The Crimson heavyweight crews face their first real test of the season on the Charies Saturday in the Compton Cup against undefeated Princeton and once-beaten M.I.T. The varsity race, to be run at 6:30 p.m., will give coach Harry Parker his first indication of how his crew will perform over the short 2000 meter course.

Earlier in the afternoon, Coach Fred Cabot's lightweight crews will take on undefeated Navy in an attempt to make up for last week's losses to M.I.T. Both heavyweight and lightweight races will run through the afternoon and will finish below the M.I.T. boathouse.

Undefeated in three races this year, the Tiger heavyweight varsity is regarded as one of the best crews in the East. A Crimson victory would put Harvard among the top contenders for heavyweight honors. Though a three-length loser to Yale last week, M.L.T. looks strong, too, and will not be overlooked.

The Crimson's four and one half length win over Brown and Rutgers last week "confirmed my belief that we're going to be a good crew." said Parker. The varsity has been rowing well this week and hopes to row the race at 33-34 strokes per minute, two or three points higher than last week.

If the varsity can make the higher stroke work, it should be able to take off faster than it did against Brown. Always a good long distance crew, the Crimson will find out Saturday if it can attain top speed over the short Sprint and Olympic course.

Despite the three-foot loss to M.I.T. last Saturday, the varsity lightweights stand a good chance of handing Navy its first loss in four races in the Haines Cup Harvard's time in the loss last week was one of its fastest in recent years, and the varsity has continued to improve this week.

Parker has made no changes in the heavyweight boats. In the lightweight varsity, a bad back has put sophomore Peter Whitman out for a week, and captain Jim MacMahon, who rowed in the four spot last week, has replaced him. Cabot has put sophomore Allan Tice, who rowed varsity two weeks ago, in at four.

Cornell, winner at the Sprints last year, opens its season this weekend, making Saturday's races a crucial preview for the Sprints May 16. As it stands now, Yale and Princeton have shown themselves the leading heavyweight crews, and despite last week's loss, the Crimson lightweights remain a top contended with M.I.T. for the sprint crown