Archive for February 2008

Feb/08

29

Marine GPS Units

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You have your big boat, and several lines with their tips bobbing gently pierce the ocean’s choppy surface. The breeze is cool and the sun warm, your beer crisp and your sandwiches fresh. Things are perfect. Well almost. You idly wonder why you’re not getting any fish. Not even a bite – nothing. You’ve given up checking, and as you turn the pages of the fishing magazines more and more aggressively you see the advertisement. GUARANTEED CATCH. FIND FISH FAST. FISH FINDERS. Your eyes are glued to the page and you begin to read, transfixed.

What is a fish finder? A fish finder is a device used – you guessed it – to find fish. They work simply and easily, and used correctly, they can help you locate schools of fish so all you need to do is just drop the line in. Fish finders work using sonar (or Sound Navigation Ranging), or sound waves. In much the same way as an ultrasound can detect a baby in its mother’s belly or a torn rotator cuff in your shoulder, a fish finder beams sound waves into the water to detect fish. The sound waves bounce off any object in the water, and back to the fish finder. The fish finder then works out how far below the surface of the water the object is – and hopefully, the object is a school of fish (or one large one!).

A fish finder is made up of several components: a transducer converts an electrical signal from a transmitter into a sound wave, which is bounced back into the transducer. The signal is amplified by the receiver and then projected onto the display.

There are two types of displays, CRT (or cathode ray tube, like a television screen) and LCD (liquid crystal display). CRTs are more expensive, and require more power, and so an LCD would be perfect for the beginner or those on a budget – they can also be easier to read. Speaking of reading, it will take some time to learn what each of the images are on your fish finder’s screen. A blip may be a shark, a tree trunk or a school of fish – you need to learn to interpret the images in order to make the best use of your device.

Then there is the frequency of the fish finder – the lower the frequency, the better its ability to find fish in larger expanses of water (deep water and wide bodies of water). A high frequency means it works better in shallow water or small areas of water. This needs to be taken into account – will you be fishing mostly in a lake, or in open ocean?

Several things can affect the working of the fish finder; elements such as water clarity, the sensitivity of the fish finder and its settings, the speed of the boat and the positioning of the transducer are just several factors that will change how the fish finder functions. Make sure you learn all about your fish finder before you take it out on the water – unless, of course, you don’t mind a lazy day reading the instruction manual and not catching a lot of fish!

If you’re a beginner, it’s recommended that you purchase a simple fish finder until you learn the ropes, as it were. Fish finders can have many functions and facilities for finding fish, and to jump in at the deep end will most certainly throw you off course.