During the yawning chasm between his benchmark performance in 1969's Medium Cool and his triumphant rediscovery in 1997's Jackie Brown, Robert Forster soldiered through a list of obscurities and Z-grade trash that sounds like a Troy McClure filmography. (You might remember him from such films as Journey Through Rosebud, Satan's Princess, and The Don Is Dead.) The one consolation for his wayward period as a hand-to-mouth character actor is that the experience has made him a self-effacing and inimitably soulful performer, so comfortable and assured within his range that he's never caught reaching for effect. A pair of Forster monologuesone about attempted suicide, the other about his boyhood fantasies of ballet dancingprovide two of the only compelling reasons to sit through Lakeboat, a disjointed and stage-bound adaptation of David Mamet's first play. A formative work for Mamet the artist and the man, Lakeboat was based on a summer he spent as an underling on a Great Lakes freight ship, and it shows early signs of his distinct, rapid-fire cadences and abiding interest in the fraternity of embattled, workaday men. A few exchanges sing with Mametian poetry and wit, but he had yet to master the finer points of character and structure, leaving these promising flourishes adrift in ill-defined relationships and a story that goes nowhere. The author hasn't straightened out these flaws in his screen adaptation, and they're only exacerbated by first-time director Joe Mantegna, a Mamet regular who capably handles his superb ensemble cast, but demonstrates little style or dramatic tension. Mamet's younger brother Tony stars as an ineffectual, middle-class Jewish college student who leaves a Chicago port as a boy and returns a man, thanks to three months' exposure to the grizzled eccentrics aboard a Lake Michigan freight ship. Led by first mate Charles Durning, a WWII veteran with a predilection for egg sandwiches, the crew includes George Wendt as his assistant, J.J. Johnston as a heavy drinker who keeps flasks in the call boxes, and Denis Leary as a fireman who eyes four gauges and a porno magazine. As the summer wears on, Tony develops a special camaraderie with Forster, a sensitive and reticent loner who recognizes his creative talents. Andy Garcia appears unbilled as a sailor who missed the morning call after a night out; the possible reasons for his absence are speculated over in pointless black-and-white flashbacks that were apparently intended as comic. The men in Lakeboat are not individuals so much as Men in the abstract, and the rite of passage Tony endures to join their ranks is assumed rather than dramatized. Mamet's autobiographical play gives access to the source of his unique sensibility, but his prodigious gifts had yet to take shape.