What's wrong with this

[MarkE]

   The way to go is to increase the volume of the vessel, but that requires energy to
    displace the liquid as per Archimedes. So that's a definite no-no!
             John.

Tinman speaks as though he really believes that he has already successfully changed the weight and/or buoyancy of a submersible without changing any:  The total mass of the submersible, the total volume of the submersible, or the density of the surrounding fluid.  Sunday awaits!

[minnie]

  Flamin' Gallahs,
                     my crystal ball is showing me a Nobel prize winner!!!!!!
                          John.

[tinman]

Tinman speaks as though he really believes that he has already successfully changed the weight and/or buoyancy of a submersible without changing any:  The total mass of the submersible, the total volume of the submersible, or the density of the surrounding fluid.  Sunday awaits!

Like i said many time's,the fluid inside the vessle is changed to a gas state. This increases the internal buoyancy volume of the vessle-the vessle rises to the surface. The gas is then returned to a liquid state,and the buoyancy volume once again becomes a negative-the vessle sink's. I am finding it hard to believe as to why this seems so dificult to believe-what laws of physics dose this break?.
Below is a quick crappy sketch. Which vessle(vessle's) has/have the most buoyancy.

[TinselKoala]

Like i said many time's,the fluid inside the vessle is changed to a gas state. This increases the internal buoyancy volume of the vessle-the vessle rises to the surface. The gas is then returned to a liquid state,and the buoyancy volume once again becomes a negative-the vessle sink's. I am finding it hard to believe as to why this seems so dificult to believe-what laws of physics dose this break?.
Below is a quick crappy sketch. Which vessle(vessle's) has/have the most buoyancy.

The spheres of steel all have the same weight, or rather mass,  and volume, but the addition of water in one of them, and air in another one, will mean that their actual "as filled" weights will be different. And since density is defined as mass/volume, the one with water in it will be the most dense and so will have the least buoyancy. The one with compressed air in it will have slightly less buoyancy than the ones that are completely empty (0 psi).
The one with the 20 liters of water inside will have the _least_ buoyancy.  If you flash the water to steam without letting any escape ... the thing will still have the same mass, therefore the same density, so its buoyancy _will not change_.


Negative 20 psi pressure? Whaaat? How do you get less pressure than a total vacuum (0 psi)?

[MarkE]

Like i said many time's,the fluid inside the vessle is changed to a gas state. This increases the internal buoyancy volume of the vessle-the vessle rises to the surface. The gas is then returned to a liquid state,and the buoyancy volume once again becomes a negative-the vessle sink's. I am finding it hard to believe as to why this seems so dificult to believe-what laws of physics dose this break?.
Below is a quick crappy sketch. Which vessle(vessle's) has/have the most buoyancy.

If the volume of all spheres are the same then the buoyant force exerted by a surrounding fluid is the same for each.  If the dry weights of the spheres including their contents are the same then because the buoyant forces are the same, the wet weights are the same for each, and the net buoyancy is the same for each.

As long as there is the same number of moles of H₂O and air ( mostly N₂ and O₂ ) in each sphere the state of the H₂O :  solid, liquid, gas, or plasma inside the sphere does not alter any:  the mass, the dry weight, the wet weight, or the buoyancy.