The Waikiki siblings dominated the field of about 327 in the annual event that consists of a 400-meter swim, 10-mile bike ride and 3-mile run. Matt, 18, pulled away from his older brother early in the run to finish in 47 minutes, 22 seconds. Chad, 21, finished in 48:39, followed closely by Tim Marr, 24, in 48:57.

"The swim was a little rough; the surf was up," said Matt Seymour, who just completed his freshman year at the University of Hawai'i. He emerged from the swim in third place. Once he caught his brother, they "kind of dropped Timmy" on the flat out-and-back bike course.

Chad Seymour, who qualified for Ironman last Sunday by winning his age group at the Keauhou Kona Triathlon, made a better transition from the bike to the run, forcing his younger brother to push hard early.

"Actually, I prefer the longer (races)," said Chad, who works at Island Triathlon & Bike. "He usually beats me in the shorter ones."

KATHERINE NICHOLS

Katherine Nichols, a 37-year-old writer and mother of two, won the women's competition in 53:18, her third win in this event since 1998. Heidi Van Brocklin, 28, battled a pack of about four other women, but cinched her top-three standing during the run and finished in 56:45. Former Miss Hawai'i Candes Meijide Gentry, 26, overtook several women during the run to finish third in 57:05.

"Heidi passed me like I was standing still," laughed Gentry, who is working on an MBA at UH, performing in Diamond Head Theater's production of "Follies" and training for her second XTERRA (an off-road triathlon event held in Maui).

Van Brocklin, a Navy diver based at Hickam Air Force Base, is currently preparing for Ironman Canada in August. She said she was able to separate herself from the group yesterday by the halfway point in the out-and-back run. This was her third triathlon.

One of several outstanding age-group performances came from 45-year-old Ashely Dustow, who won his division and finished 27th overall in 54:19.

The North Shore Triathlon is the second in the three-race Na Wahine Triathlon series, where female athletes can win awards for participating, according to series organizer KC Carlberg. The other races are the Lanikai Triathlon, which was held in April, and September's Na Wahine Sprint Triathlon.