Gearhead: Portable Fish Finders

finder finder
AN ELECTRONIC FISH FINDER IS MORE VALUABLE AS A STILLWATER FISHING TOOL THAN ANY ROD, REEL, OR LINE. SMALL FISH FINDERS EASILY FIT A FLY FISHER’S NEEDS. ABOVE IS THE AUTHOR’S DO-IT-YOURSELF FISH-FINDER SETUP ON HIS PONTOON BOAT.

For many fly fishers, lakes and reservoirs are an enigma. Sure, you can read about stillwater fly fishing in Trent’s excellent column or in books from experts such as Hal Janssen and Denny Rickards, but the translation from the written word to real life can often seem as complicated as proving Fermat’s Last Theorem. Online videos aren’t much better. This is especially true for fly fishers who have spent most of their time on a guide boat drifting down a river, but even experienced stream anglers can find static waters more than a little confusing. A few fruitless hours of blind casting, staring at a bobber, or dragging a fly behind a float tube is enough to convince many that fly fishing in motionless waters is either too difficult or seriously overhyped. Dispirited or distrustful, they return to flowing water where the world, once again, makes sense.

Without a doubt the biggest problem with lakes is the lack of readily visible fish-holding features. On a river, flowing water usually tells you where to place your fly. Seams, pockets, pools, and riffles are all relatively easy to decipher. Take away the flow, move the opposite bank hundreds of yards away, and the water becomes almost inscrutable.

Hiring a knowledgeable fly-fishing guide is obviously a good way to learn the ins and outs of a lake. But what if the guides are fully booked, or there isn’t one on the water you’d like to fish? While it might seem like cheating to some folks, a fish finder can really shorten the stillwater learning curve. In fact, I’d argue that a fish finder is way more valuable as a stillwater fishing tool than any rod, reel, or line. It won’t solve every problem, but it will let you know where the fish are or are likely to be. Once the finder has put you in the right place, you can apply the wisdom of the experts with a lot more confidence.

For this column, we’ll be looking at small, low-cost fish finders, the kind that can be used on a float tube, inflatable pontoon boat, kayak, canoe, or rental boat. These are the sort of craft most of us can afford and that don’t require a trailer and tow vehicle. They represent a cost-effective way to get onto still waters and in some cases, where access is limited, the only way.

While these smaller  fish finders don’t feature the astounding imaging and mapping technology found on the thousand-dollar-plus units used by the techno-savvy bass and offshore guys, they are still very sophisticated pieces of kit. Technology that was available only on the expensive units a few years back has migrated down to the small-finder market. Even the cheapest units have features that make the underwater world a whole lot easier to understand. Let’s take a quick look at a few things a finder can do that will make a big difference in your stillwater fishing success.

Finding Fish (Well Duh!)

The ability to find fish is perhaps the biggest confidence booster that these devices provide for folks who are new to stillwater fly fishing. Even if the surface of the water appears completely devoid of life, the finder will betray the presence of fish. Simply knowing that your fly is in the general vicinity of something with fins instills confidence, which has an uncanny way of improving your odds.

But don’t despair if you don’t immediately see fish on the finder as you paddle away from shore. That doesn’t mean they aren’t around. With the exception of expensive high-end finders, which have side-scan or 360-degree transducers, regular finders register only fish that enter into the somewhat limited scanning area below your craft. The real value of the finder is in the other details presented on that brightly colored screen.

Depth

While seeing fish on the finder screen can certainly be helpful, knowing the water’s depth is often more valuable. Stillwater trout don’t hold in specific lies, like their moving-water brethren. Instead, they’ll be actively searching for food, and this search usually correlates with water depth. Find the right depth, and your chances of intercepting hungry fish go up significantly.

On most lakes, the insects and crustaceans that fish love to eat tend to be found in areas where sufficient light reaches the bottom to support plant growth. While it varies from lake to lake, this usually means you’ll want to fish in areas that are less than 25 feet deep. Most of the time, simply checking the finder will keep you from straying too deep, but some finders also provide a deep-water alarm if you find you get too distracted.

Drop-Offs

It can really pay off to fish in areas where shallow water transitions into deeper water. Trout and bass both show a preference for these areas, especially as the surface water warms up in the summer. It may be a pronounced drop-off, where the water suddenly plunges from 10 feet to 20 feet, or a more gradual slope that takes you from 5 to 10 feet. Either way, keeping your fly in this transition zone can really boost your chances of getting bit.

Substrate

One of the nice things about fish finders is they can tell you if the bottom is soft or hard. While it is possible to distinguish soft sediments with finders that have a gray monotone screen, they really stand out with full-color displays. Most finders show hard, rocky bottom as an almost solid red line, while a soft bottom presents a wider, more fuzzy band, which often features orange or yellow.

Muddy bottoms are important because they are typically home to chironomid larvae. With population densities ranging from 5 million to 50 million per acre, chironomids represent a huge biomass in many lakes. When 50 million larvae turn into 50 million pupae and begin an agonizingly slow ascent to the surface, it tends to get the attention of trout. Fish will slowly cruise along, vacuuming pupae as they go. Under these circumstances, a chironomid pupa pattern suspended below an indicator can be deadly. Often, the fish will show on the finder and let you know how deep to set the fly. If not, start about a foot off the bottom and shorten the distance in one-foot or two-foot increments until you hit the magic depth.

