Have you seen or heard of the Rail Gun?

[markjay]

On the same note (sort of)..:

http://www.dailymail.co.uk/sciencet...using-underwater-bubble-help-swim-faster.html

 

[moonloops]

On the same note (sort of)..:

China reveals plans for 'supersonic submarine' using underwater bubble | Mail Online

The new sub is based on Soviet technology developed during the cold war.

Another Chinese copy of a sneaky Russian idea..