has issued a warning against spectators flying drones over the Sydney to Hobart yacht race, with a chance the small craft could get caught in sails or damage boats.
CASA spokesman Peter Gibson said drones pose the highest risk during the start and finish of the world famous race.
"The Sydney to Hobart start attracts large crowds and there are low flying aircraft over Sydney Harbour," Mr Gibson said in a statement.
"A drone flown low over the water could hit a yacht or get caught in sails."
Drone pilots should use the Can I fly There? app before flying a drone, Mr Gibson said.