Watching ''U-571,'' you can always sense where the action is headed, but you're never sure just how it's going to get there. The movie wastes no time letting us know that it's willing to kill off key characters, to leave our heroes in a lurch and then dig them in deeper, and deeper still. Mostow, it's clear, was heavily influenced by the leaky-rivet, nuts-and-bolts existential physicality of ''Das Boot'' (1982), Wolfgang Petersen's celebrated German U-boat thriller, perhaps the first World War II movie realistic enough to imagine a submarine as a giant yet claustrophobic sardine can. Like ''Das Boot,'' ''U-571'' depicts underwater warriors as cocooned and vulnerable, sleuthing through the sea with only an eggshell of tin to separate themselves from death.
This, however, is the rollicking American version. The setting may be ''serious,'' and scrupulous in its historical detail, but the filmmaking is strictly for kicks -- we might be watching ''Dying Hard to Save Private Ryan.'' Mostow is a junkie for narrative, and ''U-571'' has been designed to leap from one suspense gambit to the next (a stowaway enemy sailor, a battery that dies at just the wrong moment).
The movie is filled with grandly ominous images of sinking ships, zooming surveillance planes, and torpedoes that propel their way through the water like skinny metal sharks. When the submarine has to dive 400 meters beneath the surface to avoid detection, you can practically feel the water pressure crushing in on the sailors.
There's an element of dread-soaked comedy -- and, it must be said, of unabashed gimmickry -- to the director's orchestrated high-risk sweepstakes. Still, Mostow, like Howard Hawks, has a knack for using action to reveal his characters' inner moxie. Most of the performers in ''U-571'' have been cast subtly against type, an effect that's only enhanced by the severity of their military haircuts, and we're held, in scene after scene, by the emotion in their faces: the husky authority of David Keith, the surprising tremulousness of Jon Bon Jovi (completely unrecognizable without his rock-dandy mane), the prickliness of Harvey Keitel, and the tersely woeful heroism of Matthew McConaughey.
The entire movie is structured as a test of Lieutenant Tyler's (McConaughey) leadership -- does he have the mettle to take charge? -- but by the end, we're really watching McConaughey finally earn his stripes as a star. He's a face of stoic courage amid the movie's sound and fury.