When you change the depth offset to display the correct depths, does this setting remain when the unit powers down? Does it remain with the data for the lake you set it on or, does it remain and apply to every body of water until it's reset to default?

Yes, if you turn the unit off with the power button.

Depth offset changes the depth readout and 2D sonar, it does not adjust the contour mapping. Using Lakemaster mapping you have Water Level Offset in the HB Chart menu.

I mainly use the offset when doing mapping so the contours are in the correct location. I add the distance the transducer is below the surface.

If you use 83/200 kHz, you get a wide surface clutter line, and as you add depth with offset, the surface clutter is placed lower on the display.

So, if I properly power the unit down, the offset will be saved to the lake map it was set on, or will it apply the offset to any other lake the next time I power on, requiring me to set it to no offset on each use if I'm on a different lake.

It affects all the map locations the same amount at the same time.

If you use a 3' offset at Lake Fork and then go to Twok, it will be the same 3' offset. If you leave it that way and go to Toledo Bend it will be the same 3' offset.

If you use the map offset, that does the same thing.

Thanks, Wayne. You da man..

Thought the offset was going to be a useless feature for me when I got my Bird/Lakemaster chip, come to find out - it's been handy as it can be.
Not just for running the lake but for locating areas that I want to look at. It has really helped on a couple of new lakes for me this fall. Set my offset, highlight the depth zone I'm finding fish at and then look for areas that are similar. Makes it simple on new (to me) lakes.

I thought the offset was better than crushed ice since day one. Not only does it let you get accurate depth readings on different lakes, but also on a single lake that is constantly changing levels. Your shallow water alarm doesn't do you much good without it.

Ok.....so how and why exactly do you set it? Is it to compensate for the lake level fluctuation? Or is it to accommodate the depth of the transducer under the surface?

Like this?.....my transducer is two feet under the water surface below my TM motor...so I set water level to -2'? Or am I way the hell off? If it is for lake level fluctuations, how do you know what it should be set at?

There are 2 different depth offsets you can adjust. One for lakemaster map and one for transducer, and the one they are talking about is the lakemaster depth offset for the map contour lines.. To set it for a specific lake put your boat on a particular contour and adjust the depth offset till the number on the contour line matches your depth finder depth reading

and for the transducer just measure how far transducer is below waterline