Quote Originally Posted by Moveon View Post
Steve That sounds like a good plan to try to see what's going on. Do you know the shelf that goes out from the East Bank into the lake the farthest. This is the area South of the entrance to the "H" where the shallow water reaches out the farthest into the lake. It's about half way down the East Bank from the entrance to the "H" area. The "H" is the first Cove or bay on the right after you leave the launch ramp at the South End of the pit and head North.

The area drops off from around 5 or 7 ft into 20 then again it will drop down into about 35 to 40 ft of water. The ledge there is not straight but jagged and some areas of the ledge go out further into the lake than others. It's about Fifty feet to 100 ft out off the bank. And it's inline with the handicapped ramp and the main sign board by the porta-poti. The other line of sight used to be a cross up on the East Bank and some rocks along the shoreline. That should get you into the general area of the drop off I'm talking about.

I'm using the Humminbird 898 SI unit and the latest software from about 2015 on that unit. My GPS signals are taken from a elevated position above my engine at the rear of my boat near the transducer. I get accuracy readings of about 2 ft or 3 ft according to the screen readings. But they still could be off as just because the screen estimates the accuracy at 2ft that doesn't always mean it's true IMHO.

Yes I know of the flat you are talking about. Which Lakemaster card do you have exactly? I know on both of my Great Lakes cards (versions 2 and 3), Bluegrass is a high definition lake, but it wasn't surveyed by Lakemaster, which is why it isn't a "Lakemaster High Definition Survey". Next time I am out on Bluegrass I will run Autochart Live on it to see if there is any difference from the Lakemaster chart and post a screenshot of the difference.

Quote Originally Posted by JustinM
Navionics maps are pretty accurate out there. I've never seen one off by 20 feet there
Me either. You aren't generally going to get that much error with Navionics or Lakemaster. That is why I believe it is more than likely GPS related. I have GPS issues sometimes on Bluegrass/Loon/Otter, where my units show me over 100 ft away on land. It usually only happens for a couple seconds before it gets back on track.