Well....no thoughts, but plenty of searching has turned up several sites with LOTS of info. Doesn't look as though there is any one set formula, there are so many factors involved from what I can tell. Maybe one of our sailors will come in here and give us a hand. In the meantime, these ought to give Ben food for thought:Tide predicting machines- hitory of (noaa)
Main page for NOAA's Tide Site
Good luck!