Hi, all, I`m new to this so I hope that I am not posting in the wrong spot or any other blue, but I was wondering if there was any problem with adding topo plus Australia 5mt maps to the Garmin 400c. It seems to me to be a good way to have the best of both worlds, land and sea, however I was`nt sure whether you can disable the built in water maps and run the topo ones independantly. Thanks in advance if anyone has some advice.