You may recall the tragic tale of the Hunley, a Confederate submarine that sank a Union ship and led to the deaths of three submarine crews. You might be surprised to learn that it wasn't the first submarine used in battle. That would be the Turtle, an underwater vehicle conceived by Yale student David Bushnell in the 1770s. Bushnell was interested in underwater bombs, and built the Turtle to deliver them in service of the Revolutionary War.
Over the next year, the Turtle began to take shape. (A local clockmaker, Isaac Doolittle, helped design and construct some of the most ingenious parts.) About seven feet across in each direction, the whole thing was basically one giant cockpit. The pilot—or, as one admirer put it, “the adventurer concealed within”—sat on a chair in the middle. He was accompanied by half an hour’s worth of breathable air, which he could replenish by bobbing up to the surface and uncapping a couple of bronze tubes in the ceiling.
A complex series of pedals, cranks and hand rudders allowed said adventurer to move in all three dimensions: to sink and rise, move forwards and backwards, and turn. For daytime visibility, he could peer through a series of glass peepholes.
Read about the Turtle and its military missions at Atlas Obscura.
(Image credit: Zenit)