Defending champions Blair Tuke and Peter Burling are in fifth place after the first day of racing at the world 49er sailing regatta in Buenos Airies.
With the field split into two fleets the New Zealand pair managed two wins, ruined by an 18th in the day's other race.
Burling and Tuke have won the last two world titles.
Croatian, Spanish and Polish crews fill the top spot.
Fellow New Zealanders Marcus Sommerville and Aaron Hume-Merry are ninth.