Two 15-year-old District of Columbia high school students will sail for Greenland aboard a U.S. Coast Guard icebreaker this summer as part of their high school marine science program.

Going along for the two-month, 5,000-mile trip will be 10th graders Robert Crawford and Ranaldo Coates, students at Randall High School, First and I streets SW. The school, which has had an aeronautics and marine scinece program since 1976, teaches many of its students scuba diving at an indoor city pool, flying at Manassas airfield and how to measure pollution in the nearby Potomac River.

But Crawford and Coates will be the city's first students to participate in the 10-year-old U.S. Coast Guard program that sends more than 500 youths to sea every year.

Most of the youths are Naval Sea Cadets or members of the Boy Scouts of American explorer program, and most go to sea for only a few days or a week, according to Coast Guard spokesman James R. Ward. On one longer trip, two Sea Cadets sailed to Antarctica aboard a Coast Guard icebreaker.

The two Randall High School students were chosen because of the school's unusual marine science program and for "good community relations," said Ward. Randall is near the U.S. Coast Guard headquarters at 2nd and D streets SW.

Coates and Crawford will sail on the 269-foot polar icebreaker Westwind. The ship, assigned to the Great Lakes in winter, breaks open a sea lane every summer to carry supplies to the U.S. Air Force base at Thule, Greenland.

The boys' parents last week were still having difficulty envisioning their youngsters sailing into Arctic waters.

"Will there be dangers?" Lorette Coates asked Randall High School Principal Otis W. Thompson at a briefing last week. "No, not if they dress warmly," he responded.

The two boys seemed calm about the Coast Guard's invitation to visit the Artic.

"I don't know what I'll see except for a few icebergs," said Coates, "but it will give me experience for what I'm interested in . . . scuba diving and maybe going into the Navy." f

Crawford and Coates, who have sailedonly on small boats in the Potomac, will fly to Cleveland June 27 to join the Westwind as it prepares to head up the St. Lawrence River to Newfoundland and then to Greenland.

On the two-month round trip the boys will work in effect as apprentice seamen, "helping in the engine room, on deck crews, in the infirmary, everywhere," said Ward.

But like the rest of the 150- to 200-man crew of Westwind, Crawford and Coates will get "shore leave" in Montreal, Saint John, Newfoundland and Disko Island, Greenland, according to Thompson.

Although they will be sailing within 800 miles of the North Pole, "the temperature will be no lower than 32 degrees because it will be summer and the sun will be shining 17 to 18 hours a day," Thompson told the boys and their parents. The youths were chosen for the trip on the recommendation of their science teachers. About 125 of Randall's 300 students are in the marine science program.

The school and the boys must raise the money for the trip, including round-trip plane fare to Cleveland and four dollars each (the minimum fee required by federal law) for every day they spend on board the Westwind.

Johnson said the United Black Fund, part of the nonprofit United Way of the National Capital Area, will help pay for most of the boys' trip. Calvin W. Rolark, president of the United Black Fund, said that UBF would contribute $1,000 of the $1,400 cost of the trip. The remainder will be made up by the boys and their families.