4. Sea Devil
Sea Devil was the work of Wilhelm Bauer, a Bavarian inventor, and engineer. His first sub built in 1850 sank in water during a demonstration nearly costing him his life. This didn’t stop him from further experimenting with more hand-powered submarines. When the Russian government eventually funded his work, he built a new vessel after which he settled for his premium “Sea Devil,” a 52-foot sub that could carry up to a dozen men.
This ship embodied a host of technological advances. It had numerous ballast tanks for enhanced buoyancy, a propeller, an internal treadmill and a crude airlock. Sea Devil made well over 130 successful dives but eventually got lost at sea.