Marine Electronics Part 2
1st Jan 2013
Once you have made the decision on which brand and model of fish finder you are going to purchase you must now decide where to mount the transducer and which transducer to purchase. Alternatively you could make the decision to upgrade from the standard transducer. There is no doubt in my mind that the best position to mount a transducer is externally as this method will achieve two things. Firstly you will get an accurate sonar display of what is beneath your craft and secondly you will get an accurate water temperature measurement. On the downside your transducer is now exposed and risks being damaged when de trailering or beaching on a Ski Boat or Jetski, and on a Kayak the fibreglass on the hull may be damaged as you beach. A safer and neater option is to mount your transducer internally which will protect the transducer from damage. You will then need to also fit an external temperature probe as your unit will now be reading hull temperature not water temperature.
Recently I tested the difference between internal and external transducers. I firstly fitted two transducers to a Jetski. One was the standard transducer and one was an Airmar transducer. I went to a local reef and found a shoal of fish and then alternated between the two transducers and was amazed at the difference between the two signals. I couldn’t see half of the fish with the standard transducer! The second experiment was to go out to sea in a Kayak where I moved the transducer around various positions. I tried through two layers of fibreglass which I could not get a signal. I tried through one layer of fibreglass where I got a reasonable signal, and lastly I hung the transducer over the side where I got a perfect signal. This experiment proved to me that if you are really wanting to use your unit to see fish, especially at the bottom of the water column when you are bottom fishing, drop shotting or jigging I would suggest mounting your transducer with a suction cup or Velcro.
Whichever method you use it is vitally important that there is no air between the transducer and where the signal exits your craft. The Airmar internal transducers sit in a sealed unit which contains anti freeze. If you are in any doubt how to fit your transducer leave it to the experts.
To summarise transducers are like buying a top of the range Kayak and purchasing a budget paddle, or buying a HD television and playing video tapes on it. To get the optimum benefit from your unit get the best transducer or you will miss opportunities. So now you can pop along to your local dealer and ask them about an upgrade.
In the next Marine Electronics we will look at a few installations.