Originally Posted by karlT
Are the heights of both high and low the same on both sets of data ??
Yep, times and heights for high and low water are identical, it is just the mid tide data that differs. As I said the strange bit is that the base data comes from the same Garmin 'Atlantic tides v5' CD but the two Garmin programs obviously interpret this differently.
Smithyyy - I agree that the high and low times and heights are slightly different from those in a printed almanac, but in the past I've found the Garmin to be more acurate locally.
I will have to get out my old plotter and see how it compares to the new plotter. And see how the new tidal data on my new map cartridge compares with the old.