If I understand correctly: a pressurized container can propel itself if you would take off the "lit" because there is now an open end that can no longer apply a normal force for the pushing gas, resulting in a net force at the other end of the container.
I would say the concept above applies if the container would be in space as well as if it would be in a medium such as water.
Now my question is: if we would now take a vacuum container underwater (I assume a vacuum container in space would just be called an empty container) and we would remove the lit, would it also be propelled (in the direction of the lit now of course)?
Intuitively, one part of me says yes, as long as the difference pressure with respect to the water is the same the resulting force should be of equal magnitude in the opposite direction.
However an other part of me says no, a low pressure inside the container would just decrease the time it takes for the container to fill up with water and besides the water rushing in would push the closed end of the container, resulting in no net displacement.
This little thought-experiment has been bugging me for the past couple of days so any input would highly appreciated!