A fishfinder or sounder is an instrumentused to locate fish underwater by detecting reflected pulses of soundenergy, as in sonar.
A modern fishfinder displays measurements of reflected soundon a graphical display, allowing an operator to interpret information tolocate schools of fish, underwater debris, and the bottom of body of water.
Fishfinder instruments are used both by sport and commercial fishermen.
Modernelectronics allows a high degree of integration between the fishfindersystem, marine radar, compass and GPS navigation systems.
Fathometer Fish finders were derived fromfathometers, active sonar instruments used for navigation and safety todetermine the depth of water.
The fathom is a unit of water depth, from which theinstrument gets its name.
The fathometer is an echo sounding system formeasurement of water depth.
A fathometer will display water depth and can make anautomatic permanent record of measurements.
Since both fathometers andfishfinders work the same way, and use similar frequencies and can detect boththe bottom and fish, the instruments have merged.
Operating theory In operation, an electrical impulse froma transmitter is converted into a sound wave by an underwater transducer, calleda hydrophone, and sent into the water.
When the wave strikes something such asa fish, it is reflected back and displays size, composition, and shape ofthe object.
The exact extent of what can be discerned depends on the frequencyand power of the pulse transmitted.
Knowing that the speed of the wave inthe water is 4921 ft/s in seawater, 4800 ft/s in freshwater, the distance to theobject that reflected the wave can be determined.
The process can be repeatedup to 40 times per second and eventually results in the bottom of the ocean beingdisplayed versus time The temperature and pressure sensitivitycapability of fish finder units allow one to identify the exact location ofthe fish in the water by the use of a temperature gauge.
Functionality presentin many modern fish finders also have track back capabilities in order tocheck the changes in movement in order to switch position and location whilstfishing.
General interpretation The image above, at right, clearly shows the bottom structure—plants, sedimentsand hard bottom are discernible on sonar plots of sufficiently high power andappropriate frequency.
Slightly more than halfway up from the bottom to theleft of the screen centre and about a third away from the left side, thisimage is also displaying a fish – a light spot just to the right of a'glare' splash from the camera's flashbulb.
The X-axis of the imagerepresents time, oldest to the left, most recent bottom on the right; thusthe fish is now well behind the transducer, and the vessel is nowpassing over a dip in the ocean floor or has just left it behind.
The resultingdistortion depends on both the speed of the vessel and how often the image isupdated by the echo sounder.
Fish symbols in the screen of thefishfinder Fishfinders usually have a "Fish Symbol"feature, which will display a FISH symbol for almost any echo not connectedto the bottom or the surface.
More specialized units use a detection of aspecial fingerprint in echosignals.
With those you can find living fish and fishthat have recently died.
With these units also in some cases fish spawn willbe shown as a large fish.
Some kinds of seafish will be not marked as fish, butyou will see an echo.
Fish arches With the Fish Symbol feature disabled, an angler can learn to distinguishbetween fish, vegetation, schools of baitfish or forage fish, debris, etc.
Fish will usually appear on the screen as an arch.
This is because the distancebetween the fish and the transducer changes as the boat passes over thefish.
When the fish enters the leading edge of the sonar beam, a display pixelis turned on.
As the fish swims toward the centre of the beam, the distance tothe fish decreases, turning on pixels at shallower depths.
When the fish swimsdirectly under the transducer, it is closer to the boat so the strongersignal shows a thicker line.
As the fish swims away from the transducer, thedistance increases, which shows as progressively deeper pixels.
The image to the right shows a school of white bass aggressively feeding on aschool of threadfin shad.
Note the school of baitfish near the bottom.
Whenthreatened, baitfish form a tightly packed school, as the individuals seeksafety in the center of the school.
This typically looks like an irregularlyshaped ball or thumbprint on the fishfinder screen.
When no predators arenearby, a school of baitfish frequently appears as a thin horizontal line acrossthe screen, at the depth where the temperature and oxygen levels areoptimal.
The nearly-vertical lines near the right edge of the screen show thepath of fishing lures falling to the bottom.
General history in sporting and fishing Early sporting fathometers forrecreational boating used a rotating light at the edge of a circle whichflashed in sync with the received echo, which in turn corresponded to depth.
These also gave a small flickering flash for echos off of fish.
Like today'slow-end digital fathometers, they kept no record of the depth over time andprovided no information about bottom structure.
