CAMBRIDGE, Mass. -- Ktejil Borch of Norway won the men's championship singles Saturday in the Head of the Charles regatta.
Kathleen Bertko of the United States took the women's championship singles at the regatta in which 20 course records were set.
The 49th annual event took place on a three-mile course in the Charles River between Cambridge and Boston.
Borch defended his championship and broke the 31-year-old record with a time of 17 minutes, 12.313 seconds.
Bertko won in a course record of 18:33:015 and beat three-time defending champion Gevvie Stone. Miroslava Knapkova of Czechoslovakia was third.
Competitors in the regatta race against the clock, leaving the starting line in single file, approximately 15 seconds apart.
Borch is the 2013 world champion in the doubles with fellow Norwegian Jakob Hoff. In Saturday's race, Hoff finished second and former Olympic champion Mahe Drysdale of Australia was third. Borch was the 27th starter last year but started first Saturday.
"I didn't have to pass a lot of people this year," he said. "That was the biggest difference. But I also didn't have other boats to follow. It's different when you're being chased."
Borch won despite being "very sick" recently.
"I only had one gear," he said. "I just tried to push through real hard. I had no race rhythm."
The 30-year-old Bertko, a native of Oakland, Calif., finished second in the lightweight doubles event of this year's world championships with Kristin Hedstrom.
Bertko briefly found herself tangled up with Emma Twigg of New Zealand, who finished fourth, at one of the bridges, but quickly recovered and regained her momentum.
"The adrenaline kicked in right after that," she said.
It was Bertko's third time in the regatta, and she said negotiating the winding course with underpasses under several bridges is still a challenge.
"I tried to keep a good course," she said. "I'm not super comfortable out there."
She said competing as a lightweight this season has gone very well and credited her racing and training partner, Hedstrom, a member of the 2012 Olympic team, for much of her success.
Sam Stitt and Matthew Miller of the Potomac Boat Club won the men's doubles after finishing second last year, while Inge Janssen of the Netherlands and Magdalena Lobnig of Austria captured the women's doubles.
With a southwest wind behind the boats and gentle conditions on the course, records started falling early. They were established in eight straight events for racers 50 and over: the men's and women's singles, doubles, fours and eights.
Some of the records were obliterated. Gregory Benning of the Cambridge Boat Club shattered the 20-year-old course record in the 50-and-over men's singles, chopping almost 40 seconds off the mark.
NOTES: This year's event, the largest two-day regatta in the world, had 6,971 competitors in 2,045 boats from 37 states and 251 international entrants from 23 countries, including the first in history from Mongolia. Dulguun Bassanclava and Tuvshinzaya Gantulga of the Mongolian Rowing Association finished 18th and last in the men's championship doubles but drew great cheers from the fans along the course. ... Defending champion University of Washington and 2011 champion Harvard head the entries for the men's championship eights race Sunday.