Asubmarine trapped under the polar ice cap in the Bering Strait sounds like an exciting concept — throw in a couple of scientists and a beautiful whale-watcher and there’s a hook — but “Sub Down” sinks under the weight of silliness and cliches.

Stephen Baldwin toplines as some kind of scientist who’s “fun” and “cool”: The audience can tell this by his loud-print shirts, goofy Dutch-boy haircut and snarky anti-military attitude. He’s joined by fellow researchers Tom Conti and Gabrielle Anwar on board the USS Portland.

All is well — the researchers are researching, the sub crew is horsing around — when a Russian sub collides with the Portland and it sinks to the bottom of the sea. Well, it’s a big ocean, but darnit if two random subs don’t collide. You gotta hate it when that happens.

Unfortunately, the inherent drama in a submarine movie seems to have left the building, and the script by Howard Chesley is monumentally uninvolving.

But warning No. 1 comes right at the beginning: The director is credited as Alan Smithee. Uh-oh.

Baldwin smirks his way through with a wink, and Chris Mulkey, as the sub’s commander, valiantly tries to find a character. Anwar and Conti try, try, try, but ultimately, “Sub Down” drowns.

Stefano Mainetti’s music overwhelms; underwater effects and Hiro Narita’s photography are OK.