The once and future presidential yacht Sequoia has passed her first test after refurbishment and is, figuratively, on her way back to Washington. She'll make a lot of way stops before arriving here permanently in 1988.

Fresh from a $2 million renovation at Virginia's Norfolk Shipbuilding and Dry Dock Co., the Sequoia underwent her first trial voyage Thursday on the Elizabeth River. "As far as I know, the sea trials went as planned," said one midlevel employe.

The Sequoia had been the presidential yacht since Herbert Hoover's administration spared it from rumrunning duties on the lower Mississippi during Prohibition. She became famous through ensuing administrations as a place for such diverse activities as diplomacy and presidential poker parties.

In one of the more lamentable decisions of his administration, President Carter sold her as an economy move and, when she was rescued for renovation by the nonprofit Presidential Yacht Trust, she was destined to become a floating nightclub in Florida.

The wooden-hulled 104-foot craft, built in 1925, will go on fund-raising tours -- including one to the Statue of Liberty rededication -- before being turned over to the government in 1988. Donations for Douglass

An interesting chapter of Washington's past is reflected by an invitation just arrived from Elaine Dym, president of the D.C. League of Republican Women. The league is sponsoring a $10-a-person picnic (with larger donations gratefully accepted) Saturday in Anacostia, with proceeds to go toward continued restoration of the Frederick Douglass home near 13th and V streets SE, part of the national park system.

What's this, the Republicans co-opting the abolitionist and speaker revered by black Americans and admired by most others? By no means; in Douglass' lifetime, the GOP was Abraham Lincoln's party, which freed the slaves.

Douglass, a noted orator and journalist who had been born a slave on Maryland's Eastern Shore, was appointed to successive posts by Republican presidents -- by Ulysses S. Grant in 1871 as assistant secretary of a diplomatic commission to the Caribbean island of Santo Domingo and later as a D.C. territorial legislator; by Rutherford B. Hayes in 1877 as U.S. marshal for the District (the first black U.S. marshal anywhere, an appointment that kicked up a storm); by James A. Garfield in 1881 as the D.C. recorder of deeds, and by Benjamin Harrison in 1889 as U.S. minister to Haiti. Douglass died in his seventies, precise age unknown, in 1895.

There's a slight "oops" factor in the formal invitation to Saturday's picnic: It spells his name "Douglas."

It wasn't until Franklin D. Roosevelt's New Deal that blacks shifted allegiance significantly to the Democratic Party. More Happy Days

Yesterday Metro Scene reprinted an advertisement that appeared Friday under the classified heading "Happy Days" in which the anonymous signer lamented the diet he or she is on. (This column has no access to the identity of the advertiser.)

Here's the text of a second ad, published yesterday:HAPPY DAYS

LML -- Phase 2. It's cup & saucer time. 125/LAV.

What does it mean? If 125 was his or her weight, the dieter has lost no poundage since we saw the first ad. Stay tuned.