These units are battery operated and the signal is transmitted back to the receiver. So, don't expect a lot of range or HD resolution. But, if you simply want to know how deep the water is ahead of you so that you can make better choices, this is it. For me, I would need to cast it with a rod/reel loaded with heavy braid. The areas I'd likely cast to would hopefully hold big snook and in the spring they love this color. I don't want the "dog ate my homework" story to become the "snook ate my transducer" story.
Fish finders were derived from fathometers, active sonar instruments used for navigation and safety to determine the depth of water.[1] The fathom is a unit of water depth, from which the instrument gets its name. The fathometer is an echo sounding system for measurement of water depth. A fathometer will display water depth and can make an automatic permanent record of measurements. Since both fathometers and fishfinders work the same way, and use similar frequencies and can detect both the bottom and fish, the instruments have merged.[2]

In operation, an electrical impulse from a transmitter is converted into a sound wave by an underwater transducer, called a hydrophone, and sent into the water.[3] When the wave strikes something such as a fish, it is reflected back and displays size, composition, and shape of the object. The exact extent of what can be discerned depends on the frequency and power of the pulse transmitted. Knowing the speed of the wave in the water, the distance to the object that reflected the wave can be determined. The speed of sound through the water column depends on the temperature, salinity and pressure (depth). This is approximately c = 1404.85 + 4.618T - 0.0523T2 + 1.25S + 0.017D (where c = sound speed (m/s), T = temperature (degrees Celsius), S = salinity (per mille) and D = depth).[4] Typical values used by commercial fish finders are 4921 ft/s (1500 m/s) in seawater and 4800 ft/s (1463 m/s) in freshwater.
BABY STEPS: You don't have to spend a ton of money or be an engineer to get your kayak electrified. Here we have the Lowrance X50DS. The fishfinder and the installation kit will run around $250. Look at what you spend for a rod/reel/braided line, and you'll find this kit is certainly affordable. The display is 4-level grayscale, and the battery pack contains AA batteries. However, what it may lack in fashion it makes up by function. The battery pack goes in a dry bag, and the unit itself is easily removed at the end of the day. It features a built in temperature sensor and 120 degrees of wide angle coverage.
As we mentioned, the strength of a fish finder is in how well it can locate the fish, which is why you need a high-quality transducer. CHIRP technology is one of the best you can find, and it provides a 200-watt RMS signal that can reach down to 1,600 feet in fresh water and 750 feet in salt water. Overall, you can find plenty of fish with this device.

In summer and winter, water temperature is very important - these units will help you discover areas that should be comfortable for your target species. Safety is found in structure, for prey and predator alike. The illusion of safety for baitfish equates to food for prey. So locating proper structure is certainly important. It's been said that 90% of the fish can be found in 10% of the water. Believe it. If you're fishing structure in the middle of a lake or a man-made reef, knowing what's below you is important. Now you know.
Whether you're off to a nearby stream for some fly fishing or heading out into the open waters for a deep sea fishing adventure, the right fishing gear will make your trip even more exciting. When the weather's nice, find a quiet spot to cast your line with a new fishing reel. Pick up a rod and reel combo that's ready to go right out of the box or customize your fishing gear with a separate rod and reel.
Raymarine has a few units that come with a built in GPS. The Dragonfly 4Pro, Dragonfly 5Pro, and Dragonfly 7Pro all have built in GPS. Pay close attention to the unit you are buying, because if you are looking for built in GPS the standard Dragonfly 4 and Dragonfly 5DVS do not have that feature built in. You absolutely have to go Pro to make sure you get the GPS you’re looking for.
Ice fishing is work. Just to get a line wet, you’ve got to drill and scoop. Just to keep a line wet, you’ve got to clear ice from the guides. There are a ton of little things that can make a hard-water outing much more challenging than fishing on a sunny summer afternoon, so it should be no surprise that smart ice anglers have come up with a pile of gear hacks to make any day on a frozen lake a little easier, more comfortable, and a lot fishier. You could fill a book with these tricks, but here are four that every serious ice fisherman should know. They all require a few inexpensive items you probably have lying around at home.
Just getting started using a fish finder? Know the basics but want to get more out of your fish finder? Not sure you’re reading your fish finder display correctly? Don’t worry, we’re here to help. This short tutorial will teach you how to make sense of your fish finder display so you can tell what’s a bait fish, what’s a trophy catch and what’s just a submerged tree that you’ll snag on. Take just 7 minutes to go through this tutorial and at the end you’ll be able to read your fish finder display for:
GARMIN ECHOMAP 73SV FISH FINDER LIKE NEW CONDITION. Condition is Used. comes with everything in the box as new except the mounting screws for transducer, I only used this for about 1 year, then went to a garmin echo plus chirp unit, everything works like new , has original box, I know the transducer alone will sell for $200-249 alone when new any questions feel free to email me!

Whether you're an experienced fisherman with boating experience or a beginner casting from the shore, eBay has the gear you need. Once you have the rods, the rompers and the boat, you still need fishing hooks, lures and tackle boxes. eBay has a great selection of fishing gear for sale. Browse spinning reels, rod and reel combos, fishing line, tackle boxes and rod cases. Whether it’s Okuma or Rapala, hook removers or baitcasting fishing reels, there’s no need to trek to the outdoor warehouse to peruse rows and rows of fishing products. With easy-to-navigate categories and plenty of options, eBay’s online fishing shop offers everything you need to head out to sea or into the quiet creek for the catch of your choice. Check out eBay's lures section to find the soft bait and hard bait that you're looking for. You’ll also find marine electronics like fishfinders—whatever it takes to help make that elusive prize catch. And if you’re in the market for a trolling motor, you’ll find that here as well, and at a great price.