Quote Originally Posted by rnvinc View Post
I would guess those are indeed the dock posts starting in the left water column at about the 18ft SI Range line ...

This would mean the dock was a little over 18ft from the xducer before the sound pulse actually 1st contacted the dock posts ...

Echoes of a vertical structure all the way to the centerline would mean the xducer would be right up against the dock posts = shorter distance to xducer ...

Rickie
OK ... I can grasp that. But, why would the fish or trees show up "above" the dock posts ?? If the SI signal is 90deg/side, why wouldn't it show a solid object (that rises above the water's surface) reaching all the way to the center line/prop wash image ?? Don has the range set at 50' ... so if the dock is around 20' away from the transducer, it would seem that it should show the posts going all the way to the surface (or at least a image above the ball of fish).

Had I only seen the screenshot, and not been told of a dock being there, I would never have suspected there being a dock in the image ... and probably figured the "matchsticks" images to be tree trunks or posts from a dock that no longer exists.

... cp