Structure

For anyone looking to catch largemouth and smallmouth bass, fishing to structure is often important. Most of the time, this means casting to obvious shoreline features such as downed trees, boat docks, or rocky points. But a significant percentage of bass don’t hold tight to shore. This is where the finder becomes an almost essential bass fishing tool. Anything that sticks up from the bottom can hold bass, whether it’s a rock, a tree stump, or a sunken boat. Run your fly close to these pieces of structure, and sooner or later, something with a big or small mouth is going to attack it.

Baitfish

I love fishing streamers in lakes. The underwater grab is incredibly addictive, whether it’s the sharp tug of a trout, the high-torque bang of a largemouth, or the slam and power run of a striper. Occasionally, you’ll come across a school of baitfish being attacked on top, but more often than not, the action is going on some distance below the surface. Trolling a fly is one way to find fish feeding on baitfish, but you run the risk of running your fly too shallow or deep. A fish finder will clearly show baitfish schools and will also show any trout, bass, or stripers that are busy killing them.

Low-Cost Fish Finders

Having covered the main reasons to get a finder, let’s look at some of the units that are currently on the market. There are plenty of finders that show water depth, bottom type, and fish for under $100. Some of these units use a floating transducer that looks like a tennis ball or rubber duck, which sends a Wi-Fi signal to your smart phone or to a handheld device. While I imagine the smartphone-based ones could work for folks fishing from the bank or a stable boat, I’m not sure I’d feel comfortable using my smart phone as a finder in a float tube, pontoon boat, or kayak. If money is tight, by all means get one of these units — it will certainly help you catch fish. But if your budget is a bit more forgiving, I suggest you start your shopping at the $100to-$250 mark. Here are three portable finders you might want to consider.

Humminbird

For many years, the Humminbird Fishin Buddy was the obvious choice for fly fishers. This easy-to-use, onepiece finder and transducer was powered by 6 AA batteries and was pretty easy to mount on float tubes or rental boats. Longtime friend Lee Haskin swears by his Fishin Buddy 120, which he uses to locate stripers in San Luis Reservoir. As several pictures on the Internet clearly show, Lee has found some very big stripers in San Luis.

Unfortunately, Humminbird has discontinued the Fishin Buddy line and seems to have replaced it with the Piranha MAX 4 PT. The PT is the portable version of their Max 4 finder, which features a 4.3-inch full-color display and dualbeam sonar, which projects two beams in concentric cones under the watercraft, one wide and consequently low-resolution and one narrower and with higher resolution. The PT comes with a carrying case, suction cup transducer, 12-volt battery, and charger. The finder will show plenty of detail, but the beam width is somewhat small in shallow waters. The wide (28 degree) beam covers only a width of 5 feet in 10 feet of water. The MAX 4 PT currently retails for $169.

Lowrance

The Hook 2 4X Bullet All Season Pack is Lowrance’s portable finder setup. The finder has a 4.0-inch full-color display and includes a GPS plotter. The transducer has a single 40-degree beam that will provide just over 7 feet of coverage in 10 feet of water. The Pack includes a carrying case, 12-volt battery, and charger, along with several accessories for mounting the finder and transducer.

Having GPS on a fish finder may not seem too important at first, but once you start using it, you’ll realize just how useful it can be. Being able to mark waypoints by pushing one button and then being able to navigate easily back to that exact same spot can change the way you fish. Whenever you pass over an interesting bit of structure or a drop-off, you just tap the button and the finder sets a waypoint. Pretty soon, you’ve got a bunch of fish-attracting features that you can return to time and time again. Based on current pricing, the Hook 2 4X Bullet All Season Pack can be yours for $250.

Garmin

Garmin’s Striker 4 Portable Bundle provides the finder and transducer, as well as a storage pack, 12-volt battery, charger, and a variety of finder and transducer mounts. The finder has a 3.5-inch full-color screen and GPS. The transducer provides CHIRP technology in addition to dual-beam sonar. CHIRP stands for compressed high-intensity radiated pulse, which is technospeak for a sonar that uses a sweep of frequencies to create high-resolution images. CHIRP reveals details that are indistinguishable with a normal finder, which can be helpful in certain circumstances. I own a Striker 4 and am not sure how much value CHIRP would be for folks who fly fish only for trout, but if you are also interested in targeting bass, the cleaner images of structure and baitfish schools are really helpful. The Striker 4 Portable Bundle will currently set you back $169.


We have only scratched the surface here of what’s available on the finder market. I deliberately covered low-cost finders from established brands that are designed to work with float tubes, kayaks, and rental boats. These units provide more than enough features to help you catch fish. But if your budget has wiggle room, there are certainly a lot of other options out there. If the manufacturer or an aftermarket supplier (such as FishfinderMounts.com) provides a suitable accessory kit, or you don’t mind doing a bit of DIY, it’s quite possible to mount sophisticated finders on your craft. Obviously, this is wonderful news for folks who, in addition to fly fishing, also have a serious tech obsession. Just remember you’re on the water to fish. . . .