They had poor accuracy,especially in rough water, and were hard to read in bright light.
Despite thelimitations, they were still usable for rough estimates of depth, such as forverifying that the boat had not drifted into an unsafe area.
Eventually, CRTs were married with a fathometer for commercial fishing andthe fishfinder was born.
With the advent of large LCD arrays, the high powerrequirements of a CRT gave way to the LCD in the early 1990s and fishfindingfathometers reached the sporting markets.
Today, sporting fishfinderslack only the permanent record of the big ship navigational fathometer, andthat is available in high end units that can use the ubiquitous computer to storethat record as well.
Commercial and naval units Commercial and naval fathometers of yesteryear used a strip chart recorderwhere an advancing roll of paper was marked by a stylus to make a permanentcopy of the depth, usually with some means of also recording time so that thestrip charts could be readily compared to navigation charts and maneuveringlogs.
Much of the world's ocean depths have been mapped using such recordingstrips.
Fathometers of this type usually offered multiple speed settings, andsometimes, multiple frequencies as well.
At high frequency settings, high chartspeeds, such fathometers give a picture of the bottom and any intervening largeor schooling fish that can be related to position.
Fathometers of the constantrecording type are still mandated for all large vessels in restricted watersof land).
See also Bathymetry Echo soundingFessenden oscillator Game Boy Pocket SonarSensor SonarSounding line Notes References Fish-finder.
In Encyclopædia Britannica.
Retrieved October 1, 2008, from Encyclopædia Britannica OnlineMarine Electronics Reviews External links Post-war economics: Fisherman who caught multibillion-dollar deal FinancialTimes, 9 December 2009.
Fish Finder Information The anatomy of afish finder, technological advances, side imaging versus down imaging.
Realed to Fish Finder US Review
Garmin Striker 4 Built-in GPS Fish Finder fish finder
This Garmin Striker 4 Built-in GPS Fish Finder from: Garmin, Their ASIN : B017NI17HQ Listed with price at $119.99, Now visitor can buy this product at $99.98, Following in the success of the STRIKER fishfinder series, Garmin is proud to announce the new STRIKER fishfinders with ClearVü technology. These devices are designed to allow you to mark your favorite fishing spot and easily navigate back to it tomorrow, saving you time and money. STRIKER series fishfinders are available in 3.5-, 5- and 7-inch display sizes. fish finder .
Garmin Striker 4 Built-in GPS Fish Finder fish finder Features
CLEARVÜ SCANNING SONAR - Shows you more of what is in the water around your boat. This high-frequency sonar gives near-photographic images with detailed representations of objects, structure and fish.
THE POWER OF SIMPLE - Offers a keyed interface with dedicated buttons. The device is easy to use and easy to install. Available in 3.5-, 5- and 7-inch display sizes. Water rating IPX7
Deeper Smart Sonar PRO+ - GPS Portable Wireless Wi-Fi fish finder
This Deeper Smart Sonar PRO+ - GPS Portable Wireless Wi-Fi Fish Finder for Shore and Ice Fishing from: Deeper, Their ASIN : B01CQLVO5U Listed with price at $203.86, Now visitor can buy this product at $187.00, Deeper Smart sonar Pro+ is a wireless, cast able echo-sounder compatible with iOS and Android smartphones and tablets. Wi-Fi connection Enabled to maximize both the distance between the Deeper Smart sonar Pro+ and the device holder up to 330ft/100 M and the Depth range up to 260ft/80 M. Advanced high-frequency technology enables the Deeper Smart sonar Pro+ to quickly transfer more accurate data. The higher scanning frequency allows th fish finder .
Deeper Smart Sonar PRO+ - GPS Portable Wireless Wi-Fi Fish Find fish finder Features
Wi-Fi connected wireless, castable, portable smart fishfinder; NO Internet or Cellular data required! Compatible with iOS and Android
Perfect tool for all styles of fishing: shore-, ice-, bank-, boat-, kayak-, river-, float tube fishing; operating on Fresh water and Salt water
The only portable sonar on the market with GPS enabled onshore bathymetric mapping feature! Create your map and analyze it on your PC vi
Humminbird 410210-1 HELIX 5 CHIRP GPS G2 Fish finder fish finder
This Humminbird 410210-1 HELIX 5 CHIRP GPS G2 Fish finder from: Humminbird, Their ASIN : B01M2VLBQF Listed with price at $299.99, Now visitor can buy this product at $276.00, At Hummingbird, innovation is the core of everything we do. The new HELIX Series is no exception-delivering our full array of technologies, including the intuitive REFLEX interface, precise Broadband CHIRP, incredible Imaging SONAR and the mapmaking power of Auto Chart Live. Fueled by DNA that is unmistakably Hummingbird, the HELIX Series also features a jaw-dropping industrial design. From top to bottom, it's plain to see that findin fish finder .
