An echo sounder or other device for measuring water depth, especially for navigation and fishing.
- ‘The NOAA guidelines call for the boat's position to be held in one spot for five minutes with depth finder readings taken every 30 seconds, then all 10 readings averaged out.’
- ‘When you find a likely spot, check the chart for wing dams and other obstructions and head slowly straight in, watching your depth finder.’
- ‘When underway, use your depth finder to stay in water deep enough for your boat's draft.’
- ‘Elaborate electronics are not necessary but a depth finder, VHF radio and probably a cell phone are.’
- ‘The depth finder showed 40 ft, and you could see the bottom.’