There is provided a nitride semiconductor light emitting device. The resulting laminated panel structure is then cut into a plurality of modules each having at least one compartment containing at least one chip. The system includes a skimmer element having a skimmer orifice arranged to receive the sample ions from the first vacuum chamber into a second vacuum chamber where the skimmer orifice is of a first size. By positioning the hydrofoil underwater and alternating between positive and negative angles of attack, a diver may generate forward propulsion by manipulating the controller to correspondingly alternate the buoyant force produced by the buoyancy compensator between levels below and above neutral buoyancy.