Drawbridge openings for pleasure and commercial vessels passing under the Woodrow Wilson Bridge will be sharply reduced for two months, Transportation Secretary Samuel K. Skinner said yesterday.

For drivers of the more than 160,000 vehicles crossing the Potomac River bridge each day, the restrictions should result in fewer traffic delays from drawbridge openings, particularly during the day. The existing ban on rush-hour openings remains.

Standing under the bridge at Jones Point on the Alexandria shoreline, Skinner told a news conference that the recent rash of traffic backups caused by electrical problems with the drawspan prompted his action.

"Our objective is to get the bridge fixed, keep traffic moving and not . . . cause unnecessary hardship on commercial users as well as the boating public," Skinner said.

The secretary heads the Coast Guard, which regulates the channel, and the Federal Highway Administration, which owns the bridge carrying the Capital Beltway over the Potomac between Alexandria and Prince George's County.

Under the emergency regulation, which went into effect yesterday, most vessels too tall to clear the 50-foot vertical distance from the water to 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 at noon each weekday with an hour's notice.

On weekends and Labor Day, the drawbridge will be opened between midnight and 6 a.m. with two hours' warning, and at noon and 9 p.m. with an hour's notice.

Most commercial vessels may use the drawbridge between 10 a.m. and 1 p.m. each day. Larger vessels require 24 hours' warning and a permit.

Currently there are no weekend limits on openings. Commercial vessels may travel between 9 a.m. and 4 p.m., and pleasure craft between 10 a.m. and 3 p.m. An hour's notice is required for an opening.

The temporary restrictions will be in effect for at least 60 days while engineers correct the electrical problems that are preventing the drawspan from opening and closing correctly.

"I have every reason to believe that at the end of 60 days, we'll have a system in place that will allow us to go back to the regular schedule," Skinner said.

He said a $100,000 backup electrical system will be installed and an electrician will be stationed on the bridge during openings.

The plan was endorsed by the nation's largest pleasure boat association, but the largest commercial user of the drawbridge was lukewarm toward the limits.

James G. Boatner, president of Robinson Terminal Warehouse Corp., a newsprint storage and handling plant on the Alexandria waterfront, said the commercial restrictions may pose scheduling difficulties for a freighter that carries half the company's newsprint.

Robinson Terminal is owned by The Washington Post Co. and supplies newsprint to The Post and 50 other customers in the region.

Before the news conference, Boatner complained to Rep. Stan Parris (R-Va.) that the limits were drawn "in the dark" without consultation with area officials.

Boatner also confronted Skinner before the news conference, saying Robinson "is a very small part of the overall problem" because the company averages one passage a week.

Skinner's announcement carried political overtones. Parris may be in a tough reelection campaign this fall against Alexandria Mayor James P. Moran Jr.

Democrat Moran convened a meeting of area officials last week to come up with a proposal for drawbridge opening restrictions and has been reaping publicity.