HANOVER, N.H.-The Harvard men's swim team is off the blocks and racing toward that coveted third consecutive Eastern Seaboard Swimming Championship. When the score was posted here last night at Dartmouth's Karl B.Michael Pool, Harvard-with 162 points-held more than double the score of the Princerton squad which, through the five events contested on the opening evening, lagged a distant second with 80.

Stealing the show yesterday was the Crimson's Ted Chappell. Seeded third when he stepped to the blocks at the call for heat four in the preliminaries of the 500-yd. freestyle. Chappell went on to establish himself as the man to beat with a pool record 4:26.71.

With that mark, Chappell moved in to the number one slot, earned lane number three for the evenings final, and qualified for the NCAA Swimming and Diving Championships, to be held in Austin, Texas, in three weeks. Still not satisfied, the sophomore erased his earlier standard with a smoking fast 4:25.09. Chasing Chappell to the finish was co-captain Bobby Hackett, who used this race to slip in under the NCAA qualifying time with a 4:26.39.

Plowing hard through the waves to a third-place finish and completing the Harvard sweep. All-American Larry Countryman missed by less than half a second the 4:26.71 that would have sent him to Austin.

"All was thinking about was Harvard getting the 1-2-3 in the race, my exact place was not important," Chappell said last night.

Looking to follow that first act, individual medleyists Mike Coglin. Tom Verdin, and Tony Meier grabbed first, second, and fourth respectively in the 200-yd.race. For Coglin, it was his second win in this event. The 1:52.80 he needed to steal the crown in the friendly waters of Blodgett Pool two years ago.

Navy's Joe Murphy battled to his second 20.97 of the season to take first place honors in the 50-yd. free. Murphy's unexpected duplication of his personal best enabled him to eke out the win with Princeton's Andy O'Hara and Harvard's co-captain Geoff Seelen only inches behind him.

When diver Jeff Mule completed dive number 11, a forward one and one-half somersault with two twists, the gifted sophomore had amassed 444.70 points, topped only by Cornell's John Krakora. this year's champion from the one-meter board.

With the evening winding down, Harvard's own Fearsome Foursome-the 400-yd. medley relay squadron of Geoff Seelen, Jim Carbone, Meier, and Mike Miao-handed coach Joe Bernal his first victory for that event in his four trips to the meet, since taking over the reins at Harvard. The winning time, 3:24.76, missed the 3:23.76 needed for NCAA's but Seelen's 51.68 on the backstroke leg earns him a career-closing trip to the meet.

"These young men are capitalizing on the opportunity to fulfill their long-awaited goal of maintaining the championship," coach Bernal said last night. In the process, they are turning in fine individual efforts, giving themselves the opportunity to see the materialization of the superior performances they began to aim for at the outset of the season".

THE NOTEBOOK: Yardling Courtney Roberts joined Meier and Coglin in opening up a makesshift barber shop at the Hanover Inn on Wednesday night.

Armed with scissors and clippers, the three apprentice barbers solved the problems of style-conscious teammates Andy Lockman, Jon Sappey, and Chappell.