Side Imaging Forums > 997c SI, 998c SI & 999ci HD SI

997 SI- Range setting &depth

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BalticProject:
Hi.
Three weeks ago finally I became a happy owner of HB 997 SI.Since that time I used it two times only,so I'm very begginer.Before I was using HB Matrix 47 3D but that model  was below my expectations.
Mostly I'm gonna use my new 997SI for  serching II WW shipwrecks and planes within my area (Baltic Sea, Poland, small town Darlowo)
Recently I tested my echosounder on 180' wreck of bulkcarrier(sank in 1984)

My quetion is:
What should be the  range setting/depth ratio to achive best image?How wide must be the "inside channel"?
Rgds
Michal

RGecy:
It depends on what you want to see.  Here is the kicker, if you are in 80' of water and you have your range set 100', well 80% of the screen area is going to be just dark area from the water column.  You would want to set you range to say 200', and now you have more visibility.

Now, in shallow water say 20' deep, 200' may be too wide.  Now you can drop it back down to 100'.

I would say a good rule is to always set the range at least 2 times the depth of the water.  As it gets deeper, we know this number will get smaller.

Good Luck,

Robert

George:
Michal

You might want to try a speed between 2 - 4 MPH and play with the side imaging going from shallow to deep water. Take the time to learn what the system is capable of, it might help you to better understand how to get the most from the unit.

I believe that some of the folks that are looking deep have modified the SI transducer on to some kind of a fish which is trolled deep carrying the transducer.   

sixwarden9:
I have searched the posts on this site and others and found that most people are using 2 to 3x the depth
for their range. I took mine out for the first time last night in calm water
ranging from 4-25 feet with the range at 150. When my range was at 150, I did
not appear to get a full picture, both the left and the right sides of the image
were dark, no pixels on the screen active. When I dropped the range to 100-120,
the pictured filled the screen. My question is:

Should I be getting more picture (with less detail of course)or is the width of
the sonar return relative to depth, i.e. deeper water, wider return possible?
All of my scanning was at 455, when I switch over to 800 KHz it was virtually black.

My unit was set to defaults.

RGecy:
At 800khz, the beam angle is smaller and actually will not reach as far at shallower depths.  The 455 should give almost 180 deg coverage, but again at 4' depth, you will notice some shadows.

Here are some images showing the beam coverage.

Robert

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