Yes, I'm afraid so Snakes on a Plane fans, it seems that it's already been done, but on a submarine.

According to a secret source over at film ick this idea isn't new, just have a look at this IMDB entry for a film called Fer-de-Lance made in 1974, also known as Death Dive and...Operation Serpent!

An American submarine leaves Tierra Del Fuego, and one of its crew has secretly brought aboard a container full of poisonous snakes which escape storage and bite key personnel on the submarine, causing an accident that cripples the vehicle so that it drops to the bottom of the Southern Ocean. Worse still, the snakes are still at large on the submarine and complicate the efforts of the crew to escape the sunken vessel.

Oh lord, and it even starred David Janssen of The Fugitive TV series.

There I was, for a fleeting moment, believing that Hollywood had found some originality. Still, who'd have thought they'd have the guts even to remake this!