China claims it has found a way to create a supersonic underwater vessel that could travel from China to San Francisco in less than two hours using new developments in supercavitation. This could be extremely useful for travel—but also for the development of underwater weapons. In fact, this is a military project.
This technique was originally developed for Shakval, a torpedo capable of reaching 230 miles per hour (370 km/h) developed by the Soviet Navy during the Cold War. The size of the bubble and the speed was limited.
Now this new Chinese research claims they have found a way to generate a much bigger air bubble, drastically reducing friction of large underwater vessels. They say they would be able to create a full-size supercavitating submarine capable of reaching the speed of sound underwater—about 3603 mph (5,800km/h). That or a stealthy large supersonic nuclear missile, of course.