With only the Harvard heavyweights sitting out this weekend, the Harvard and Radcliffe crews are all vying for national championships this weekend.

On the Cooper River in Camden, N.J., both the Harvard and Radcliffe lightweight crews will row in the Intercollegiate Rowing Association (IRA) Championships.

On the opposite end of the country, the Radcliffe heavyweights will line up at the start of Lake Natoma course in Rancho Cordova, Calif.

The men's lightweight crew will need to overcome arguably the best crew in the country in order to claim a national title.

"I think Princeton has proven themselves to be the class lightweight crew," senior coxswain Sujit Raman said. "They have won every race this year."

The Tigers, who are ranked No. 1 in the latest USRowing poll, defeated the No. 3 Crimson on April 24 with a time of 6:20 seconds to Harvard's 6:24.55.

No. 2 Columbia will also be a tough competitor in the race. The Lions edged out the Crimson in the Eastern Association of Rowing Colleges (EARC) Sprints on May 9. Columbia finished in 5:52.12, while Harvard came in just behind at 5:52.83. Princeton won the race with a 5:50.4.

"I'm confident that if we put together our race, we will be as tough to beat as anyone else," Raman said.

The men will race in the heats at 6:30 a.m. tomorrow. The finals will be held at 3:15 p.m.

"Since Sprints, we've focused on some technical adjustments that will hopefully make us go faster at nationals," Raman said. "A lot of it is breaking things down to their basics and looking at ways to make the boat go faster."

The No. 4 Radcliffe lightweights also will face tough competition from the Tiger crew.

No. 1 Princeton crew will be stiff competition for the Black-and-White, as will No. 2 Villanova and No. 3 Virginia.

On April 24, Radcliffe lost to the Tigers on the Charles River after Princeton blazed to a 7:30.74. Radcliffe was well behind at 7:44.86.

The week before, Radcliffe fell to Virginia, 6:46.4 to 6:47.0.

Then, two weeks ago, at the Eastern Association of Women's Rowing Colleges (EAWRC) Sprints, Radcliffe placed third behind the Tigers and the Cavaliers.

Princeton finished in 6:31.2, followed by Virginia at 6:36.3 and Radcliffe at 6:37.5.

The Radcliffe heavyweights will also face a tough field. Currently No. 6 in the country, the Black-and-White will face a group that includes the five crews ahead of them.

No. 1 Washington, No. 2 California, No. 3 Brown, No. 4 Princeton and No. 5 Virginia are all among the teams competing in the first varsity races.

Princeton, Brown and California each received seeds and were separated from each other in the three heats.

The Black-and-White have fallen to both Brown and Princeton this season, although the races were early in the year.

The Bears rowed to a 6:29.9 while Radcliffe stroked to a 6:34.6 on April 3.

The next week, Princeton edged Radcliffe, 6:40.8 to 6:41.5.

In the EAWRC Sprints, the Crimson placed fourth, well behind Brown, Princeton and Virginia.

Radcliffe's heat will contain Princeton, No. 8 Michigan, No. 10 Michigan St., No. 11 Boston University and No. 12 Oregon St.

The Radcliffe second varsity eight will row in a heat that includes Princeton, Washington, California and Michigan. Washington is seeded in the race.

The varsity fours will face Washington, California, Virginia and Wisconsin. Washington is again the seed in the race.

The races begin today and will run through Sunday.