Garmin Fishfinder 400C 4-Inch Waterproof Fishfinder and Dual Frequency Transducer

The Garmin Fishfinder 400C has a high-resolution display and is an excellent way to find fish in both saltwater and freshwater.

But, first, what’s a fishfinder?

A fishfinder is a specialized type of echo sounding system, like a fathometer. A fishfinder makes use of active sonar to detect both ‘the bottom’ and fish, and displays the results on a graphic display. In contrast, a fathometer uses a digital display for its results. The way these devices work is that a transducer produces an electrical signal that is converted to a sound wave propagated through the water by a hydrometer; the sound wave is reflected off both the bottom and the fish, received by the hydrometer, and converted back to an electrical signal by the transducer. This signal representing the reflection is amplified and displayed; this process is repeated forty times per second.

The Garmin Fishfinder 400C not only shows you the location of fish on an ultra-bright 4″ QVGA color LCD screen, but also uses GPS navigation to show where you were, where you are right now, and where you plan to be. The UltraScroll feature updates the screen at a speed equivalent to the live movement of fish, allowing the display of fish at high boat speeds.

You can use this fishfinder in both saltwater and freshwater; you can choose one of two transducer versions of this model, either dual beam or dual frequency. If you’re fishing in saltwater, you would tend to need a greater range, for which the 500 watt dual-frequency transducer is best suited — this version of the fishfinder will show a depth up to 1500 feet. If you’re fishing in fresh water, you’ll need the 400 watt dual-beam version, which, though showing only a depth up to 900 feet, broadcasts a much wider cone of propagated sound waves. And, because both versions of this fishfinder has CANet compatibility, sonar information generated by this unit can be shared with other CANet devices aboard.

This waterproof fishfinder weights one-and-a-half pounds, and measures 5 3/4″ x 5″ x 2 3/4″. The ultra-bright full-4096-color screen measures 2 1/2″ x 3 1/4″ with a resolution of 320 x 240 pixels, and provides a night-mode for readability in low light conditions.

The full package includes the Garmin Fishfinder 400C, with either the dual-beam or dual-frequency transducer, a mounting bracket, a power and data cable, a protective cover, and an Owner’s Manual, with complete details on installation and operation.

Other features included within this unit are:
– Audio alarms
– Split-screen zoom
– See Through Exposure (exposing any fish in cover)
– Fish Symbol ID (identifying fish by size)
– AutoGain Technology (to minimize clutter and maximize targets)
– Whiteline Indicator (to show a soft or hard bottom)
– Adjustable depth line (to show depth of underwater objects)
– A-scope (a real-time display showing fish passing through beam)
– Bottom lock (a display of the return signal from the bottom)
– Water temperature graph and log
– Water speed display

Now, let’s evaluate the unit. The display is clear and easy to read in all light levels, and contains a lot of detail about what’s happening underneath your boat. All types of fish are easily identified based on their reflections. The water temperature feature is very useful, because of the tendency of some fish to seek warm water, others, cold. The on-screen menus are easy to read and use, and the device works quite well in conjunction with a Garmin GPS.

The manufacturer’s suggested retail price is $320. On a scale of 1-5, I rate this fantastic device a 5.