Color sounder

Classic fishfinder or GPS sounder?

First of all, we need to differentiate between a fishing sounder and a GPS sounder.

Fishfinder only:

The simple fishfinder has no GPS. This is generally the case for older fishfinders such as Helix 5 G2 HD or Helix 5 G2 DI. Very useful for fishing with their 2D sounder technologies or DownImaging for the DI version, at a very affordable price.

GPS sounder :

GPS fishfinders, such as those in the Striker Garmin or the Lowrance Hook2 4x range, incorporate a GPS positioner for obtaining the boat's position, creating fishing points or tracks.

This last function is very useful when you're sailing. If you get lost in the fog, the GPS will have automatically created a track (waypoints) as you go, enabling you to turn around and follow the same route easily. The Garmin striker 5cv is a great little GPS fishfinder featuring advanced DownVü sounder technology (see below), while the even smaller Garmin striker vivid 4cv is equipped with the same technology.

Worthknowing: The sounder Garmin Striker Vivid, in addition to GPS, features the QuickDraw function, which lets you create your own bathymetric surveys. In this way, your device will record the relief of the seabed discovered during your navigations.

Sounder technologies

The main technologies on the market today are: 2D , Down Imaging, Side Imaging.

You may find different names for different manufacturers and brands, but they are the same technologies:

• Down Imaging = ClearVu = DownScan = DownVu.

This is a precise, clear view from below the boat (vertical), showing the seabed in near-photographic quality.

• Side Imaging = SideVu = SideScan.

This is a view that detects what's happening on either side of the boat, with a scan of up to 120m on either side. This type of transducer or transom allows a wide survey of your fishing spot from both sides of the boat, discovering more fish, new riprap, new wrecks, etc. than you would have seen with Down (vertical) technology.

• 2D technology is the classic view under the boat.

In addition to these new technologies, you'll find probes equipped with a water temperature sensor, for example, and other useful functions for your fishing sounder.

Large Depth

Depth sounders are generally much more powerful, with sounder modules ranging from 1000w to 3000w, depending on the model. These fishfinders are compatible with powerful 50/200 kHz frequency probes, such as Airmar probes designed for deep-sea fishing, up to a depth of 1000m depending on the probe.

These probes are available as through-hole or transom probes, or as glue-on probes.

Deep-sea fishfinders from Furuno include the furuno fcv 628, FCV 588, FCV 288, FCV 295 and FCV 1150 and from Simrad, the S2009 and S2016.

Some fishfinders are also compatible with CHIRP! This sounder technology offers better target separation and improved bottom detection.