Southern Illinois coach Ray Essick will be the new chief mentor of Harvard's varsity swimming team.

Although the appointment is not yet official, authoritative sources revealed that barring unforeseen circumstances Essick will formally assume the post later this week.

Robert B. Watson, director of Athletics, offered the spot to Essick yesterday afternoon by phone. His appointment marks the end of a three-week search initiated when former head coach Don Gambril quit his job for a position as the coach at the University of Alabama.

"Don [Gambril] really put the air back in the balloon," Essick said yesterday of the Harvard swimming program. "And I think that with the returning lettermen and the really quality freshmen coming next year, we definitely have the potential to compete on a national level."

Essick, a University of Illinois graduate, produced 21 All-Americans in his seven-year stint as head mentor of SIU. His teams have tallied a 38-20 dual-meet record overall and placed in the top 20 at the NCAA national swim meet every year under his guidance including two 11th place finishes in 1971 and 1972. His squads swept their way to the Mid Western Conference championships those two seasons as well.

"He really upgraded our program here at SIU," Joe Mitch, director of sports information at Southern Illinois, said yesterday. "We feel our program is at a very high level nationally and that Ray is definitely responsible for it. You can imagine how sad we are to see him go."

A screening committee composed of the two team co-captains, Fred Mitchell and Phil Jonckheer, and several other Athletic Department officials reportedly met last weekend and narrowed the list of candidates down to four men of which Essick was apparently the front-runner.

Essick's appointment now goes to the Harvard Corporation and the Board of Overseers for final approval, but these groups traditionally go along with the decision of the screening committee automatically.

Hess Yntema, All-American swimmer for the Crimson, said yesterday, "We [the swimmers] are kind of upset at the way the Athletic Department went about looking for a new coach. Ever since The Crimson got the Sanders story they've been really secretive about the whole process. They told us that this time, we'd read about our new coach first in The Globe."

Watson said that the announcement about the new coach would come later this week, "probably Friday." He said the decision had not yet been "technically made."

Essick, who will turn in his resignation at Southern Illinois this morning, expressed confidence about his new job at Harvard. "I think I have the experience and ability to coach on a national level and with the athletes we'll have next year," he predicted, "I think that's where we'll be."