TAMPA, Florida — Ross Lindman gently pats the black hull of his intimidating 25-foot aquatic robot. Then he gestures to the bomblets strapped to either side of it. “This,” says the Columbia Group vice president, “is an underwater Predator.”

Lindman isn’t kidding. On one side of the Proteus, the Columbia Group’s experimental submarine, are two 220-pound bomblets. They’re merely for display here at the Special Operations Forces Industry Conference, but the passersby get the picture.

And that doesn’t remotely approach what the Proteus can carry. Either side of the sub can hold up to 1,600 pounds of cargo.

“You can strap different types of mines and ordnance to it,” Lindman says, 3,200 pounds’ worth. That’s way more firepower than the two Hellfire missiles that fit aboard the Predator, the iconic drone plane that serves as a muse for Lindman’s sub.