SHOWTIME: If autumn winds are howling, it must be time for the 21st U.S. Sailboat Show in Annapolis, the nation's oldest in-the-water boat show.

Sure enough, it opens Thursday at City Dock with VIP/Press Day, when tickets are $20 apiece, then runs Friday through Oct. 8 (Columbus Day) at the regular daily rate of $8.

In addition to the usual glittering array of yachts, special features include 1989-'90 Whitbread 'Round the World maxiboat competitors The Card (now owned by Ted Turner Jr., who plans to do the 1992-93 race) and Fazisi, the first Soviet Whitbread entry.

Some top Annapolis racers will stage a "Sail for Sight Regatta" in connection with the show at 5:30 Thursday to benefit the RP Foundation . Call 1-800-638-2300 for entry details.

The Sailboat Show will be followed by its sister Powerboat Show, Oct. 11-14. For show information, call (301) 268-8828.

FORGOTTEN STREAM:

Folks in Colmar Manor are organizing fall trips on the Anacostia to explore the Washington area's other river.

A canoe trip is scheduled Saturday, leaving Bladensburg Marina at 9:30 and returning about 1:30. Participants must be 18 and have some canoeing experience; the fee is $5. Canoes provided.

JUST DUCKY:

With duck hunting season nigh (it opens Oct. 19 in Maryland), the Ward Foundation plans its 23d annual wildfowl art exhibition next weekend at Wicomico Civic Center in Salisbury. The show is named for Crisfield's famous Ward brothers, whose decoys are worth small fortunes.

Show hours are 10-8 Saturday, 10-4 Sunday; admission is $4 adults, $3 for seniors and students, kids under 12 free. Call 1-800-742-4988.

STICKY STUFF:

Rock climbers can try out the latest in climbing shoes for free from 2-7 p.m. today at Carderock Park. Hudson Trail Outfitters will have ropes set up and gear on hand to test. Carderock is a mile outside the Beltway off Cabin John Parkway. SHOES OF THE FISHERMAN: Five top professional bass fishermen will hold a fishing seminar Saturday to benefit the Fellowship of Christian Anglers. Jimmy Houston and Woo Daves head up the program, which runs from 6-9 p.m. at John Hanson Middle School in Waldorf. All youngsters admitted free.

For information, call Ken Penrod at (301) 572-5688 or Jim Kundreskas, (301) 934-2025.