The U.S. Coast Guard will continue to limit openings of the Woodrow Wilson Bridge drawspan for an additional four months while mechanical repairs are completed, but will open the bridge more often for commercial ships in the late evening.

Most of the current restrictions would remain intact under the new guidelines through Jan. 25, 1991. But in addition, commercial vessels will be allowed to request openings during the period from 9 p.m. to midnight each day.

Under the extended restrictions, most vessels too tall to clear the bridge can have the drawspan raised between midnight and 4 a.m. on weekdays, after giving two hours' notice.

In addition, the drawbridge may be opened each weekday at noon with a two-hour notice rather than the one-hour notice that has been required. On weekends, the drawbridge will be opened upon request at noon, 9 p.m. and between midnight and 6 a.m. with two hours' notice.

The extension of the restrictions drew general praise from state and local transportation officials.

"We are pleased that we have the extension," said Tara Hamilton, spokeswoman for the District's Department of Public Works, which operates the drawspan.

"This is reasonable," said Alexandria Mayor James P. Moran Jr.

According to Joan Morris, spokeswoman for the Virginia Department of Transportation, "at least it's not what we had before" any restrictions took effect.

Thousands of motorists were angered during the summer when the bridge stuck open, causing traffic backups on the heavily traveled Capital Beltway.

In response, transportation officials from the District, Maryland and Virginia recently called for permanent restrictions on the times when the drawbridge may be opened. The officials also asked that the bridge no longer be opened for recreational boaters.

Michael Sciulla, vice president for governmental affairs for the Boat Owners Association of the United States, said his organization could accept the emergency restrictions temporarily, but not forever.

"Washington, believe it or not, is a port city," Sciulla said. "I think that it would be fundamentally unfair for one group to lock another out."

Officials of Robinson Terminal Warehouse Corp., the main commercial shipper whose vessels require the bridge to be opened, could not be reached for comment. The company is owned by The Washington Post Co.