A fishfinder is a device used to measure water depth and detect underwater objects using sound waves. It operates on the principle of echolocation: the device sends a sound signal into the water, which bounces off the bottom or other objects and returns. By calculating the time it takes for the signal to return, the fishfinder determines the distance to the target.

Types of Fishfinders

Single-beam – measures depth at a single point. Simple and affordable models.

Dual-beam – provides more accurate imaging with a wider coverage area.

Multi-beam (3D fishfinders) – creates a three-dimensional image of the underwater terrain.

Side-scan sonar – scans large areas on both sides of the boat, often used for fish finding or locating sunken objects.

Ice (winter) fishfinders – designed for use through ice, commonly used in ice fishing.

How to Choose a Fishfinder?

Frequency: Low (50 kHz) for deep water scanning, high (200+ kHz) for detailed imaging in shallow water.

Power: Determines how deep the signal can penetrate.

Screen type: Color or monochrome, with screen size affecting viewing convenience.

Additional features: GPS, depth mapping, Wi-Fi or Bluetooth connectivity for smartphone integration.

Where Are Fishfinders Used?

Fishing (both recreational and professional).

Navigation and boating.

Hydrography (studying underwater terrain).

Finding sunken objects.

Different types of fishfinders are used in fishing, depending on the fishing conditions and the angler’s preferences. Here are the main types:

1. By Scanning Type

Classic (2D fishfinders) – display a simple image of the bottom and fish as arches or dots. Suitable for most situations.

Structure scanners (SideScan and DownScan) – provide detailed images of the bottom structure and objects located to the sides or directly beneath the boat.

3D fishfinders – create a volumetric view of the underwater environment, useful for finding fish in complex conditions.

2. By Mounting Type

Fixed (boat-mounted) – installed on a boat, featuring powerful transducers, large screens, GPS, and extra functions.

Portable – compact devices that can be carried, often working via Wi-Fi or Bluetooth with a smartphone.

Wireless (castable) – small fishfinders that can be cast with a fishing rod, transmitting data to a smartphone (e.g., Deeper, Lucky).

3. By Seasonal Use

Summer fishfinders – standard models for boat or shore fishing.

Winter fishfinders – designed for ice fishing, showing fish activity under the ice hole, including flasher models (e.g., Garmin STRIKER 4, Humminbird ICE HELIX).