I few times I lost markers
Once in a while I forget to pick up a marker buoy and it's usually gone when I remember that I left it and go back to try to find it. But then I've got the good kind of markers. Normally I retrieve them before leaving a spot. And I don't use ten markers anymore like I did when I first started using them years ago. I use to mark a long ledge with them and then try to troll cranks along the outside part of that ledge or drop off. It just got to be too much work and didn't really help me catch any more fish.
These days I just buy a topo map or hydrographic map of the lake I fish that shows the contours in 1ft intervals and the Humminbird SI unit shows a map view with an icon that represents my boat on the map. So I can see where the drop off are located on the hydrographic map and where my boat is in relation to the drop off at all times using GPS technology and Lake Master Maps that are on SDHC cards that I simply plug into my Humminbird Unit.
The only problem is the map accuracy and the limitations (accuracy limits) of the GPS system itself. Only accurate to Plus or minus 3 meters 95% of the time.
But the main complaint is that the State IDNR did the lake survey and they didn't cover the entire lake bottom during the survey. I watched them doing the survey at the South End of BlueGrass Pit. So I know where they went with the boat and the equipment that day. I even talked to the girl that did the survey for the State. It was cold that day and they got in a hurry and skipped a lot of the lake bottom. She told me how they used a computer program to interperlate the data. They use a program similar to AutoCad to drop the topo lines but they have to guess about areas that they didn't cover. There are areas in Bluegrass that have bottoms that come up and go back down a lot more than a normal lake would. This area was man made when they mined the ground and it's not a consistant bottom contour. So the program that's predicting where the drop off is going to be is off by about 50 ft in some areas of the lake. That's bad if you are trying to follow a contour and the map is not accurate. The map shows your boat in 20 ft of water and your depth finder says you are in 5 ft of water. Not good for slow trolling for crappie. Other areas of the lake are more accurate on the map view. But the one area where I've caught limits of fish is where the surveyors missed big time.
I Noticed that the survey boat only did East/West transverses and didn't go North/South. Which is why she missed a lot of the lake bottom. In other words she half-assed the survey.
And Lake Master must have purchased the data from the State of IN as I don't see where they claimed to have performed the survey themselves.
The saving grace is that next years Lake Master is going to sell a new program that will allow us to make changes to the maps. Auto map Pro will also let me show the lake bottom using Side Scanning Data and I can add new data points to the map to help redefine the contour lines on the hydro graphic map of my lake. But this new SDHC card will set you back about $250 for the Pro version and another 100 bucks for the lower priced version.
Check out the LakeMaster Web site for further details. Do a Google search on Lakemaster to find the web site link.