Fish finders are electronic devices that let fishermen and fisherwomen see what is going on under water. Some might say that fish finders take the fun out of fishing, since most people who fish for the sport of it know that spending time out on the water drifting from spot to spot is sometimes more than half the fun of fishing. Experienced fishermen and women also know that some days not matter what they do, a glimpse of what is happening under the water even if it is electronically can definitely speed up the catching.
Fish finders although small and simple to use are actually quite complicated inside. Fish finders work by sending out a wave of sound which travels down through the water and bounces off any fish, weeds, rocks, and the lake bottom that are in the path of the sound wave. The fish finder then measures how long it takes for the sound wave to reflect and bounce back up to the transducer. Any areas of the sound wave which are “shadowed” can be interpreted as fish or other underwater structures. The results are then displayed on a viewfinder which is located in the boat above the water level which shows in good detail what is swimming around your bait.
Transducers are the part of the fish finder that emits and receives the sound wave. Sound waves travel out in degrees of coverage depending on how much area is to be viewed. Settings vary with each manufacturer; however a wave can travel out at around 55° for a wider scan of the deeps or at a narrower 15° or so for when you are trying to see what is down an ice fishing hole.
The narrower the degree the more powerful the wave can be. The sound wave can be sampled at 150 kHz when focused allowing for deeper penetration into the water, but when the fish finder is set at a 55° view the sound wave is only travelling at about 96 kHz which may not travel as deeply into the water.
Transducers are usually permanently mounted to the stern or hull of the boat, but some can be removed so fish finders can be moved between different boats. A new generation of fish finder transducers are the size and shape of a golf ball. They are then attached to a fishing line and cast out into the waters you are fishing or simply dropped down the ice fishing hole. The results are then sent wirelessly to smart phones via Bluetooth technology. This makes carrying fish finders extremely easy for people fishing from shore or on foot ice fishing.
The display screen is an LCD display panel typically about 5” x 7” which is kept in the boat usually mounted at the helm. Originally, displays were in low resolution black and white images not much better than a calculator, and the information displayed was vague at best, but 21st century displays feature great resolution and multiple colours giving viewers the most accurate and detailed information that the transducer can send up. The high resolution allows the display to show clearly what size of fish is being scanned and how many there are.
Weed beds can also be differentiated from the lake bed and the contour of the lake bottom as it drops off can even be displayed similar to a topographical map on land. Multiple colours in the display can show the water temperature cooling as water depth increases, and of course water depth. Displays that can be viewed on smart phones are also perfect for use in canoes or kayaks where electric power for the device may not be readily available.
Most fish finders will also function as a depth sounder showing water depth where your boat is travelling. This feature is a big help when sailing on new waters for the first time where captains may not be familiar with what lies beneath the surface.
Fish finders are amazing devices for any fishing enthusiast. Shop around your favourite outdoors store to find the model that best suits you, your boat, and your method of fishing. Prices vary with some models starting at just a couple hundred dollars, and well worth it once you see what is (or isn’t) swimming under your boat.
Copyright 2019 Mike Wilson