Humminbird 410210-1 HELIX 5 CHIRP GPS G2 Fish finder fish finder Features
5-Inch Color WVGA Display
CHIRP Dual Beam PLUS Sonar
Precision Internal GPS Chart plotting with built-in Anima cartography
Micro SD card slot for optional maps or for saving waypoints
Venterior VT-FF001 Portable Fish Finder, Fishfinder w fish finder
This Venterior VT-FF001 Portable Fish Finder, Fishfinder with Wired Sonar Sensor Transducer and LCD Display from: Venterior, Their ASIN : B013DZJDWE Listed with price at $85.99, Now visitor can buy this product at $39.99,
Specification : 1. Measure Units: Meters / Feet 2. Display: TN/Anti-UV LCD display 3. Backlighting: LED 4. 4.6cm diameter Round transducer sensor 5. Depth Range : Max: 100m (328ft) ; Min: 0.9m (3ft) 6. Sensor Beam Angle: 45 degrees 7. Operating Temperature is from -20°C to 70°C (-4°F to 158°F) 8. Uses 4 x AAA batteries (not included)
Package Included : 1. Fish Finder Disp fish finder .
Venterior VT-FF001 Portable Fish Finder, Fishfinder with Wired fish finder Features
Detect and display water depth, approximate fish location, short & tall weeds, sand & rocks on seabed. Updated(since 2017): It can remember setting. Do not need to reset it everytime.
Apply to lake, river, sea and other fishing environment. Depth range from 3ft to 328ft.
Round transducer with 25 ft cable and removable transducer float. Can be used for fishing off the dock, on a boat, and ice fishing.
Updated Version Venterior Portable Fish Finder, Handh fish finder
This Updated Version Venterior Portable Fish Finder, Handheld Fishfinder with Wired Sonar Sensor Transducer and LCD Display from: Venterior, Their ASIN : B01MZ6BWI5 Listed with price at $89.99, Now visitor can buy this product at $39.99,
Specification : 1. Measure Units: Meters / Feet 2. Display: LCD 3. Backlighting: LED 4. 4.6cm diameter Round transducer sensor 5. Depth Range : Max: 100m (328ft) ; Min: 0.9m (3ft) 6. Sensor Beam Angle: 45 degrees 7. Display the nature or circumstance of bottom of Sea (i.e. grass, rock and sand) 8. Operating Temperature is from -10°C to 45°C (14°F to 113°F) 9. Uses 4 x AAA batteries (no fish finder .
Updated Version Venterior Portable Fish Finder, Handheld Fishfi fish finder Features
Detect and display water depth, approximate fish location, short & tall weeds, sand, and rocks on seabed. Setting can be saved when turned off.
Apply to lake, river, sea and other fishing environment. Depth range from 1M to 100m. NOTE: The depth is measured from the sonar sensor, not the float.
Round transducer with 25 ft cable and removable transducer float. Can be used for fishing off the dock, on a boat, and
Humminbird 410160-1 PIRANHAMAX 4.3 DI Fish finder wit fish finder
This Humminbird 410160-1 PIRANHAMAX 4.3 DI Fish finder with Down Imaging from: Humminbird, Their ASIN : B01MFAV2WK Listed with price at $149.99, Now visitor can buy this product at $149.99, PIRANHAMAX 4 DI | MAX Series | 410160-1 Sharper image. Sharper teeth. With modern styling and large, 4.3" color LCD, the new MAX 4 will give you a fresh perspective on what’s below your boat. Thanks to a redesigned, even easier-to-use interface, unlocking the power of optional Down Imaging, Fish ID+, fish alarms, depth alarms and zoom has never been simpler. Feature for feature, it packs a technological chomp that no fish finder in fish finder .
