The Ancient Origins and Early Combat Use of Submarine Technology

The submarine is a surprisingly ancient technology—at least in its early, primitive forms.

The idea is quite simple, that a well-enough-sealed boat ought to be able to submerge and resurface. It's the practicalities that make the whole thing difficult.

It is generally considered that the US Civil War was the first use of submarines in combat; these were primitive machines with very limited operating endurance and navigational capabilities.

These submarines were more like torpedoes: you pointed them in the right direction and hoped they went straight.