Submarines from the depths (of overlooked history)

What was it about the 1860s Hunley? How did a few, determined Southern partisans manage to build the first submarine to win a naval battle with the U.S. fleet during the Civil War?

Where did they get their ideas? Perhaps from earlier concepts like the Brandtaucher ('incendiary diver'):

.

But the concept of one wealthy planter, if this story from Simon Lake is to be believed, was not as courageous as the Hunley's crews (subsequently lost) or submariners of today. The story is about another Hunley predecessor, the pumkinseed-shaped New Orleans submarine, photos of which can be found at NavSource archives.

.

According to the story Lake got from a friend, which can be read here, the slaveowning planter arranged for two of his most intelligent slaves to demonstrate the vessel's diving capability for spectators at the launching. The vessel disappeared as planned, but never surfaced. The author describes the story as almost certainly a tall tale. Let's hope so.

.

Submarines are always silent and strange.