"Gray Lady Down" tickles me more than any movie title in recent memory. Could it be a distress signal from an old folks' home? The name of a tyrannical dowager in a costume melodrama? A new rock group? A new barbiturate? Johnny Carson's writers should have a field day with it in future appearances of Carnac the Magnificent.

In fact, the title refrs to the cleverly named, illfated Neptune, a nuclear submarine which becomes the object of elaborate rescue operations after being rammed by a blundering. Nowegian freighter. The Neptune's shake down cruise is transformed into a swan song, but skipper Charlton Heston and about 40 crewmen remain alive in the mortally damaged sub as it teeters on a ledge 1,400 feet beneath the surface and 60 miles off Bew London, Conn.

Stacy Keach commands the rescue fleet, which relies on a pair of exotic miniature submarines, the DSRV and the Snark, to reach the survivors.

"Gray Lady Down" might have been conceived as a companion feature to Universal's earlier "Airport '77," in which a submerged 747 was rescued by the Coast Guard, whose personnel, vessels and techniques proved more photogenic and intriguing than the would be fictional aspectas of the film. In this installment of "Your Navy in Action" the Universal spotlight shifts to Submarine Development Group One, which develops and maintains craft like the DSRV, which can mate its hatch to that of a sunken sub and transfer two dozen rescuees per ship.

Although DSRV duty would seem novel and exacting enough for the purposes of movie suspense, it plays anticlimactic second banana to the tiny Shark, a two man vessel operated by David Carradine and sidekick Ned Beatty. Before the DSRV can attach itself to the Neptune, the snark is required to clear the escape hatch of silt and debris. While the methodical resue operations proceed, the Neptune keeps slipping closer to a watery grave and thje suspense theoretically intensifies. "Gray Lady Down" is by no stretch of the imagination an exemplary suspense thriller, submarine division. At best it's a tolerable exercise in stalwart hokum, a cliche snack that won't provide much nourishment but won't back up on you either. Presently negligible may be the best term for it.

I was looking forward to an entertaining clashof wills and acting styles between Heston and Carradine, but their characters never meet. Heston encounters some perfunctory animosity from executive officer Ronny Cox, who was slated to take over command of the Neptune. Carradine is temporarily thwarted by Keach, who insists on replacing Beatty with one of his own men. Neither source of conflict adds up to anything except a delayingaction.

The idea of Carradine and Beatty as inseparable technician buddies may have a special charge of humor for moviegoers who recall "The Big Bus," in which Beatty played an engineer named Shorty Scotty who was devoted to his "top assistant" Jack, played by Howard Hesseman. It's difficult to keep a straight face when Beatty sorrowfully asks, "Three's a crowd, huh?" as Carradine prepares to submerge with a stranger.

Carradine seems an amusing choic as a maverick naval officer, a lone sea wolf preoccupied with demonstrating the value of his invention, the Snark. He's infinitely more comfortable and convincing in "Gray Lady Down" than he was in Ingmar Bergman's "The Serpent's Egg, although a potentially hilarious opportunity has been lost by failing to cast him opposite Heston, who projects a square sort of heroic authority that almost cries out to be challenge by Carradine's sly, laid back air of superiority.

Universal continues its curious habit of self contempt by inserting a sequence in which some sailors make fun of scenes from "Jaws" when the sound in a wardroom projector conks out. Ingratitude, they name is Universal. Far be it from the landlubber like me to point out the obvious, but if any movie provokes merriment among U.S. Navy personnel, it is likely to be "Gray Lady Do wn."