At the moment, we are working on our first prototype. The Unsinkable II  is the first iteration of our wax-based buoyancy system. When paraffin wax melts, it expands by up to 16%. The wax, which is held in a piston chamber, pushes the piston head out as it melts, effectively increasing the volume of the submersible. This increase results in a larger displacement of water, and therefore a larger buoyant force. Using paraffin waxes as a medium for depth control avoids the requirement of expensive syntactic foams and provides the benifit of variable buoyancy. On the flip side, the challenge becomes making it efficient enough to consume reasonable amounts of energy. The Unsinkable II is a challenge in balancing energy requirements with cheaper, more versatile buoyancy technologies.