Referred to as a fishfinder, graph, sounder or recreational sonar, these products provide anglers with the ability to locate and target open-water baitfish, game fish and cover. This underwater-viewing advantage helped launch sportfishing markets like never before, as anglers were able to better understand depth contours, bottom composition and structure location, plus how fish related to this environment.
BUT DOES A FISHFINDER REALLY FIND FISH? Does a woodchuck really chuck wood? Sorry jackwagon, I had to go there. A fishfinder works on the same theory as deep space telescopes identifying distant stars. It doesn't see "fish" but it does see things that don't look like water. Once the data is processed, the resulting image is therefore labeled fish. Therefore, these units absolutely process the data and tell you if fish are in the beam. But alas, they don't know what they're eating, or if they're even in the mood to eat. But, I do believe that fish will almost always eat if given the right offering. But, you have to find them first.
Unless you know where fish are lurking, casting out anywhere on the water doesn’t necessarily guarantee a bite. Finding where the hot spots are will help you save time and money while fishing. That’s where fishfinders come in. An essential part of any modern angler’s arsenal, a fishfinder makes catching more fish easier.  Fishfinders help you pinpoint the honey hole using SONAR so you can see where the fish are and at what depth they are hiding. No more wasting time, tackle or line on deserted spots in the water. From standalone units, fishfinder/GPS combos, networked or multi-function displays, West Marine offers a wide array of fishfinders from the top brands on the market today. Keep reading for tips on finding the right system for your boat.
Winter weather may run us inside, but that doesn't mean the sport sleeps. Those "other things" I mentioned will be covered when I write my book, but for now they will have to wait. In the mean time, let's discuss some other "deep thoughts". Or should that be "thoughts about the deep"? Or maybe it would be "I thought this water was deeper". This article is about depth finders, or more commonly called "fish finders". In this issue, we'll discuss your options when it comes to selecting one of these gadgets, along with tips for temporary or permanent installation.
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.
A fishfinder or sounder (Australia) is an instrument used to locate fish underwater by detecting reflected pulses of sound energy, as in sonar. A modern fishfinder displays measurements of reflected sound on a graphical display, allowing an operator to interpret information to locate schools of fish, underwater debris, and the bottom of body of water. Fishfinder instruments are used both by sport and commercial fishermen. Modern electronics allows a high degree of integration between the fishfinder system, marine radar, compass and GPS navigation systems.
The swivel sinker is similar to the plain one, except that instead of loops, there are swivels on each end to attach the line. This is a decided improvement, as it prevents the line from twisting and tangling. In trolling, swivel sinkers are indispensable. The slide sinker, for bottom fishing, is a leaden tube which allows the line to slip through it, when the fish bites. This is an excellent arrangement, as the angler can feel the smallest bite, whereas in the other case the fish must first move the sinker before the angler feels him.
A sinker or plummet is a weight used when angling to force the lure or bait to sink more rapidly or to increase the distance that it may be cast. The ordinary plain sinker is traditionally made of lead. It can be practically any shape, and is often shaped round like a pipe-stem, with a swelling in the middle. However, the use of smaller lead based fishing sinkers has now been banned in the UK, Canada and some states in the USA,[4] since lead can cause toxic lead poisoning if ingested. There are loops of brass wire on either end of the sinker to attach the line. Weights can range from a quarter of an ounce for trout fishing up to a couple of pounds or more for sea bass and menhaden.

Bait: If you're not using live bait or cut bait, you'll want to use artificial bait or lures. Most artificial lures resemble the type of bait fish or other food, such as worms or shrimp, that the fish you're trying to catch normally eat. These artificial baits can be scented and have metal spoons attached to them or be painted in metal flake to reflect light in the water. Other types of bait include jigs and jig heads, spoons, flies and spinnerbaits, which you can attach artificial or real bait to, and attractants to make artificial lures smell lifelike.