Modern Humminbird sonar, left, identifies lake depth with a color selection system, while Mega-360 sonar imaging, right, provides a 360-degree view of bottom structure and fish all around the boat.

Humminbird fish finders were born in—and still live in—the bass and inshore fishing world. Started in 1971 in Eufaula, Alabama, and spearheaded by Tom Mann, Humminbird’s first depth flasher brought ...