I guess that’s how ship cannons worked at the time. Powerful but heavy to move, slow to reload, not very accurate… more of them would give you the only way to have sustained firepower.

But Leonardo also left a lot of these sketches that look less like actual projects and more like the superhero fantasies of an extremely gifted six years old. “And look, this shit has cannons… Cannons EVERYWHERE! Bam! Kapow!”. I guess it’s what happens when your so great at drawing that even the doodles you do when bored look like masterpieces.