Why doesn't my side scan show the posts or pilings from docks when I pass by?
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Why doesn't my side scan show the posts or pilings from docks when I pass by?
Are you going too fast? Can you see a shadow of post? Not being rude but are you sure you know what you are looking for? Also how wide of distant is it set on. Try just one side of SI ,make it about 50 feet and go slow and if that work you can slowly change setting,also get close to post as you go by.
You might check to make sure that you have it reading the correct sides also if it is lowrance. You can flip left and right.
set it on the 455 setting. It will give you the shallower reading.
Pilings and other vertical structures are challenging with SI...
Like Gene mentioned boat speed is the most common culprit...due to the fact that fewer of the sonar pings are actually reflecting off the structure...before the boat passes completely past the piling...
This can be overcome with 2 possible scenarios..(depending on the unit)...
*Slow the boat down to allow more pings to hit the vertical pilings...
*Raise the Chart Speed..(if the unit is HB)...to stretch the pings across the display more...
Distance from the pilings vs SI beam angle also has a major effect on the amount of the structure that the sonar ping actually reflects off of...
Notice in the following depiction how the HB 800kHz 130° coverage only hits the bottom section of the bridge pilings...resulting in far less of the is sonar ping to be reflected back to the xducer..
http://i477.photobucket.com/albums/r.../HB/piling.jpg
This can be overcome somewhat (like brushnjigs mentioned above)...by using the wider HB 455kHz 180° SI sonar beam in combination with the above mentioned points of slower boat speed and/or higher Chart Speed...
Rickie
I had this same question when I first started using my 998c. They really don't look like post or pilings and they will not show up in the water column. If you are using green for your palette, look in the green area when you pass a dock and you can see what looks like shadows on the bottom. These are the post you are looking for and they are unmistakable once you figure out what you are seeing.
I was traveling slow, about 20 feet away in about 15 feet of water but did have it on left and right as I have a Lowrance HDS9 GEN2 Touch. What was troubling was that I was picking up brush piles on the right side of the boat and no docks on the left side. I thought maybe the left side was not working but later found the same was true for the right side when I reversed directions. To further complicate matters, I found remnants of an old dock that was completely submerged including verticle pilings that looked like what I thought I should be seeing. Is it a question of algae growth on the wood?Quote:
Originally Posted by genec
And by the way, God did die for us that we may live!
If you were going slow and that close ,you should have seen post or shadow,the post will be light and shadow dark,on a
Lowrance are you sure that the right side on sonar is right side on transducer,you can reverse it?
Sugget you play with the choice of palette colors till you find one that is easy for you to see/interpret. Use just one side for docks, I use the right side since I've got a side console boat. Adjust the screen so you can see the entire right or left side to get better detail. Get a suitable memory card and try different palette colors, speed and settings and record the different passes/settings on the memory card. Then load the pics on your computer and you can study them to find the best setting(s) for you/boat and conditions. Try and leave the settings visible so you can then easily identify which one(s) work the best. Don't ask how I can suggest this tip. :banghead Every day will be different due to water clarity, weather conditions, etc., but once you learn the base settings you can adjust a bit I have a G1 and I can adjust the ping speed in one of the sonar menus but don't know for the Touch models.