CRAMPED, ISOLATED, AND HEAVILY-ARMED: What life is like on a Navy submarine

With deployments underwater typically running 90 days, life onboard a submarine is anything but normal.

Cramped quarters are the norm, and sailors must have the right technical know-how as well as determination to spend months underwater at a time.

To even be eligible to be a crewman aboard a submarine, applicants must pass a series of grueling tests, psychological evaluations, and intensive courses.

Of course, even once qualified, serving aboard a submarine is not a walk in the park.