China appears to be close to one of the greatest technological breakthroughs in military history: the supersonic submarine. I know that that sounds ridiculous but it is possible. As a military buff, I had to share the story. The submarine is based on “supercavitation” technology that was used earlier on torpedo technology but the Chinese have reportedly used to envelop an entire submarine that could theoretically allow it to cover the distance between Shanghai to San Francisco in less than two hours. If that (likely hyperbolic claim) is attainable, it would constitute less time than it sometimes takes to just get through the security line at Dulles International airport (of course some international flights seem shorter than TSA lines these days). It is not clear what the submarine would look like (this is a conventional nuclear Chinese submarine).
The new submarine is being developed at the Harbin Institute of Technology’s Complex Flow and Heat Transfer Lab. It uses the concept of an air “bubble” that reduces resistance for the sub. The technology has worked with torpedoes. Supercavitation technology was used on a torpedo called Shakval by the Russians that was able to reach a speed of over 370km. The problem has been the rudder within such a bubble (and the corresponding limits on steering) as well as other challenges.
The new sub would constantly have to “shower” a special liquid membrane on its own surface to achieve the level of supercavitation. The question is whether such technology could be made practical for deployment even in small numbers. I would also have environmental concerns (that generally do not concern the Chinese government) over these liquids released into the oceans as well as the obvious danger to sea life with a submarine moving at such a high speed under water.
China’s close ally, North Korea, in the meantime appears to be working on subcavitation technology.