The first in the U.S. Navy's new class of Virginia submarines was commissioned just last month.

But already, the mad scientists over at Darpa, the Pentagon's way-out research division, are bored.

They want a sub that can run with a fraction of the crew of current boats. So Darpa has put together a new, $97 million effort to build the submarines of the future, code named Tango Bravo. Last week, the agency held a classified meeting with defense contractors and researchers interested in bidding on the project.

At the heart of the Tango Bravo project is a problem that's older than U-Boats: how to run a sub without packing the crew in like fish in a can. Why the concern? Well, it's not for the sailors' comfort. "People are expensive," notes GlobalSecurity.org director John Pike.

For years, the Navy has been pushing to run bigger and bigger ships with fewer and fewer sailors. It took a crew of about 320 to run the World War II-era Fletcher destroyers. Today, an Arleigh Burke destroyer uses the same number of men – but, at 8300 tons, it's three times as big.

Things have been different on submarines, however. While crew sizes have basically remained stable, sub sized have only doubled – a lot less than the destroyers' three-fold increase.

One way to cut down on the number of people is to automate the sub, particularly its attack center and sonar battlestations. Those areas require 17 people on the Virginia class submarines, Darpa notes. The agency wants to see that crew cut to eight, with "a set of systems should be proposed which can replace the current VIRGINIA Class sonar, fire control, and tactical data display systems."

But even with a crew trim, space on a sub is still beyond cramped. "There's never enough room for people," says retired Rear Admiral Hank McKinney, the former commander of the U.S. Pacific Fleet's submarine force. "On the Los Angeles class [of subs], a third of the crew didn't have bunks of their own. Seawolf – same problem."

Tango Bravo's solution: take the torpedoes, and store them outside the sub, not within. "They take up a lot of room inside what we call the people tank," Adm. McKinney notes. And it's something that's been done on a number of submarines before. Tomahawk missiles were kept in the ballast tanks in some of the later Los Angeles-class subs, for example, to increase the number of torpedoes that could be kept aboard. What's more, the latest Mark 48 torpedoes aren't even maintained on the ship, McKinney observes. "They're prepped before hand, and then left alone."