Moderated Discussion Areas
ContinuousWave: Small Boat Electrical
SONAR Readings In Less Than 3-Feet of Water
|Author||Topic: SONAR Readings In Less Than 3-Feet of Water|
posted 01-23-2007 05:36 PM ET (US)
[I] hooked up a [Humminbird] Matrix 17 on [a Boston Whaler] Katama this past fall with a transom transducer set per instruction. I ran the wire along the gunwale because I was originally getting interference using the rigging tunnel. Made sure mininum depth is to menu setting of 1 (lowest you can go). The display always messes up if I get shallower than 3.5-feet. I get good bottom readings [in water deeper than] 3.5-feet but when I reach this depth it is just a screen full of lines. Generally okay if deeper than 3.5-feet unless going fast. It is just the shallow water.
[Give] suggestions or [report] similar problems.
posted 01-23-2007 07:39 PM ET (US)
My Humminbird Matrix 97 goes to 2-feet then flakes out.
Maybe customer sevice can help.
posted 01-23-2007 09:55 PM ET (US)
I left a detailed email message with Humminbird tech support. Let us see what they say. I also added that if I cannot resolve this issue the unit will be sold and I will purchase a Garmin.
posted 01-23-2007 10:14 PM ET (US)
I have a personal contact there let me know if you need it.
posted 01-23-2007 10:27 PM ET (US)
I'm wondering why you need to have your fishfinder read in less than 3.5 feet of water. Can't you see the bottom or the fish in this shallow of water?
posted 01-23-2007 10:56 PM ET (US)
Does your unit have a keel offset feature? You can adjust this to read actual water depth or the depth from the bottom of your boat. Prop wash in shallow water can interfere with the signal, try it at rest. Make sure your transducer is at the proper angle. Just a few thoughts, good luck.
posted 01-23-2007 10:59 PM ET (US)
Good suggestion. Offset
posted 01-23-2007 11:11 PM ET (US)
I just went to the Hummingbird web site, your unit has the keel offset feature. It shows how to adjust it on page 46 on the online manual. This unit also comes with an optional dual frequency transducer, Make sure your using the right setting for shallow water, I believe 200 is the proper setting.
posted 01-26-2007 05:02 PM ET (US)
Thanks for your help! Will check my settings. WT: it is hard to visually judge water depth when it gets shallow, that is for me at least. It can also change really fast too when cruising in the Chesapeak bay.
Also, I received a response from tech support:
"John--The unit should work in shallow waters over 2.5 feet. You may want to adjust your noise filter, and your surface clutter filters while you are in the shallow waters as this may correct the problem you are having when you are in 3.5 feet of water.
posted 02-03-2007 09:21 AM ET (US)
You may need to make some adjustments to your unit. Most of these devices have many controls which can affect their operation. If you want to optimize the results for very shallow water you will likely have to alter the settings from the default position.
posted 02-03-2007 09:30 AM ET (US)
Also, in shallow water you will generally only be able to use the device as a depth sounder. The beam of the transducer's sound wave is very narrow and you won't see anything but a bottom echo unless a fish happens to be directly below the transducer. At three feet the beam spread on a transducer with a 20-degree cone angle is only about a foot.
You don't mention the frequency of your transducer, but generally a 50-kHz transducer is intended for deeper water and won't work as well in shallow water as a higher frequency transducer. This may be affecting your results.
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