The Flagship Restaurant, a 57-year-old seafood institution on Washington's Maine Avenue waterfront, will be sold to the owners of another area seafood landmark, Phillips Seafood Restaurant of Ocean City, Md., for more than $6 million.

The sale of the 1,250-seat restaurant is expected to be completed today, said Brice Phillips, whose family owns the six Phillips restaurants in Ocean City, Norfolk and Baltimore.

The Flagship is owned by Daisy Mahan and Ethel Brown, whose familes have been in the seafood business for half a century.

The Flagship restaurant closed its doors yesterday without any advance notice. Employes said they reported for work to find a note on the door saying the restaurant was closed.

Over the past year, Brice Phillips said he, his wife Shirley and their son Steven have been studying sites in the metropolitan area for another restaurant. "It's been our desire for a long time to be in the nation's capital and to be in the area where the Flagship is," said Phillips.

"Our family has owned the restaurant for over 50 years," Mahan said last night. "We felt it was time for us to retire.

"The Phillipses are going to make a very lovely restaurant," Mahan said, adding that Phillips will spend $2 million redecorating the restaurant, which will be renamed Phillips Flagship.

The history of the restaurant -- known for its rum buns -- dates back to 1928 with the founding of Carter Lanhardt Inc., a wholesale seafood business started by Mahan and her brother Bill Carter. After Carter died, his wife Ethel Carter Brown and Daisy Mahan took over the business.

Originally, the firm owned its own fishing boats, nets and oyster beds and expanded by opening a small restaurant called the Flagship.

In the early 1970s, when the District government redeveloped the waterfront, the original Flagship was demolished and a new restaurant was built across the street.

Phillips, which opened in 1928 in a small tar-paper shack in Ocean City, today is a multimillion-dollar operation that dishes up food to more than 25,000 persons on its busiest days.

Its 5-year-old restaurant at Baltimore's Harborplace is ranked by Restaurants and Institutions magazine as the nation's fifth-largest restaurant in sales, with annual revenue of $14 million.

Phillips said the Flagship should reopen by the end of the year and after remodeling will "project the same image as we do in our other restaurants."

Employes of the Flagship complained that some 200 workers -- some with as much as 40 years tenure -- found themselves unemployed when they showed up for work yesterday. "They closed the restaurant with no notice to us," said Mary Lilly, 37, a part-time cashier at the Flagship. "It was rumored for the last couple of months that they were going to sell the Flagship, but the managers denied the rumor."

Lilly's brother Floyd Pitt, 25, prepared food at the restaurant for about four years. "I didn't find out until this morning at 9:00," Pitt said. "I asked them about a month ago and they told employes they weren't going to sell it."

Mahan said the reason they didn't inform Flagship employes about the impending sale was that the restaurant "had a lot of parties booked and we didn't want them to walk out. We will give them severence pay, but there is no agreement with the new company to reemploy them."

Phillips said the workers "will certainly have the opportunity to be with Phillips if they like."