“There they are, between 30 and 40 feet,” I said anxiously to my companions as I pointed to several red arcs against a blue background on my fishfinder screen. I quickly hit a button to create a waypoint, then made a wide swing, to keep our trolling lines from tangling while my buddies went aft and adjusted the metered depth on our downriggers. Once back on the pink line that marked our track, I motored toward, then over the waypoint. The marks were still there and we counted off the seconds until our baits should be in the fish. First one rod bent, then another and we were doubled up.
Just like scents and calls in deer hunting, marine electronics won’t make you a better angler, but they can make you a more successful one. And just like the smart phones we all carry around nowadays, their capabilities often exceed those of the people who use them. Recent technological advancements have provided us with an incredible array of useful and helpful products, the utility and value of which ultimately come down to the user’s ability.
Sounders
Let’s start with depth sounders or “fishfinders.” Even when I’m not fishing, but especially when I am, I wouldn’t go on the water without one, and more often, two. For starters, I always want to know how deep the water is. Then, I want to know if fish are present, how many and at what depth; and that’s just scratching the surface of what they can tell you.
A fishfinder is a sonar apparatus. It transmits sound waves through a transducer, then receives and interprets the echo. Older models or “flashers” consisted of little more than a circular display that would flash different colors indicating depth of the bottom and the fish, leaving a lot of interpretation to the user. Newer versions provided a 2-D digital display that is much easier to understand for beginners. Pretty basic stuff so far.
Different sounders use different frequencies. Older (a relative term) broadband sounders use frequencies around 50, 83 and 200 kHz of ultrasound. The basic difference between them is cone angle. The 83 has a cone angle of 60-degrees while the 200 is 20-degrees. The former shows a broader area and can reach greater depths. The latter shows a smaller area, but with more detail and less clutter. You might use lower frequency to find the fish, then switch to higher to determine the size and number of fish present.
More advanced sounders use CHIRP (compressed high intensity radar pulse). They continuously sweep through a range of frequencies – 28-51kHz (low), 85-155kHz (medium), 140-250kHz (high), creating a more complete and detailed picture. For even more detail there’s high-definition (HD) (400 and 800 kHz) an ultra-high-definition (UHD) (1,000 – 1,200 kHz) frequencies.
Bob Humphrey
Interpretation
A big part of effectively using electronics involves interpreting what you see. On conventional downward scanning units, the basic return from a fish usually looks like an arc, often red but you can customize color pallets. The bigger the arc or object, the bigger the fish, sometimes. More precisely, longer, deeper arcs generally indicate larger fish. If you’re using 2D sonar, it will show those arcs as one or more different colors. Smaller fish may only show 1 or 2 colors (red and magenta, for instance), while larger fish may show 3 or 4 colors, including orange and yellow.
However, concentrated baitfish may appear as a single image, and look like a larger fish. The subtle difference is that bait balls or clusters will have a “fuzzy” edge on the top and bottom while a single fish should show a more distinct edge. Boat speed might also factor in, showing large fish or bait balls as small blips if you’re going too fast. Also, a big component of the return is from the fish’s swim bladder, so fish with larger bladders give larger returns. An extreme example would be a bluefin tuna, which would show a big red arc, and a similar-sized shark, which would appear as a fainter white mark.
Sounders can also tell you the type of bottom you’re fishing, which can be important. Colors can vary by manufacturer, but in general, darker red means rocky bottom, which might be what you’re after if you’re targeting smallmouth bass. Paler orange or yellow might be muddy bottom, better for largemouth bass. Deep sea anglers might find more haddock and cusk on muddy bottom and more cod and redfish on rocky bottom.
At times sounders will show a distinct line at a consistent depth below the boat. This is likely a thermocline and represents a break between warmer, more oxygenated surface water and colder, less oxygenated subsurface water. This can be useful as certain species may prefer to be above or below it. As surface waters warm, cold water species like trout and salmon spend more time lower in the water column. Because it’s something of a temperature barrier, you may also find fish concentrating just above or below it.
There’s a couple features you may or may not want to use. One shows echo returns of fish as little fish icons rather than red arcs or blobs. I don’t recommend it. You should learn to interpret what you see and this mode will often show schools of bait simply as bigger fish. In this mode anything that creates a signal bounce-back between the transducer and the bottom will show as a fish icon, be it weeds, a mayfly hatch blob, or an actual fish. Another is the fish alarm, which beeps every time a fish (or anything else) is marked. It might be useful if the fishing is slow and you’re not watching the screen. It also might be mildly entertaining, at first, until it starts ringing like a telephone. To each their own.
