Sealed bids for the president yacht Sequoia were ceremoniously opened in Postsmouth, R.I., yesterday and Thomas Malloy of Cranston, R.I., was found to have the highest bid - $286,000.

Maybe you think that's the end of the saga of the venerable yacht, coveted by historic preservationists, by Hustler publisher Larry Flynt (whose $200,000 was ninth out of 174), by industrialistart collector Armand Hammer (whose $251,000 bid was third), but not by President Carter, who ordered it sold as an economy measure.

Wait. There may be troubled waters ahead.

The winning bid will not be accepted officially, until Monday. This afternoon, there will be an emergency meeting of representatives from the Department of the Interior, Defense and Justice to determine whether the sale is legal.

On Monday, the Under Secretary of the Interior wrote to the Secretary of the Navy, making the "stong recommendation that you proceed no further with the sale" until determining whether the yacht qualifies as an historic monument."It's clear that the Sequoia is likely to meet the criteria for the National Register," he wrote.

However, the Interior Department cannot rule that the yacht does meet the criteria unless the Navy Department requests Interior to make that decision.

Interior, Department and other preservationists have made previous such requests, less strongly worded, but the Navy Department has gone along on schedule with the sale.

The delay between opening bids and accepting one is designed to give the Navy time to check on the financial capabilities of the buyer. Malloy had sent in, as requested, a certified check for 20 per cent of the purchase price.

He identified himself as the president of the Leisure Craft Corporation in Florida. Malloy could not be reached for comment yesterday, but WJR-TV in Providence identified him as a contractor who has plans to begin a tourist and cruise business in Newport - buying the Sequoia is Leisure Craft's first venture the report said - and to organize rock concerts.

Malloy had told the sales office staff that he wanted no publicity now, but hoped to [WORD ILLEGIBLE] the Sequoia to the America's Cup Trials of [WORD ILLEGIBLE] this summer.