Beside the glittering waters of the Washington Channel, the Wilson Boat Line's catamarans, pier and other vessels and belongings were auctioned off for nearly $1.5 million yesterday, ushering in a new and less certain era for the 103-year-old tour boat enterprise.

The boat line, which had until yesterday offered sightseeing tours down the Potomac River from its pier at 6th and Water Streets SW, to Mount Vernon, was declared bankrupt in April by a federal judge. Efforts to arrange a private sale of the heavily indebted company were reported to have foundered. So yesterday's auction was held in an attempt to pay off the boat line's debts.

As auctioneers sold off everything from the line's three 103-foot catamaans to hydrofoils, a vacuum cleaner, model ships and a wheel of fortune, there were signs that the Wilson Boat Line would likely be revived under new owners.

Such hopes appear to ride on Thaddeus A. Lindner, president of a parking lot firm here called Colonial Parking Inc., who offered a successful $150,000 bid that includes the right to lease the Wilson Boat Line's current pier for 93 years.

Lindner, speaking cautiously, said he hopes eventually to resume tour boat service from the 6th Street SW pier to Mount Vernon with the aid of several investors, whom he refused to identify, and the owners of Potomac Boat Tours Inc., who already operate two sightseeing vessels on the river. Did yesterday's auction mark the demise of the Wilson Boat Line? "I certainly hope not," Lindner replied.

The auction appeared to end a 20-year saga for Joseph I. Goldstein, a man of considerable wealth, business ingenuity and some notoriety, who purchased the Wilson Boat Line for an amount he described yesterday as $1,250,000 in 1958. Goldstein flew here yesterday by helicopter for the auction from his Prince Frederick, Md. home, landing on the roof of the pier where Wilson tour boats are docked.

"I'm a poor man. Once I was worth $10 million. I don't know what I'm worth now - probably nothing," Goldstein, who is Maryland Comptroller Louis L. Goldstein's brother, remarked during an often whimsical interview. Yet he conceded he had made a profit - how much he would not say - on the Wilson Boat Line and a companion venture - his purchase and resale to the U.S. government, apparently at several million-dollars' profit of Marshall Hall, a former amusement park across the Potomac from Mount Vernon.

Despite yesterday's auction, substantial debts incurred by Goldstein's boat venture may still remain unpaid. Charles A. Doctor, a Maryland legislator and bankruptcy lawyer who is the court-appointed trustee for the Wilson Boat Line, said the $1,468,750 proceeds of the auction would fall about $2 million short of the boat line's almost $3.5 million debts.

The line, according to Doctor, owes about $2.6 million to Commercial Credit Business Loans Inc., which financed Goldstein's 1974 purchase of the three red, white and blue catamarans named the Liberty, the America and the Freedom. Doctor said the boat line also owes about $300,000 in D.C. and the U.S. taxes. The remainder includes debts to a wide variety of the boat line's suppliers.