Bear I'm mind that I'm no physicist, my knowledge of hydrodynamics is limited.Please bear in mind that I'm no physicist, my knowledge of hydrodynamics is limited.
I've been thinking that when you push a floating object to the bottom of a swimming pool and then release it, it will get back to the surface with considerable force.
Could this be used, for instance, to impulse a very hydrodynamic rocket pulling it to the bottom of the sea in some kind of more-dense-than-water capsule and then release the rocket to launch it out of the water without using any fuel?
If there are any ambiguities to my question please let me know.