Has anyone used the lakemaps that T.Martin sells to overlay the Navionic's chip? they seem to be the best solution to update so I do not have to repurchase a Navionics platinum card that was out of date only 3 month's after i bought it , the new Navioncs cards now have river chanels and roadbeds on them which i thought the old one had until I got it on the lake. I sure wish Navionic's would just sell us the updated version.

I don't have one but be sure you understand what you are buying. It doesn't "update" you Navionics chip, it overlays the roads and creek beds using the "tracks" feature of your fishfinder/GPS. You buy them one lake at a time. Depending on how many lakes you fish you might come out ahead financially by buying a new map chip.