Raytheon has demonstrated a way of launching a small UAV from a submerged submarine to perform littoral ISR. The demonstration was conducted under a program with the U.S. Naval Undersea Warfare Center called SOTHOC - Submarine Over The Horizon Organic Capabilities. Here's how it would work:
1 - The submarine launch vehicle (SLV) is ejected from the boat's trash disposal unit and ballasted to descend to a safe distance from the submarine. 2 - the SLV's centers of buoyancy and gravity are offset so that it rotates end over end and sheds the deployment weight. 3 - a float collar inflates to add buoyancy and pulsed to bring the unit to the surface at a controlled speed. 4 - a wind vane deploys. 5 - a water drogue stabilizes the SLV on the surface. 6 - aligned into the wind by the vane, the launch tube pivots to a 35-deg, angle and launches the expendable, electric-powered UAV.
During the shallow-water demonstration in September, Raytheon says, two SLVs were deployed over the side of a surface ship. "The vehicles descended to 80 ft., reverted to positive buoyancy, floated to the surface, stabilized in variable sea states, aligned into the wind, and then launched an inert representative UAS at precise orientation and velocity," it says. In November Raytheon plans to deploy an actual UAV from an SLV "dropped over the side", and early next year it intends to launch the UAV from a submerged submarine off Hawaii.
Raytheon's idea looks simpler, but much less eye-popping than Lockheed Martin's Cormorant concept for an immersible unmanned combat air vehicle that could be launched and recovered by a submerged submarine via the boat's missile tubes. The Skunk Works demonstrated the splashdown and recovery concept under DARPA contract, but the program was terminated. Looks cool though:
Video: Lockheed Martin