A device for controlling an underwater actuator by using an ambient pressure potential at the operating depth may include a chamber including a first cavity, a second cavity and a third cavity; the first cavity including a gas at a first pressure including one of at surface atmospheric pressure, lower than surface atmospheric pressure, or a vacuum; the second cavity including a first fluid at a second pressure including at least one of at underwater ambient pressure or higher then underwater ambient pressure and being connected to a underwater fluid supply; the third cavity including a second fluid at a third pressure including at least one of underwater ambient pressure or higher than the underwater ambient pressure and being connected to the actuator.