Hello all, I devised a concept a couple years ago for renewable energy and hit a stumbling block: How do you insert a buoyant object into the bottom of a water column with the smallest amount of energy? Recently I revisited the concept and found some similar work online including this youtube video. From my understanding, this concept is flawed because he's pumping the water in some fashion which uses energy. Otherwise the water would spill out of the bottom side opening. I've attached an image to help visualize my question. My question is this: Like holding your hand on a straw to hold water in place when lifted out of the water ... Can you seal the top of the water chamber (Valve A) to insert an object into the unsealed bottom of the water column (Valve B)? Likewise, can you seal the bottom of the chamber (Valve B) and unseal the top chamber (Valve A) to allow the object to float to the top? Any thoughts are appreciated.