More than two dozen shivering sailors were fished from the chill waters of the Potomac River yesterday afternoon after their sailboats capsized in winds that gusted up to 58 miles an hour as a sudden and unexpectedly violent squall ripped across the Washington area.

Although 12 persons were taken to hospitals, no serious injuries were reported among those brought to shore after spending as much as 20 minutes amid the whitecaps and four-foot waves of the rain-swollen river.

However, one unidentified Northwest man was still missing early today after high waves swept him from a rented rowboat about 500 yards off Mount Vernon. Two other persons in the boat were rescued, authorities said.

As many as a dozen small vessels were reported damaged or disabled on the Chesapeake Bay as the line of squalls moved eastward, and three boats with at least five persons aboard were reported still missing early today. The boats were last sighted in the Annapolis area, according to the U.S. Coast Guard.

At least 39 persons, from both disabled and capsized boats, were reported brought to the Washington Sailing Marina alone, after the northwest winds tore through a fleet of sailboats assembled on the Potomac for weekly races, ripping their billowing spinnakers from swaying masts.

The ferocity of the winds created what one of yesterday's rescuers, D.C. Police harbor unit officer D.F. Scott, called the worst scene he had ever witnessed on the river.

"It was wall-to-wall overturned boats," Scott said. "We were pulling people out of the water right and left."

Although it was difficult to compile firm figures amid the chaos of the capsized boats and struggling sailors, D.C. police said they pulled 16 persons from the river, Fairfax County rescue authorities reported pulling out six, and rescue workers from National Airport were credited with three more. In addition, Prince George's County fire officials said that in conjunction with airport and harbor unit boats, they saved 16 from the area around the Woodrow Wilson Bridge.

Boats from the sailing marina also pulled gasping, dripping, blue-fingered sailors from the brown waters of the river, whose temperature was estimated at about 48 degrees. Private boaters in motorboats were credited with other rescues.

Among those rescued by one of the marina's boats was Virginia State Del. James Dillard (R-Fairfax) who said he spent 20 minutes in the river after the boat he and two others occupied lost its rudder and capsized.

Still other sailors whose 14- and 16-foot craft were flung against the sea wall of the Naval Research Laboratory in far Southwest, were pulled to safety by laboratory fire and rescue personnel.

"We were literally being smashed back and forth against the sea wall," said Karen Hunt of Vienna. Although not a Catholic, she said, "I was saying Hail Marys for 15 minutes."

Finally, she said, firefighters from the lab came to her aid, and although her fingers were so cold she had a hard time holding to a rescue ladder, she climbed to safety.

Other boats were driven by the northwest winds to various points along the river's Maryland shore, and the colorful spinnakers that some had hoisted earlier when the squall was only a few dark clouds on the horizon, were flung into nearby trees.

The sails flapping in the trees as the wind roared over the river "was a sight I'd never seen before in my life," said Gordon Rutkai, who rents sailboats at the Fort Washington Marina in Prince George's County.

Many persons on or near the river yesterday had experiences that left them awed or amazed by the suddenly unleashed power and fury of the elements.

Although the storm had been brewing all day, according to Officer Scott, and the atmosphere had been changing since 1:15 p.m., it was at 3:30 p.m. when "all hell broke loose."

Speaking of the river, under the force of the fierce wind, an employee of Washington Boat Line, an excursion line, said: "I've never seen it look like that."

John Peacock, 31, and his wife Erlene, 30, were on the river for the sailboat race yesterday when "a great big squall came through with maybe 30 miles per hour gusts that kept up long enough to tip the boat upside down," he said.

Although both he and his wife were wearing wet suits and life preservers, he said she was "terrified."

He perched her atop the boat and she was pulled into a rescue boat, while he remained in the water for as much as 20 minutes more, clinging to the craft and driven with it by the wind through the raging river, he said.

His fingers had begun to turn purple by the time the D.C. police got to him.

John Loe of Washington had already helped friends anchor their 19-foot boat at piling No. 4 at the Washington Sailing Marina when the winds rose.

Although the boat's anchor had been dropped, the boat and the anchor were flung across the width of the river.

"It was amazing," Loe said.

Further south, near the Belle Haven Marina, Rich Van Doren and Hugh Hutchinson were in a 19 1/2-foot power boat when the wind picked up.

It appeared, one of them said, that the wind was "making little tornadoes out of the water." They moved their boat alongside a sharply listing sailboat to pick up two handicapped occupants who said they could not swim.

"It was really something," Van Doren said.

Alexandria fire department battalion chief Douglas Phillips, who headed rescue operations for those brought ashore at the Washington Sailing Marina, said the storm caught everyone by surprise.

"There was no warning at all," he said.

In the words of a National Weather Service forecaster, the squall line stemmed from "a cold front that came down from the mountains and developed in intensity in a very short time.

"We had very little time to react to it."

The Coast Guard reported that several boats capsized in the Chesapeake Bay as the squalls passed through and that a number of others were in distress. About two dozen persons were rescued from the bay, of whom four were actually plucked from the water, the Coast Guard said.

Officials said Coast Guard vessels equipped with radar would continue searching the bay near Annapolis throughout the night for the three missing boats.