Color sounder

Classic sounder or GPS sounder?

First, you must differentiate between a fishfinder and a GPS unit.

Sounder only: 

The simple sonar does not have a GPS. This is usually the case for older sonar units like the Helix 5 G2 HD or the Helix 5 G2 DI. Very useful for fishing with their 2D sonar technology or DownImaging for the DI version, at a very affordable price.

GPS sounder : 

GPS fishfinders, such as the Garmin Striker or the Lowrance Hook2 4x series, have a built-in GPS positioner that lets you obtain the boat's position, create fishing points or tracks.

This last feature is very useful when you're navigating. If you get lost in the fog, the GPS will automatically create a trail (waypoints) as you go, allowing you to turn around and follow the same route easily. The Garmin striker 5cv is a very good small GPS sounder with advanced sounder technology: DownVü (see below), even smaller the Garmin striker vivid 4cv is equipped with the same technology.

Good to know: TheGarmin sounder Striker Vivid , in addition to the GPS, have the QuickDraw function that allows the creation of its own bathymetric surveys. Thus, in your device will be recorded the relief of the bottom discovered during your navigations.

Sounder technologies

The main technologies of the current market are: 2D, Down Imaging, Side Imaging. 

You can find different names depending on the manufacturer and the brand, but they are the same technologies:

• Down Imaging = ClearVu = DownScan = DownVu.

This is a clear and precise view from below, in line with the boat (vertical), which shows a representation of the sea floor in almost photographic quality.

• Side Imaging = SideVu = SideScan.

This is a view that will detect what is happening on each side of the boat with a scan of up to 120m on each side of the vessel. This type of transducer or transom allows for a wide scan of your fishing spot on both sides of the boat and discover more fish, new riprap, new wrecks, etc. that you wouldn't have seen with downrigger technology.

• The 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 features for your fishing sonar.

Depth Large Depth

The depth sounders called "Deep" are generally much more powerful with a sounder module of 1000w to 3000w depending on the model. They are compatible with powerful 50/200 kHz frequency fishfinders such as the Airmar fishfinders designed to search the deep sea, up to 1000 m deep depending on the fishfinder.

These probes can be found in the through probe or transom probe format, but also as a glue-on probe.

Furuno's deep-finder products include the furuno fcv 628, FCV 588, FCV 288, FCV 295 and FCV 1150 and Simrad's S2009 and S2016.

Some sonar units are also CHIRP compatible ! This is a sonar technology that offers better target separation and improved bottom detection.