A team of divers searched Rock Creek Park's Lake Needwood without success yesterday for a 37-year-old Rockville man and his teen-aged son, who are presumed to have drowned in a Sunday afternoon boating accident.

The father was identified as Berhanu Tebeje of 214 N. Adams St., an Ethiopian student at Montgomery College. His son, Daniel Berhanu, 16, had just finished the 11th grade at Richard Montgomery High School, according to a spokesman for the Maryland-National Capital Park Police, the agency handling the search.

William Herren Sr., the Montgomery County Fire and Rescue squad officer in charge of the diving team, said he and five others dived for more than six hours yesterday, covering an area equivalent to three football fields in the section of the 20-acre lake where witnesses said they last saw the father and son.

Tebeje and his son apparently dived from a rented National Capital Park rowboat into the lake at about 5:40 p.m. Sunday in an attempt to rescue Tebeje's 3-year-old son, who had fallen into the water. The child, who was wearing a life preserver, surfaced a few seconds later, but his father and older brother vanished, apparently unable to swim, officers said.

Other boaters at the popular recreation spot rescued the 3-year-old. Two other sons, ages 6 and 7, remained in the rowboat and were uninjured.

Part police have closed the lake.