America has gone one better than Germany in the race to develop the world's most powerful submarine-launched robot aircraft. US arms giant Raytheon has announced a model which can be deployed at depth without modification to the submarine.
The new U-UAV is dubbed SOTHOC, for Submarine Over the Horizon Organic Capabilities. The launch system works by deploying a sealed can through the sub's waste disposal lock. The can then sinks away safely to get clear of the boat. On reaching a preset depth it dumps weight to become positively buoyant and ascends to the surface. Once stable at the surface, it aligns itself into wind and launches a one-shot, disposable UAV.
The UAV would normally fly its mission autonomously, avoiding the need for the mother sub to show any communications masts. If the sub was to directly receive any data gathered, it would need to put up a mast within range of an eventual download transmission, however.
Raytheon have now tested SOTHOC successfully at Rhode Island's Narragansett Bay test range, but thus far only by dropping it in the sea from a surface vessel.
"In future demonstrations, we will deploy a UAS from an actual submerged submarine," promised Ken Pedersen, Raytheon advanced projects veep.
"This capability will be a keystone for real-time situational awareness at significantly increased ranges," said Mark Rodrigues of the Naval Undersea Warfare Center.
While a fully submerged sub is extremely hard to detect, the very water which hides it also cuts it off almost completely from any real idea what's happening above the waves. It's quite hard even to relay data from other units - while a sub can receive special very-long-wave radio under water, the bandwidth is limited.
A SOTHOC or mast-launched German VOLANS could act in effect as a flying untethered periscope, able to gather a lot more information than a sea-level mast and without the need for so much exposure by the submarine.
This sort of thing could be especially useful for subs like the US Navy's SSGN special-forces motherships, intended to act mainly as bases for operations ashore.
SSGNs might, in fact, use something bigger and more sophisticated than SOTHOC - being converted nuclear-missile boats, they have lots of sizeable launch tubes already designed for launching large air vehicles. But SOTHOC will no doubt carve a niche, as just about any sub could use it without modification. ®