Lowrance elite 4x dsi HELP!

So I have the unit that is in the title. I have been using it for a couple of seasons but am still pretty rusty with it. I was fishing the other day and I decided I needed help. my unit is in the back as I have a tiller steer rig. as I was going along I spotted a brush pile in about 12 feet of water. I throw out my marker to come back and fish it. as a ease back over the marker I cannot find the bush pile! I scanned the area for a while and never spotted it or felt it with my vertical rig. this happned severl times throughout the day. am I miss reading my unit or am I missing ith my markers? is th unit lying? lol how much area is covered by the unit? how should I have the unit set up? I need help!

A couple of tips that I've seen others benefit from.

First, if you want to drop a marker, you need to do it as soon as the brush is on the right side of the display. If you wait until it's centered you are well past it.

Schools of shad can look a lot like a bush until you see them a few times.

Understand that the DSI sonar ping is a narrow fan shaped deal, that is shooting at a 45deg angle @ 800kHz setting or 75deg angle @ 455kHz.

In 12 fow ... that brush could have been anywhere in the signal ... and the 800kHz signal would be about 10ft wide - the 455kHz signal would be around 18ft wide.

Without the unit having GPS capability, you're stuck with having to drop markers. And like Catfan says ... you want to be dropping them as soon as the image comes on the screen. To which I would add .... have more than one marker ready to drop/throw, and drop/throw them off each side of the boat so that you have more than one point of reference to come back to.

Here's where I got the angle/distance references : (thanks to Kosmo)

http://i826.photobucket.com/albums/z...newDIbeams.png



... cp :kewl

The way I mark and return to this type of cover is that I run a split screen....2D/DI. Since 2D is a cone, and therefore out in front of the DI, I see the cover appear in the 2D first and then it shows in the DI. If I'm using two markers, I will drop one when the cover shows in DI and then drop one when the tallest part of the cover is in the 2D. That shows me the starting point and the approximate center of the pile.

Thanks for the replies guys I appreciate it alot. I will try again this weekend! I am determined tp figure it out