Which is why I asked in the first place. You point out a very basic fact which the guys who say "My tide clock is right on!" seem to have ignored. Unless they do adjustments which they haven't shared with us. You were the only one who did in your #36, thanks. That's what I was expecting and was surprised by what I can only now deem tidal incompetenceYou need a tide book aboard giving time corrections for different locations to adjust your clock as you travel. Don’t leave home w/o one!