Defending Star Class champions Mark Reynolds and Hal Haenel were among three groups of Americans to hold second place in their classes after the second day of competition.
Courtney Becker-Dey of The Dalles, Ore., was second in the Europe Class and Californians Jeff Madrigali, Jim Barton and Kent Massey were second in Soling.
Reynolds, of San Diego, and Haenel, of Los Angeles, finished fifth in their race to fall one point behind the Brazilian team of Torben Grael and Marcelo Ferreira.
Becker-Dey finished eighth to fall six points behind Kristine Roug of Denmark.
The U.S. Soling team fell out of the lead it held after the first two races by finishing ninth in the third race and trail the German team of Jochen Schuemann and Thomas Flack by two.
In the Tornado Class, John Lovell of New Orleans and Charlie Ogletree of Kemauh, Texas, were tied with Austria's Andreas Hagara and Floridan Schneeberger for third place behind Spain and Australia.