While the Harlequin Dinner Theatre in Rockville has made a game attempt to revive it, Meredith Wilson's musical, "The Unsinkable Molly Brown," barely floats these days.

It was never one of Broadway's best efforts, but Tammy Grimes' performance as an indomitable hillbilly with social ambitions, two upbeat numbers ("I Ain't Down Yet" and "Belly Up to the Bar, Boys") and a lavish production were enough to propel it to a 532-performance run back in the early 1960s.

At the Harlequin, a youthful cast is carrying on with the fervor of a drunken barn dance. But the relentless vigor of the performances and Dallett Norris' boisterous staging do not achieve the intended goal, which is presumably to fill up the droops and voids in the script. As any poker player knows, bluff and a pair of deuces can carry you only so far.

Mary Ellen Nester carries the burden of the show as the backwoods tomboy who marries into a mining fortune, tries to crash Denver society, fails, flees to Europe to get culture and finally finds a moment of renown when she survives the sinking of the Titanic. Nester is a chipper actress, but while she tries to emphasize Molly's generosity and her warmth, she can't entirely get around the fact that this is--jokes or no--a musical about a very single-minded social climber. "It's not the money I love," Molly admits at one point. "It's the not havin' it I hate."

As Leadville Johnny Brown, the prospector who gives her everything--a brass bed, a set of china, a red dress and two fortunes (Molly inadvertently burns the first wad of bills in the potbellied stove), William I. Howe has a lusty singing voice and a strapping presence not unlike the young Howard Keel. As yet, however, he's not a very confident actor. When Molly will get some sense into her stubborn head and go back to him becomes--in this production--less a romantic than an academic question.

Within its usual limitations, the Harlequin has concocted bright fold-out sets and properly garish costumes. All those bright colors notwithstanding, "The Unsinkable Molly Brown" is really a rather colorless show.

At the Harlequin Dinner Theatre through November.