A 10 m deep bucket is getting pretty far afield, but regardless... the water is not pressurized relative to the top of the bucket (because there isn't one). The pressure is unevenly (but laterally symmetrically) distributed to the walls and bottom. If all of those forces are balanced, as they must be, there is no thrust. That would occur if there were an imbalance between the top and bottom, and again there is no top. Would a rocket work if you cut the top off?