Most sounders allow you to adjust the sensitivity or gain. The default setting is “auto,” which is usually fine for most applications, and for folks who don’t like to tinker. Increasing the gain will pick up more detail and smaller objects, but may also show more clutter, especially in cloudy water. Contrarily, lowering the gain might “weed” out bottom debris and vegetation.
Any and all of the above work well but if you really want to see what’s going on under the surface there are some exciting new technologies. As the name implies, Sidescan provides views up to 600 feet on either side of the boat; and you can imagine the utility. It’s nice to know what’s below but sometimes it’s even more useful to know what lies ahead. For that, there’s Forward View. Both require matched transducers.
Then there are technologies with various trade names like RealVision, which create and display a 3-D image of what’s behind and to the sides. They’ll also retain and continue to display the information so with each successive pass you create a more complete image of what’s going on, and return to the location that shows the most fish.
Depending on the make and model of your sounder, there’s a whole range of other adjustments you can make to fine tune your search. One is scroll speed. Slow is better for drifting or stationary fishing but if you’re running and searching, bump up the scroll speed. Another is bottom search limit. The unit is constantly searching from the surface to whatever the maximum depth it’s set at. If it’s set at 100 feet but you’re not going over 40, adjust it for a quicker reaction time and more detail.
Bob Humphrey
Integration
Modern multi-function displays (MFDs) incorporate chart plotters and other functions that increases utility exponentially. You use one to find the fish and the other to find your way, and with a split-screen can do both at the same time. And the more you use them together, the more useful you’ll find them. The sounder will tell you where the fish are, but the plotter might tell you why. Maybe there’s a shoal or reef that concentrates bait, a point or narrow that creates eddies or turbulent water. Don’t forget to pay attention to bottom type as well. In time you’ll find yourself using the charts as much if not more to find the fish.
Plotters typically come with at least basic navigational charts installed. There are plenty of more advanced options, which I highly recommend. Some are proprietary or brand specific while others are more adaptable. Many require a subscription, which is not a bad idea, especially if you fish areas where wind, tide or current can shift bottom sediments around, or aids to navigation (ATONs) are re-positioned over time. Also, some incorporate user input to create super-accurate bottom structure hydrography.
iIf you travel the same area on any kind of regular basis, tracks can be invaluable, especially if you don’t have radar. Let’s say you’re coming in from a day offshore and the bay is shrouded in fog, not an uncommon occurrence. You could make your way back to the launch with a chartplotter alone, but being able to follow a track makes it so much easier, and safer. Just don’t forget to make those tracks on clear days. Somewhat the same is true for routes, and you can create a route without actually traveling it.
Next we venture into the realm that just a few years ago would have been considered science fiction. Spot-Lock technology allows you to pair your chartplotter with your trolling motor to hold you in one place. The advantages should be obvious but if you find a school of fish, just set a waypoint and lock onto it and your motor will keep you over them. You can also program your motor to follow a track or route, perhaps along an edge or drop-off. That’s already pretty cool but wait, there’s more…
Technology also allows you to pair your VHF radio with your chartplotter’s GPS. In the best case scenario, you can send your exact location to your fishing buddies over the airways, without anyone else knowing. In the worst case, rescuers like the Coast Guard can easily locate you in times of distress.
Redundancy
If you have the means, multiple MFDs are not a bad idea. If one is good, two are better. At the very least, it offers the option of two larger displays rather than a single split screen. You can run your sounder on one and chartplotter on the other. Despite manufacturer’s best efforts (and sometimes due to user error), electronics can malfunction. That’s when having a back-up really comes in handy. I run two 12″ MFDs on my big boat and that’s gotten me safely back to port more than once. In a pinch, and if you have sufficient cell coverage, it’s not a bad idea to have a navigation app on your smart phone.
Bob Humphrey
Conclusion
When it comes to fishing and icebergs, it’s what lies underneath the water that’s often most important; and while it’s a lot of information, above is just a few tips. Don’t get discouraged if you’re overwhelmed at first. There’s a saying in business school that when things don’t go according to plan you should view it not as a problem but an opportunity. Use the time during slow fishing periods to tinker with your electronics. Play around with unfamiliar features and learn how they work. Go fishing with others who know what they’re doing and ask questions. It takes time to become proficient, and you’ll likely forget a lot between seasons, but over successive seasons you learn and retain more and the process gets easier.
