Efforts to have the presidential yacht Sequoia declared an historic monument before a Rhode Island contracter named Thomas Aquinas Malloy sails off with her on Monday continued here yesterday.

Staff people from the Department of Justice joined with members of the Department of the Interior yesterday to urge the Department of the Navy to "follow due process." This would consist of Navy's making an official request for Interior to make a decision on the yacht's historic status. If the Sequoia is then found to qualify for the National Register, as the Under secretary of the Interior has said he thought she would, the Navy would then receive "advice" from Interior on how the yacht should be treated.

Until now, the Navy Department has skipped that step. Instead, it proceeded with the auctioning of the yacht, after President Carter announced that he wanted it sold, and Malloy was found on Wednesday to have the highest bid, $286,000.

However, the Navy Department does not accept that bid officially until Monday, and negotiations among the various government departments are expected to continue today.

Even if the Sequoia is declared an historic monument, it is possible that Malloy eventually will be able to buy her. Covenants on the sale of an historic monument could or could not be recommended. And since Malloy has indicated that he wishes to use the yacht as an "historical tourist attraction," his plans could meet a possible requirement that the yacht be used as a museum.

However, if the yacht is sold to Malloy on Monday without its historic significance being sought, the Navy Department could be open to a lawsuit from the Department of Justice or anyone else charging that dueprocess was not followed in the ale.