Humminbird 410160-1 PIRANHAMAX 4.3 DI Fish finder with Down Ima fish finder Features
Lucky Portable Fishing Sonar, Handheld Wired Fish Fin fish finder
This Lucky Portable Fishing Sonar, Handheld Wired Fish Finder Fishfinder Alarm Sensor Transducer with LCD Display from: Lucky, Their ASIN : B06XF17CWV Listed with price at $59.99, Now visitor can buy this product at $39.99, Use the sonar sounder in normal ways Fix the float position in advance. Toss the sensor and float into the water. For kayak fishing 1. Attach the Side-Scan Adapter to the boat hull using the mounting tabs; 2. Break though the hull of a boat. Place the sonar sensor against the hull bottom 1 inch underwater. For ice fishing 1. You should clear the snow on the ice layer. Make sure the surface is smooth enoug fish finder .
Lucky Portable Fishing Sonar, Handheld Wired Fish Finder Fishfi fish finder Features
◆ Fish and bottom contour readout: It detects and displays water depth, approximate fish location, short & tall weeds, sand & rocks on bottom.
◆ The device suits for variety fishing environments: It can be used for off shore fishing, boat fishing, ice fishing, lake fishing, sea fishing and so on. You can also use it on a moving kayak with speed below 5mph
CB CHROMEBATTERY 12V 7AH Sealed Lead Acid (SLA) Batte fish finder
This CB CHROMEBATTERY 12V 7AH Sealed Lead Acid (SLA) Battery for Piranha MAX 160 Fish Finder from: CB CHROMEBATTERY, Their ASIN : B006LO9XHA Listed with price at $30.66, Now visitor can buy this product at $21.90, 12V 7AH Sealed Lead Acid (SLA) Battery for Piranha MAX 160 Fish Finder
12 Volt 7 Amp-Hour Sealed Lead Acid (SLA) batteries with T1 Terminals by Chrome Battery are constructed with lead calcium alloy and absorbed glass mat AGM technology which allows a completely maintenance-free and high-performance operation. Fiberglass mat separators and high cell compression extend battery life by delivering superior vibrati fish finder .
CB CHROMEBATTERY 12V 7AH Sealed Lead Acid (SLA) Battery for Pir fish finder Features
ReelSonar iBobber Wireless Bluetooth Smart Fish Finde fish finder
This ReelSonar iBobber Wireless Bluetooth Smart Fish Finder for iOS and Android devices. from: ReelSonar, Their ASIN : B00LEA2FS0 Listed with price at $99.99, Now visitor can buy this product at $74.00,
iBobber: Love at First Cast.
This pocket-sized fish finder is as mobile as you are! The iBobber is the smallest and lightest personal sonar depth finder on the market. It is a castable, portable, and wireless fish finder that syncs with the free app on your smartphone or tablet up to 100’ away. This thing is really cool!
Engineered with patented sonar technology providing accurate readings of bottom contours, fish finder .
ReelSonar iBobber Wireless Bluetooth Smart Fish Finder for iOS fish finder Features
• Patented sonar fish identifier technology
• LED beacon
• Rechargeable battery and charge status indicator light
• 10+ hrs battery life
• Accurate sonar readings down to a depth of 135'
• 2 Snap swivel connections for use as bobber or as remote fish finder
• Free app on iOS and Android
• Bluetooth Smart sync up to a distance of 100' for best battery life
Lucky Portable Fish Finder Sonar Sensor 147 Feet Wate fish finder
This Lucky Portable Fish Finder Sonar Sensor 147 Feet Water Depth Sounder LCD Screen Echo Sounder Fishfinder With Fish Attractive Lamp For Ice Fishing from: Lucky, Their ASIN : B076LXR32Z Listed with price at $169.99, Now visitor can buy this product at $79.99, Lucky fish finder is especially designed for amateur and professional fisherman. It can detect the water depth and find out the fish easily. Just enjoy your fishing time!
Screen brightness: You can alter the screen brightness from 1 to 9. Detect sensitivity: It controls how much detail is shown on the display. You can set up the sensitivity from 1 to 10. The more sensitive it is, the more detailed it fish finder .
Lucky Portable Fish Finder Sonar Sensor 147 Feet Water Depth So fish finder Features
★The fish finder, with 2.4inch TFT color LCD screen, can detect and display underwater contour, water depth, water temperature and fish size with depth. It has two user modes: WIRELESS/SIMULATION. You can try all functions in simulation mode and go fishing in wireless mode.
★The sonar sensor, with fish attractive lamp, makes it easier to detect fishes. It has a transparent replacement cover, so you can see where th