Humminbird Side Imaging Forums
Side Imaging Forums => 798c SI => Topic started by: LLCC on October 17, 2012, 02:56:10 AM
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What do I need to do so that Bridge piles will appear straight upright on Side Imaging?
Currently, the bridge piles from my SI appear to point 45 degrees forward.
Thanks in advance!
LL
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Hi Lawrence
Post a picture, so we can see what you mean.
mvh
Rüdiger
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Hi,
This is typical when the transducer is tilted, either forward or backward. Adjust the transducer so that it is as horizontal as possible while scanning.
Regards,
Rickard
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Thanks for your replies!
Let me try with a screen capture...
I'm sorry, I'm a Mac user so I dunno how to get a screen capture image of Humviewer window.
OK, I managed to paste this in a Word Doc. I hope you can see what I mean... The SI image has the pile marked in red, shows the piles pointing inwards. The DI image show the pile upright.
I'll try to shift the transducer around this weekend to see if it does the trick. Problem is that I cannot see such things out on the water. Only when I view it on Humviewer can I see things like pier piles, logs etc. So doing anything is a tedious process of making an adjustment on water, then coming home to review the recording.
Best,
LL
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The SI image has the pile marked in red, shows the piles pointing inwards. The DI image show the pile upright.
I can't see any issues with the images. The DI view is just a combination of the SI views that has been rotade 90 degrees clockwise. Left SI view has been mirrored to fit with right SI view in the DI view. Scale differences makes the piles look longer and steeper in the DI view than in the SI view. The angle between the piles indicates they don't stand upright. Do the piles stick up above the surface?
Rickard
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I agree with Rickard in that the piles seems slanted.
Chuck
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I agree they appear to be slanted. If it was something with the unit or transducer they would both be slanting the same way. And so would everything else you scan.These get closer together at the top. Seems like your settings are a little hot though.
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My settings are the default settings of the unit other than changing the water to shallow saltwater.
This place where the image was taken has several outlets pumping water from a power station into the sea. There is lots of bubbles in the water. The piles stick out of the water and are the legs of a pier that runs out to sea.
Tomorrow, I'll go and try another transducer angle to see if it changes things.
Thanks for the suggestions!
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Introduction of air (bubbles) in the water usually breaks up the signal and not bend the displayed objects display.
Let us know of the next run.
Chuck
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From the DI and SI it looks like your transducer might be a little to high also. Seems to be getting a little interference.looks like the top part of your beam is being slightly blocked. Or you were in rough water and the boat was moving up and down a lot. I noticed your boat speed was at 0.2 mph try scanning at 3 to 5 mph and match your chart speed to your mph.
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No chance to go out at all. Groan! Its been raining and raining... and raining.
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I finally managed to get back to this pier. And you guys are spot on! Looking at the pier from its broad side, all the piles appear to be vertical. But get under the pier, and what appear to be a single pile is actually a V pile. The sounder was imaging correctly all this while!
Thanks for the feedback!
LL
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Glad to hear everything was good with your unit. Just goes to show how much these units can teach us about whats under the surface.
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On a calm windless day, have your normal boat setup with your normal load(gear, maybe 2nd angler, etc), then
use a large carpenter's level mark the boat tilt front-to-back and side-to-side. Then back in your garage attempt to duplicate this setting front-to-front and side-to-side on your trailer. Then you check your transducer with your carpenter level.
Next on a calm day, check your side-scan using highway bridge pilelings idling at 2-5mph(use your normal boat scanning speed that you prefer). A pileing should be slightly tilted because the pileing top will be a shorter distance than the bottom of the pileing on the sonar ping.