Humminbird Side Imaging Forums
Side Imaging Forums => 997c SI, 998c SI & 999ci HD SI => Topic started by: jimf on April 16, 2010, 10:45:32 PM
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I like to ask 2 things.
Why do I get lines for fish marks. No ^'s for fish.
is my trasducer to high in front or back. I heard that will have something to do with it.
AND the bottom hardest. This picture I have here is it a hard or soft bottom ? I'm getting fixed up because I was setting in 3 feet of water with BIG rocks under my boat and I had no red line for bottom hardest. The only thing I had was a second ocko on the screen with some red in there but the top line was blue with green and thats soft bottom so I can't understand the bottom hardest here.
This picture was taking with grass right near the boat. So this red on the bottom means what ?
Thick red means hard or soft bottom
OR thin red means hard or soft bottom ?
Thanks
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I am not expert and it has been a few years since I spent much intense time on the water but in my opinion the "v" is over-rated. For a fish to "v" it must past through the cone just perfectly. In shallow water you will see many less "perfect" fish. With the SI units I would be more concerned with the transducer being set for SI and not for "v" fish signals.
While I haven't had time to do much experimenting yet with my Humminbird units as far as bottom hardness I would say you are over a hard bottom in the picture above. The red is very red and it is also very wide. Once again though you are in very shallow water and this can change the way some units work. Remember as the depth changes the intensity of the returning signal changes and interpretation of the signal changes. Experience will help you in the end.
I am sure the experts will be here shortly and help.
James
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I also agree that the v is over rated...
I notice that your speed is only .3mph..which is pretty slow to get a v image of a fish...
A fish has to enter the cone..pass thru the cone..and then pass out of the cone to get the v....
At .3mph the fish is more likely to stay in the cone for some time..therefore..not giving the optimal v...
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It is highly unlikely you will ever see an arch is 5' of water - the sonar cone is only roughly 1/3 the water depth (200kHz beam), so you are looking at a spot only 2' wide on the bottom, directly under your boat.
A suspended fish has even less cone than that, and most fish will move out of the way if your boat passes that near in such shallow water.
Regarding the bottom hardness - yes, the wider the red band, the wider the area that your sonar is returning a strong signal, which is indicative of harder bottom. But you have an SI unit, which will tell you more about the bottom content than any 2D sonar could.
You will see more arches with the 50kHz beam, as I recall the beam width is roughly equal to the water depth.