A U.S. Navy research document from 2010 outlines the Naval Surface Warfare Center (NSWC) Carderock Division‘s efforts to create a working design of a manned vehicle capable of both airborne flight and submerged travel. The craft was intended to provide stealthy transport for Special Forces units into and out of operating areas. This wasn’t the first study of its kind to propose such a “transmedium” vehicle, defined as one capable of operating in multiple domains, such as in the air and underwater, but building such a craft has proven itself time and time again to be difficult, to say the least. It’s not clear how far the Navy’s efforts went, but the document’s conclusions are significant in that they show that over a decade ago, Naval researchers concluded that a “working design is feasible within the current state of the art.”
Aircraft that could also operate under the sea have long been pursued by the U.S. Navy and other militaries. A number of often unworkable or heavily compromised designs have been proposed and even tested by armed forces around the world since at least the 1950s, including various forms of submersible aircraft, to more modern designs like the short-lived Lockheed Martin Cormorant. While the degree to which these designs have been able to operate in both the sea and air environments vary greatly, among the “holy grails” of aerospace research is a truly hybrid vehicle, a submersible aircraft or “flying submarine” that can travel near-seamlessly between the sky and the sea.
In 2010, NSWC Carderock published its study of just such a vehicle concept. The idea was to research the feasibility of designing a vehicle that combined “the speed and range of an airborne platform with the stealth of an underwater vehicle by developing a vessel that can both fly and submerge.” The ultimate goal was to work towards developing a vehicle that could insert and extract Special Forces units at much greater ranges and speeds than existing platforms at the time, and be able to do so in locations that were “not previously accessible without direct support from additional military assets.” There have been far less ambitious boat-submarine concepts brought to life as of late, that try to address the issues of getting around the inherent limitations of existing swimmer delivery options. But the technological chasm between creating a vehicle that can transition between the surface and subsurface of the ocean and creating a true flying submarine is absolutely massive.
The study was born out of a Broad Area Announcement (BAA) issued by DARPA in 2008 calling for design proposals for such a Special Forces vehicle and defining a Concept of Operations (CONOP) for potential designs. NSWC Carderock based its study off of that CONOP, which outlined the need for a vehicle whose capabilities included:
– Deployment from a naval/auxiliary platform;
– take-off from the water surface and transit 400 miles airborne, then land on the water surface;
– submerge and transit 12 [nautical