Comprehensive Basic Guide on How to Read a Fish Finder for Bass
January 13, 2021 by Rick Wallace from tacklevillage.com
Using a fish finder effectively to help you find more bass and get a picture of the kind of structure you are fishing is fairly simple. But there are a few concepts to understand first, which we will cover briefly here.
Your fish finder has a transducer that sends down the sonar signal in waves. When the sound waves bounce back off the bottom, the fish finder will interpret these returning signals into the visual picture you see on your screen.
Fish Finder Screens
Most fish finders have color screens these days (including most fish finders under $1,000) and depending on the strength of the “return” (the sonar wave bouncing back) that will generate a particular color on the screen.
Using the default settings, Lowrance fish finders (and many other brands) use a Yellow/Red/Blue color palette so that the hardest returns (such as a rocky bottom) show up as yellow and the softest (say weed on the bottom) show up as blue. You change these default colors, but this is a popular palette to use.
Bass show up as the tell-tale arches, usually with a mix of colors across the spectrum. That covers what comprises the picture on your screen with conventional sonar imaging.
Most transducers (and fish finders) these days have the ability to do monochrome structure downscan imaging. This gives a better indication of the structure (weeds, rocks, submerged trees) as it shows up in much more precise detail.
Bass will still show up on this, but they’ll appear as blobs rather than the telltale arch so they are harder to spot. (Lowrance’s FishReveal technology applies an arch to fish on the downscan imaging, which is particularly handy, especially if you have a small screen and can’t really do the split screen.)
Split Screen Fish Finder Views
Most anglers will fish with a split screen on their fish finder with half showing the conventional sonar and the other half showing the structure downscan imaging - that way they get a good view of the bottom and the structure associated with it but can also see any fish and schools of baitfish.
The other dimension (literally) to modern fish finders is sidescan. Not all fish finders will have sidescan, but those with 3D transducers have this functionality. Basically, side scan involves sending out a horizontal signal which provides a picture of the water either side of your boat or kayak.
Sidescan sonar is great for when you are bass fishing in a river or lake and casting towards the bank or other structure off to the port or starboard side. You can see structure very clearly and also fish. This technology is a real game changer for many fishermen and women. If you’ve got a fish finder with sidescan, then there really is nowhere for the fish to hide!
That covers the key capabilities that are important in fish finders. A few other considerations you’ll need to consider are:
You need to decide what’s the best screen size for you. In general, bigger is better, but with fish finders, cost is very much dependent on screen size. This means you can get a fully featured unit with sidescan such as the Humminbird HELIX (see our review here) for very little cost if you are prepared to go for, say, a 7-inch screen. This is great for kayak fishers or those with small motor boats where you can mount the fish finder close to where you are sitting. But on a large boat you want a larger screen size - preferably nine inches and above and that’s when the costs begin to mount up.
This very much depends on your boat. For kayaks and light craft, the fish finder can be mounted on a gimbal and removed as required. This helps ensure it is safe while towing the vessel or when it is parked in the street.
On a large boat with a cabin, most fish finders are mounted in the dash. Obviously there is a bit more to this and the unit is not detachable, but it is simple enough to do.
Batteries for Fish Finders
Fish finders don’t draw too much power, so you can get away with a relatively small battery. On larger vessels they tend to be wired into the boat’s electronics, but on kayaks and small boats with outboard motors, you need a separate battery. Small AGM or lithium based batteries are the best option (see our guide to selecting a fish finder battery here).
Trolling Motor Integration
Most sonar brands, including Lowrance and Humminbird, have the capability to link your fish finder and trolling motor so you can navigate to way points or hold in a particular position. This is a handy feature and is covered briefly in our article on bow mount trolling motors.
A final word on brands! As you’ve probably picked up, for recreational inland or coastal fish finders, the big brands are Lowrance and Humminbird, and to a lesser extent Garmin. Various people swear by one brand or the other and we are no different. I use Lowrance whereas another of the Tackle Village team is a devoted Humminbird user. In truth they are both great brands, although you tend to get used to one brand and it can become hard to swap without a compelling reason!
Sportsmen Guide carries a great selection of fish finders for bass. Visit their site to compare different fish finder brands and models based on the concepts discussed above.
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