Electronics don’t replace the fisherman’s skill and fortune… but they help him a lot! One of the most important is the fishfinder, a display that works in tandem with a transducer and provides you with data on the depth, morphology of the seabed and the possible presence of fish. We were in Palma de Mallorca to test the new pair of products launched on the market by Navico: the fishfinder HDS Live Unit and the transducer Live Sight.
fishfinder basis? the sonar
“The sonar differs from a video image – explains the fishing champion Danny Geysen – because it measures the distance between the source of impulse and one or more objects, using sound waves. The sonar shows us a history of the various distances from all objects, including fishes, that have passed under or beside our boat. With a series of features that allow you to understand the scenario hidden in the depths of the sea, from the size of the fish, the speed at which it moves, the type of seabed (sandy or rocky) to the most recent novelty of Lowrance, the Live Sight feature. So we will get an idea of the fish around and we can “tag” the prey by choosing the best bait.
The FishReveal function makes the interpretation of fish recognition data as easy as possible.
Well, but how to recognize the fish? First of all by the color. In Lowrance’s HDSLive unit the colors – yellow, red, blue – indicate the signal’s return strength. Yellow indicates a higher power while blue indicates a weaker one. This is useful both to understand the type of bottom, but also the size of the fish. Why? Simple, the air is the best reflector of the signal emitted by the sonar. The bigger a fish is, the more air it has in its blood.
On the screen we will see an arc that represents the position with the color inside. The yellower the arch, the bigger the fish. It must be said, however, and experienced fishermen know it, that a large arch on the screen, without the presence of yellow, could be given by a large fish that has not crossed the center of the cone of propagation of the signal. The sound waves emitted by the transducer in fact propagate in the water assuming a conical shape. The limit of sonar, however, is that it cannot identify and represent forms. This is where the Down-scanning system comes into play: we can imagine it as the home scanner. Thanks to many small scans, the fish will no longer be displayed with arches, but with “dots”.
Another important function of the HDSLiveUnit is Side-scanning: while both sonar and Down-Scanning are facing the bottom of the sea, this points to the sides of our boat thanks to a special transducer, the Active Imaging. This, combined with the fishfinder, allows you to sound up to a distance of 40 meters per boat, acquiring more defined images.
Finally, the Live Sight function allows you to see in real time everything that happens under your boat. It should be used to see the fish approaching the bait and thus “tag” the depth of our line or the launch distance. Another peculiarity is the effect “ghost rail”, a color trail that follows the fish that move under our boat, even in motion. This allows us to easily distinguish between fish statio- nary on the bottom from those that are moving.