It was a rare balmy San Francisco afternoon, and Gary Hart took time out to go sailing. The Colorado senator has not given up his quest for the Democratic nomination , he said in an often-repeated refrain just before the opening of the Democratic National Convention. A flurry of controversy surrounding Walter Mondale's handling of the issue of who will chair the party has given Hart backers hope that the ''lightning'' might strike and the miracle might occur that would put their man on top when the delegates pick a candidate Wednesday night.
But the intense Coloradan has apparently adopted a mellow California style for the San Francisco convention that includes time out for sailing and for a pop concert. He's aiming no direct hits at his chief opponent, Mr. Mondale.
''We are going to send Ronald Reagan back to his ranch in 1985,'' he told a meeting of Hispanic delegates, while avoiding mention of Mondale.
While convention participants fumed over what many saw as the Mondale debacle , which included reports of firing party chairman Charles T. Manatt, just as the convention opened in Mr. Manatt's home state, Mr. Hart understated the move as merely ''surprising.''
Hart also proclaimed himself to be well satisfied with his role at the convention. ''I don't feel shut out at all,'' he said on Sunday. ''It's a much more open convention than most people realize.''
The noncombatant tone is intentional, according to his press secretary, Kathy Bushkin. ''He doesn't like to pick fights,'' she says. ''He really doesn't.''
As a result, the Hart effort almost moves into limbo at the start of the convention. But his delegates are standing firm. ''Our delegation is rock solid, '' says Irwin Nowick, a Los Angeles lawyer who is a Hart delegate. One San Diego delegate, sporting a sombrero plastered with a Hart bumper sticker, refused to consider the possibility of her candidate's losing, as she cheerfully affirmed her allegiance.
Meanwhile, Mondale delegates have been holding steady, all but assuring him a slim majority of the nomination votes.
The Hart camp concedes that Mondale has almost locked up a first-ballot victory. ''We think it's most unlikely'' that another ballot will be needed, Hart volunteer Frank Mankiewicz explains.
So why continue?
''Our delegates really want to go forward,'' says Mrs. Bushkin. Many are newcomers attracted by the new-generation theme of the Colorado senator. They have nothing to lose in supporting their candidate to the end. One Hart worker says: ''Our delegates are not the kind of party hacks who signed up a year and a half ago because they thought we were going to win.''
Moreover, Hart workers say, they want to create the right atmosphere just in case some catastrophic event turns the convention Gary Hart's direction.
The one tangible achievement that the Hart campaign is reaching for is a stronger platform plank against using military force in Central America. The minority plank, which Mondale opposes, is one of only a handful of proposals, including those of Jesse Jackson, which threaten to spark controversies this week on the convention floor. The tiffs could be tame compared with fights over 25 planks in 1980, when Sen. Edward M. Kennedy of Massachusetts challenged President Jimmy Carter and forced him to accept Kennedy platform planks.
But if Hart is staging no disruption of Democratic harmony, then his presence and that of his loyal followers at least are a reminder that Mondale remains only a narrow winner within his party who polled only 38.6 percent in primaries.
Says Minneapolis Mondale delegate Tom Beaver wistfully, ''It would help party unity a great deal if (Hart) would call a halt to his campaigning'' and agree to back Mondale.
Hart delegate Burt Margolin, a Los Angeles member of the California Assembly, counters, ''No one is suggesting that we're not going to come out of this convention unified. Candidates have a tendency to take their candidacies down to the final night.''
As for Hart, he has promised privately as well as publicly to work hard for the Democratic ticket, even if he won't concede before Wednesday. But it's also clear that many of his backers will be less enthusiastic, even with the addition of the widely applauded vice-presidential choice of Rep. Geraldine A. Ferraro of New York.
Hart delegate Irwin Nowick says that if Mondale wins the nomination, ''I'll hold my nose and vote for him.''