A roundup of the week Aug. 31-Sept. 4

BOATING—JOEL HALPERN of Bronxville, N.Y. won the Marina Del Rey (Calif.) Offshore Powerboat Classic to clinch the national powerboat points championship. Driving a 38-foot Cobra with twin 428-inch MerCruiser engines, Halpern covered the 188-mile course in two hours, 27 minutes to finish five minutes ahead of Restaurateur Rocky Aoki, who is second in the season points standings with one race remaining.

Skippering a Soling off the Rochester Yacht Club, 26-year-old ELLEN GERLOFF of Seabrook, Texas won the eighth and final race on Lake Ontario to break a tie with Julie Ratray and win the Adams Cup Regatta, which brings together regional women's champions from eight U.S. districts.

John Bertrand of San Francisco won the world Laser-class sailing title in Kiel, West Germany. Bertrand wrapped up the championship after finishing five races with 13 points.

BOWLING—EARL ANTHONY of Tacoma won the $60,000 Waukegan (Ill.) Open, defeating Tom Wright of Millbrae, Calif. 279-194. Anthony rolled eight straight strikes en route to his 25th career PBA win.

CYCLING—CORNELIA VAN OOSTEN HAGE of the Netherlands won the women's world road cycling championship at Ostuni, Italy, covering the 38.5-mile course in 1:39:14.

PRO FOOTBALL—In the final week of exhibition games, Detroit handed Baltimore its fourth straight loss, 24-9. Washington continued to sputter, losing 9-7 to the Chicago Bears; the Redskins were 2-4 in preseason play. Safety Steve Freeman recovered three fumbles for Buffalo, each leading to a touchdown as the Bills defeated Cleveland 28-10. Atlanta got scoring passes of 28 and 37 yards from Steve Bartkowski to beat Green Bay 26-7. Jim Hart hit 16 of 24 passes for 303 yards and two touchdowns as St. Louis defeated Kansas City 31-14. Cornerback Monte Jackson blocked a punt and converted it into the game's only touchdown as Los Angeles beat San Francisco 10-3 to finish undefeated in preseason play. Miami also was unbeaten, downing New Orleans 20-7. Dallas Fullback Scott Laidlaw scored two fourth-quarter TDs and a third in sudden death as the Cowboys beat Houston 26-20. Pittsburgh's offense netted 473 yards, while the defense yielded only 204 to the New York Jets in a 41-6 Steeler victory. A 102-yard kickoff return by Isaac Hagins was not enough as Tampa Bay lost to Cincinnati 24-13 for a 1-5 preseason record. The other expansion team, Seattle, finished the exhibition season with the same record, losing to Oakland 45-28. Wide Receiver Charlie Joiner scored both Charger TDs as San Diego beat the New York Giants 14-13.

GOLF—ROBERT W. WILLITS, 58, of Kansas City won the 17th annual World Seniors championship in Colorado Springs, Colo., defeating 66-year-old Richard Stevenson of Borrego Springs, Calif., four and three.

HARNESS RACING—STEVE LOBELL, driven by Billy Haughton, was the winner of the second (1:56[2/5]) and fourth (2:02[3/5]) heats of the 51st Hambletonian to take top money in the $263,524 classic for 3-year-old trotters at Du Quoin, Ill. (page 22).

HORSE RACING—MITO WISE DANCER ($5.80), with J. C. Wiley aboard, won the $566,042 Ail-American Derby for quarter horses at Ruidoso Downs, N. Mex. The 3-year-old colt covered the two furlongs in 21.56 seconds for his ninth straight win.

SWIMMING—WENDY BROOK from Ossett in Yorkshire, England, a 20-year-old student /teacher, swam the English Channel in a record-breaking eight hours, 56 minutes. Crossing from Dover to Gris Nez, Brook bettered Tina Bischoff's record set in August by seven minutes.

In California, 21-year-old PENNY DEAN, who attends Pomona College, swam the Catalina Channel from Rancho Palos Verdes to Santa Catalina Island in seven hours, 15 minutes, 55 seconds to break Lynne Cox' record by 92 minutes.

The following day, 15-year-old JOHN YORK of Manhattan Beach knocked 10 seconds off the men's record for the Catalina Channel swim. John, who stands 5'3" and weighs 107 pounds, swam the 21-mile strait in eight hours, 49 minutes and 50 seconds. The old record had been set by David Cox, Lynne's brother, in 1972.

TENNIS—CANADA upset the U.S. 2-1 in the Stevens Cup senior team tournament in New York. Bob Bedard of Canada beat Vic Seixas 2-6, 6-4, 6-4, and American Hugh Stewart defeated Lorne Maine 7-5, 6-1. Bedard and Maine defeated Seixas and Stewart in the deciding doubles match 7-5, 4-6, 7-6. It was the first time the U.S. has lost the Stevens Cup since its inception in 1964.

Second-seeded BJORN BORG of Sweden won the $125,000 United States Pro Championship for the third year in a row, defeating Harold Solomon 6-7, 6-4, 6-1, 6-2, at the Longwood Cricket Club in Brookline, Mass. Borg won $25,000 to boost his 1976 earnings to $182,000.

MILEPOSTS—CHARGED: Five Olympic weightlifters, by the International Olympic Committee's medical commission, with using illegal drugs at Montreal. The violators are gold medalists VALENTIN CHRISTOV (Bulgaria) and ZBIGNEW KACZMAREK (Poland), silver medalist BLAGOI BLAGOEV (Bulgaria), and PHILLIPE GRIPPALDI (U.S.) and ARNE NORRBACK (Sweden). The IOC is considering what action to take against the lifters.

FIRED: By the Montreal Expos, first-year Manager KARL KUEHL, 38. The Expos, headed for their worst record since joining the National League in 1969, lead the majors with 85 losses (they've won 43). Kuehl's replacement for the remainder of the season is former San Francisco Giants Manager Charlie Fox.

HIRED: DARRELL JOHNSON, 49, as manager of the Seattle Mariners, one of the two American League expansion clubs that begin play next season. Johnson was fired by Boston in July, when the Red Sox were playing .477 ball after having come within one game of winning the 1975 World Series.

HIRED: By the WHA Minnesota Fighting Saints, GLEN SONMOR, 47, as head coach. Sonmor will also serve as general manager of the new franchise, which replaces the one of the same name that folded midway through last season.

HIRED: JOHNNY WILSON, 47, as head coach of the (Denver) Colorado Rockies (formerly the Kansas City Scouts), the newest franchise in the National Hockey League. Wilson, a forward in the NHL for 11 years, was the coach of the WHA Cleveland Crusaders last season.

DIED: DOUG DAVIS JR., 59, one of the leading trainers in Kentucky thoroughbred racing; of a heart attack; in Versailles, Ky. Davis died just two days after his 4-year-old filly, Dancers Countess, won the $125,000 Matchmaker Stakes at Atlantic City. In a 36-year career, Davis saddled 50 stakes winners.