"Force 10 from Navarone" is an oafish account of what appears to be the least necessary and plausible commando operation of all fictional World War II. Now at area theaters, the film is a belated sequel to "The Guns of Navarone," one of the big hits of 1961.

I recall "Guns" as more of a schlepper than a rouser, but at least it was a professionally polished adventure melodrama. Playing commando with Gregory Peck, David Niven, Anthony Quinn, Anthony Quayle, James Darren and Irene Papas wasn't all that thrilling, but writer-producer Carl Foreman and director J. Lee Thompson touched all the melodramatic bases and rationalized the mission itself.

The sequel opens with climactic scenes from "Guns," which remain the most dynamic moments in "Force 10" as well. The late Robert Shaw and Edward Fox, inheriting the roles originated by Peck and Niven, respectively, reenact a scene from the tail end of the film, satisfying what someone must have thought of as obligatory formalities.

The sequel proper commences back in England when the Navarone veterans are reunited for an operation aimed at keeping a bridge in Yugoslavia from falling into the hands of the Germans. This mission, called Force 10, is commanded by a testy young American officer played by Harrison Ford, who is compelled to accept Shaw and Fox against his will. He has a point, since they've been assigned what appears to be a tangential mission: Knocking off a double agent named Lescovar, currently operating with the Yugoslay partisans.

Lescovar is alleged to have betrayed the Navarone mission. I can't recall anything of the sort from the first film, in which the commandos were briefly diverted by the treachery of a young woman named anna, supposedly a mute and a greek partisan. Perhaps Lescovar originated in the Alistair Maclean novel and has now been revived. At any rate Force 10 proves a raggedy, disorganized scheme from the outset. The relative importance of the major objective and the minor objective become submerged in the overwhelming dullness and irrelevance of the movie itself.

Harrison Ford can't seem to conceal his disaffection. He sounds curiously disembodied, as if he were phoning in his dialogue. I suspect he disliked what he saw of his wooden performance when it came time to dub the dialogue. His frosted line readings are the coup de grace. This self-destructing performance is the most impressive act of sabotage in the picture.

The script is so slack that one feels grateful for an egregiously awful performance-Richard Kiel, the "Jaws" of "The Spy Who Loved Me," as a vicious giant of a collaborator, Barbara Bach of the same film has been enlisted for token sex appeal. Carl Weathers, drafted from "Rocky," appears as a black sergeant whose defiant, outspoken racial consciousness is a mere 30 years or so ahead of its time.

If any one made a respectable effort to invest this story with authenticity or tension it is not apparent on the screen. Even the big spectacle, the demolition of a dam, is going to look unimpressive to moviegoers who've already been to "Superman" and seen the identical illusion depicted with far more skill.

Ironically, the director of "Force 10," Guy Hamilton, a veteran of the Bond spectacles, was originally hired to do "Superman." It's terrifying to imagine how "Superman" might haved ended up if Hamilton had imposed the sluggishness of "Force 10" upon it. Perhaps the company simply went into a funk during the long Yugoslav locations.

It seems more likely that the screenplay never made much sense to begin with, dooming the filmmakers to go through the motions. In the case of Ford even going through the motions seems to be aking the impossible. "Force 10" is a mission that should probably have been aborted. Instead it's been allowed to abort on the screen.