|Ericsson first drew a traverse sketch of his idea and then drew over it with a long view. As one can see Ericsson "showed his work" by working out the math on top of the drawings.|
|A rough idea of his monitor's submerged propeller system.|
Ericsson's "monitor system" not only was about designing ships with armored turrets, but also building them with a submerged screw propeller that was safe from hostile fire. In Ericsson's mind, the water surrounding a ship was just as important as any metallic armor protecting the exposed area.