Simon Lake, famed American submarine builder, spent years working with the Austro-Hungarian Navy, the Imperial Russian Navy, and the U.S. Navy. In addition to making military contributions, he worked on the 22-foot Explorer, a "baby submarine" designed for undersea farming and exploration. Above the surface, the Explorer resembled a "pair of milk cans on a raft," but when submerged, it could actually harvest $3,000 to $4,000 worth of sea sponges, clams, and pearl oysters per acre. Not bad for a four-wheeled pleasure craft incapable of working independently from its mother ship.
Onto the specs: the Explorer could descend 300 feet while tethered to a 500-foot cable, could accommodate a crew of two men and two passengers, and received air from a hose attached to the mother ship. Occupants would communicate with the surface by telephone. It drove along the ocean bottom using 30-inch iron wheels. Unlike its more conventional counterparts, the Explorer came with a crane for harvesting and depositing sea sponges into a large basket lowered into the ocean. Propellers near the front wheels would gather oysters by gently sifting the mud beneath them, thus preventing damage to their shells.
Read the full story in "Midget Sub to Seek Riches on Sea's Floor"