By Bill Carson:
I am amazed at how many anglers have bought in to Side Imaging technology but fail to fully employ the technology. Perhaps this is because they do not understand or see the advantages of using it?
First a brief explanation of Side Imaging: Keep in mind that its predecessor, 2D sonar, has been around way longer than Side Imaging or Down Imaging (SI or DI). 2D sonar is a sound wave emitted in a cone shape. A 2D sonar running 200 kHz in 30 feet of water is seeing 10 feet of real estate at the bottom. This represents one third of the distance to the bottom at the bottom, and because it is a cone shape, does not give as great of detail as SI or DI. SI/DI operates on two frequencies, 455 and 800, and they direct the sound like a fan. This allows far greater detail for spotting fish, bait and structure well out from under the boat and can reveal which side of the boat it is on.
In Photo A, we see fish under the boat in about 30 feet of water (remember this represents 10 feet of bottom), but on the SI we can see what is a much larger group of larger fish 118 feet out to the right side. This affords us the opportunity to touch the object with our finger on the screen with the Humminbird ONIX and drop a waypoint where the fish are. We can then go to the waypoint and catch them.
Before we can target the fish, we must have bait. SI is the best at dictating which side of the boat to throw the cast net on. How many times have you marked bait and tossed the net only to pull it up empty. The reason for this is the “view” of the bottom based on 2D versus SI. In this example (Photo B), it is clear that throwing the net on the port side of the boat would have yielded a net full, but the starboard side would have missed even though the 2D showed the mother lode of bait.
SI works fantastic in shallow water because of the shadows resulting from targets. These shadows allow the angler to detect fish without getting on top of the fish and scaring them. Check out these bedding fish in Photo C.
Hopefully this has shed some light on effective use of the technology that will help turn your trip into more catching and less fishing!
Bill Carson is the Field Marketing Manager for Johnson Outdoors Marine Electronics Inc. in Alpharetta, Georgia.