This is my "Flying Fish" submarine project. It’s designed to have positive buoyancy with an inverted wing generating a downward “lifting” force so that your forward motion allows you to fly to depth of approximately 500 feet. If your forward motion stops then you’ll rise to the surface as a fail-safe feature. There is an on-board powerplant to generate the needed electrical power while underwater with the battery bank acting as minimal storage & reserve power. The 3 cylinder K-75 engine runs on propane and has a recirculating system for cooling the exhaust gases. Oxygen is injected and mixed in the air box before entering the engine. It’s like a rebreather system for an internal combustion engine. This submarine travels to the dive location at or near the surface using outside air to converse the oxygen supply, which is stored in K size gas cylinders. The total dive time is estimated to be 6 hours.

http://www.solidsmack.com/contests/solidsmack-awesome-sauce-design-contest

I'd like to thank Drew Hauck for the awesome flight instruments used in the cockpit